Page 1 of 1

chasing intermitant electrical glitches?

PostPosted: December 31st, 2008, 9:46 am
by grumpyvette
The secret of effective diagnosis and troubleshooting is to have a logical plan.
The secret of effective diagnosis and troubleshooting is to have a logical, well-ordered system. Following a logical step-by-step procedure will get you to the root cause of a problem quickly and efficiently. and you can,t go into the process assuming you know the answer before you test, let the facts you find lead you to the answers,you may waste a great deal of time chasing what you assume is a bad injector or a faulty ignition only to find its a clogged fuel filter, low fuel pressure or a loose electrical connection, Repair manuals will have a diagnostic tree that goes in a logical progression. It will ask a question, usually yes or no, and depending on the answer will branch off in two or more directions. The last box in the tree will have the problem and how to correct it. The example shown is a simple one. A more complicated system will have branches going into specific tests and then have 2 or more branches from there depending on test results.
If your experiencing intermittent electrical issues you will obviously need to get out the shop manual for your year corvette, a multi meter and do some isolate and testing, but be aware that loose or corroded connections , will be hard to isolate, as they seldom present a consistent, solid open or dead short in the wire,theres several electrical connector plugs that connect thru the firewall near the battery location that are subject to corrosion issues and frame grounds that might be suspect, obviously theres sensors that can be defective.

links with lots of sub-links that should be useful, most guys ,faced with isolating an electrical issue, seem to get over whelmed, but if you get out the schematics, use a multi meter and some logic in tracing the circuits, and start pulling fuses and measuring resistance and voltage, take the time to read the manual ,pull trouble codes,and if required get a scan tool or a data logging program for your lap top computer, and using the shop manual, you can generally isolate the cause, but don,t get fixated on the idea that all misses are ignition, electrical related, theres potential mechanical, and fuel delivery issues that could be involved.


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
because of connectors and wiring like this
Image ... 98674.html
You will need some basic test equipment to perform your diagnosis.
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

Image ... 98674.html

take notes your memory may not hold the exact numbers & results you need to refer bacK too.

many FLAKEY problems in the cars electric system can be traced to bad grounds, loose connections, loose grounds, and pinched wires, on older cars corrosion is also a factor.
water that gets into the wireing can be a huge problem,
many times a V.O.M. meter can help isolate the cause.
think back, have you installed gauges, interior panels,installed body panels, rugs or interior components recently, just before the problem started, a screw in the wrong place, an overly tight bolt,or components pinching wires or grounds that were not re-tightened correctly can easily hit , pinch or cause problems with wires.
theres usually a REASON things started to go weird, and more times than most of us want to admit its something we did previously or failure to keep the car dry thats the source.
systems don,t have to be related to cause problems, a pinched wire can drain the battery over several days, your turn signals or interior lights might not work if an engine ground or ground to the dash electronics is loose, pull fuses,check grounds, get a darn factory shop manual, its MANDATORY WITH MOST OLDER PERFORMANCE CAR OWNERSHIP!
USE IT TOO isolate and correct those problems.

Re: chasing intermitant electrical glitches?

PostPosted: February 4th, 2009, 2:01 pm
by grumpyvette
Here are some instructionals and tutorials on how to use a VOM ... eruse2.php,11 ... lected.htm ... 528008fdea

1.To do any logical trouble shooting on electrical issues you must have a good wiring diagram of the car.

2. remove all fuses.
3. place an amp meter in the positive battery line.
4. replace fuses one at a time.
(replace one record the current then remove the fuse, and proceed to the next fuse and circuit.)

5. now with this information you must isolate which circuits should have caused or continute to cause the electrical drain, and which should or are not a problem.
6. once identified and isolated the circuit can be examined isolated from others and fixed, with the shop manual, and A V.O.M. METER.

looking for a problem of this type is like looking for a needle in a hay stack unless you use a procedure like this and it will overwhelm you.

I frequently get questions about why cars, most of us own that are used mostly as weekend toys and not as daily transportation,cars that sit for a few days between use seem to be plagued with battery's that won,t stay charged, well ive gone over this a few times so heres a few links of related info