DeerHunter812

I have a 1998 12 valve cummins that seems to have a fuel problem. When I attempt to start my truck after sitting overnight or after sitting several hours, it starts for a few seconds and dies, then I have to prime the fuel system and restart it. The fuel is bleeding off but I can not find any fuel leaks. Can anyone tell me what the problem is or the part that should be replaced on it?

Thanks much!

CarlJensen

Fuel lines will leak air in but not drip any fuel out. Loss of fuel head results in hard start. If you do a search here under "hard start" you should get a ton of reading on it. This is an old problem with lots of good info available. Use the "search" function at the top of the forum page.

DeerHunter812

Yeah, the search button would be awesome if I could find the EXACT problem that I have in a timely manner. I have now searched for well over an hour and still no luck and my time is VERY limited to be able to sit at a computer so if there is anyone out there who would be kind enough to give me a hint, I'd appreciate it.

Thanks much

kawi600

You could be sucking in air from a bunch of different places. The most common is the return hose on teh back of the injection pump. Metal fuel lines rot, especially behind the tank and on top of the sender.
I replaced my fuel puckup with a vulcan draw straw, ran diesel fuel hose from the tank to teh engine bay, and replaced all the hoses around the IP.
Also, if your setup is anything like the older 2nd gens.. keep an eye on the line from the fuel filter to the IP. Cummins has an updated part that addresses vibration fatigue that can lead to a large amount of fuel being lost. If your fuel line has a braided hose section in the middle youre already updated.
I strongly recommend a fuel pressure gauge. You can tie into the fuel system with some hoses and adapters from vulcan performance. Youll want a gauge that reads to 35psi or more, preferably.
Also, you can get a sight glass tube commonly used in boilers from grainger or mcmaster-carr to spot air in the fuel. I patched one into a fuel hose leading into the lift pump since this is where air is most likely to show up. After this point its positive pressure and youll see leaks.

CarlJensen

Did not realize you were that rushed. I replaced ALL the fuel lines in mine with deisel rated hose purchased from west marine, solves that problem. The fuel heater also can leak air into the system where the electric lines go in. As said the best way to find ALL leaks is to apply low pressure air to whole system and start searching for drips. 10psi, or less, applied right at fuel fill with a cloth or similar block around air hose to capture some pressure. Leaks will start to show in a few minutes. Sounds goofey but it works. Also, as said, the lines to lift and injection pump should be looked at closely. Mine had a soft line from lift pump to pre filter that went south on me.

infidel

This will help a lot http://www.cumminsforum.com/forum/94...m-writeup.html

DeerHunter812

Awesome reading. THANKS! AND...thanks to all who replied to this message. I appreciate your time.

DBO63

I had the exact same problem on my 97. I replaced my lines and that didn't help my truck. So i took it to the shop my pump timing was off.