Help Please. Cold idle stall

[bluespongebomb]

Have a 94 K3500 4x4, 5 speed, dually. 6.5 Turbo. Have replaced and relocated pmd to front bumper. New ops, lift pump, starter, batteries, and wire filter harness.

Considering either fuel pump shut-off solenoid or crankshaft sensor.

TRUCK STARTS EASILY, BUT DIES WHEN MOTOR IS COLD. OUTSIDE TEMPERATURE DOES NOT MATTER. Usually have to turn key off and then cycle back on. Starts right back up. Does this continually untill you get it going down the road good. Will run all day with no fishbytes, hiccups, anything. Shut it off for a few hours and starts dieing all over again, untill you get it moving good.


PLEASE HELP. LOSING FAITH IN 6.5 TURBO ENGINES.

[JohnC]

Does it slow down and die or cut off like the key was shut off?

Have you verified the lift pump is actually running when it dies?

When was the last time the fuel filter was replaced?

Are there any diagnostic codes stored?

Is the fuel fresh and the right blend for the weather conditions?

Is air getting into the fuel system when it sits?

...

[bluespongebomb]

Yea it just dies like I shut the key off. Usually restarts. Only does this on first cold starts, any weather. If i make it out of my driveway and get rolling, it will not give me any more trouble at all, except for a very occasional fishbyte.

I havent put a gauge in-line of the lift pump to see if it is losing power or not. Sometimes I can hear the pump still running, sometimes not. The ops and lift pump are fairly new. Sometimes I have to turn key off the back on to make the pump kick in again on the start cycle. My truck has a starter solenoid, but someone also installed a 4 post solenoid on the passenger side fender well. Thought maybe it was going bad.

Fuel filter has been changed recently. Brand new Batteries and Brand new High tourqe gear-reduction starter.

DTC Code 35 is only one at present.

Just refilled with fuel on Sunday the 24. Havn't added any additives. Have always just ran store bought fuel. Weather around here has been 20-60'F degrees. This problem has been going on for a while, even during warmer weather.

Unsure if air is getting into fuel system or not. Always fires first time. Will also start immediatly after with no cranking. Always has fuel at the filter housing. How would I check for air in the fuel.

Also put on brand new fuel cap because of the large amount of vaccum in the tank.

All help appreciated.

[mrwilecoyote]

DTC 35 - Injection Pulse Width Error (Time Short)
Sounds like a bad PMD. You say you replaced it ? Where did you buy it ? There's a clown selling"tested " ones on ebay. Junk IMO. I have heard of a bad PMD causing a DTC 35 on rare occasion and your other symptoms point to it. Also how did you relocate it to the bumper ? IN other words how'd you extend the wiring ? The ground wire needs to stay on the pump not get extended. A 94 LP will only run when there is oil pressure. You won't hear it when just turning on the key. Only 96+ OBD!! run the pump for a few seconds after KO.

[bluespongebomb]

Did replace the PMD from SSdiesel supply. Also bought heat sink and extension harness to route it to front bumper. Left original PMD and ground in stock location. I thought the PMD was more likley to fail after being warm. My problems ONLY happen at first time startups. Will run perfect the rest of the day. Pulled 11,200Lbs over the rockies and over rabbit ears pass. Only problem I had was after it had set for SEVERAL hours and cooled back down. Started and died a couple times and then was fine. Drove the 1500 miles back home perfectly. Same problem now runs perfect if I can keep it running long enough to get out of the driveway, and moving down the road.

The lift pump starts pumping on start cyle from starter solenoid, and then once oil pressure builds, powers from the OPS. Is that correct?

Thank you.

[Kennedy]

So the PMD is brand new correct?

I'd look at the ignition switch as a common source of grief on these older trucks, usually transmission grief is the result.

Good luck getting 80HP from 6.5 with a chip :rolleyes:

[mrwilecoyote]

The lift pump starts pumping on start cyle from starter solenoid, and then once oil pressure builds, powers from the OPS. Is that correct?

Thank you.

no. To my knowledge that only occurs in 96+ Trucks with OBDII
You have a 94 with OBD1. It will not run at all with the key on. It will only run when OPS senses oil pressure(A common fail point). You can manually override the OPS by applying power to pin G on the DLC. It should be the bottom row all the way to left.

[JohnC]

Actually, he's right. The lift pump on ODB1 trucks is powered whenever the starter solenoid circuit is energized.

[bluespongebomb]

So pmd faliure can be indicated by a code 35. pmd faliure is more common when engine or pmd is hot. For $300 i would like to be pretty sure it is pmd.
Best place to get a good new one?

