Engine/Transmission (1998.5 - 2002) Fuel pressure gauge reading negitive

[WStrong]

My fuel pressure gauge (Westach 0-15) started to read below zero when ever I turn on the key and stays there. When I shut the key off, it returns to zero. I've checked all the wiring and it seems good. It has always worked perfect 'till now. Has anyone else had this problem? I know there is pressure because the pump cycles properly and it runs real good. Thanks.



















98. 5 3500 QC 275s, BHAF, DS Boost Fooler, full gauges, 4" exhaust,

 

[darkhorse]

That sounds really wierd. I haven't got an answer for you but I'd sart by checking the electrical connections especially the ground.

 

[JStemann]

Sounds like the sending unit. My gauge started going negative about a year ago. Sometimes it would show normal, others it would show neg, sometimes in between.



After confirming with a mechanical gauge and checking all wiring, a new sending unit took care of the problem. Unfortunately, I think it may be starting to go, again.



Hope this isn't something I have to change every year.



jeff.

 

[JClement]

Have you tried disconnecting power to the gauge when the engine is off and re-connecting? My autogauge rezeros every time power is cycled to it. This includes if the battery voltage spikes too low during a hard start. (Cold or low battery). If this happens at the wrong time the readings can be really strange.

 

[RobertMiller1]

lfp

My lift pump did that when it failed. I just assumed it was the draw or vacuum from the VP44 sucking fuel, since the LF was not longer pushing fuel.



Just because you hear the lift pump making noise doesn't mean it is putting out pressure.

 

[Ron Bissett]

Originally posted by WStrong

My fuel pressure gauge (Westach 0-15) started to read below zero when ever I turn on the key and stays there. When I shut the key off, it returns to zero. I've checked all the wiring and it seems good. It has always worked perfect 'till now. Has anyone else had this problem? I know there is pressure because the pump cycles properly and it runs real good. Thanks. When you turn the key on the pointer moves to zero ? and it stays there, then how did it return to zero? was it not at zero. ? When key is turned to on pointer will show PSI for a few seconds then move to Zero ,when motor statet should move to PSI (14 to 15 psi) when motor turned off with key back to zero or any other place it wan't to go to up or down don't matter . on turn of key to on psi for a few second then down to zero start then to PSI . Ron Bissett in Metro Louisville KY.





















98. 5 3500 QC 275s, BHAF, DS Boost Fooler, full gauges, 4" exhaust,

 

[Gary - K7GLD]

I know there is pressure because the pump cycles properly and it runs real good.



Sorry - but the fact the pump can be heard running, and the engine still functions, is NO assurance the LP is actually pumping any fuel! Hopefully, your problem IS just the guage or sending unit - but *I* would dern sure make absolutely certain that LP was operating properly as the FIRST item on the agenda.

 

[jzenk]

FP gauge reading

Here's what happened when I had the same problem. Ordered a Westach gauge and rubber hose from Geno's and got the "negative" pressure reading. What I finally found after hours of prodding around with the diddle stick was a tiny piece of plastic stretch wrap (packing material???) inside the hose. Pulled it out and reinstalled and life's been good ever since! Gauge instantly came to life. Good luck & hope this helps, Jim:--)