can,t find whats wrong? start with the basics



can,t find whats wrong? start with the basics

Postby grumpyvette » October 29th, 2008, 5:11 pm

IF YOU DON,T YET HAVE A FACTORY SHOP MANUAL FOR YOUR CAR YOUR WORKING AT A DISADVANTAGE
it is always helps to post your location,when posting questions, at least the city & state your located in because theres a good chance an experienced hobbyist or mechanic on this site may be reading this, located local to you, who is willing to help either for free or at low cost! or at least post advices and places to get parts locally
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Ive been building engines for over 40 years now, eventually even my hard head learned, a few things, but I,m sure willing to learn and ask questions, and use any new info posted
can a few of you gentlemen explain to me why??
when I suggest isolating and testing each separate potential component of both the fuel and ignition, systems and checking the engines valve train and checking compression, fuses, and sensors and pulling trouble codes and using the factory shop manual and a few tools like a mufti-meter and compression gauge, IR TEMP THERMOMETER,VACUUM GAUGE, and listed tests, even when I supply rather extensive links showing extensive detailed info, the majority of the guys reading thru the threads obviously ignore the info that could be used too locate the source, isolate it test it and fix it rather than making random wild guesses without any facts or testing?look if you don,t isolate the problem to its source thru accurate testing there,s almost no other logical way to locate and fix the problem.
GUYS I NEVER SAID I,M A GREAT MECHANIC, BUT I HAVE LEARNED THAT IF YOU TAKE THE TIME TO BREAK THINGS DOWN INTO THE SIMPLEST PART AND DO A BIT OF RESEARCH, FINDING ANSWERS IS FAR LESS INTIMIDATING OR DIFFICULT,
[b]youll need to isolate any problem to its source, be it engine, drive train, suspension,fuel system, electric, cooling, exhaust, etc. then further logically isolate it to the defective component, or part needing adjustment or replacement


like the old saying how do you eat an elephant......one little bite at a time! :D

all the answers are readily available, theres known testing procedures and listed test results you can expect, and procedures listed in the shop manual for isolating and testing components, you don,t need to be a genius, you just need to be logical and persistent and not afraid to learn new things while getting your hands dirty at times[/b]
THE FASTEST AND EASY ROUTE IS TO ISOLATE AND TEST< NOT RANDOM GUESS WORK
buy a CHEVY SHOP MANUAL FOR YOUR YEAR CORVETTE!
set and verify your ignition timing, pull trouble codes,set your tps and iac,, then check for vacuum leaks on the lines and intake,then get out your multi meter and verify all the sensors, chances are good its a defective heat sensor or defective o2 sensor, a logical step by step approach will lead you to the problem, youll be amazed at what youll learn reading links. use of a shop manual and multi meter can be very helpful
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http://www.harborfreight.com/5-in-1-dig ... 98674.html
[b]learn to use the factory shop manual, and a multi meter and LISTEN to the engine closely, tapping and high pitch whines can indicate defective injectors or fuel pressure regulators, fuel pumps,mis- adjusted valve train components, worn distributor parts, check all the fuses and electrical grounds and corrosion on connections thats something thats frequently over looked etc.

http://www.chevythunder.com/Flow%20chart%20index.htm
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http://www.professionalequipment.com/ex ... ermometer/

having a good cross check tool like a quality IR temp gun, and a decent multi meter, sure helps find the truth as far as a defective gauge or sensor
READ THESE LINKs

viewtopic.php?f=50&t=10012&p=38779#p38779

viewtopic.php?f=36&t=63

viewtopic.php?f=32&t=1401

viewtopic.php?f=32&t=2697

viewtopic.php?f=50&t=10623&p=45691#p45691

viewtopic.php?f=32&t=168

viewtopic.php?f=32&t=596

viewtopic.php?f=32&t=1773

viewtopic.php?f=32&t=661

viewtopic.php?f=32&t=302

viewtopic.php?f=50&t=9478&p=34812&hilit=sensors+camaro#p34812
rule one
if your installing a new component ,read the manufacturers instructions carefully and call the tech guys if ANYTHINGS not 110% clear
RULE two
IF something won,t fit or function...[color=#BF0000].STOP
, call the the tech guys ,after you re-read the manufacturers instructions carefully and measure carefully so you sound at least 1/2 way like you know what talking about, then call the tech guys if ANYTHINGS not 110% clear
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RULE three
STOP AND DO THE REQUIRED RESEARCH if youve got questions
I never mind sounding dumb as long as I get the correct answers, so I won,t LOOK dumb by doing something wrong
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rule four
isolate the problem to a lack of or Mal -function in,engine compression,ignition,lubrication,cooling, fuel supply,drive-train,or suspension, or a mechanical or electrical fault as soon as you can, this can only be done by testing and verification, don,t guess or assume anythings correct until you verify it yourself

yes reading the sub linked info is mandatory if you want answers

http://www.helminc.com/helm/welcome_sel ... M2S049ETF8

CHECK ALL YOUR FUSES WITH A MULTI METER
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http://www.clarks-garage.com/shop-manua ... tm#oil-low

http://www.davidfarmerstuff.com/

when ever you get into unexplained symptoms the answer remains the same....in every case,.... you drop back to the basics and do a few tests, get out a multi meter and verify every fuse is good, and you have 13 volts at the battery and youve got at least a 1/2 tank of fresh fuel, before you start chasing your tail, thinking about more complicated problems
find the cause, you isolate, each function or system or malfunction to its related components then test, each individually, use of the shop manual is almost mandatory

