VP died last night

[dripley]

Starter going out? Same thing mine did when it went. How old is ti?

Edited September 27, 2015 by dripley

[ronman]

No, the starter is not going out. It's a little over 3 years old and has a contact kit in it.

Not that that makes any difference, because the fact the fuel pump isn't running means there is something else going on.

Edited September 27, 2015 by ronman

[Hawkez]

Battery terminals?

[Mopar1973Man]

No, the starter is not going out. It's a little over 3 years old and has a contact kit in it.

Not that that makes any difference, because the fact the fuel pump isn't running means there is something else going on.

 

Again... Alternator noise damage. MOSFET's that control the lift pump circuit are damaged. Take notice there is 2 white/yellow wire powering the lift pump directly from the ECM.

 

0.07 is not exactly good...

 

0.01 to 0.03 is normal.

 

0.05 is marginal...

 

0.10 is failed...

[ronman]

You yourself say 0.1 is the limit in this article. Now you're saying 30% lower than that is too much?
So what am I to do, order a half dozen alternators from every parts house in town, buy them all, install them, test them, and play a neverending round-robin game of alternator returns? I drove almost 80 miles the other day chasing down every alternator in the metro Orlando area. Only one of them came anywhere close to your numbers - and that's the one I bought. And it tests "OK" on the testing rig at the parts store that they use to approve/deny warranty, so what's your suggestion? Suck up the $130 alternator that's "OK" and go buy another one? Because they aren't going to take it back as failed unless it tests so, and there aren't any others available for a couple days...

 

The truck started, twice, and cranked/cycled the fuel pump more than 10 times while I was priming the new VP44. It has cranked over every single time I've turned the key for the last 9 years and 170,000 miles. So to make sure I'm on the same page, the old, OEM alternator that measured 3.4VAC ripple allowed this to happen, and the new, remanufactured one that tests at 0.07VAC ripple is what's causing it not to (except when it does?)

 

Or are you suggesting that the ECM is now somehow compromised?

 

Forgive me if I'm slightly incredulous, but something does not add up to me.

[ronman]

And to the failed ECM point, would a failed ECM still illuminate the WTS light? Would it still show codes?

[dripley]

I dont know that your ECM has failed. When mine failed it showed so many codes I got writers cramp. No code for the ECM being bad. The WTS worked and so did the fuel pump. 

[ronman]

Correction: fuel pump runs for ~1sec when I turn the key.

[98whitelightnin]

I had a shop in Tampa rebuild my oe alternator for $99 a few years ago. My buddy is fighting this right now, had to go down to winter haven Friday night to pick his truck up. Got there and it started but and died about 10 times while trying to load it on the trailer. Batteries went dead and the air dog wasn't working right. It would either not come on or come on and pump up about 5 psi or jump up to 20 and the truck would fire, run long enough to slam it in gear and drive 2 ft. He is getting a 1689 code but we haven't torn into it yet to figure anything out.

Edited September 27, 2015 by 98whitelightnin

[Mopar1973Man]

You yourself say 0.1 is the limit in this article. Now you're saying 30% lower than that is too much?

 

Thing is there is no absolute number. 0.1 is for sure damaging. As for normal is 0.01 to 0.03 on average. Some weird problem reported near the 0.05 mark but random in nature. Thing is the more and more I talk to people the more I keep learning and trying to narrow down. The biggest thing is unhooking and test driving with a alternator wired in usually test if it failed out not. The strange then is I've seen some fail as low as 0.05. Now is that because of poor testing, junk digital meter, or human error?

[dripley]

Correction: fuel pump runs for ~1sec when I turn the key.

at least the lift pump is acting normal.

[JAG1]

Better ground connection from alternator to battery will help reduce some AC noise. As does having good grounding thru out the rest of the truck helps.

 

  I tested my alternator ground since it grounds only thru the engine mounting bracket  and found a lot of resistance. I guess due to the painted coating on the bracket.

 

Disconnect the batteries and check with an ohm meter between the negative battery clamp and alternator housing. That's how I found a bad grounding there.

 

I ran a separate ground wire from back of alternator housing to neg battery post . I believe  a separate alternator ground wire is a good thing.... since its kind of like mike fighting forest fires.

[ronman]

It starts right away if I jump the small terminal on the starter to +12V. So I've got a 3' wire with an alligator clip run down there until I get some time to get it in the garage and actually troubleshoot it...

[Mopar1973Man]

Starter circuit is pretty simple. The starter relay powers the Brown wire going down there so I'm going to say either the relay, fuse, or weak connection.

 

[ronman]

On ‎9‎/‎22‎/‎2015‎ ‎10‎:‎56‎:‎38‎, Mopar1973Man said:

 

Yeah... I say you found it. This one was just as bad at about 3 VAC... As you can see the diodes are well cooked. Increasing the size of the alternator may just increase the failure. As amperage goes up so does the heat on the diodes so make sure the diodes are rated even higher than the 200 amps other than that you just going to cook them quicker. Also remember to increase your gauge of wire from the alternator stock wire is only marginal good enough for the full 140 Amps.

 

Watts (Heat) = Voltage (13.5 to 14.5) x Amperage

 

As more amperage means more heat...

 

That's the diode pack from my 2.53V alternator...

 

Edited November 1, 2015 by ronman

[Dieselfuture]

On September 27, 2015 at 8:29:49 AM, Mopar1973Man said:

 

Thing is there is no absolute number. 0.1 is for sure damaging. As for normal is 0.01 to 0.03 on average. Some weird problem reported near the 0.05 mark but random in nature. Thing is the more and more I talk to people the more I keep learning and trying to narrow down. The biggest thing is unhooking and test driving with a alternator wired in usually test if it failed out not. The strange then is I've seen some fail as low as 0.05. Now is that because of poor testing, junk digital meter, or human error?

When you do this AC test, do you check it at idle or do you rev it up? At idle after rebuilding mine I'm at 0.02-0.03 and if I rev it up I can hit 0.1 at about 2200 rpm

[Mopar1973Man]

Then now time to unhook the alternator and retest if the problem goes away the alternator has failed.

The truth is the best diagnostic tool for this is a O-scope... Most people are not going to want to buy one.

http://www.ebay.com/bhp/automotive-oscilloscope