Fueling & Injection - OMG Losing Fuel Pressure Again......
11-10-2010, 05:59 PM
Ok, I have a 98 Z28, I installed the racetronix 255 w/ hotwire kit and ran it to the ALT. Some how I am losing fuel pressure every 4 days. I can drive 200 miles and then all the sudden I lose fuel pressure somehow. It has happened twice now....
It has a brand new battery now. (1 week old)
My fuel pressure regulator has 188K on it, when I bought the aftermarket sock for the pump there was no place to plug the FPR hose to, so I just clamped it to the case of the pump so it wouldn't flop around.
When it starts acting up my fuel pressure goes from 58lbs to 5lbs and stays there, it sounds like it has a huge cam in it, but its stock. If I give it a little gas it dies, the starts right back up. The pump also whines (high pitch) when I am losing Pressure.
Sorry about the on going story just trying to get all the details out there, maybe someone can help me out.....Thanks in advance.....
11-16-2010, 01:51 PM
Update: Starting losing fuel pressure today, had to keep my foot on the gas in order to get home. When I got home I took my foot of and it died. I don't know what to look for, all I did was put a 255 pump in and that's it. Any Idea's
11-16-2010, 02:00 PM
well me and another guy on here both have 98 z28s and we are having very similiar problems. OUR problem is the O-Ring on the FPR keeps popping off and causing us too lose alot of fuel pressure and the car wont hardly do anything when it comes off. My only advice to you would be to check the o-ring on the fpr. hope this helps. Also i hope you have the hatch mod cut out so you can get easy access to your pump
11-16-2010, 02:02 PM
also if your fpr has 188k on it, you may just need to change it. you can get one at the local parts store they arent very much. If i were you that is most deff where i would start. Becuase the fpr controls and regulates all the fuel pressure going to your fuel rail. Try a new FPR with a new o-ring on it. You should be good to go
11-16-2010, 02:04 PM
Sounds like fuel pressure regulator.
11-16-2010, 04:45 PM
Thanks for the info, I feel a little better now, I will be getting one of them thursday. Then give it another 200 miles and see if it happends again.....Auto zone 45 bucks
11-16-2010, 06:21 PM
Does it sound like it could be vapor locking? When I hook my Fuel Pressure Gauge to the rail (when the car is acting up and still running) I bleed the fuel from the clear hose on the gauge and there are air bubbles in the hose. When the car is running at 58psi it doesn't have any air bubbles....
11-16-2010, 09:11 PM
hmm im not sure to be honest with ya...if it were me i would start with the fuel pressure regulator it controls everything pressure related all the way to the fuel rail...start there im sure thats what your problem is
11-17-2010, 01:50 PM
Sweet, I drove 34 miles today and it acted up again, get home put the gauge on it and it reads flickering 20psi, bleed it real quick and goes up to 58 then falls quickly to 5 psi and then dies. I will replace the FPR tomorrow. I hope this is it. Thanks for the help ryan
11-18-2010, 08:01 PM
Would this 90 degree kink in this line connecting to the check valve have anything to do with losing fuel pressure you think?
11-19-2010, 03:57 PM
yes it very well could.. any kinked fuel line would cause a low pressure problem. try to unkink it and see what happens...if it does it again im putting money on the FPR
11-19-2010, 04:03 PM
lol, well i fixed that kinked hose lastnight and just got home from my 40 mile trip, well it screwed up again. So today I am getting the FPR and driving 40 more miles after i fix it tonight and see if it fix's the low pressure.....
11-20-2010, 02:38 PM
UPDATE: Still losing pressure, Oh well. Guess I will be putting a stock pump back in it. I never had any problems until I put this 255 pump in.
11-20-2010, 07:58 PM
That was a vent hose...
Did you check the supply hose for kinks above the tank?
Also next time the car acts up, remove the gas cap & see if there is a vacuum in the tank. Then replace cap & see if car acts OK.
11-21-2010, 02:20 PM
UPDATE: So today I dropped the tank and found the main line going to the fuel filter had some kinks in it, so I replaced it with 3/8 fuel line hose for now till I can get the plastic line.
So I put everything back together and put 9 gallons of gas back in it. Started it up and it ran for 5 minutes with 58PSI then it dropped to 48 and just stayed there (pump whining loud).
There is a purge valve solenoid on the driver side by the fuel rail it was making a loud ticking sound, (never heard it do that before). So I am lost on what to do now. My pump is only a month old, could I have over heated it due to that kink and now it just don't want to work right?