erase old trouble codes and pull new codes after each change, made.
read the codes, and follow the FACTORY SHOP MANUAL INFO
there could be several reasons and a few tests will limit the potential problem areas,valve float, restricted fuel pressure,or volume, badly adjusted carb floats, wrong jets, wrong power valves, dirty or restricted air filter, cam timing, ignition timing, carb being badly adjusted,valves being badly adjusted, ignition advance curve not correct, timing tab or damper, not correctly indicating TDC, etc. ignition spark should be bright blue and impressive, if its, weak,narrow, yellow or red theres a problem so research the cause, verify the coil and voltage

you start by dropping back to the basics , adjusting or verifying or correcting each potential problem area and eliminating it as the cause, then and only then moving on to the next area, guessing will drive you nuts and cause you to throw large amounts of un-necessary parts at the problem with little resulting improvements. a logical step bye step approach is best, youll need to verify cylinder compression, ignition, strength and timing and fuel and air delivery, ID also suggest a compression test and a general checking over,each potential engine and drive line sub-system carefully, with a timing light,vacuum gauge, fuel pressure gauge, VOM meter , ETC. and adjusting valves, checking for vacuum leaks, check fuel pressure and post clear pictures of spark plugs as they give a ton of info if you know how to read them, etc.it helps a great deal to know what your working with ,ID suggest starting, by verifying TDC and having the correct timing tape on your damper then,start with 8 degrees btdc and verifying the full advance of 36 degrees total is all in at 3200rpm as a base line, once youve got that, as a standard you can tune and run the car and eventually try tweaks to the basic ignition curve if needed, once you have an ignition base line, move on to the carbs tuning, you also need to keep in mind that what goes in as a fuel /air mix needs to go out as a much expended volume of hot gases and a restrictive exhaust will effectively block most attempts to get more power from an engine, so measure exhaust back pressure. you might be amazed at what a couple hours research into the subject will do to help you build a much more durable engine, and actually reading thru links and sub-links and asking questions helps a great deal

you might be amazed at the number of times "CARBURETOR PROBLEMS" are cured with getting the IGNITION, TIMING AND ADVANCE CURVE WORKING CORRECTLY, and check out the simply things your 100% sure you did correctly, because I can,t begin to tell you how many times I see guys who have the firing order on the ignition wrong, or guys that install a 4/7 swap cam and still use the standard ignition firing order or guys that never verify TDC and ignition advance curves.
get an IR temp gun and check for wild variations in exhaust temps, get a compression test done, do a logical check to verify each cylinder fires etc.

Id also be pulling and changing the oil filter and inspecting the old one for metallic debris indicating a worn cam lobe, assume EVERY SUB SYSTEM could be miss adjusted or defective EVEN if you just replaced parts recently
basically an in depth tune-up and system verification is whats needed

viewtopic.php?f=54&t=4611


viewtopic.php?f=70&t=202


viewtopic.php?f=55&t=109

can,t get it started? these bits of info should help

always drop back to basics
check your battery cable connections
check your fuses and get out your shop manual.
IF you have the option pull trouble codes.
have you verified TDC on the damper and timing tab?
have you done a compression test?
are all the spark plugs firing correctly?
did you degree in the cam or just DOT-to-dot install it?
whats your fuel pressure?
have you verified the carbs float levels?
does fuel run out the site holes at idle?
are the needle& seat valves working correctly?
whats your ignition timing?
do you have voltage at the coil?
whats your plenum vacuum?
have you verified the engine got no vacuum leaks?
whats the oil pressure?(did you check the dip stick?)
have you adjusted the valves at idle?
does the distributor timing advance with rpm increases?
have you tried a different carb?
what are the plugs gaped at?
does this happen without an air filter?
have you verified you've have functioning power valves?
what jets are you using?
is there visible fuel flow from the boosters?
whats your battery voltage?
whats your exhaust back pressure?
are you totally sure the fuel free of water and fresh?
have you pulled trouble codes?

drop back to basics, don,t assume you did anything correctly until you verify, its been done correctly.
first remove plug #1 and your valve covers and the distributor cap
stick a large ratchet/socket on the crank bolt and stick your thumb over the #1 plug hole rotate the engine until you feel compression building the rotor on the distributor should be approaching the #1 plug, now watch the timing tab and damper mark, it should line up at the TDC (TOP DEAD CENTER) marks , if its lined up with #6 and you get no compression on the #1 cylinder when the TDC lines up the engine needs another rotation,if you get compression on the #1 cylinder when the TDC lines up with rotor pointing at #6 the distributor 180 out) and the distributor needs to be pulled rotated 180 and re installed.
If your running a carb, now verify you have 4-5 psi of fuel pressure and your getting spark at the plugs once the distributor cap and wires are installed, verify the firing order and once it starts back off each rocker nut at idle until the rocker clicks than tighten slowly just to the point it stops clicking and then add 1/4 turn of preload. verify your exhaust is not clogged, a partly melted catalytic converter can kill off power fast


