starter relay is grounded
08-16-2011, 09:31 PM
#1
On The Tree
Thread Starter
starter relay is grounded Another problem with a starter.
My swap was running, and one day I went to start it, heard a 'click' and then the all the electronics went dead. I have since tested the battery-it's OK-and replaced the starter-brand new one under warranty. I have found that the pole where the starter switch hooks up, and the pole with a wire that goes into the starter body are both grounded. Any ideas what could cause this? My first thought is bad grounding body to engine to frame, but it was running before, so that seems strange. I'll check that tomorrow.
I also verified that the wire going from the key switch to the starter is not grounded. I disconnected it from the starter to verify that it is the starter which is grounded, and not some part of a wire going to it.
My swap was running, and one day I went to start it, heard a 'click' and then the all the electronics went dead. I have since tested the battery-it's OK-and replaced the starter-brand new one under warranty. I have found that the pole where the starter switch hooks up, and the pole with a wire that goes into the starter body are both grounded. Any ideas what could cause this? My first thought is bad grounding body to engine to frame, but it was running before, so that seems strange. I'll check that tomorrow.
I also verified that the wire going from the key switch to the starter is not grounded. I disconnected it from the starter to verify that it is the starter which is grounded, and not some part of a wire going to it.
08-17-2011, 06:36 AM
#2
How did you determine it is grounded, with an ohm meter? What resistance did you read?
A starter motor is just a big coil of wire. The solenoid is too. You should read very low resistance with an ohm meter. When the starter starts spinning it reacts with the magnetic fields and that is what keeps the current from blowing up. But with the rotor stationary you should only be measuring a few ohms to ground.
Chances are your solenoid is bad. I have seen dirty battery posts cause the problem you are describing more times than I can count.
You can test the starter by hooking jumper cables up to it while it is out of the car. Hook one cable to the case and the positive cable to the fat wire going into the starter. If that works your problem is probably in the solenoid. You can test that by jumpering a screwdriver across the two big lugs. That bypasses the solenoid and sends battery power straight to the starter.
Solenoids are pretty easy to take apart and rebuild. There is a copper disc in there that gets shorted across the two big lugs. Cleaning that up with sand paper or a file then cleaning all the copper dust out of the inside will often make them work like new again.
Sometimes with an old car the ignition switch starts going bad. When that happens you won't get a full 12 volts to the start lug on the solenoid. That may give it enough juice to click but not enough to start. Running a jumper wire straight to the start lug, or wedging a screw driver from the starter battery lug to the start terminal, will test whether the problem is in the ignition switch wiring.
A starter motor is just a big coil of wire. The solenoid is too. You should read very low resistance with an ohm meter. When the starter starts spinning it reacts with the magnetic fields and that is what keeps the current from blowing up. But with the rotor stationary you should only be measuring a few ohms to ground.
Chances are your solenoid is bad. I have seen dirty battery posts cause the problem you are describing more times than I can count.
You can test the starter by hooking jumper cables up to it while it is out of the car. Hook one cable to the case and the positive cable to the fat wire going into the starter. If that works your problem is probably in the solenoid. You can test that by jumpering a screwdriver across the two big lugs. That bypasses the solenoid and sends battery power straight to the starter.
Solenoids are pretty easy to take apart and rebuild. There is a copper disc in there that gets shorted across the two big lugs. Cleaning that up with sand paper or a file then cleaning all the copper dust out of the inside will often make them work like new again.
Sometimes with an old car the ignition switch starts going bad. When that happens you won't get a full 12 volts to the start lug on the solenoid. That may give it enough juice to click but not enough to start. Running a jumper wire straight to the start lug, or wedging a screw driver from the starter battery lug to the start terminal, will test whether the problem is in the ignition switch wiring.
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reedld (07-16-2020)
08-17-2011, 11:52 AM
#3
On The Tree
Thread Starter
There is continuity between the switch pole on the solenoid and the negative terminal on the battery. I didn't measure the resistance of this connection, but it's pretty low.
The starter/solenoid assembly is a new one. I think the odds of having purchased a bad stater which is failed in the same way as the last one are very low, so I don't think rebuilding the solenoid will do any good.
I'll check all of your suggestions tonight and report back. Thanks for the assistance.
The starter/solenoid assembly is a new one. I think the odds of having purchased a bad stater which is failed in the same way as the last one are very low, so I don't think rebuilding the solenoid will do any good.
I'll check all of your suggestions tonight and report back. Thanks for the assistance.
08-17-2011, 05:10 PM
#4
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sounds like a bad chassis ground, the load from the starter "click" then all went dead says the high amp load from the starter caused an open circuit. Put a jumper cable from the battery negative to the engine block, try to start. If the engine cranks normally there is a bad negative somewhere.
08-18-2011, 09:42 PM
#5
On The Tree
Thread Starter
I just came in from the garage. There are zero ohms between any of the following places: chassis, battery negative terminal, body, engine block, starter body, starter switch terminal on the starter solenoid, and the wire going into the starter from the solenoid.
The starter is brand new in the past week, and the battery is only two months old.
This weekend I'll take the starter out and bench test it with jumper cables.
The starter is brand new in the past week, and the battery is only two months old.
This weekend I'll take the starter out and bench test it with jumper cables.
08-20-2011, 10:45 AM
#6
On The Tree
Thread Starter
The starter runs without fault during a bench test. I cleaned up all of my grounds, and checked them again, no problems there. I can crank over the engine by hand, so I know it's not siezed.
I broke the factory ignition switch, so it's currently hotwired with some toggle switches. The switches are less than two months old.
Looking back at basics there either has to be a short somewhere in the starter circut, or the load on the starter motor is super high, right? This is driving me crazy!
I broke the factory ignition switch, so it's currently hotwired with some toggle switches. The switches are less than two months old.
Looking back at basics there either has to be a short somewhere in the starter circut, or the load on the starter motor is super high, right? This is driving me crazy!
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MrPatMagee (01-20-2023)
