Thank you Mr. Martin. I traced the blue/yellow wire from ASD relay back to PCM. Its sending a good ground signal. If wires and grounds and pins are testing good it must be faulty alternator right or is it the relay. Im lost guys.

 

I must be counting the pins wrong because I would have never guessed thats where pin 51 was. Now im thinking all my other pin checks were the wrong pins. Is there any way someone could shoot me a picture of what pins are which so I could retest please. Another week of wondering until my FSM is going to drive me crazy

 

 

Thank you so much again Mr. Martin. Im stuck with a simple test light for now but im showing good on all the pins wannadiesel and you have mentioned as well as very thoroughly checked all wires to ensure they are solid. Any more thoughts. I know yall are probably tired of kicking a dead horse but im ata a loss

 

I applaud your tenacity on trying to actually find the culprit, as opposed to many who think throwing parts at it will solve their issues.

 

I appreciate it thrashingcows. I know I could externally regulate it or throw a transpo part on the alternator to make it internally regulated but I feel like id just be covering something up. I do dread taping up my harness but it gives me a chance to move some things around ive meaning to for a while. I just wish I could figure out what the heck is going on. I put a new alternator on him about 6 months ago as well as a cps. Their from a regular ol auto parts store but I figure if either one was faulty it would have showed up sooner. Im just thankful for yall guys on this forum. Yall are very knowledgeable and will to help out and thats rare these days. Ive been lookin to this forum for years when I had problems or ideas for the best mods. Just regret I didnt join and start posting sooner. Thank all of yall again. Hopefully we'll get this figured out.

 

Pop that black plastic cover off the back of the PCM 60 pin connector. Look closely at the back of the connector (where the wires go in) and you will see that at the beginning and end of each row of terminals, there is a number cast into the plastic that represents the number of that terminal.

 

Copy. It was getting dark and I couldnt see very well but with the help of a flashlight and the diagram jmartin sent me I got it figured out. I was counting them correctly. Everything checked out good but hes still surging and overcharging.

 

How can you tell the difference between battery voltage and battery voltage -1v with a test light?

Likewise, how can you tell the difference between 0v and 0.8v on a ground pin with a test light?

That's the sort of fault you're looking for. You need a meter.

 

Its all I had at the moment chief. I plan on putting a meter on them tomorrow. Will post results.

 

Well I put a multimeter on him.
Key off pin 3- 12.03
key on pin 9- 11.00
At idle pin 3- 14.30
pin 9- 13.12
pin 57- 14.33
grounds at idle
Pin 5- 6.10
Pin 11- 5.10
Pin 12- 5.10
Pin 51- 0.87
Tested ohms as well key off
Pin 5- 4.10 ohms
Pin 11- 4.10 ohms
Pin 12- 3.90 ohms
Pin 51- 72.00 ohms

 

Also I took the alternator to get bench tested and its functioning perfectly

 

If that's volts, your grounds are way bad. If it's millivolts (mv), then it's about normal.

If your ohmmeter is correct, your grounds are way bad. To check, shorting the leads together should get you 0 ohms, or very close.

Pin 57 is about normal. You're measuring the collector of a transistor driving the relay coil. With grounds at 5.1, I would have expected about 6, though. It's possible that between measurements the grounds got good.

I think you documented an intermittent PCM power ground, which is what everybody here has been suspecting all along.

 

Its volts and all is correct. My meter was shot so I had to buy a new one. Which grounds should I check. Battery to block. Battery to body. Alternator to block.

 

How would I resolve intermittent pcm ground