READ THRU these links, and the sub linked info in them, should help


viewtopic.php?f=55&t=109

viewtopic.php?f=70&t=202

viewtopic.php?f=70&t=875

viewtopic.php?f=56&t=495&p=26600&hilit=clogged+converter#p26600

viewtopic.php?f=70&t=3301

viewtopic.php?f=44&t=773

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=1411

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=967

viewtopic.php?f=81&t=1189&p=2447#p2447

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=270

viewtopic.php?f=32&t=1401&p=3104#p3104

viewtopic.php?f=55&t=1475&p=3325&hilit=testing+sensor#p3325

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=1015

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=1115

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=196

http://forum.grumpysperformance.com/viewtopic.php?f=62&t=882&p=1390&hilit=+propane#p1390

viewtopic.php?f=44&t=773&p=1123#p1123

viewtopic.php?f=44&t=808&p=1180#p1180

viewtopic.php?f=44&t=808

viewtopic.php?f=44&t=777

all it takes to find out why your not making the hp you think you should be is actual testing to find out what your dealing with and what needs improving or changes
be fore you make changes you need to have a base line your working from
do these tests

did you verify TDC or just install the cam dot-to-dot?

whats your compression read?

whats the battery voltage read when the engines running?

post very clear pictures of all 8 plugs?

whats your EXACT ignition advance curve?

whats the plenum vacuum read at wide open throttle?

whats the exhaust system pressure in the collector pipe read at wide open throttle?


viewtopic.php?f=56&t=495

viewtopic.php?f=55&t=109

viewtopic.php?f=70&t=202

viewtopic.php?f=70&t=1809

viewtopic.php?f=70&t=4683


watch the video

http://www.youtube.com/watch?v=YdIGZ-tV ... re=related

is it mechanical?
look for broken parts, loose connections, leaky hoses
are the CATS clogged or the O2 sensors faulty
check the compression in all cylinders
re-adjust the valves
look for vacuum leaks
look for loose serpentine belts
look for cooling system problems
check the trans fluid level and condition
check oil and fuel levels
check the rear differentials fluid level and condition
check the engines oil level and condition
check the brake fluid level and condition
change the filters
check the throttle body is opening completely
verify the TPS and IAC are set correctly, and use some carb/throttle body cleaner to clean up the TB.

what are the engines oil pressure, fuel pressure and cooling system temps?
if somethings wrong there's usually symptoms that point to the source!

IS it electrical?
verify the MAT, MAP, and or MAF sensors are working correctly
verify the coolant temp sensor and knock sensor are working
set the ignition timing
install new plugs with a .045 gap
verify the O2 sensors ok
look for loose grounds, on the engine,gauges,battery
check the battery voltage
check the fuel pump and relays
use a V.O.M. to verify plug wire resistance
check/replace the distrib cap.
VERIFY ALL SENSORS and FUSES and CONNECTIONS are ok, verify the voltage on the systems correct

IS it fuel related
verify the pressure and flow
verify the injectors are functioning correctly
read the old plugs
use a ir temp gun to verify exhaust temps
throw a couple cans of injector cleaner and 8 oz of MARVEL MYSTERY OIL into a fresh tank of fuel, it can clean out lots of minor varnish in the system

when you try to track down any problem with a cars engine you need to start with the basics of
fuel pressure,
and a compression check,
checking for vacuum leaks,
checking the valves are adjusted correctly,
verify the battery has a minimum of 12.5 volts
and the alternator boosts that while running to over 13 volts
verifying that your timing marks are at T.D.C,on the damper
verify that the timing tab indicates true T.D.C.
have a quality timing light and know how its used
and your ignition timing curve is correct, and smoothly advancing as the rpms build.
verify the timing is close to the shop manual suggestions
check all the fuses and engine grounds,
and get out a infrared temp gun and look for marked changes in the exhaust temperatures, indicating non-firing cylinders or fuel distribution issues
verify the oil temperature and pressure
verify the engines got less than 2 psi of exhaust back pressure
learn to read spark plugs as they are a great indicator of conditions in the combustion chamber
learn to use a vacuum gauge
if you have one a fuel/air ratio meters a big help
BUT HAVE A SHOP MANUAL and take the time to READ IT!

tools you really need
SHOP MANUAL
timing light
vacuum gauge
IR temp gun
degree wheel
dial indicator and stand
fuel pressure gauge
V.O.M. meter
torque wrench
magnifying spark plug reader
lift or (4) 12 ton jack stands
basic mechanic hand tools
floor jack


90% of your problems will be found just running thru the check list and following the shop manual suggestions, yes diagnostic software , and owning a scanner is a very good idea!

yes I know your 100% sure the ignition timing and the plug wires are correctly installed..CHECK THEM AGAIN CAREFULLY SEVERAL TIMES

The first thing ID do is VERIFY the CAUSE, OF THE PROBLEM FOR THAT, THRU ISOLATING AND TESTING, COMPONENTS AND SYSTEMS
A SHOP MANUAL IS ALMOST MANDATORY,

