99 6.5 diesel inermittent problem

[RunMonkeyRun]

Hello everyone new here, okay 6.5 gods I am in a state of confusion. I have been having hot start problems for awhile, it doesn't happen all the time but when on a job I am afraid the dam thing won't start, when it does happen I have to wait for the truck to cool down, I have checked to see if the fuel is going threw the IP and it is, so that is that. It has increasingly been getting worse and know finally something has given.

New problem: Well I have to crank the engine for about 10-15 seconds for it to start, when it does start it runs like a piece of crap like it back fires, I fried the positive cable and battery from starting it so many times. I got it running today and took about 10-15 seconds to start and it clunked and sputtered and then idled fine. Let it run and then reved the engine to about 2000rpm a few times, started sputtering and then died again.

I ahve done alot of work in this truck threw machanics and it is killing me, so from reading the post and searching I am thinking it might be the FSD/PMD, the IP is only a year old, all new injectors ruffly a year ago, new waste gate solenode, and much much more crap.

I have the 99 c3500 hd with 495000 klm and 395000 on the engine, why the difference you ask well bought the truck new and the engine went @100,000klm, GM covered the engine under warranty thank goodness.

So wondering where to start? work truck is not making any money sitting and costing me lots of money running hahaha.

Sorry for the long post and thank you for reading it and any input.

Buy the way I get no codes what so ever!!!!

[cnbo4]

I have a 1994 6.5 turbo diesel. Pretty much the same problem. Mine starts when cold and then won't start hot. Let it sit overnight and away we go. Except I can't take it anywhere. So I ordered a new PMD.(By the way the previous owner just replaced it and added a remote mount cooler.)I replaced the oil pressure switch and when the new PMD arrived I took it for a ride. Got home and No Start. Plugged in new PMD and...:o ..NO START.Seems to be pumping fuel from the IP. What gives? Any idea?The only difference from your vehicle is that when mine starts it runs good. Thanks for reading and I hope we can get some advice.

[Robyn]

Hello and welcome
Has the rig tossed any codes (Check engine light)
could be a fuel shut off solenoid but I think its more serious than that.
Has the lift pump (frame mounted electric) been checked for function?
If there has been codes we need to know what they are???? You can get a small inexpensive code reader and get them from the system via the SES light.
Give us some more info if you can and we will proceed from there.
Loads of smiles and a zillion miles
Robyn

[Robyn]

OOOps I see no codes ????????????????/
Well this calls for more drastic measures. One really needs to scan the thing with a OBDII to zero in on the issue

[Beedee]

Check your grounds, you should be able to do a search and find out where they are. I had a problem awhile ago and it was a ground. 1/2 hour with some emery and it hasn't missed a beat since.
Good luck
Brian

[RunMonkeyRun]

Mine was doing the same thing at first, when hot would sometimes not start, it could happen at any time, basically when ever it felt like not starting, would sit for hours until it cooled down. It has only gotten worse and know it fewbarred.

Robyn it has not tossed any codes what so ever, lift pump was changed a year ago aswell, grounds all have been checked even changed the starter for the 5 time in a year and a half, and the machanice clean averything including all glow plugs, what is a good laugh after spendin $1300 doing all this the negative cable for the driver side battery was barely bolted on, changed the waste gate solenoide a year ago and sure enough changed in may, ya so lets say Iam pissed off a tad, no alot actually. Maybe I should test the lift pump? now I need to learn how to do that becasue quite frankly I am tired of getting ripped off!

[Robyn]

The lift pump is down on the frame just about under the drivers butt ( at least on my 94 so its close)
You can test the pump by jumpering the relay in the relay box on the fender and then opening the fuel drain cock on the top front of the engine. Place the little drain hose in a can. You should get a nice free stream of fuel at about 5 psi.
Be sure you dont have a pump relay issue. If your lift pump is not running the rig will start (usually) but can display many poor running symptoms.
You can do the pump check with the engine off, Or you can open the drain cock with the engine idleing. If the lift pump is not working there will be no delivery of fuel and the engine will most likely die as it is depending on the internal pump in the IP to do all the work which it was never designed to do.
OH no to be redundant but what about the fuel filter?
Let us know what you get.
Robyn

[RunMonkeyRun]

I have changed the fuel filter about 2-3 weeks ago. I will check the lift pump, mind you to see if it starts is one thing now!

[RunMonkeyRun]

If I turn the key to the on position would that also get the lift pump working? to see if anypressure is coming out of the tube.

[JohnC]

The DB2 pumps are known for hot start problems when the head/rotor wears out around 125K miles. Not a real issue with the DS4 pumps, but that could be due to the fact that they usually die for other reasons. If the pump is high miles, it may have trouble making pop pressure when hot. Sometimes thickening up the fuel with a quart or 2 of 2-stroke oil will mask the problem: a good diagnostic tool.

[RunMonkeyRun]

Fuel comes out of the pea-cock are whatever you call, I tryied starting it and it almost went but still no go, the ip pump maybe has 80000 klm on it.

I was just looking at all my grounds and everything seems good. Personally how the hell can you see where the harness is on the fsd/pmd? the only thing I see looking at the fsd is a ground wire coming up and mounting on the pump. Is there different types of 6.5, and if so how can I tell what one it is?

At this point I am ready to give up and scrap the dam thing, I have never changed the cdr on it but dam I get alot of blow by, possibley another issue.

My head hurts again just thinking about it.