I have noticed lately that my fuel pressure has increased and I don't know why. I haven't changed my fuel filter in about 9200 miles or so. It will be due in a few hundred miles as I change it every 10k. My truck will have 50k on it.

Does anybody know why my fuel pressure would increase??

It was normally around 7 psi or maybe 7.5 psi at idle before, say 500 miles ago. Now it is consistently reading about 8.5 to 9 at idle. It seems to be maintaining a consistent 1.5+ psi or so no matter what im doing with it. But, I can still pull it down to 4 or maybe even 3 at WOT.

I am testing a Smarty on it now, but this increase in FP was noted before that. And, I do plan to upgrade the fuel system sometime in the near future to Walbro or FASS.

I am not complaining, I am just curious why the increase. IT doesn't make any sense. The temps have cooled off a little from this summer, could that have something to do with it? Or what about a change in fuel with the ULSD stuff or whatever it is we are getting now? Any ideas?

 

Where is the fuel pressure sensor located? Pre or post filter? If it is pre-filter then maybe the filter is partially clogged causing backpressure. Try changing out your filter and see what happens.

If changing out your filter doesn't change the pressure reading or if the sensor is post filter then maybe it is the cooler weather.

 

Tim,

Mine is hooked up directly to the CP3 so it is post filter. I will be changing out the fuel filter real soon. Like I said, it is not a concern or bothering me. I just couldn't understand how it could increase like that. Logic would tell me it should be decreasing somewhat (even if very slightly) as my fuel filter gets more miles on it. Not increasing.

And, I thought cooler weather would decrease the pressure too. right?

This is not a concern......just a mystery. I didn't know if anybody else may have seen their FP increase due to fuel or weather or maybe some other reason.

 

Could be your sending unit.

Can't be your right foot.

 

I dont have a fuel pressure gauge, but my filter only is good for about 6000 miles before it starts to bog the motor down under heavy throttle.