fuel pressure problems
Thread Starter
Heel & Toe
Joined: Sep 2018
Posts: 22
Likes: 3
From: SW Missouri
fuel pressure problems
I have an 88 with a stock L98. I recently changed out the injectors with a set of rebuilt Bosch 3 from SouthBay Injectors. I also replaced all the o-rings on the fuel rail and changed out the regulator diaphragm. The car now runs great and idles smother than it ever has. Now for the problem. It will not hold pressure. It runs at 32-34 lbs and goes up to around 40 lbs when I rev it. As soon as I turn it off the pressure drops instantly. As in it drops to 5 lbs in about 5 seconds. There are no leaks anywhere. I pulled the vacuum hose from the regulator and it is dry. If the car sits for any time at all when I start it it has to turn over several times. Then when it does start it runs great and idles great. There is no indication that it is running rich. No white smoke and the tailpipes are dry.
Does anyone have any suggestions? Could I have messed something up when I replaced the regulator diaphragm?
Thanks in advance for any advice.
Does anyone have any suggestions? Could I have messed something up when I replaced the regulator diaphragm?
Thanks in advance for any advice.
Racer
Joined: Jul 2022
Posts: 494
Likes: 162
From: Wilmington,Delaware
I have an 88 with a stock L98. I recently changed out the injectors with a set of rebuilt Bosch 3 from SouthBay Injectors. I also replaced all the o-rings on the fuel rail and changed out the regulator diaphragm. The car now runs great and idles smother than it ever has. Now for the problem. It will not hold pressure. It runs at 32-34 lbs and goes up to around 40 lbs when I rev it. As soon as I turn it off the pressure drops instantly. As in it drops to 5 lbs in about 5 seconds. There are no leaks anywhere. I pulled the vacuum hose from the regulator and it is dry. If the car sits for any time at all when I start it it has to turn over several times. Then when it does start it runs great and idles great. There is no indication that it is running rich. No white smoke and the tailpipes are dry.
Does anyone have any suggestions? Could I have messed something up when I replaced the regulator diaphragm?
Thanks in advance for any advice.
Does anyone have any suggestions? Could I have messed something up when I replaced the regulator diaphragm?
Thanks in advance for any advice.
Thread Starter
Heel & Toe
Joined: Sep 2018
Posts: 22
Likes: 3
From: SW Missouri
After running some of the test suggested here on the forum, everything pointed to a faulty FPR even though it was new. So I put the old one back in. It was still in decent condition and I only changed it because I had it apart. That seemed to fix it. I then I made a 120 mile round trip to pick up the only new one available in SW MO. So far, so good. Goes to show that just because something is new dont mean it works. Thanks for the help.
Racer
Joined: Jul 2022
Posts: 494
Likes: 162
From: Wilmington,Delaware
After running some of the test suggested here on the forum, everything pointed to a faulty FPR even though it was new. So I put the old one back in. It was still in decent condition and I only changed it because I had it apart. That seemed to fix it. I then I made a 120 mile round trip to pick up the only new one available in SW MO. So far, so good. Goes to show that just because something is new dont mean it works. Thanks for the help.
