1995 6.5- engine shuts off for split second at highway speeds

[ccole]

Hello all- I have had this happen a couple of times now and cannot figure out what is going on here. While driving at highway speeds in my 1995 6.5 non-turbo, the engine will shut off for a split second while driving. None of the electrical instruments (radio, gauges, etc) shut off or anything like that, only the engine (and its just for a split second). It almost like a gasser pickup that just misses or "cuts-out" for a split second. It doesnt do it real often; approximently 4 times on a 30 mile highway drive the other day. But, it does seem to be gettting worse. Any suggestions?

One thing to note... I am on the fire department and had a call that required speeds of 80 mph for about 5 miles. After speeding at 80 mph and then slowing down, it really acted up for a while. Also seems like it running short on fuel or something?? The fuel filter was replaced about 200 miles ago and the electric fuel pump really seems to pump lots of fuel when bypasses for "constant on" for testing purposes. Any suggestions and thank you!!

[ccole]

anybody have any clue/suggestions on this? Thank you!

[moondoggie]

Good Day!

Random cutting out is often due to the FSD / PMD. Do some searches - this has been covered extensively. Basically, a dying FSD / PMD almost never throws a code.

If it feels like a gasser with an ignition miss, especially under load, that's often the lift pump system. With the engine idling, open the drain valve (bolted to the 'stat housing on my 95s). Fuel should come out the drain tube rapidly. If not, & the engine kills, the OPS isn't feeding power to the lift pump when the engine's running (likely), or the lift pump has failed (certainly possible).

Good Luck & Blessings!

[JohnC]

Don't know if this is the same or not, but my '95 used to do something I would describe the same way. It wasn't violent, just like a momentary missfire. I never did get to the bottom of it, although I had a big list of things it wasn't (PCM, lift pump, PMD, OPS...). One thing I did not try was removing the optical filter. I also captured some data from the scanner once that lead me to believe that the TCC might be disengaging for a brief moment then re-engaging.

Good luck! ;)

[tommac95]

I have experienced this as result of fuel filter needing cleaning/replacement.

I think the FSD/PMD stays open long , but cannot provide enough fuel for smooth run.
In my case , i was slothlike/lazy ... the symptom ocurred during two periods when i had failed to renew the fuel filter after a year of ca 18000 miles. I may now use this as an indicator to swap filter. Each time i refused to service the filter until my max speed dropped to 50mph. [terrible to admit!] Fortunately i have redundant series filtration. Much of the problem was a globule {circa a shotglass volume} of algal crud/glop [non-biologist groping for descriptors] which normally hung out below/outside the primary filter , but got accelerated onto the exterior of the filter at speed , especially over bumpy roadway. To my miserable credit i dismantled the filter hsg and cleaned off the glop last summer , after it slowed my progress the second time.

Suggest check fuel filter ....

[moondoggie]

Good Day!

Good grief, I forgot my own advice: If a diesel is doing anything wrong, change the fuel filter 1st. Thanks for bringing this up. Even if it doesn't fix his problem, you really can't hurt anything changing the fuel filter. (Well, sure, you can of course, but you sure don't want to avoid changing the fuel filter because something might go wrong; better to gain knowledge of & experience in changing it.)


Blessings!
(signature in previous post)

[ccole]

Thank you all for the info. I think I will start with the simple stuff as suggested, such as the fuel filter. I also have a new lift pump I purchased awhile back and think I will put in on as well for precautionary reasons. Thank you again!