i went to go get my car tuned last friday and we ran into a few problem. the 1st problem was the irratic idle that jumps from 500-1100 rpm fast. we fixed that problem already, we didnt hook up the coolant on the tb and the sensor was messed up so we replaced it. it idles fine now. my 2nd problem that i cant solve is my fuel pressure is at about say 50 psi and when we pull the vacuum off the fpr the psi drops to about 46.... it only drops about 4 psi. and then during the dyno run when the psi is at 50 it jumps around from 45-50 up and down sometimes... i am running aem fuel rail, aem fpr, bbk hi volume 255 lph fuel pump, and 720cc injector with the hondata stage 2b with the pr3 obd1 ecu... the aem fpr is suppose to rise fuel psi per pound of boost which it isnt doing. i changed out the fpr to stock one, changed the fuel filter, checked the fuel pump, checked for vacuum leak. don't what know could be the problem now... only thing i can think of is the injector? the tuner maxed out the injector on the 720cc and it still was reading lean under 10psi of boost @ 255 whp. also have the 3 bar map sensor and i doubt its the injector cuz it was working in my friend's car. and also the jdm pr3 ecu is suppose to be obd0 but somehow it is obd1.... the tuner said that was also weird about it also. any tuner out there that know what i can do please help! TIA


ls b16 vtec
81.5mm 9:1 endyn rw piston
eagle rods
itr intake manifold
jg throttle body
act 4 puck
12lb flywheel
turbonetics t3/t4 .57 trim ar63
drag3 manifold
hks 40mm wastegate
greddy type r bov
spearco FMIC
bbk 255 lph fuel pump
aem fuel rail
aem fpr
hondata stage 2
3 bar map sensor

base run was at 255whp @ 9-10lbs

didnt really get to tune it, i have to fix all the problems then go back and tune it.

 

Uhm shouldn't your tuner be able to see whats going on through hondata???

 

he told us to work with changing the fuel filter and fpr and then fuel pump... all those are good so i don't know where to narrow it down to right now.

 

ttt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tRaCeBuStAbUsTeR &raquo;</TD></TR><TR><TD CLASS="quote">he told us to work with changing the fuel filter and fpr and then fuel pump... all those are good so i don't know where to narrow it down to right now.</TD></TR></TABLE>

Sounds like a reasonable request. Ussually when the fuel pressure doesn't track with the boost pressure your fuel system isn't up to par. IE: clogged filter, pump doesn't flow enough etc. I would double check all of these before doing anything else.


-Ryan

 

umm i changed it already.... i need to know what else could be the problem

 

The only other thing I could think of is a vacuum line leak somewhere going to the FPR. Just trying to help.

 

u said u checked the pump. id say try changing the pump. put in a stock one or something and see how that works.

oh yea and why does your fuel pressure drop when u take the line of the fpr. it should go up

 

Same problem happened to my friend david (devine on the boards) when he was dynoing at secret services, turned out it was the fuel pump. (walbro 255lph) changed it to a holley unit and it has been fine ever since than!

 

i meant it doesnt raises that much... i remember before it raises like 10-15 psi or something and now it just goes up like 4 or 5.... something doesnt seem rite... ill try to change the pump back to stock to see what happens then

 

check the FPR...

 

i changed the fpr, the fuel filter and checked the fuel pump.... im prob gonna change the fuel pump