Electrical - where to begin

[Moosemoon]

Thanks. I am using Power Probe ECT 3000. I have a DMM as well.
However - the ‘shorts’ are totally my user error
Going to try again later today.

Yes I have really good diagrams and legends for the fuse boxes.

 

[Moosemoon]

We have checked some grounds and I think I have a ’friendly’ diagram to check others. Will lift the fuse box today to check connections to PCM.
Also putting the scanner on it later.
Dealer says knock sensors functioning as they should Even though still getting P0332 code - that’s why we are chasing elec.
Not quite up to pulling the alternator yet to test the rectifier (as I understand it - the rectifier is made up of 3 diodes). Auto parts store couldn’t test it.
Indeed, this guy could have attached a ground incorrectly. After 1 year and 23 months, during the coldest darkest time of our Idaho winter, it seems he threw it together to get some $ in his pocket. I picked up the mess at 24 months.

 

[S33k3r]

I don't know what your money situation is like, but if it is okay, buy a replacement alternator and swap them. If that doesn't fix anything, return it.

 

[Moosemoon]

I don't know what your money situation is like, but if it is okay, buy a replacement alternator and swap them. If that doesn't fix anything, return it.

Yeah - probably not throwing parts at it just yet. Rather try to do a bench test on the alternator. Thanks for the thought, though.

 

[Moosemoon]

Did not need to lift fuse box. Duh. Anyway, checked the connections and what we could see of the harnesses. The terminals were clean and pins straight. Harnesses are dirty, but wires show no clear damage - but?

Alternator tests good with scanner - but it only tests charging. Will see if rectifier can be tested while in truck.

Fuses are all to be good.
A.I.R. fuse not present.
O2 sensor test with scanner tests rich but I don’t know how to interpret the numbers. Exhaust smells really bad and truck seems to be guzzling gas.

The engine bay looks very clean - the only place where there was some paint overspray was electrically fine. I can find no corroded connections to ‘play’ with.

Dealer appt. 9 May. Am continuing to note other things that need fixing. Told service rep that there would be a long list….

Thanks for all your help. Will keep you posted as the adventure continues.

 

[Fless]

If you want to, take a look in your scanner for the short- and long-term fuel trims (STFT, LTFT) for both banks. Post up all 4 values at warm idle, then also at 1500-2000 rpm.

 

[Baja_Bob]

The voltage regulator and rectifier are built into the alternator, there is info online on how to check them, if either one was bad you wouldn't get the correct voltage output, do you still use the factory battery cables? Being that old they could look fine on the outside but be corroded on the inside, a bad ground cable could also cause problems.

 

[Moosemoon]

If you want to, take a look in your scanner for the short- and long-term fuel trims (STFT, LTFT) for both banks. Post up all 4 values at warm idle, then also at 1500-2000 rpm.

will try to do that today. Last decent day before more snow and many chores to do….

 

[Moosemoon]

The voltage regulator and rectifier are built into the alternator, there is info online on how to check them, if either one was bad you wouldn't get the correct voltage output, do you still use the factory battery cables? Being that old they could look fine on the outside but be corroded on the inside, a bad ground cable could also cause problems.

If I understand you correctly, if the rectifier in the alternator is leaking ac then it won’t be supplying enough voltage to charge the battery?
I don’t think the cables are original and they appear fine but I will check them more closely today.

 

[Moosemoon]