After replacing the lift pump and the injector pump in my 2002 5.9l Cummins I had it towed to the garage again this morning. As in the previous two cases the truck would run for less than a second on fire up and that would be it. After the fuel lift pump got replaced and it happened again, the mechanic said it has to be the injection pump so that got replaced for $2500 but here we are again with the same problem. Any suggestions?

 

What was it doing before? Do you have any codes coming up? Is there fuel coming from a cracked open injector? What is you fuel pressure at the injection pump? Were the codes cleared from the previous time?

 

It runs like a top except when it won't start. There is more to the story. When this problem first appeared I was in another town and had it towed to the Chrysler dealership who said it was the fuel lift pump, which they replaced with a defective new one! My fuel injector warning light would come on under load. The mechanic in my home town determined that the defective new pump was putting out under 8 psi and my fuel pressure light only comes on below 6psi so, they replaced it on warranty. Just as an aside the Chrysler Dealership would not cover the replacement labour. The startup occurred again and they did a diagnostic (computer) on the injector pump which showed no error codes. The mechanic after consulting with a cummins fuel injector pump specialist determined that it must be the 10% of the pump that is not measurable by the computer diagnostic, so it got replaced. And here we are, at the present. I hope he has a eureka moment because he was obviously perplexed.

 

When this first happened, did it just die? Sputter and die? When was the fuel filter changed last? Are the truck batteies good? Are the grounds good?

 

Batteries fine, fuel filter changed. When the truck stalls after startup, the start is as effective as always, but it runs for a second at most then dies. No sputtering. It's almost as if the computer fails to inform the lift pump that the truck needs fuel.....

 

Bump the starter, but don't let it start. This will cause the lift pump to run for about 25 seconds. This will tell you if the lift pump is working.

 

I had the lift pump replaced for the third time in a month. The mechanic checked the electrical for the lift pump and noticed it has a RELAY THE SAME AS THE AIR CONDITIONER so switched the two of them in case this was the problem (a relay switch versus $3500 worth of injector and lift pumps!). I bump the engine every time to listen for the lift pump and/or watch the fuel pressure light go out. So far so good, but a very painful process. The original injector pump was probably working just fine.

 

You might want to think about getting gauges. Here it some good info: gauge info

Its a long read, yet lots of good info.

 

Thankyou STODG73 for the advice about guages, and the information. My truck continues with the same problem, starting effortlessly for a couple weeks and then suddenly not. I found that if I turn it over for 10 or 12 seconds, let it sit a minute then turn it over some more, that it will fire up, then its good for another two weeks. The mechanic had switched a relay for the lifter pump with an air conditioner relay as they are the same, just in case that was the problem. I have religiously bumped the starter and listened to ensure the lift pump runs before starting the truck, and the fuel pressure light goes out when the starter (the third replacement in a 2 months) runs. Do you think there is some sort of electrical input between the injector pump and the injectors that isn't actually part of the injector pump, as it was replaced apparently needlessly? The mechanic is baffled and said he would search the internet for ideas. Perhaps he even checks Dodge Forum! It's the first place I would check.