Engine/Transmission (1998.5 - 2002) Is LP on its way out?

[JStephens]

I posted this question on another thread but got no answers then did a search and could not find any concrete information. My fuel pressure gauge says that I have good pressure (14 - 16 psi idle not under 10 WOT) but the problem is that it consantly bounces between 14 and 15 psi. Just flutters between the two at idle. When I pull fuel pressure down under load it still flutters but not as much. Should I look at replacing my LP or is this fluctuation normal.



Thanks

 

[lmills]

Your probably seeing a pressure flucuation from VP-44 drawing fuel. Guys have had this issue in the past. It comes from the pulses of the injection pump. You can either live with it, or others have installed a small valve in the pressure feed line going to the gauge which helps tone it down a little bit. The pressure look good though.

 

[mediccummin]

I had the same thing, added a small valve like lmills said and the pulsating is all gone, also protects your sending units from getting beat up. Good luck.....

 

[JStephens]

No sending unit. Just straight diesel to the gauge.

 

[lmills]

Doesn't matter if you have a sending unit. You are seeing pulses from the VP-44. The pulses have been known to destroy a sending unit on electric gauges. I think it could probably do damage to mechanical gauges also, but not as fast.

 

[JStephens]

Oh, I do have a needle valve on the line going to the gauge. Just barely open.

 

[JStephens]

Note to self.

Dear self,



Always check the simple things first. Such a fuel filter.



I service this every 10,000 miles. Only had 8,000. This afternoon FP pulled down to 8PSI idle so changed it and all is back to normal.