I’ve been having a “hard start” problem with my ’02 Duramax since March. I had the problem and assumed it to be a problem with my filter, so I replaced the filter, but still had difficulty getting it started until I hit it with a quick shot of ether, at which point it started right up. Unfortunately, the problem continued, so I took it to the local dealer, but they were unable to diagnose the problem within a few days. I needed the p/u, so I told them to put it back together and I’d bring it back after the w/e. When I picked it up, it worked fine for a few weeks before the problem started again.

The actual problem is that the truck HAS started fine when it is cool, i.e. in the mornings, or after it rests for a couple of hours, but after driving for 15-20 minutes, it won’t start without either waiting for it to cool, or giving it a quick shot of starter fluid. I took it to another dealer across town last week, and they diagnosed it as an injector problem, and replaced all eight injectors under warranty. I picked it up Friday, drove it home, but the problem remained. I took it back in on Monday, and they called me back and told me the primer pump had gone out, and would cost $1005 to fix, and is not under warranty. I questioned the service rep because it didn’t sound right to me. I’m certainly no diesel mechanic, but to me, it didn’t make sense that it could be the primer pump, and just needed explanation as to how, once it loses its prime, it can regain that prime after a couple of hours, or sitting overnight. I posed the same question to the service foreman, and he said he couldn’t explain that, but that it could happen, and maintained that he thought it was the primer pump, but would check it again this morning. Every bit of my personal research, and discussion with two other dealers seems to indicate that the injector pump is the more likely diagnosis.

I explained this to the foreman, and he didn’t like that I questioned his diagnosis, and was somewhat condescending, but said he would check it again this morning. After talking to him this morning, he indicated that the pressure was abnormally low, and that it could ALSO be the injector pump going out. He also said that even after resting for four hours yesterday, they never could get the p/u to start without repriming. Is it pure coincidence that I have ALWAYS (for three months) been able to get it to restart (immediately, without any hesitation) after a couple of hours, but the day that it goes to the dealer and I question their diagnosis that it suddenly won’t start after it has cooled?

Anybody have any thoughts on whether this sounds like one, the other or both? Is there any possibility that the injector problem could create a problem with the pump, and that GM might be inclined to help out with the warranty on the injector pump?



It's frustrating, as a life-long Chevy owner, to see so many injector-related problems on the Duramax.

I’ve been having a “hard start” problem with my ’02 Duramax since March. I had the problem and assumed it to be a problem with my filter, so I replaced the filter, but still had difficulty getting it started until I hit it with a quick shot of ether, at which point it started right up. Unfortunately, the problem continued, so I took it to the local dealer, but they were unable to diagnose the problem within a few days. I needed the p/u, so I told them to put it back together and I’d bring it back after the w/e. When I picked it up, it worked fine for a few weeks before the problem started again.

The actual problem is that the truck HAS started fine when it is cool, i.e. in the mornings, or after it rests for a couple of hours, but after driving for 15-20 minutes, it won’t start without either waiting for it to cool, or giving it a quick shot of starter fluid. I took it to another dealer across town last week, and they diagnosed it as an injector problem, and replaced all eight injectors under warranty. I picked it up Friday, drove it home, but the problem remained. I took it back in on Monday, and they called me back and told me the primer pump had gone out, and would cost $1005 to fix, and is not under warranty. I questioned the service rep because it didn’t sound right to me. I’m certainly no diesel mechanic, but to me, it didn’t make sense that it could be the primer pump, and just needed explanation as to how, once it loses its prime, it can regain that prime after a couple of hours, or sitting overnight. I posed the same question to the service foreman, and he said he couldn’t explain that, but that it could happen, and maintained that he thought it was the primer pump, but would check it again this morning. Every bit of my personal research, and discussion with two other dealers seems to indicate that the injector pump is the more likely diagnosis.

I explained this to the foreman, and he didn’t like that I questioned his diagnosis, and was somewhat condescending, but said he would check it again this morning. After talking to him this morning, he indicated that the pressure was abnormally low, and that it could ALSO be the injector pump going out. He also said that even after resting for four hours yesterday, they never could get the p/u to start without repriming. Is it pure coincidence that I have ALWAYS (for three months) been able to get it to restart (immediately, without any hesitation) after a couple of hours, but the day that it goes to the dealer and I question their diagnosis that it suddenly won’t start after it has cooled?

Anybody have any thoughts on whether this sounds like one, the other or both? Is there any possibility that the injector problem could create a problem with the pump, and that GM might be inclined to help out with the warranty on the injector pump?



It's frustrating, as a life-long Chevy owner, to see so many injector-related problems on the Duramax.


;) Sorry I can't give you an answer but I just had to respond to your post with this... For your first posting on the Forum, You sure have a doozy of a question.

There are many highly qualified Diesel Pros who view the site daily and I expect they will be able to give you some guidance.
:exactly:

Good Luck and sorry to hear about your problems.:(

Thanks for the welcome. I tend to be a little "wordy" sometimes, but wanted to give a detailed explanation to get the best answer.

Michael

how many miles on the truck?

MMiddleton,

Yours is not the only truck with some of the same problems with priming. Take a look at my posts on this. Mine has been the the shop since 5/28. Truck only runs for 15 to 20 min and loses prime. The latest news on this is they are replacing the checkvalve on mine tomorrow then the area service manger and the factory will deside the fate. The Shop Service Manager gave up.

