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Hot Electrical problem


JerryW

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So for the last 2 race weekends I have had an electrical problem where if the car stalls I cannot restart it when hot, but could when things cooled down. At buttonwillow on Sunday I died coming off the track actually on the scales, but after letting the car sit for 15 mins was able to restart and get the car on the trailer.

 

This last weekend at Thunderhill I had a problem where the car started to buck and die (some what similar to an out of gas situation) and the car died in the pit in lane. After a tow back to the paddock I replaced the battery with a full size group41 from down town thinking the light weight battery had died or I had bad cables when hot.

Sunday was fine with the new battery until the race where i had a significant lack of power from the start and within 2 laps was having to nurse the car until I could pull into a safe area so the yellow didn't have to come out. While there the car died and would not restart (starter wouldn't even turn).

 

Throwing a jump box on to the car always allowed a start. Voltages were 12.7 and today 11.8. Starting the car today (with the jump box) showed no charge out of the altenator so I pulled that>

 

On the back of the altenator is a black rectangular box with a female termilal that plugs into the back of the Alt. This had broken off from the mounting plate and was hanging free. Looking at PET this appears to be

a condensor with part no: 944 603 143 00 which is available from Pelican as a special order part.

 

Do you guys think this condensor could be causing (or lack of) the symptoms above ?

 

Thanks

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Hi Jerry I spent many years in the alternator and starter rebuilding industry. The capacitor is not the problem. It does not even need to be there. It is there to help eliminate radio noise.

 

If you have the Bosch alternator (most do) the good news is that very rarely does the alternator itself have a mojor problem.

 

There is a larger part that is held in by two screws. On some alternators it is a rectangular box on others it is low profile and has a round section. This is the regulator/brush holder (if this is a Bosch Alt.) Remove brush holder and check to see if either brush seems very short. Usually only one wears out. Don't ask why, I haven't a clue. If both look to be adaquately long then very possible the regulator section of alternator is bad. If one is too short to reach commutator of alternator (area where brushes ride on Rotor) then very possibly you can just replace brushes and be on your way.

 

Check with a local hardware store or power tool store. They should have brushes for electric tools that you may be able to use. If not check the yellow pages for an Automotive electrical rebuilding company. They should be able to bench test unit and repair or replace brush holder/ regulator for you.

 

Before doing that make sure you have battery voltage at the B+ wire (big one) at the alternator when battery is hooked up and kill switch is on. Make sure it is not touching anything when you do this. The small wire is the one that goes to the light on the dash. With the key on ground that wire and check to make sure the light is on in the dash. This wire activates the alternator to get it working. If the light does not come on then check fuses with a test light.

 

Call me if you need further assitance.

 

Charlie

805-286-1732

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OK thanks. I'll keep digging. Would an oil leak that sprays around the alt (possibly into the back of it) cause issues (don't remember if oil is conductive like water or not).

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Pulled the voltage regulator and both brushes are very short. I've picked up a new regulator and will install that. However I got into a "while you are in there mode" and have started to pull the intake manifold to find my oil leak. I guess I'll take the alt with the new regulator up to Kragens and have them test it out of the car. I picked up an old spare alt at the swap meet today so I have got that as a spare.

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Jerry, I had a similar issue at Fontana. My alt. quit working at some point that I did not notice (not checking the guages so driver error). When starting the car for the race, the starter barely had enough power to start the car. On the first lap of the race, the car started cutting out. The issue was low voltage that caused the car to run bad and to quit.

 

If your alt. was bad, that could be the problem. The only question I have is why would it start later. Did you jump it every time to get it started? Even if you did, if the alt was not charging, the car would not have continued to run. If the alt was bad and you replaced the battery and it later had the same problem, question answered.

 

I am going to put in a better alt. guage and a large idiot light (idiot driver light? ) to try to prevent a reoccurence of the problem.

 

Good luck, I don't want any excuses when Charlie and I show up an Infinion.

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So I spent part of the day at the partsheaven swapmeet where I picked up a spare alt for $20 and a new voltage regulator. Once I got home I started into the car. Did a rewire of the battery==>Starter==>Alt with 1/0 welding cable. Redid the ground wires with the same with an extra ground over to the engine. Pulled the intake manifold to find the mysterious top of engine oil mist issue -- appears to be the AOS to throttle body line from the top of the AOS, it was loose and also cracked.

 

Alt is ready to go back in with the new regulator after I get it tested at Kragen (hate to put it in button everything up and find the problem isn't fixed !)

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It is possible for the alternator to quit working if it got soaked with oil. The fan on the face of the alternator blows air through the alternator so if it was only getting on the back most likely the oil did not cause the problem.

I have never seen one shorted out due to water or oil. Alternators get wet all the time and continue to work.

 

Sounds to me like a brush problem. This is the most common failure I have seen. Bosch made great alternators in this era.

 

Charlie

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  • 2 weeks later...

Well - Kinda

 

Pulled the altenator and the regulator had very worn bushings. I replaced the regulator and had the alt tested at Kragens, but caught a case of "while you are in there"

 

So

1) Rewired everything from the battery to the alt with 00 welding wire.

2) Pulled the intake to search out the high oil leak

3) Replaced the AOS oil seals

4) Just in case sealing the back of the upper Balance shaft housing.

5) Building a new air filter setup with intake in the front bumper

6) Added Volt Meter into the dash so I can monitor the state of the charging system.

7) Replaced some of the large AOS hoses as they were hard and cracked.

 

The intake goes back on tomorrow so I will finally start the car and check the voltages.

 

(Oh and been sick for 2 weeks with this damn cough !)

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Well - Kinda

 

Pulled the altenator and the regulator had very worn bushings. I replaced the regulator and had the alt tested at Kragens, but caught a case of "while you are in there"

 

So

1) Rewired everything from the battery to the alt with 00 welding wire.

2) Pulled the intake to search out the high oil leak

3) Replaced the AOS oil seals

4) Just in case sealing the back of the upper Balance shaft housing.

5) Building a new air filter setup with intake in the front bumper

6) Added Volt Meter into the dash so I can monitor the state of the charging system.

7) Replaced some of the large AOS hoses as they were hard and cracked.

 

The intake goes back on tomorrow so I will finally start the car and check the voltages.

 

(Oh and been sick for 2 weeks with this damn cough !)

 

YES!!! 14.25V when running, 13.05 key off, and 12.95 key on. Voltmeter is working correctly showing me the charge system so I am now officially happy.

 

Also redid the swaybars so this next weekend will be interesting as we test the settings.

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No _ I actually think it was the alt regulator bushings, when everything got hot and expanded it was no longer charging. But I wasn't betting on anything and decided to do everything that could play in those circuits _ havent managed to get it as hot under the hood as I'd like but we will see this weekend !

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