• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Weird Problem

Hill Top

Hill Top

Active Member
Messages
120
Reaction score
91
Location
Texas
I have a friend who has a 95 with 6.5, he says when driving at times when he lets off accelerator engine races like its trying to run away. I never had this problem myself.
 
ak diesel driver said:
I'm assuming ds4. Could be pmd or the IP is failing.
Click to expand...

Okay yeah it's a 98 not 95. So he's running down the hwy at 70, takes his foot off the accelerator and the RPM's shoot up to 3500 and black smoke, can you explain how IP going bad or pmd? I dont have a pmd on my truck so never experienced problems.
 
Pmd controls the fuel and are known to fail in wot. Is it that way all the time now? Usually they stay in wot mode. IP can break the armature but not necessarily stay in wot.
 
PDM factory location is on side of IP under intake, bad spot... Heat from motor just cooks em.. There is an extension harness, think it's like a 15' section to relocate the PDM. Best place is somewhere it gets lots of air (mounted mine to grill). Best to also carry a spare PDM just in case ya know... I'd look into that to see if PDM is still in or close to stock location, if it's an IP issue then $$$ add up pretty quick...

Sent from my LG-TP260 using Tapatalk
 
ak diesel driver said:
Pmd controls the fuel and are known to fail in wot. Is it that way all the time now? Usually they stay in wot mode. IP can break the armature but not necessarily stay in wot.
Click to expand...
Not sure it stays that way all the time. But sure sounds like the PMD from your explain.
 
It's a poor design from GM... Check into it, If it's in stock, on intake, on side of block, or even on inner fender move it. It's weatherproof so don't worry about it gettin wet or anything.. Can easily mount it with couple 5/16" self-tappin screws... The extension harness is just 2 wires, simple

Sent from my LG-TP260 using Tapatalk
 
Ryanhanson3 said:
PDM factory location is on side of IP under intake, bad spot... Heat from motor just cooks em.. There is an extension harness, think it's like a 15' section to relocate the PDM. Best place is somewhere it gets lots of air (mounted mine to grill). Best to also carry a spare PDM just in case ya know... I'd look into that to see if PDM is still in or close to stock location, if it's an IP issue then $$$ add up pretty quick...

Sent from my LG-TP260 using Tapatalk
Click to expand...
Yeah I already told him to check PMD location. I'll relay your advice as well.
 
Try the 2000rpm test. If you can't hold it steady without the rpm fluctuating most likely it is the IP going bad. If you have the balls and quick reflexes, try the blip test. Blip the throttle pedal about halfway down and release it several times quickly. If the motor takes off with your foot off the pedal and keeps on racing up, SHUT IT OFF! Your IP is shot and has just gone into runaway mode.
 
Check the oil level. Check for other fuels causing engine runaway by getting into the intake. Turbo seals blown for example and high blowby feeding the engine through the CDR.
 
You must log in or register to reply here.
Back
Top