THESE LINKS should help
remember most problems come down to the basics of DO YOU HAVE FUEL?, IGNITION, OR COMPRESSION?, OR IS THERE SOMETHING MECHANICALLY WRONG,? once youve isolated the basic problem its source will become rather obvious in many cases

viewtopic.php?f=80&t=728

viewtopic.php?f=55&t=1241&p=3037&hilit=+sensor#p3037

do a compression test and inspect the rocker movement very carefully on EACH CYLINDER and POST THE RESULTS to insure your not fighting a mechanical issue before we start, verify the rockers are adjusted and verify TDC on the damper and timing tab ARE REALLY INDICATING TDC on the engine, then verify your ignition advance starts at about 10 degrees BTDC at idle and smoothly advances to about 36 degrees at 3200rpm, use a VOM or multi meter to verify each spark plug wire reads UNDER 2000 ohms per foot,and that youve got 13 volts at the coil with the engine running at idle
check for vacuum leaks
verify your float levels,if you have a carb and fuel pressure with either a carb or injectors
while your at it post clear pictures of each spark plug labeled with the cylinder it came from
pictures like this tell a great deal
Image

viewtopic.php?f=50&t=10623&p=45691#p45691

you really need to purchase a multi meter and a SHOP MANUAL and look thru the schematics
without testing theres almost no way to locate the source of your problem,, testing will tell you

http://www.helminc.com/helm

Image
Image
http://www.harborfreight.com/5-in-1-dig ... 98674.html
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: can,t find whats wrong? start with the basics

Postby grumpyvette » December 1st, 2008, 10:44 am

viewtopic.php?f=70&t=270

IF THE PROBLEM SEEMS TO BE IGNITION RELATED LOOK HERE
remember most problems come down to the basics of DO YOU HAVE FUEL?, IGNITION, OR COMPRESSION?, OR IS THERE SOMETHING MECHANICALLY WRONG,? once youve isolated the basic problem its source will become rather obvious in many cases
first check your shop manual for the fuse and fuse able link locations
fuses are located in several locations and fuse-able links near the battery

tracking down a MISS/STUMBLE, or other problem?

viewtopic.php?f=52&t=196&p=1324&hilit=+adjusting#p1324

viewtopic.php?f=70&t=270&p=1289#p1289

viewtopic.php?f=50&t=609&p=1298#p1298

viewtopic.php?f=50&t=821

viewtopic.php?f=4&t=1337&p=2921&hilit=infrared#p2921

viewtopic.php?f=50&t=817

viewtopic.php?f=50&t=383

viewtopic.php?f=50&t=268

viewtopic.php?f=50&t=477

viewtopic.php?f=50&t=46

http://www.clarks-garage.com/shop-manua ... tm#oil-low

http://www.procarcare.com/includes/cont ... fPbs1.html

http://www.americascarshow.com/Detail.a ... 4&mid=1638


more info
youll be way ahead if you buy a factory shop manual and a multi meter and decent timing light and start with verifying TDC , pulling trouble codes,when trying to isolate problems
start with the fuses and verifying sensor function,
If you were local Id suggest driving over and we could get this sorted out, in most cases in under an hour or two
basically drop back to basics and approach the problem in a step-by-step fashion verifying each step as you progress and its a simple check list issue

http://forum.grumpysperformance.com/viewtopic.php?f=50&t=3110&p=12074&hilit=multi+meter#p12074

http://forum.grumpysperformance.com/viewtopic.php?f=32&t=1401&p=4126#p4126

http://forum.grumpysperformance.com/viewtopic.php?f=50&t=54&p=67&hilit=dropping+distributor#p67

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=875

http://forum.grumpysperformance.com/viewtopic.php?f=44&t=621&p=831&hilit=dropping+distributor#p831

BTW SUSPECT A VACUUM LEAK?

get out your oxy-acetylene torch or a propane torch, don,t light it but turn it on so gas is flowing and place the tip near any suspected leak points, while a buddy watches the tach, anytime the gas gets sucked thru a crack the rpms will jump higher in direct relation to the amount of extra fuel the engines getting, no, oil, fluid,or crud's or stains are left on the intake and its simple too do process

also verify the carb float levels are correct, and the throttle blades open fully,verify theres spark at all the plugs and verify the firing orders correct
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Posts: 14105
Joined: September 14th, 2008, 1:40 pm
Location: florida

Re: can,t find whats wrong? start with the basics

Postby grumpyvette » January 22nd, 2009, 10:30 pm

can,t figure it out
buy the shop manual and ask questions on the site here
potential problem
posiable cure



Vacuum leaks
-check hoses, or just replace them outright if theyre not already mint.
-test each component (egr, dist, etc) for leaks with a vacuum pump.


Carb out of adjustment
-follow idle adjustment instructions found easily on the internet
check float level and fuel pressure


Carb is worn or just generally buggered
-check for a worn throttle shaft. This goes with the vacuum leak test.
-replace the carb with a good one.


Worn rings or valve guides or poorly seated valves-perform a _leakdown_ test. Don't waste time on a compression test unless you don't have the means to do a leakdown test.

