battery or alternator?



battery or alternator?

Postby grumpyvette » November 27th, 2013, 3:38 pm

jim wrote: grumpy i just purchased a 1973 chevelle that had not been started in 12 years, naturally the battery was dead as a rock, so I jump started the car once i replaced the old battery,and got it to run with fresh gas and a new fuel filter, but once I got home the car would not start...any ideas?


CONGRATS on the new purchase of a project car!
the first thing Id want to check is that the battery cable connections were clean on both ends of both cables and that the car could be jump started and made to run, then id start trouble shooting, theres a couple simple tests you can do once the new battery is installed, with a multi meter
before you start the car the battery should read near 12 volts, once the cars started the alternator should be providing about 13.8-14.5 volts,Immediately after start up the alternator should be charging between 13.8 and 14.5 volts and gradually drop as the battery charges up. get a trickle charger to charge the battery and a /battery minder,to keep it charged as frequently not driving the car for a few weeks at a time is sure to reduce battery life.
a new battery may not be fully charged so Id charge it over night with a trickle charger, and you didn,t say if the engine spins over on the starter easily indicating the battery and starter are good or if its just not firing and running......if the engine spins easily the starter and batter are not nearly as suspect as the carb and ignition.
id sure start with flushing out the fuel system, and giving a car that had not run an oil change and fresh oil filter, air filter plugs, and a basic tune-up.
i,d throw a can of injector cleaner in the fuel tank, and a quart of marvel mystery oil in the crank case and adjust the ignition timing, carb float levels , verify fuel pressure,verify ignition timing, check all the fluid levels in the radiator AFTER replacing the coolant/antifreeze and verify the oil pan was full and transmission, fluid level was good.
btw CHECK THE BRAKES,(CALIPERS PADS, DRUMS SHOES ETC, BRAKE FLUID, U-JOINTS, AND WHEEL BEARINGS asap


READ THRU THE THREADS AND SUB LINKED INFO


viewtopic.php?f=36&t=3222&p=8575&hilit=test+alternator#p8575

viewtopic.php?f=36&t=8493&p=37179&hilit=battery+drain#p37179

viewtopic.php?f=70&t=2133&p=33461&hilit=trickle#p33461

http://www.hotrod.com/techarticles/gene ... ewall.html

viewtopic.php?f=52&t=196&p=35390&hilit=adjusting+valves#p35390

viewtopic.php?f=55&t=109

viewtopic.php?f=70&t=4683
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: battery or alternator?

Postby grumpyvette » June 2nd, 2014, 10:01 am

http://www.hotrod.com/techarticles/engi ... uick_test/

Disconnecting the battery while the engine is running isn’t a valid test for alternator function and may damage sensitive electronic parts. Instead, use a common voltmeter and the following test procedure. Although some of the steps reference typical GM alternators, the basic methodology is valid for any charging system.

01
Test voltage across the battery terminals with the engine running. A good alternator should maintain battery voltage between 13.9 and 14.8 volts (14.2 is optimum). Even worst-case, with all accessories turned on, there should be at least 13 volts at the battery. Be sure that the engine is running at a high enough rpm for the charging system to function (especially if running a one-wire alternator excited at a specific rpm). If voltage is low, go to Step 02. If voltage is over 15 volts, go to Step 05.

02
Connect the voltmeter between the alternator’s output (BAT) terminal and Ground. If voltage is 13.6–14.6 volts, the alternator is OK, but power isn’t getting to the battery. Go to Step 03. If voltage is under 13.6 volts, go to Step 04.

03
Check the battery cables and alternator charge-wire for bad connections, improper cable and wire size, or corrosion. Repair or replace as needed. Recheck as per Step 02. If voltage is a constant 13.6–14.6, the problem is solved. If voltage is normal, but slowly decreases, go to Step 04.

04
Check the alternator drive-belt. Adjust its tension or replace as needed. On a street car, the crank pulley should be three times larger than the alternator pulley; fix as needed. If voltage is normal but slowly decreases after these repairs, your alternator is OK but can’t keep up with the vehicle’s current demands; upgrade to a higher-output alternator. If you get an immediate under-13.6 volt reading, go to Step 05.

05
Test the voltage regulator. For external regulators, go to Step 06. For internal regulators, go to Step 07.

06
Unplug the harness from the regulator. With the engine running, connect a jumper wire from the connector’s B+ Terminal to the connector’s Field terminal (on most GM cars, that’s respectively the red and blue wires). Only do this for 30 seconds at a time. The engine will bog down. The alternator should have an audible whir and ramp up to max output. If you see a visible arc, repair or replace the regulator. If there’s no arc, the alternator has an open Field circuit or worn-out brushes. Fix or replace as needed.

07
GM SI alternator internal regulators can be checked as shown in the photo. If voltage goes up during this check, repair or replace the internal regulator. If voltage is lower than before, repair or replace the entire alternator. Late-model GM CS alternators don’t have serviceable regulators; the entire unit must be replaced.

Read more: http://www.hotrod.com/techarticles/engi ... z33Uhrtws7
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



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