boost4s2k

my fuel pressure goes from 44-45 down to 30 and below during wide open throttle, this doesnt seem normal to me first turboed car help please

srmofo

fuel pressure should go up. What pump do you have? and a little more info on your setup wouldnt hurt.

JrOz

weird cuz that happened to me this week and i was like wtf??... i have a stock jdm type r with a jacksons racing superchager kit... aem fuel rail and regulator with 440 injectors... min went from like 42 to about 32 psi... i also have a walbro 255 fuel pump..

boost4s2k

i have a 255 pump i got with my turbo kit 650cc injectors have a synchronic fuel pressure regulator with stock fuel rail also my fuel pressure sensor is on my feed line not on the fuel rail

Foowee

I bet you city boys are using the stock wires to power your walbro. Go to the junk yard, get a few headlight relays. Go to the autoparts store get some blade connectors and about 10ft 10ga. wire.

Hook up the stock wires to the blades on the relay that have the little coil going between them on the diagram. Then run a long piece of the thick wire from the positive terminal of your battery to one of the switch side blades. Run another piece of thick wire from the other switch blade to the + on your pump. Run another thick wire from the - on your pump to ground.

Tell me if you have fuel pressure issues after doing so...

jetspeedz

i would stay away from those cheap bosch relays, there are much better heavy duty automotive relays. However i have rarely seen oem wiring issues to the pump.

boost4s2k

im gonna take the fuel up out tomorrow check it out make sure no wires are loose put my stock pump back in and if it starts and i have no problems with the pressure its the gas pump

96 GSR-T

i know this is a stupid question but do you have a vacumn line running to the regulator?

Foowee

The reason you haven't seen any oem wiring issues is because your car isn't running yet.
I've been using oem honda headlight relays for the setup I described for several years now. Stick to bikes... or come back with some real world experience after you get your car running.

96 GSR-T

There is nothing wrong with Bosch Relays, running 2 of them to both my pumps and I know several others using them as well...... Honestly I have never had a complaint about anything Bosch I even use their oil filters religiously and I will be running 2 bosch pumps this year too.

jetspeedz

lol funny, i was doing this over 10 years ago when it was just rev hard vs drag when you were probably never on the scene.. used oem wiring then and still didn't have issues.

Foowee

Okay, since you're the expert. Why is this guy losing fuel pressure?

boost4s2k

i think its a faulty fuel pump its on its way out ran the car for 3 hrs with out a problem then it started acting up pressure dropped 2 psi then another 2 and so forth had got out of the car and then when i got back it it was at 20something

jetspeedz

i would also look at the pump, if the wiring was bad the pump would probably not prime or it could cut out if its an intermittent short not drop psi like your describing.

96 GSR-T

check your fuel filter too......

boost4s2k

so i took out the pump and double checked everything wires were good put it back in so i messed with the fpr i put 2 vacuum lines one it from one source and when i boost now the fuel pressure goes up from 42 to 60 psi... so im guessing everything is fine

jetspeedz

glad you got it sorted out

boost4s2k

me too ive had head ache after head ache with it....thanks for the help