1996 chevy silverado 6.5 td surging and stalling

[bhouldey]

Hi I have a 1996 silverado 6.5 TD with 370,000 on it pmd has been relocated to inner wheel well 3 years ago. truck starts and idles well. during acceleration it randomly surges and stalls and takes 30 seconds or so before it will start back up. then it runs fine for a while and does it again, I have done the lift pump test and i have a steady stream of fuel coming out of the hose attached to the t valve when valve is open frequancy of stalling is getting worse, Any advice would be greatful for any advice thanks Brad

[PrivatePilot]

Moved to 6.5 engine forum.

[racer55]

Stalling is most often PMD related but not always.

A much better location for the PMD is outside the engine bay since temperature swings are a factor for thier longevity.

It may help to get you the right information if you were to copy and paste the diagnostic checklist to your next reply with the appropriate answers filled in and the tests done.

[FloridaHorseman]

Originally Posted by racer55

Stalling is most often PMD related but not always.

A much better location for the PMD is outside the engine bay since temperature swings are a factor for thier longevity...

I've seen all the recommendations for moving the PMD outside the engine bay and understand the reasoning behind them. But I too have mounted the PMD & heat sink on the inner wheel well with good success. It's on a L bracket just under the driver side battery tray, where it gets solid air flow from the fan air deflected off the front of the engine. Even in 90F+ Florida temps I can place my hand on the PMD without getting burned. Make no mistake, it's very warm. Those transistors are whoppers! But I don't like the idea of the PMD connector and the PMD itself being close to road debris and road spray with bumper or grill mounting. 40k and over a year in the wheel well position and so far so good.

And the surging problem suggests to me the IP pistons are becoming worn and not supplying consistent pressure to the injectors. ~FH

[Bison]

Originally Posted by bhouldey

Hi I have a 1996 silverado 6.5 TD with 370,000 on it pmd has been relocated to inner wheel well 3 years ago. truck starts and idles well. during acceleration it randomly surges and stalls and takes 30 seconds or so before it will start back up. then it runs fine for a while and does it again, I have done the lift pump test and i have a steady stream of fuel coming out of the hose attached to the t valve when valve is open frequancy of stalling is getting worse, Any advice would be greatful for any advice thanks Brad

You could've air coming in pre LP.
Do the clear IP return tube.
To be sure adequate fuel reaches the IP,fuel pressure should be taken at the IP inlet.

PMD is always suspect.

[JMJNet]

x3 with PMD. It is always a suspect with any stalling regardless of its location.

Surging is also a sign of something bad with the IP.
Unfortunately, that is an expensive part so we want to eliminate the cheap ones first before condemning the IP.

But check for all other things first like electricals, etc.

Sounds like LP have been tested, which eliminate one issue.