Failing valvetrain-bent or broken pushrods - visual inspection
-cam lobes rounding off - total pain in the butt to do accurately, but watching the rockers in action with a careful eye can spot lobes that are _very_ worn. or busted springs loose rockers, busted rocker studs

-sticking or bent valve
- remove cylinder head, inspect replace

Cam is too big for the engine, or installed incorrectly
-buy and correctly install a cam better matched to your application

clogged fuel or air filter

replace, filter

water in gas

verify then replace fuel and filter


old or damage spark plugs

replace and re-gap

burnt or bad ignition wire, rotor or distrib cap

requires replacement

detonation damage

-requires replacing pistons and rings at the minimum AFTER CORRECTING CAUSE OF DETONATION, LIKE BAD IGNITION TIMING,OR BAD FUEL RATIO

ignition wires connected out of correct fireing order sequence.

rerun the wires correctly

badly adjusted valves

-requires adjusting them correctly then checking for problems with the valve train if the adjustment doesn,t cure the problem


less than 13 volts in battery

check voltage regulator, altenator,battery and connections


bad coil,
test/replace

if your getting PINGING/DETONATION
ask yourself these questions, because without info your working blind




WHATS YOUR TOTAL TIMING SET AT ?
and at WHAT rpm does the ignition advance reach full advance?
whats the normal engine temp?
what octane fuel are you useing?
whats the engines compression ratio?
have you changed cams?
whats the fuel/air ratio?
have you verified TDC?
which spark plugs and gap are you useing?
what carb jets and power valve are you useing?
whats your fuel pressure?
have you tried retarding the ignition timing?
is the disributor set with a known advance curve?
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Posts: 14105
Joined: September 14th, 2008, 1:40 pm
Location: florida

Re: can,t find whats wrong? start with the basics

Postby grumpyvette » February 2nd, 2009, 11:29 am

without knowing the answer to ALL the questions I posted, and probably some other questions, that those answers will bring up, your ability of finding the solution or isolating the cause of the problem will be rather difficult, with those answers it gives a much clearer picture to diagnose from...currently its about like calling the emergency room on your cell phone,and screaming
"DOC! IT HURTS LIKE HELL! FIX IT!

and when he asks questions, like
(WHAT HURTS?, HOWS DOES IT FEEL?, WHEN DID IT START? WHAT HAVE YOU DONE SO FAR? WHEN CAN YOU COME BYE?)

you say
"YOUR THE DOCTOR.... DON,T YOU KNOW!"

YES I GET GRUMPY, BUT THERE'S A LOGICAL PROCESS TO SOLVING PROBLEMS, and IM GLAD TO HELP, BUT I NEED SOME INFO TO WORK WITH TO MAKE LOGICAL CHOICES, throwing parts at a problem without verifying the cause of that problems about like the doctor telling you to take (TUMS and aspirin) for pain, not knowing you've got a broken toe, simply because that worked on the last customers (PAIN PROBLEM)

The first thing ID do is VERIFY the CAUSE, OF THE PROBLEM FOR THAT, THRU ISOLATING AND TESTING, COMPONENTS AND SYSTEMS
A SHOP MANUAL IS ALMOST MANDATORY,

THESE LINKS should help

viewtopic.php?f=80&t=728

viewtopic.php?f=55&t=1241&p=3037&hilit=+sensor#p3037
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

User avatar
Site Admin
Site Admin
 
Posts: 14105
Joined: September 14th, 2008, 1:40 pm
Location: florida

got a hard to start or non-start tpi / lt1

Postby grumpyvette » March 21st, 2009, 1:28 pm

one of the more frequent complaints I hear about is c-4 corvettes that have difficulty or intermitant start problems.
Ill assume that youve verified the ignition timing and that your getting spark plug electric and your just having a slow or intermitant start most of the time, and it doesn,t seem to matter if the engines cold, warm or hot, and that at times it starts regularly but most of the time it requires several tries but once started it runs decently?

Now by that IM refering to cars that when the ignition spins the engine over freely the engine takes its own sweet time catching, im most cases a simple test will indicate a comon source of that problem.
step one
get in the car and turn the ignition key only far enought that the fuel pump runs, and pressurizes the fuel rails and shuts off, don,t turn the key to the point the engine spins on the starter, remove the key and repeat three times.
step two
on the fourth try on the start process attempt to start the car, by spining the engine over, if you find that it almost always starts under that condition its a strong indicator that the fuel rail pressure is dropping off and the prime suspect is the fuel pressure regulator, and a leaking diaphram.
you should see a minimum of 37 psi on a tpi, 40psi-42 psi on a LT1 at the fuel rails.
replacing the OEM fuel pressure regulator with an adjustable aftermarket fuel pressure regulator will generally result in the problem being reduced or eliminated.
other comon potential problems are clogged/deffective fuel filters or deffective fuel pumps, fuel pump relays or fuses, leaky injectors fuel pump inlet screens or a bad fuel pump.

