99 C3500hd - starting trouble

[ken_man_1]

I know the forum says 98 and older, but this truck is the old body style, and kinda fits this forum.

1999 Chevy C3500HD, 2wd, Atuo trans, 7.4L Vortec.

Starts hard when it's warm. Starts immediately when it's cold, but if it's been running for more than 10 minutes and shut off for more than 10 minutes, it starts extremely hard. Now, when I say it starts hard, I mean that it cranks fine. It cranks forever before it will even pop over. Then after it pops over, it will stall immediately. The second time cranking, it will pop over quicker, but will stall again like it's run out of fuel. The third time it starts perfectly, and no issues with running or power.

The truck was worked on by the dealership originally, and they had replaced all of the injectors, because 4 of them were clogged with "debris", and couldn't be saved. So, they replaced all 8, along with a full tune-up. The truck came back, but with better starting. The problem only worsened after about 4-5 months of getting it back. It got to the point of barely running. I looked at the paperwork, and the warranty was still in effect - within 1 day!

The dealership covered the injectors AGAIN, stating that they were faulty again. When the dealership changed the original set of injectors, I noticed on the paperwork that they "replaced" the fuel filter. The tech that replaced the injectors the second time said that the filter was never replaced as he had to cut it off to replace it. So, the "debris" that made the original set of injectors go bad probably made these go bad as well. So, they cleaned out the fuel system and started from scratch. All fine and dandy.

Well, not so. Here we are, out of warranty now, and the truck starts hard. I can't believe that the injectors are bad again - they only have -at best- 7000 miles on them.

Fuel pressure is at 64psi running.

Has anyone came across this problem, because I can't seem to narrow it down anymore. Any ideas would be helpful, and certainly appreciated!!

[tblake]

Did the dealer replace the fuel pressure regulator when they did the injectors?

Does the fuel pressure hold at 64psi, or drop off immediatly?

[j cAT]

I would cut open the fuel filter and inspect for what is exactly fouling the filter/injectors ...this could be the fuel supplier or your neighbor etc. ...

the fuel tank if metal and how you maintain a good level of fuel is also a factor..

since it starts cold that usually means it has a good flow of fuel as when it is cold you are in need of a richer mixture ..when warm/hot less fuel is commanded ..the ECT tells the computer what the engine temp is... perhaps it is defective ///not very expensive and at this age it is most likely a little off ....

[ken_man_1]

tblake, the pressure reg was changed. I will test the pressure engine on/off and post what I find.


j cAT, we have a constant source of fuel here, same person fills the tanks and it's used often. We do top off when we need fuel, and it never hits less than a quarter.

I will change the filter again, just for good measure - and I'll post what I find in the filter. I'll also look into the ECT.

Just for grins, I had another truck that did the same thing to me that I could never figure out. When we were ready to take it to the dealer for a "real" diagnosis, the engine blew a head gasket. The guy driving the truck overheated it and that was it. I guess it saved us some headaches, in a way...

Thanks for the replies, and I'll get back with you soon.

[j cAT]

Originally Posted by ken_man_1

tblake, the pressure reg was changed. I will test the pressure engine on/off and post what I find.


j cAT, we have a constant source of fuel here, same person fills the tanks and it's used often. We do top off when we need fuel, and it never hits less than a quarter.

I will change the filter again, just for good measure - and I'll post what I find in the filter. I'll also look into the ECT.

Just for grins, I had another truck that did the same thing to me that I could never figure out. When we were ready to take it to the dealer for a "real" diagnosis, the engine blew a head gasket. The guy driving the truck overheated it and that was it. I guess it saved us some headaches, in a way...

Thanks for the replies, and I'll get back with you soon.

if you find debris in the fuel filter I recommend buying a locking fuel cap.

I knew of a vehicle owner that had similar problem ...he for a condom in the fuel tank getting stuck on the pick up screen ...erratic engine starting and running ...

[John T Mann]

My 6.5 turns over several times before it starts when it cranks it runs great , but even after warm its still hard to start, could it be the glow plugs

[ken_man_1]

Originally Posted by John T Mann

My 6.5 turns over several times before it starts when it cranks it runs great , but even after warm its still hard to start, could it be the glow plugs

The 7.4 is a gas truck - it has no glow plugs.

Still haven't had the time to get under the hood - as soon as time presents itself, I will post results. Sorry it's taking so long!

[hannah09marie]

My 98 with a 7.4 does the same thing but it also misses at an idle. I have replaced eveything but the pump and the injectors. Mine holds at 52 to 54 PSI. I will let you know if I find anything and I hope you find your problem. Good luck.