Is it not possible to be the crank sensor or fuel shut off solenoid on the ip?
Those are the only two things left to replace I think.

One more "little" fact. The pmd's i have purchased are in fact used pmd's for a lot cheaper price. Sorry, I know. But at time I was troubleshooting a no start, and didn't want to spend to much just to see if it was the little black box. It did fix the no start, at that time. If it is possibly a bad pmd, guess I get to spend a little more money.

[bluespongebomb]

Drove truck to work this morning. Died once in driveway and once at gas station. Ran fine to work. Drove around at work ran fine. Got ready to come home died once in parking lot. Loaded completely down with gravel. Ran good and strong for about 20 miles. The other 6 miles it kept cutting out or fishbyting. Barely made it home. Let it idle in yard. Surged 2 or 3 times and then died. Did start back up, but I turned it off and pulled the codes. Got code 13, 34, and 35 this time.

[rameye]

soon to replace also:

injection pump......

thats the way mine went....rule out the easy stuff , hope for the best..

good news is you get a nice new PMD with your brandy new pump!!

[hayhauler69]

How many miles are on the truck?
You say you never put additives in fuel?
I wonder if the new low sulfur diesel quickened the failure of the suspected injector pump?
I bought a 40 HP chip it helped power out, but it still a 6.5.
I don't think I get 40 horses out of it. I had to send it back to SSD a couple of times to reburn till the truck ran right. It would miss badly at full throttle.
I think the chip was tuned down because my injection pump is wearing also.
But not sure. I'll get a new (rebuilt) pump this year.
Good luck. Hope to hear results.

[scoobysmak]

Well I did a search for replacing ignition switch and didn't find anything. My problem is when I drive for a while and pull of the interstate and fuel up. I take back off and if I need to accelerate in a hurry (or towing my trailer), it seems to misfire (drop a cylinder) unless I let up on the gas pedal. Once I let off it acts normal again but only after driving a few miles can I put the hammer down and not have a problem (sometimes it will do this after driving a while, I do not remember if it was when I was in city traffic or not). My first guess is the great PMD, so I put a KD extension kit and a PMD cooler (I mounted it just in front of the driver, between the inner fender and master cylinder, behind the wind washer fluid with the heat sink fins pointed up and running parallel with the engine. I was shocked how hot this still gets, I can keep my hand on the heat sink but it was rather warm. Besides the front bumper what is the best location to put your extended PMD. I like the bumper idea except if someone backed into my bumper I could be stranded if they hit it hard enough). I have not done extensive testing (one run down the freeway and then stopped to get something to drink , then drove with a heavy foot after to see if I fixed the problem). I did not feel a misfire but driving felt really weird like I had a bent axle or out of balance tire may be a better description (every revolution I would speed up for part and then slow back down, but not like a vibration). This may be due to the wind was gusting at 30 MPH but not sure. I was also told that my ignition switch could be helping my problem so I purchased one. I feel rather dumb but I am guessing I need to remove the steering wheel to replace this. I have inter-mitant wipers, tilt wheel, and if you need more details to help me let me know. I just see a big pain the in the butt but maybe I am wrong, if their is a link to step by step instructions for a 94 it would be appreciated. I have not checked the lift pump or OPS sensor but I would assume it would have this misfire at all times and not just when its hot and I restart it. I got a OPS sensor relay kit and plan to install that some time this week to remove that as a problem. The batteries are just over a month old, I cleaned the ground cables on the passanger side of the block, if there is anything else that may cause a problem like this your input is appreciated.

[93GMCSierra]

Ignition switch is not the key lock and tumbler in the column but rather the electrical switch that is located under the dash mounted on the column you do not need to take off the wheel or mess with the stuff at the top, you might be able to pull it without dropping the column down, but it is easier to remove the 4 bolts that hold the column up and let it hang down a little.

[JohnC]

Sounds like you've got some flakey wiring somewhere. Check out the stalling thread at the top of this forum.

[westport70]

Had exactly the same problem last week. Even bought new pmd checked the lift pump,that was the problem.Good thing though i have a backup pms know.

[bluespongebomb]

Sorry took so long to get back. Havent had time to drive truck. Anyways, one day i walked out to my truck with the cordless hacksaw in hand and chopped off the ol'e muffler. well, wouldn't you know, I have drove that truck for over a month now, with absolulty no stalling, dying, or stumbling. Maybe problem is fixed. Hope so. Truck runs absolutly fine now. Maybe muffler and cat were plugged up enough to restrict the breathing and caused some computer or sensor shutdowns. Cat soon to come off, and new 3" downpipe, 4" exhaust and 5" tip to be installed.
Thanks for the help. People should start and use their own thread, not hijack mine or any one else's.