Ok, so i install this awhile back, never really paid attention to it. Mainly focused on the AFR and boost gauge.

Anyways, one of my buddy was driving my car and he notice, the fuel guage doesnt budget much under boost.

When the car is turned on, it sits at 49 psi. When started, and idel, its around 58psi. At full throttle, it doesnt really budge.

Is this normal or am i looking at a bad sensor? My buddy was concerned since his car fuel pressure rises when full throttle. I told him to monitor the AFR and he says its with in range.

So bad sensor?

 

How much boost typically idle is 51psi, then goes up 1psi per pound of boost.

 

7lb of boost

 

So you should go from 51 to 58 psi. It could be your fpr, have you taken the boost line off your fpr to see what happens?

 

Ill check into it. I was thinking if it was the FPR, my air fuel would be off. But it seems to in range.

 

Oh ha ha, my bad im a retard i was thinking the guage on the fpr was reading wrong not an external guage in your cab. It could be a sensor or a bad guage anyone local have a guage you could swap with for a few minutes?

 

Now, just a heads up. The Defi Advance gauges have two ways they can display fuel pressure.

They can display actual fuel pressure and they can display differential fuel pressure.

Actual fuel pressure the gauge will display the fuel pressure increase as your boost increases as described in the posts above.

If you have it in differential mode it will display the DIFFERENCE in pressure between your fuel pressure and your boost... So in theory fuel pressure rises at a 1:1 ratio with boost, so the gauge should always read your base fuel pressure and not change much at all.

Check what mode you've got it setup as. It describes it all in the manual.

 

So i set it to where the "differential" light is on on the defi link, at idel, pressure is close to 70psi!!! When i blip throttlw in neutral, maybe to .20, the prrssure drops below 50psi. Im not sure what is going on, considering my AFR is in range and perfect. Not sure why the fuel pressure is acting bizzard.

Any idea?