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Low Fuel Pressure on first start up. HELP!!

bbptech

bbptech

New member
Alright so i finally got my car started up After my XPZ Build. Im sure alot of u have seen my XPZ Build thread. Everything sounds good. Exhaust leak at the DP. No leaks. But my fuel pressure is reading at 18-20 PSI. I know that doesnt seem right to me at all. I have ZZP Fuel Logs with Fuel Labs adjustable FPR. Would i just need to turn the brass fitting in the back out till my pressure goes up? Or no?

The computer has a canned tune for now. Tune will be later in the spring.

I have the standard HP Tuners and was snanning at idle. I cant see my ST B1 or ST B2 which as i under stand is Short Term fuel trims, correct? I noticed my LT B1 was in the red and said 16.4 under it. What does this mean?

Please help me. lol.
 


bbptech said:
Alright so i finally got my car started up After my XPZ Build. Im sure alot of u have seen my XPZ Build thread. Everything sounds good. Exhaust leak at the DP. No leaks. But my fuel pressure is reading at 18-20 PSI. I know that doesnt seem right to me at all. I have ZZP Fuel Logs with Fuel Labs adjustable FPR. Would i just need to turn the brass fitting in the back out till my pressure goes up? Or no?

The computer has a canned tune for now. Tune will be later in the spring.

I have the standard HP Tuners and was snanning at idle. I cant see my ST B1 or ST B2 which as i under stand is Short Term fuel trims, correct? I noticed my LT B1 was in the red and said 16.4 under it. What does this mean?

Please help me. lol.
Click to expand...

LT B1 means "long term fuel trim bank 1" and if its at +16 then I would say you have a pretty big vacuum leak.
 
silverstreak said:
LT B1 means "long term fuel trim bank 1" and if its at +16 then I would say you have a pretty big vacuum leak.
Click to expand...

Ok well a breather is on at the moment,so that could be the cause of vacuum leak. Could that be my problem with the low fuel pressure reading?
 
No. Just try adjusting the regulator either way and see what the pressure does. Is it an aftermarket pump? Did you rewire the pump? If so check the voltage at the pump.
 
un hook fuel pressure regulator while watching FP. See what happens...should go to max while unhooked..48-53 should be normal at idle
 
01GTP said:
No. Just try adjusting the regulator either way and see what the pressure does. Is it an aftermarket pump? Did you rewire the pump? If so check the voltage at the pump.
Click to expand...

We tried adjusting the pump. No change. Voltage to pump is right. Has an aftermarket pump and has the rewire done.
 


well i got the problem solved. Swapped in a canister that had a stock pump in it and fuel pressure is at a stable 45 psi.

i either have hooked the zzp pump up wrong or its faulty.
 
there was some issue with the tube that runs in the cannister....one of the 3800 aftermarket guys has a fix for this...If I remember correctly you have to use 97-98 cannisters for some aftermarket fuel pumps to work properly.....I don't have all the emails anymore...many Hard drives ago.....but I saw you had aftermarket pump and when you changed out cannisters all was good...I haven't seen one of these in a while as I have been dealing with transaxles.
 


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