Bob

My initial thoughts are injectors. Best way to test is to run engine till hot, then install return hoses on each bank quickly while its hot then test return volume from injectors. I have been bit by trucks that would only act up cold or hot.

As for the primer, its possible, but I wouldnt spend much time looking there myself. a year or so back, we played with taking that checkball right out of the primer in search of more fuel. No gains were made really and normal operation didnt suffer.

Next time your truck fails to start, try pumping the primer a few times instead of the starting fluid and see what the results are.

are you running an edge juice? I had the same problem and traced to a bad juice box. It was throwing bad communication codes thru the cables it plugged into. When I took it out it ran fine. Took the truck to the dealer and they reset the codes and told me the PCM cable was having a bad connection. I took the Edge Juice back to where I bought it from and got a newer version and have not had a problem since. When it acted up it would not start when it was hot and I would have to pump the primer pump for it to start. Sounds very similar..Just a thought..Jim

It sounds almost like vapor lock. Though uncommon with a diesel it can happen. There are two check valves in the head that are opening and closing regularly. I am not a Tech but I have a filter head that I dissected to take some photos. Those checks have to work hot and cold. The next time it won't start pump the pressure up with the hand primer. It should pump up hard in less than a dozen strokes. If it doesn't you have located the problem. Just for something to do, remove the heater wire from the top of the filter head. Later! Frank

I'm not familiar with an "edge juice", so I presume I'm not running it. Sounds like maybe an aftermarket product, which I'm not running on the electronics/engine.

I have 116,000 miles on the engine.

I took the p/u back yesterday from the local dealer and am going to take it to another dealer (where I bought it) and get a second opinion. They ran a fuel rail test, and the pressure ranged from 14k psi to 16k psi, with the desired range around 22k. I believe that would be consistent with a likely injector pump problem. The foreman still believes both the injector pump and primer pump will need to be replaced. The p/u still starts without a problem (immediately) once it's cooled off, so I still don't buy into that theory.

Anybody know what the cost for replacing the injector pump is likely to run? Would there be any savings by taking it to a third party mechanic, provided there's nothing that can be done with the warranty?

Michael

Was the dealer ever able to fix your problem? My 02 with 130,000 miles has the EXACT same problem. Starts easy in the morning or when cool, but after turning it off (when warm) the primer button is soft and very hard to start. After I prime the pump a few times its a bit easier.

it sounds like the diag has been vage. I know we tech getevry shotgun happy with these. We need to start with the basic things. you say rail psi is at 17k when commanded to 23k. my thought is injectors or pump. as Eric said a flow test is needed. also need to install the vaccuum guage on the test port. to much to explain.
where are you located?
we have many good dmax tech here on the site and we are all over the USA,
Patrick

I'm having this same problem on my 2003 with 44,000 miles. They first thought it was the primer pump, so they replaced it. Did not fix the problem. I just had the fuel regulator replaced and so far it's starting o.k., but haven't drove it enough to see if it's fixed. Here's what they stated on the invoice as the problem: "High pressure below specs when commanded by PCM, fuel pressure reg. sticking."

I have an 01 and am having a similar problem. My truck fires up immediatly when cold and takes three seconds of cranking to start when its at operating temp. See my other post "P0094" I also have the had the dealer command 23k psi and it only put up 12k psi during the test. I have a NEW pump too. I think that the fuel regulators are probably the issue but I'm new to the DMAX. Does anyone know of a laptop program to interface with the ECM?

are you running an edge juice? I had the same problem and traced to a bad juice box. It was throwing bad communication codes thru the cables it plugged into. When I took it out it ran fine. Took the truck to the dealer and they reset the codes and told me the PCM cable was having a bad connection. I took the Edge Juice back to where I bought it from and got a newer version and have not had a problem since. When it acted up it would not start when it was hot and I would have to pump the primer pump for it to start. Sounds very similar..Just a thought..Jim
I had the same problem. THe truck would not start again after it was warm. Called edge they shipped new box, problem solved. This was discovered after many trips to the dealer. They couldn't find problem b/c I would remove edge when taking to dealer therefore problem would not occur.

P.S. fill in your sig and this will help us to help you.

How do you pump the primer? Where is that located in the truck? I couldn't get my truck to start after is sat for a week with me out of town. It is at the dealership right now.

How do you pump the primer? Where is that located in the truck? I couldn't get my truck to start after is sat for a week with me out of town. It is at the dealership right now.

Passenger side, just inboard of the "rear" battery is the fuel filter head. There's a cylindrical "button" on top of the fuel filter head about 2" in diameter and 2-1/2" tall. This is the primer. Pump by pressing down firmly and allowing it to rise back up fully before pumping again. After about 15 pumps or so, it should get harder to push down as the fuel line between the filter head and the injection pump gets filled and slightly pressurized.

I had the exact same problem. It would start fine when it was cold, but would crank for awhile after it warmed up. After about a month of this (I couldn't find time to get it to the dealer), the truck decided on its own that it was time to lay down. The dealer ended up replacing all eight injectors based upon finding a high return rate. This happened at 60,000 miles.