Engine/Transmission (1998.5 - 2002) Truck faulters and sometimes quits--HELP

[fox]

I need some advice, if you have seen this.

It shudders at idle sometimes, and will quit running down the road.

I thought I had a bad APPS but that didn't fix it.

This AM it quit and I noticed fuel pressure fell as it happened. After it sat for 2-3 minutes the fuel pump ran again and it restarted, so I could get off the interstate.

It is agrivating.

Of course the tach falls too.

I'm going to find and watch the 12volts to the VP next to see if it is dropping out.

Anyone with advice?

 

[HBarlow]

The symptoms you described are not related to APPS problems. The APPS is nothing more than an electrical link between your accelerator pedal and injection pump.

Is it setting any codes? I never experienced a VP-44 failure but I did have one transfer pump fail. I recognized it when it failed to respond to throttle input in third gear.

I would be suspicious of magic black boxes. They can fail and can create strange symptoms when they do. I would try removing them for awhile and watch for symptoms.

 

[fox]

I get codes 1691, 370, and 1693.

I know code 370 is air conditioning, which is intermitent. 1693 is the companion code.

I was just working on it and there is no B+ on pin 1 of the apps. This should be 12 volts, right?

Pin 11 on the ECM is also dead. I would not expect it to run without this 12 volts. But it does.

It will faulter at idle, and drops out of power, like lifting the right foot at speed.

 

[PatrickWilson]

Oh man a 1691. That is one of the famed death codes of the VP.

I. E. : P1691 Fuel Injection Pump Controller Calibration Error Internal fuel injection pump failure. Low power, engine derated, or engine stops.

 

[HBarlow]

Sounds like you've just become a VP-44 shopper.

 

[fox]

Update.



Yesterday, I took the fuel filter housing loose to get to the wires on the ECM.

This morning it turned on the water in fuel light!!

Anyone want to buy 36 gallons of---eggnog????

That is what it looks like.

I saved some so it can settle out and it definitely has water.

Now, it has been acting up since thanksgiving, and I for some dumb reason, bought fuel at different places.

I'm still curoius of the code set, so maybe it has two problems. ( most likey)

It ran good today on a short trip. I've been draining the filter until the light goes out and it comes on again with-in 2-3 minutes.

Time to hot wire my lift pump and get it all out, and put it new GOOD diesel.

BTW, the WIF light hasn'r been on for years.