zlow6869

so I was thinking my 94 z was having an opti issue, well after sitting at the shop for a few weeks I have realized that im having a fuel supply-volume issue, it seams ad the car isn't getting enough, I tested the fpr and the psi went up about 10 or so at idle, but when I rev the car it drops down to 30-35 psi any thoughts, I have a 2 week old airtech pump in it, would swaping to a racetronix set up be a good idea?

RamAir95TA

iTrader: (2)

Your post is slightly confusing.

What is the fuel pressure with the key on, engine off?
What is the fuel pressure with the engine running?
What is the fuel pressure with the engine running and the FPR vacuum line disconnected?
What is the fuel pressure under part throttle and WOT?
Does the fuel pressure drop off quickly after the pump stops?

Answer as many of those questions as you can and we'll go from there.

zlow6869

key on engine of 40
engine running 36
fpr unplugged its now 42
1/2 throttle it bounces between 36-39
wot-40 still bounces
and if the car dies sometimes it goes to 0

zlow6869

any thoughts?

96capricemgr

iTrader: (1)

Fuel pressure is kept at a constant when compared to manifold vacuum. So high vacuum situations like coasting or idle result in low pressure when read by a regular gauge. If your intake tract is choked up that will lead to vacuum and slightly low fuel pressure reading at WOT.

Looking around at that pump it looks like generic parts store stuff at Walbro pricing. Did you use the stock clear fuel tube or was it supplied with a piece of black hose and clamps?

Your fuel pressure looks maybe a little low but hell a cheap gauge or something could cause that.

When was the last filter change?

RamAir95TA

iTrader: (2)

I don't see any problems with your fuel pressure. Those numbers should be plenty to keep the engine running.

96capricemgr

iTrader: (1)

That was more or less where I was going, possibly slightly low but not going to cause major issues like stalling.

Big Al

iTrader: (1)

The bouncing is not right. Does it go to zero before or after the car dies? You may have a bad connection in the fuel pump wiring.

Al 95 Z28

Uwilllosetomy93lt1

Regulator/bad injector(s)....

zlow6869

well now I cant get it to die im not sure what its doing it will fire up and idle fine, havnt had time to drive it so I will try it later