Confused, ODD FP vs VF values

grimreaper

New Member
Jul 2, 2008
2,180
0
0
Dallas
car: 89 7mgte stopper head gasket, 550's afpr, walbro, lex afm, sp61gt on stock waste gate (14 psi). afpr gauge liquid filled, no 12v mod

when i jump the fuel pump from the diagnostic box, it reads 50 psi, at idle its reading 38psi wit vac on/ 44 psi vac off, my vf values are a flat 5v at 35psi vac on and hit 3.5v at 38psi vac on. seems like i have a lot of fuel so how come im still lean at idle? afm screw is about half way out and i can only get the fuel pressure up to about 43 psi or so with vac on and STILL at 3.5v.

intentions: getting the vf's to stock 2.5 or 2.25 at idle. what am i overlooking? only thing i can think of is the fact that the fuel pump is NOT at 12v at idle which might help or solve my issue should i do the mod.
 
Last edited:

grimreaper

New Member
Jul 2, 2008
2,180
0
0
Dallas
think i know whats up, the damn fpr gauge is liquid filled, and ive been told that can actually affect its reading when it gets hot,,,,, any body confirm?

on a side note, egt's where cold as hell until i dropped the fpr down a bit, now they sit pretty at 1200 in a solid pull in 4th stopping at 5500rpms. (egt probe 2-3 inches behind turbo outlet)
 

grimreaper

New Member
Jul 2, 2008
2,180
0
0
Dallas
grimreaper;1104361 said:
think i know whats up, the damn fpr gauge is liquid filled, and ive been told that can actually affect its reading when it gets hot,,,,, any body confirm?

on a side note, egt's where cold as hell until i dropped the fpr down a bit, now they sit pretty at 1200 in a solid pull in 4th stopping at 5500rpms. (egt probe 2-3 inches behind turbo outlet)

andddd more to add, in case anybody runs across this with their fpr gauge under the hood, you have to vent it when you want an accurate reading, mine shows nearly 10psi less when i run it for a bit and things heat up, as soon as i vent the gauge, back to what i was getting on cold starts in the morning. my vent is on the bottom, annoying lol. heres to thinking out loud and hope it helps some one else some day.... ignore my way high numbers in post one, i got a little happy with the wrench at first lol:slap: