Ran Fine. And Now....

So the 1992 aod vert 5.o ran fine. was just doing little things on it like cleaning and painting a few mounting pieces for the radiator that had flaked all the paint off. yesterday it would start, run 3 seconds and shut off like someone turned the key off. finally fired and i let it run till it was at normal operating temp. today, with a fully charged battery it will hardly turn over. acts like a dead or dying battery but the battery is charged and the charger was set to the "start" high setting. thing will not even roll over enough to fire. this stuff is getting a little old. any ideas on what the problem is now?

srtthis said:

im guessing starter is weak

Click to expand...

i am leaning toward that... but, yesterday it would roll over great. just not fire up. then it would fire and die within 3 to 5 seconds. finally got it to run with 1/4 pedal and after a few seconds could let go and it would idle and respond just fine. pulling plugs, cleaning all electrical today. pulling starter last. it probably needs replaced but the rest needs to be checked and cleaned too.

got into the no crank checklist.

The clamp on with 2 bolts battery terminal ends are a known problem causer. Any place you see green on a copper wire is corrosion. Corrosion gets in the clamped joint and works its way up the wire under the insulation. Corroded connections do not conduct electricity well. Avoid them like the plague...

If the starter solenoid welds the contacts, then the starter will attempt to run anytime there is power in the battery. The cables and solenoid will get very hot, and may even start smoking. The temporary fix for a welded starter solenoid is to disconnect the battery and smack the back of the solenoid housing a sharp blow with a hammer. This may cause the contacts to unstick and work normally for a while.

A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection while trying to start the car: more than .5 volts across a connection indicates a problem. The voltage drop tests need to be done while cranking the engine. It's the current flowing through a connection or wire that causes the voltage drop.

See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. .



2.) Check the battery to engine block ground down near the oil filter, and the ground behind the engine to the firewall. All grounds should be clean and shiny. Use some sandpaper to clean them up.

3.) Jump the big terminals on the starter solenoid next to the battery with a screwdriver - watch out for the sparks! If the engine cranks, the starter and power wiring is good. The starter relay is also known as a starter solenoid.

The rest of the tech note only concerns no crank problems. If your problem was a stuck solenoid, go back to step 1.

4.) Then pull the small push on connector (small red/blue wire) off the starter solenoid (Looks like it is stuck on a screw). Then jump between the screw and the terminal that is connected to the battery. If it cranks, the relay is good and your problem is in the rest of the circuit.



number 3 is a no spark in my car. number 4 it clicks but does not spin the starter. right now the starter is unbolted and hanging but still connected to power. off to autozone it goes. if thats not it i will replace the starter solenoid.

starter failed the bench test.. nuff said