First off ill start with a few things about my truck, and then tell you about my ride home. 1999 K2500. 6.5L 4l80e 280,000 miles. It has a relocated PMD (looks like a cheap ebay kit). I just replaced the fuel filter and air filter within the past few weeks. It has recently dropped below 30 degrees at night here in Michigan. The other morning, i woke up to drive it to work. Cranked over, and started fine. Drove a few miles to the expressway, got on, and took that the 15 minutes to work. Right before i was about to get off the highway, i had to slow down to let someone merge on. Once they we're ahead of me, i pushed the accelerator, and there was nothing, pushed a little harder, and it revved up and got me to work. I didn't really think anything of it except the cold. Few days pass, drove to work and back fine, school and back, also fine. This morning drove it to work, no problems either. But on my way home from work i had a similar problem. This time, i was off the highway, and sitting at a red light. As soon as the light went green, i tried to accelerate, and there was nothing. A little more gas, and she revved up and took off. Did this at every light till i got home. I have new glow plugs in the mail, even though i do not expect these to be the problem. By the time i notice it doing it, it is at operating temp. Water temp about 160 or so. Boost gauge isnt hooked up yet either. It hasnt stalled yet, so i dont believe it to be the PMD, but i am not ruling it out. My next suspicions are the lift pump, or air/water in the fuel lines. WHat do you all think? My diesel knowledge is limited, and its pitch black out so can not really troubleshoot right now.

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Checked the top radiator hose this morning when i started it. It was not stiff, so i dont believe this to be a head issue. It drove great to school today though. I guess well see what happens on the ride home.

 

just an idea, it might be the peddle. Have a dead spot in it. does it rev up fine in park or when its cold?

 

Whn it happened yesterday, it would not rev up in park either. But it drove great today for the most part (get to that in a minute) When i pushed the peddle, there was nothing, didnt bog down, so fuel wasnt flooding in. Im guessing lift pump is getting tempermental.

Now onto todays incident. drove great to school. In between classes took a drive to parts masters to see if they had a lift pump. They didnt so i decided to take a drive to advance auto. While waiting in the parts masters drive to pull out, it stalled. Threw it in park and she fired right back up. Drove it straight to advance, and bought a new PMD, since ive heard stalling starts small, and gets worse. After installing that, havent had a problem. In class now, but will report about my ride home


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My 2cents worth I am preety sure its not a lift pump issue a bad lift pump would cause bucking and jerking I had a problem with random stalling here a while back and I decided to put a new CPS in after getting advice from another 6.5 owner now here is my advice on a replacement CPS get one from NAPA or get a AC/DELCO CPS do not get a BWD brand as these are a inferior product and not worth a damn I would try the CPS first as a new they are about a hundred bucks cheaper than a PMD BTW since replacing my CPS I have not stalled at all

 

I was hoping you would chime in Mayhem, ive been reading around the site and can tell your very knowledgeable about the 6.5L. Did u have any throttle issues before the stalling occured?

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well I had a really noticable stutter before replacing the CPS I made the mistake of replacing the PPS $250 &S+H first still had a stutering issue and radom stalling once it stalled with a 10,000+ load of pipe on a trailer with no trailer brakes let me tell you that was the moment I knew that had to be fixed imediatley,I also have learned that some symptoms of PMD failure include cruise control not working,runaway throttle,and last but not least no start at all

 

By PPS you are referring to the Pedal Position Sensor? I understood by CPS you ment crank position sensor so ill go get that tomorrow if they have it instock. And yea, in regards to the PMD, ive heard a few different things, that vary by the make of the PMD. I heard that the runaway throttle was a common issue with the Flight Brand PMD. And stalling was normally seen in the black Stanadyne PMD's. The only reason i changed it, was i read that the stalling can start off small. Like the first time it stalls, it will start up right away (like what happened to me) and then will eventually get to the point where it will not start up again. I am not really experiencing any bucking or anything like that at any speed.

I should add, Ive been talking to Leroy over at PMDcable.com. He believes it to be a fuel issue, and to start off by checking the PSI at my Liftpump. Which i will try and figure how to do tomorrow. He also reccommened sparying compressed air in the line back to the tank to clean off the 'sock'... I will also try this. If i am not getting good psi from the Lift pump, i believe i will upgrade to the Walbro lift pump and Wix pre-filter that pmdcable sells. Hopefully someone else will be able to chime in.

 

yes PPS=Pedal position sensor yeah it would'nt hurt to clean out the sock or even replace it all together especially if you have been running any bioblended diesel and if i was you i would consider running 2 stroke oil in with you're fuel this will extend the life of the IP myself I run 1 ounce of oil per gallon of fuel others seem to be content with a 1/2 per gallon

 

May i ask what year your truck was? What im reading is that the acceleration pedal position sensor consist of 3 different sensors. If any of them fail, it should throw a code. Did you have a code? My check engine light is not on. And right now i add Diesel 911 to my tank. I think i might have added it a bit strong last time, do you think that would have anything to do with it? Another thing i noticed, is before under hard acceleration, i would get some black smoke. Now, even if my truck seems to be running normal, i dont get any smoke at all. What that shows to me, is it is not getting as much fuel as it used to.

Edit: Sorry to ask so many question, but really have no one else to go to other than a shop, as my knowledge is limited. But do i need to drop the tank to get the sock off? If i do go with the Walbro lift pump, and wix pre-filter, i can just take the sock off correct?

 

My 2500 is a 1994 and in the last year I havent added more than a quart of diesel 911 to my fuel but I usually get my fuel at the same place all the time and it is straight diesel that they sell no fuel issues as of yet had a issue a little over a year ago when filling up at a walmart fuel center realized they had the bioblend havent used it since and as far as black smoke goes if you have astock set up a 6.5 wont smoke much if at all I have a #9 resistor and on hard acceleration I get a little smoke at first untill the turbo catches up will fix that though next spring when I put a C7 catapillar turbo on along with new exhaust manifolds and new injectors allready have a green tag IP with less than 20k on it unless I get a Duramax before thenif I do that I will sell the Jolly Green GiantBut who knows it has been a geat truck and it would be hard to get rid of