related useful linked info

viewtopic.php?f=32&t=764

viewtopic.php?f=32&t=816

viewtopic.php?f=32&t=596

viewtopic.php?f=32&t=168

viewtopic.php?f=36&t=676

viewtopic.php?f=55&t=606

viewtopic.php?f=32&t=33

viewtopic.php?f=36&t=628&p=839#p839

http://www.firebirdnation.com/articles/troubleshoot.php


one of my friends calls me up to tell me about a real p.i.t.a. problem he was having with an intermittent ignition miss that never was consistent on his 1970 GTO
hes got some aftermarket HEI type ignition that was driving him insane because it would run crappy for the first few minutes to occasionally, hours of run time then suddenly it would correct itself and run flawlessly for days until the next time he drove the car,after it sat for a few days, it acted like the plugs needed to get hot or, the car had water in the fuel tank,or moisture in the ignition components that needed to burn off once the engine got up to temperature, or something but because once it started running correctly it was nearly impossible to locate the problem, and it almost always seemed to clear up.well a step by step check and verify approach did lead to the answer.
this intermittent issue really started to bug the crap out of him so he followed some of my advice in one of the treads and measured the battery voltage, did an alternator check, cleaned the ground connections, measured the ignition wires, and a dozen other things and took notes then went back and measured things again once it started running correctly which eventually led him to the problem..the problem was that the ignition was VERY susceptible to input voltage changes and the battery had some weak cells it was 5 years old and it took 15-30 minute's before the alternator charging the system gave it a charge level high enough to allow the ignition to function flawlessly , one the battery was fully charged everything functioned, but if the weak cells was drawing to much power and drawing down the voltage , the ignition ran like crap.
he eventually found this out as the battery charge took longer and longer and he noticed the direct relationship , once he had over 13.3 volts everything ran great , below 13 volts it ran like crap, he swapped to a new battery and the problem went away.
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: can,t find whats wrong? start with the basics

Postby grumpyvette » March 22nd, 2009, 12:18 pm

You can use the manual to understand the original design intent of the many systems on your car, and if they aren't working properly, can also give you some idea of what your favorite mechanics will be looking for as they diagnose your problem.

The FSM's are available from Helm, Inc. The following links will take you to the relevant location for all years of C4 Vettes. you can easily look up most other cars here

http://www.helminc.com/helm/welcome_sel ... NB3KJF0N6B

These links show all the literature available from Helm, Inc. for that year ...



1984

1984 Factory Service Manual


1985

1985 Factory Service Manual


1986

1986 Factory Service Manual


1987

1987 Factory Service Manual


1988

1988 Factory Service Manual


1989

1989 Factory Service Manual


1990 (Separate ZR-1 (LT5) Manuals are shown from 1990 thru 1994)

1990 Factory Service Manual


1991

1991 Factory Service Manual


1992

1992 Factory Service Manual


1993

1993 Factory Service Manual


1994

1994 Factory Service Manual


1995 (No separate ZR-1 Service Manual)

1995 Factory Service Manual


1996

1996 Factory Service Manual


OR heres a secondary source, for a condensed version

http://www.autorepairmanuals.biz/site/5 ... age/912273


ok the first step once you buy a corvette is ALWAYS buy the matching shop manual,and get a v.o.m. meter and use the shop manual, it will have detailed wiring diagrams and flow charts, and use the search feature on the site
AS AN EXAMPLE LETS ASSUME YOU BOUGHT A 1984 VETTE

http://www.helminc.com/helm/Result.asp? ... LAKTTP9VS4
very good
http://www.haynes.com/products/productID/264
fair


read these threads

viewtopic.php?f=36&t=2619

viewtopic.php?f=70&t=2700

viewtopic.php?f=3&t=325&p=397&hilit=+meter#p397

viewtopic.php?f=44&t=469&p=7163&hilit=meter#p7163

viewtopic.php?f=62&t=987&p=2395&hilit=+meter#p2395

viewtopic.php?f=50&t=785&p=1337&hilit=+meter#p1337

viewtopic.php?f=32&t=2697

viewtopic.php?f=32&t=1773

viewtopic.php?f=32&t=596
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: can,t find whats wrong? start with the basics

Postby grumpyvette » August 18th, 2009, 7:38 pm

ONCE YOUVE FOUND MAJOR ISSUES THAT NEED REPAIR, IF THEY CAN,T EASILY BE FIXED, WORKING FROM THE TOP SIDE WITH THE SHORT BLOCK STILL IN PLACE!

its time to buy a decent cheap engine stand, LIKE THIS ONE I LINKED TO , BELOW
AND A SHOP MANUAL, and THIS CD/BOOK AS A REFERENCE YOULL NEED!


http://www.themotorbookstore.com/resmchstvi.html

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=67015


read thru THESE LINKS

http://forum.grumpysperformance.com/viewtopic.php?f=32&t=699

http://forum.grumpysperformance.com/viewtopic.php?f=27&t=1018

http://forum.grumpysperformance.com/viewtopic.php?f=27&t=26

then pull and inspect the engine........once you know what you can salvage you know where the project starts from, it should take less than one weekend to pull and disassemble and inspect the engine
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: can,t find whats wrong? start with the basics

Postby grumpyvette » September 12th, 2009, 6:01 pm

OK you have some intermittent miss, stumble etc, and it bugs you but it never lasts long enough to track it down, NOW WHAT

read thru the linked info in the thread and get out the SHOP MANUAL

viewtopic.php?f=80&t=2076&p=5564&hilit=manuals#p5564

viewtopic.php?f=55&t=1241&p=2648&hilit=CODES#p2648

http://www.classictruckshop.com/clubs/e ... ac/uum.htm

http://www.eficonnection.com/eficonnection/default.aspx

Im assuming here,that you've pulled TROUBLE CODES and found NOTHING in the listed trouble codes and the SPARK PLUGS all look CONSISTENT??(none darker or lighter) and you've done a compression and leak down test, verified theres no vacuum leaks and you've adjusted your valves,and your oil pressures at least 15-20psi at idle and goes up with RPMS to about 55 PLUS PSI so you know its not a mechanical issue??
and the battery's fairly new and shows a consistent 13+ volts or so when its charging??

