engine cutting out

[legacyelectric]

Hi
My 1997 3500 with 212000 miles on it is cutting out when driving?
Let's see how can I describe it.
When driving and giving it the throttle all is fine response is good, however when the truck is leveling out and it is not accelerating it just cuts out, almost like you just shut off the engine, I don't hear the spool of the turbo anymore at that point either.

And if I leave the pedal right were it was it will pick back up and turbo spools up again and we accelerate again (truck is real jerky in a nut shell)
The truck was stalling and dying a few hundred miles ago, it took me a while to realize (from this fourm) I needed to change out my pmd.

I put an old pmd on I had from when I bought a remote cooler from ssdiesel supply. About 35,000 miles ago the injection pump was replaced and new pmd put on the remote cooler at that time.

So now as I talk about the problem I think it is either 1. pmd 2. injection pump 3. APP Sensor (Accelerator Pedel Position Sensor)
What do you guys think?

[Robyn]

Are you getting any Codes?

If no codes popping up then I am suspect of the fuel supply or possibly air getting in under load.

Make sure your lift pump is providing a good supply of fuel at no less than 1 PSI when running.

You should have fuel pressure at the IP of about 4 PSI with the engine idleing.

A dying or weak lift pump can cause a shortage of fuel and lead to power fall off and stalling.

You can install a clear plastic tube in the return line from the IP and run it up past the wipers so you can watch it.

Run the rig and clear the air out of the tube (From the install) and then the tube should stay air free when the engine is running.

If you see a stream of bubbles coming through under operating conditions then you need to trace out the source.

There is a bypass valve in the tank pickup tube that will allow fuel to enter if the sock becomes plugged. This valve will only work down to about 1/3 to 1/4 tank of fuel and then it will allow air to enter as the level drops.

Air in small amounts will driver these things crazy. (and you too ):D

If there are codes present we need to address those issues first.

Keep us posted

Best

Robyn

[legacyelectric]

Thanks Robyen
No codes are being set and I have a fuel pressure guage, pressure is good 4lbs at idle. I'll try the clear return line for air.


Thanks for the tips

Larry

[chevy1988]

Than the the 3 you metioned... Have problem with my van that has an 6.5L drivetrain from -94, so i have done a bit of research.

PMD, by the way is best of placed on a cooler that can be bougt as an aftermarket product with a 6foot harnes that makes it possible to place it for example behind the bumper or behind the frontgrill... PMD does not take heat for a very long time before failure. If you live in a very hot region you might even add a 12Volt-fan that constantly feeds tha coolerunit :rolleyes:

Another annoying detail in the pump that often fails is the optical sensor, how to change that is described on this page by an Norwegian guy:

http://www.mamut.net/royh/newsdet9.htm

Furtermore some other things, water in fuel(drain the tank until only clean diesel comes out). clogged fuelfilter... Allso check the electric system voltage (should be somewhere arround 14-14.5 Volts) and that there is no alternating current that might be the case if the diodes in the alternator is shorted out, might get help from a workshop for this. faulty alternator might burn out electronics like the PMD.

Sorry for the long answer and if the spelling os a bit off(I'm swedish)

Regards
Thomas

[KallyI]

See the thread I started a while ago.

http://www.thedieselpageforums.com/tdpforum/showthread.php?t=31123

I haven't driven it since my last post, but I assume it's still doing it.

[Beedee]

Check your grounds, they can cause all kinds of problems.

[legacyelectric]

Today I took the vac hose off the turbo modulator, and the truck doesn't jerk (fish bite) anymore but of course I don't have as much power and it really blows black smoke if I get on it.

What do you think now

Larry