long hard starts & frustrated still

[canada cold]

I am still frustrated on my problem of long starts. Vehicle is a 94 Chev van with 6.5 non turbo and it turns over about 20-30 times before starting. It it parked in a garage at 65 degreas so it it not a fuel gel problem. It has about 130,00 miles on it. A new injector pump last year, a new lift pump, new glow plugs. Took it to a gm dealer and they cannot find the problem. Took it to a diesel injection technician and they could not find the problem and they tried a new PDM at that did not cure the problem. Took it to another gm dealer and they checked the glow plug relay and it is okay. They checked the fuel pressure and it is okay. No obstructions in the fuel lines and return lines are okay. Cleaned all the battery cables positive and negative and all ground straps to the body and frame, still no change. So after spending about $500 dollars on dealers to tell me they dont know whats wrong I am at my wits end. So if anybody knows or has had this problem please let me know. Yes it also has a new fuel filter. Only codes are fuel pedal and gm says it is not related to long starts.

[dieseldummy]

Have you checked the compression? Some morning you may go out to start your vehichle and it just wont start no matter how long you crank on it, because it doesn't build up enough compression. Just an idea, I had a friend that this happened to.
Good luck,

Justin

[DAVE FERENCZ]

What kind of cranking speed does your starter give you. Sounds like the solenoid on starter is going. The engine turns over but not fast enough.

[kowsoc]

Check the time that the glow plugs are energized when engine is cold and post again. I've got a feeling that the time is too short. The coolant sensor and PCM control the time.

[canada cold]

to answer your questions the starter is turning over fast enough. The glow plugs are cycling about 10-12 seconds and the relay has been tested and it is okay. As compression i have yet to have it tested but the engine has all kinds of power once it starts. I would like to blame it on the PCM but there is no way to test them other than to replace it with a new one for another $150. Still cannot figure out what the problem is so I hope it does not quit as next week were off to Bike Week in Florida.

[12volt-dc]

it sounds to me it could your fuel is draining back to the fuel tank when you turn the motor off. 12volt-dc

[eracers999]

Try this;
Locate the fuel pump relay on the fire wall.
Pull the plug out from the bottom, as you are looking at the plug in the same position as it came out take a paper clip and jump from top row center to bottom left corner, at this time you will hear the fuel lift pump run.
Crack the bleeder on the filter.
Is there any air ???
If so bleed it out.
If not good.
Now jump in it and go through your normal starting procedure. Yes with the paper clip still in place.
What was the result???
When you get it started pull the paper clip out and plug the relay back in.
Take a test light, drop out the fuse holder for the fuel lift pump you should have power on both sides of the fuse.
Do you???
If not the oil pressure switch is suspect.
To help you out futher you will need to perform these simple tests.
Drop me a line if needed.
Kent 8166515893

[turbobill]

Are the glow plugs good? (all 8). Just because the relay is working doesn't mean that current is getting to the plugs or that the plugs are themselves working.

Have you resistance checked each plug?

[canada cold]

Kent thanks for you input but this vehicle has a mechanical lift pump which is brand new and I have lots of fuel pressure at the fuel filter. In reply to the other message all of the glow plugs are brand new last week. As for the oil pressure switch I tested it and it is fine. So I am still in the same delema Long starts

[eracers999]

Canada Cold;
What fuel filter set up are you running with the mech lift pump.
Still have got to eliminate air in fuel.
Crank engine 5 sec and crack the last fuel line before it feeds the injector pump.
Is it straight fuel or does it have air and fuel??
Next thing.
The fuel fitting that comes out of the injector pump in front, it has a rubber hose attached to it and is connected to the fuel return lines, take that fitting out and tap it on a solid surface over a white sheet of paper.
What did you get out of it??
That fitting is a one way check valve, when its open it will look like its clear through the middle, but its not it has a disk in the middle of it.
If this fitting isnt working properly it will cause symptoms of this nature.
Gotta go.
Keep us posted

[ucdavis]

So to sum up:
You've eliminated air blockage somehow (didn't say how but that was in the earlier thread, so I presume it's checked). Fuel is getting to the DS4 IP in sufficient quantity, & filtering is checked and rig is in a warm environ so fuel is sufficient quality. FSO was discussed in earlier thread & you can feel the click when solenoid bumps open @ key-on so solenoid is allowing fuel into DS4. You're not getting a but-load of white smoke on start-up (my presumption again as it was discussed earlier) so you are not getting over-fueled (if you are, badly worn injectors could contribute to this trouble, especially if IP changed recently & you've got original injectors w/130k on 'em). The only thing left for a diesel to run is actual injection of fuel into the cylinder (no?). So its gotta be instruction of the PCM to IP.
The PCM rarely fails, but it happens.
MUCH more often is bad wiring (rubbed wire or corroded/loose ground). The black ground on top of IP gives ground for FSD signal; try duplicating it by tapping a new one from top of IP (use another of the torx screws) & grounding it to the frame to a newly scrubbed-off spot & make sure it's zero resistance to the neg terminal on batt. That's easy to do & quick. If that no workee,
Then I'd go under the dash & start @ the PCM following all ground wires to their termination; you'll need a PCM pin-out diagram for that which (I think) is somewhere in the Helm or GM service manual. This'll be tedious and could take a coupla hours. More than a few here on TDP found ground trouble under the dash & fixed their ignition trouble.
And finally (or maybe it should be firstly since you should fix this anyway as long as you know it is a problem) is the APP. The dealer says it isn't related, but they can't find what is so what good are they? If the PCM is getting garbaged signals from the APP, and that is the source of fuel injection request, maybe the PCM is fighting bad input to get to injection output that makes for ignition. Might not be THE trouble, but you know there's something there giving PCM reason for pause. Couldn't hurt.
Good luck. Let us know.

[canada cold]

Thanks again guys for the input.I have tried almost everything the check valve on top of the pump has been replaced and that did not change anything. I took a jumper cable and grounded the motor directly to the battery and still no change. I will run a jumper from the pcm to ground on my next try and see if it makes a difference. As I said I am off to bike week on Saturday and hope I can make it from Canada to Florida with no troubles. Will be in touch on return with any updates.

[Fumes]

I have a 85 GMC Van with a 6.2l, and had a similar problem, but only cold, first start and when sitting outside, in winter.

What I found was where the fuel lines run under the frame on the passenger side there was a shield over the fuel lines and brake line.

When I was doing a oil change I noticed it was "damp" in this area. There was dirt/mud between the shield and frame, so I removed the cover/shield and wire brushed the lines and found pin holes in them, so diesel would slowly seep out of the lines, and let air in them.

Also, which was more scary was the brake line also had a small pinhole in it. I replaced all the lines and this cured my problem.

Hope this might help.

John G

[eracers999]

Canada cold;
I guess after rereading your original post. You say the only codes you have are with the fuel petal.
I would address that problem before doing anything.
What happens if you hold the petal down while you try to start it??
Kent

[canada cold]

Kent I tried holding the pedal down and it did not seem to make much of a diffence but when I pumped the pedal as you would a old gas carburated engine it fired a lot quicker so I presume it may be the accelerator Pedal Positioner So I guess I will have to spend another $150 to replace it and hope it is the problem. Thanks for your input.