theres four fairly common areas Id look into, lets go from least likely to most likely, first, and the least likely, but the cheapest is a bad ground, Id sure look into the condition of the engine grounds and batter cables

only slightly more likely is a bad injector or a bad injector connector, and altho the injectors read good that doesn,t necessarily mean they spray a decent pattern or flow consistently,

the fuel pressure regulator is ALWAYS, suspect until you test it and know the fuel pressure remains up around 40 psi or higher for 15 minutes after you shut off the engine, as is the oil pressure sensor, which will turn off the ignition if its defective.


now for the more likely stuff

ok now the COIL is a PRIME suspect, yes they can and do go in and out , changing voltage once they get hot at RANDOM at times
and intermittent flaws make you nuts tracking them down, loose connectors or corrosion on connectors, is also possibly a cause


the action ID suggest is to beg,borrow, buy, a scanner that puts out real time data logs, and have the wife or a buddy drive while YOU watch the data on a LAP TOP

http://www.etoolcart.com/autoxray-scanner-ez-scan-ax6000.aspx

http://www.auterraweb.com/dynoscan.html

http://www.mercedesmanuals.com/Live_Data_OBD2_Deluxe_Automotive_CAN_BUS_Code_Scan_p/u581.htm

http://www.obd-2.com/

http://tunertools.com/proddetail.asp?pr ... CMSCAN-KEY

http://www.scantool.net/

http://tunertools.com/proddetail.asp?pr ... ata-Logger

http://www.moates.net/product_info.php? ... ucts_id=54

http://www.innovationhouse.com/products ... _tool.html

http://www.extremestyling.com/Nology-PD ... ce=froogle

http://stores.channeladvisor.com/Summit ... ms/BBE-ATU

http://www.extremestyling.com/Nology-PD ... ce=froogle

step one
is always, pull trouble codes and get out the shop manual, and basic diagnostic tools, and read the manual.

step two
look for obvious changes like, verify theres no vacuum leaks from loose vacuum hoses, loose or burnt ignition wires, then, verify the IAC and TPS sensor is correctly adjusted, and your ignition timing and fuel pressure are correct, and your injectors are working with a noid light, verify youve got a minimum of 15 psi of oil pressure at idle,and keep in mind anything seriously wrong usually throws codes to give you a starting point

step three
drop back to the basics, don,t assume anythings working correctly until YOUVE verified it
start with a compression test and verify TDC and the timing marks on the damper are correct, adjust the valves, then start a check list
start with the simple stuff like making sure all the plugs are getting spark and youve got about 40 psi of fuel pressure, verify the cats are not clogged with a vacuum gauge back pressure check,verify the fuel filters been replaced recently, that theres no water in the fuel, the plugs are not fouled, and your alternator is putting out about 13.5 plus volts and your engine grounds are good

BTW FAULTY GROUNDS, IN MANY CARS AND ESPECIALLY NEWER CORVETTES CAUSE MANY ELECTRICAL ISSUES SO IF YOU HAVE INTERMITTENT ELECTRICAL ISSUES CHECK THEM CAREFULLY
Image

HERES SOME INFO POSTED ELSWARE
"Most grounds are on the drivers side of the block above the oil filter or on the rear of the drivers side cylinder head . There are also a few on the frame under the battery tray , and a couple on the top of the frame about 12" back from the radiator, housing.,as well as one on the drivers side behind the kick panel and one passenger side behind kick panel. There are more Ones under the battery tray are the most likely to be corroded in my experience.
LCD dash ground is behind drivers kick panel . There are also several electrical grounds down just above the oil filter and one behind the passenger kick panel for the ECM. and a couple on the rear of the drivers side cylinder head, Grounds are a constant issue on most c4's. Hope this helps."

http://forum.grumpysperformance.com/viewtopic.php?f=32&t=1401

http://forum.grumpysperformance.com/viewtopic.php?f=50&t=609

http://forum.grumpysperformance.com/viewtopic.php?f=32&t=168

http://forum.grumpysperformance.com/viewtopic.php?f=32&t=661
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: can,t find whats wrong? start with the basics

Postby grumpyvette » February 3rd, 2012, 2:01 pm

Image
Image

logically tracking down a problem requires a basic understanding of how things work or at least how they are intended to function correctly, i recently had a guy call and ask me how to by-pass his VATS ,on his 1991 corvette, well the conversation reveled the main problem was the car would not turn over or start so my first questions WERE, whats the battery voltage, and does it drop as you turn the key/ DOES THE ENGINE SPIN IF YOU TURN IT MANUALLY WITH A WRENCH ON THE DAMPER , DOES THE STARTER CLICK? are there any trouble codes?
well thru a logical check list it turned out he simply had a blown fuse and a badly corroded battery cable, once those were replaced the car started and ran fine!
BTW ACTUALLY READING THRU THE POSTED LINKS AND SUB LINKS might help

viewtopic.php?f=36&t=63&p=3403&hilit=vats#p3403

viewtopic.php?f=36&t=520&p=645&hilit=vats+resistor#p645

viewtopic.php?f=32&t=2697&p=18904&hilit=battery+cable#p18904

viewtopic.php?f=32&t=5926&p=18255&hilit=battery+cable#p18255

viewtopic.php?f=70&t=4846&p=13265&hilit=battery+cable#p13265

viewtopic.php?f=80&t=728

viewtopic.php?f=32&t=596

viewtopic.php?f=32&t=1401

viewtopic.php?f=32&t=168
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: can,t find whats wrong? start with the basics

