Engine/Transmission (1998.5 - 2002) Fuel pressure on the rise?

[Rob Thomas]

Hello boys,



Ok, here's the story, I have the stock lift-pump in the stock location, and a Carter pusher-pump by the tank, two mechanical pressure gauges, pre and post. No recent engine/fuel changes.



Since installation of the pusher, I have had 21 psi pre, and 20 psi post filter at idle, all is good. Then this past week I have been noticing a rise in pressure, on Sunday it was 25 pre and 24 post at idle, and yesterday and today it's up to 29 pre and 28 post at idle.



WOT pressure's are the same as before the rise, as are crusing pressure's. I will be going over the fuel system to see what the hell is goin' on, later today. I'm just kinda curious if this has been seen before by anyone, or if someone has any input to save me some time.



As always, Thanks,

Rob

 

[Gary - K7GLD]

My pressures took a small rise as well - I suspect a small amount of seating in of impellers inside the pumps might account for it - at least to a degree... Also, brushes can seat in, and increase drive motor RPM and power as well...

 

[Turbo Horseman]

It will be interesting to see how your injector pump and other parts hold up to these pressures.

 

[RADdodge]

You might try to disconnect the electrical connection on one pump at a time. The pusher pump should reduce the psi by about 6 – 7 psi, the lift pump by about 14 or so. It should tell you which pump has a stuck relief valve.

 

[Huff N Puff]

More voltage to the pumps will increase the pressure

You might start by checking the charging system. Small voltage changes will increase the pressure. High loads on the alternator will drop the voltage,therefore droping the pressure,and visa versa. My pressures were too high, and I had to add heavy wattage resistors to drop the pressures. Merv