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]

 

[Baja_Bob]

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?

The alternator produces AC voltage, the rectifier in the alternator turns it to DC volts that the vehicle uses. If the rectifier was bad it would send AC voltage into the battery and vehicle systems. If you get 13-15v DC output from the alternator, it works properly.

I don't mean to add any more confusion to your original problem.

 

[treehan77]

Have you actually load tested the battery or had it checked?

 

[Moosemoon]

The alternator produces AC voltage, the rectifier in the alternator turns it to DC volts that the vehicle uses. If the rectifier was bad it would send AC voltage into the battery and vehicle systems. If you get 13-15v DC output from the alternator, it works properly.

I don't mean to add any more confusion to your original problem.

No added confusion. Additional explanation is welcomed and in my case often necessary. Based on that alternator is good - doing it’s job.

 

[Moosemoon]

Have you actually load tested the battery or had it checked?

Have tested battery thru my scanner - it does more than report DTCs. No starting issues. Lights strong when just running off battery. Think that part is good.

 

[Moosemoon]

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

Did not get to this today. Will post when I do.

 

[Moosemoon]

Could a faulty crankshaft sensor lead to getting the knock sensor code? I would think crankshaft sensor would have it’s own code but just thought I’d throw that to those who know waaaay more than I do.

 

[treehan77]

I would be questioning the knock sensors since that is the code you are getting. It is recommended to change the brittle harness when they are replaced.

 

[treehan77]

You can at least check each one for resistance with your multimeter. You can do a rudimentary function check since they should create AC voltage also. Maybe your meter has a “remember peak” setting and you can test each sensor and compare. Keep in mind your results could be the knock sensor itself or the harness could be bad

 

[Moosemoon]

I would be questioning the knock sensors since that is the code you are getting. It is recommended to change the brittle harness when they are replaced.

The harness was replaced with the knock sensors. One set o’reilly; latest AC Delco .Dealer says they are working. There are other codes suggesting some electrical issues and now the radio will not turn on. Instrument panel light is dim - brightened once when I hit just the right bump.

HOWEVER, I’ve read that 50% of ac delco sensors are also bad out of the box. Have no idea if mechanic(s) tested ks before closing up and hoping for the best.

 

[Moosemoon]

You can at least check each one for resistance with your multimeter. You can do a rudimentary function check since they should create AC voltage also. Maybe your meter has a “remember peak” setting and you can test each sensor and compare. Keep in mind your results could be the knock sensor itself or the harness could be bad

I watched that video this morning. But cold, windy, and snowing here so that adventure will have to wait for a warmer day.