Postby grumpyvette » November 2nd, 2012, 4:59 pm

If you suddenly start having a problem, logic would point to a recent change or some change youve made as a potential source, but parts do break,
I may be able to help you locate and isolate the source of the sound,or part thats failed
but chances are good, if its related to a ticking or knocking sound, its a valve train related clearance issue.
find out what the knock sound is before assuming its a cam or ordering parts, you can,t assume anything you need facts and those are found by tearing it down and inspecting components and doing things like compression tests.
theres little sense in installing a new cam until you find out IF its the cam that failed and if it WAS, WHAT CAUSED IT TO FAIL?, if you don,t correct THAT installing the next cam would only result in a similar problem, and more cash wasted your problem could be as simple as a bad rocker or as complex as a cracked block,or cracked crank, only careful inspection and testing will show you what your dealing with and whats required to fix it!
tracking down a "NOISE" especially engine or drive train
First of all - don't assume your problem or noise is cause by your repairs or recent work, thats NOT always the case, but its always a good idea to verify everything.. It is likely one of those corollary laws related to Murphy's law - never assume that you problem is caused by the last thing you changed on your motor. something unrelated breaks occasionally while the work your doing is being done. Guys always seen too jump to the assumption that whatever they changed caused the problem. Unfortunately, it ends up being a coincidence - and those people spend a lot of time and money chasing a problem that they assume is related to the work they did. You HAVE to be systematic and thorough diagnosing the problem
you need to do a step-by-step test and verify approach to isolate and locate the source of the noise or problem, the only logical route to take is to look at each potential area that COULD be a problem and verify it is either the cause or not the cause,it will be reasonably easy to locate the source of the noise if you put the car up on 4 frame support,jack stands or a two post lift and have a friend rotate the tires as you look for the source, run the various accessories, test things with a shop manual to verify function, use a multi meter and don,t assume anything works until you prove it does. think about when the problem occurs and under what conditions , you might need to start the car or hit the brakes , run the engine or adjust something, test sensors etc.but with the car up off the tires it should be far easier to locate the noise origin
try to locate the source to the engine,transmission ,drive train, rear differential, brakes, etc. is the source related to the gear the cars in?, tire rotation> in or out of gear? is the noise consistent in forward, reverse? on/off the brakes, is it electrical in nature? are your fluid levels ok? are all the vacuum lines, and electrical connectors and grounds connected?
[/b]

YES READING THE LINKS HELPS


viewtopic.php?f=52&t=6237

viewtopic.php?f=51&t=2919

viewtopic.php?f=50&t=6572&p=21512&hilit=down+tear#p21512

viewtopic.php?f=50&t=5893&p=18037&hilit=reluctance#p18037

viewtopic.php?f=87&t=4687&p=20859&hilit=tear+down#p20859

viewtopic.php?f=70&t=7309&p=24862&hilit=meter+manual+gauge#p24862

http://www.lectriclimited.com/frequentl ... ns.htm#A01

viewtopic.php?f=52&t=528

a step bye step approach should find the source very quickly, you just have to look at the issue from each potential source vs the whole engine
1
is the sound directly related to engine rpms?
2
does the sound changer if the transmission is shifted or in neutral?
3
if you temporarily remove the fan belts does the noise change or stop?
4
have you tried to adjust the valves at idle?
5
Have you done a compression test?
6
can you post clear pictures of the spark plugs,labeled as to cylinder number

you might be amazed at what you can learn reading the posted links I posted here and above , rather than making random guesses, step back and start checking, read the links, and think about each sub system.


viewtopic.php?f=50&t=208&p=16848&hilit=detonation+damage#p16848

viewtopic.php?f=51&t=2919

viewtopic.php?f=52&t=7716&p=26282&hilit=busted+valve#p26282

viewtopic.php?f=52&t=6237&p=19552&hilit=+busted+busted+rocker#p19552
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: can,t find whats wrong? start with the basics

Postby bob » May 24th, 2013, 5:34 pm

I was over at Grumpy,s shop today ,to ask about whats involved in making a repair on a cooling fan, on a friend of mines car.
Grumpy told me to get it driven over there,and when it got there he looked at it for a few minutes, and Ive got to say, its rather interesting watching him work.
Grumpy asked my neighbor a great many questions and then he got out a meter and within minutes, he had located a loose, corroded and obviously badly connected sensor.
A few minutes of clean-up with a abrasive pad on that sensors connection, and cutting off and replacing the connector clip on the wire connected too the sensor had the fan working.
The time it took was about 20 minutes from start to finish.
Grumpy told the guy the repair charge was a 6 pack of ginger ale, next time he was in the area! :mrgreen:
bob

 

Re: can,t find whats wrong? start with the basics

Postby Indycars » May 24th, 2013, 9:31 pm

I know Grumpy doesn't do it for the money, but I hope he donates just half of what it would have cost him at the repair shop to his website. Plus something for having no 2nd trip and NO aggrivation! Unless he is a Veteran of the US military or similar hardship!
Rick
Too much is just enough!!!

- Check Out My Dart SHP Engine Project: viewtopic.php?f=69&t=3814
- Need a Dynamic Compression Ratio Calculator: viewtopic.php?f=99&t=4458
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