Engine/Transmission (1998.5 - 2002) Fuel Pressure

[GregBarnes]

I've been experiencing what I'd describe as occasional missing when accelerating while driving my 2nd generation Ram 2500 4x4 Diesel (1999). Having experienced a lift pump failure before, I checked the fuel pressure at the filter housing. I read 14 psig with the engine idling and it sits there for awhile. After a few minutes the pressure drops to about 7. 5 psig. I've read that fuel pressure while cranking is supposed to be about 7 psig... but did not know that it would drop while the engine is at an idle. I could use the bleed valve to dump some fuel and then see the pressure return to 14 psig. The process will repeat itself with the pressure dropping again?



Based on this... any ideas? Is this normal operation of the fuel pump at an idle and what could cause the missing if it's not fuel related?

 

[EGaskamp]

That doesn't sound normal to me. I've never had that happen to me before. I'd go ahead and change the LP. The missing kinda makes me worry though. Do you have any codes? It almost sounds like the VP is going.



Eric

 

[mhenon]

I had one (1) miss while driving through west TX one night. That started a down hill slide until the VP was replaced.

Not sure on your fuel pressure.

Mike

 

[Texas Diesel]

Let me wade in here.



I had the same exact problem you describe, for almost a year.



The culprit was the LP. It was giving erratic pressure. The only indication was the fuel pressure gauge would 'buzz'.



My LP did exactly as you describe, 15PSI-7-15-5-14-6 etc. Always or intermittantly fluctuating.



I went through 2 more LP's (new) to get one that would not cause the gauge to buzz.



It seems that the pressure spikes would cause the VP give eratic fuel injection.



Hope that helps.