L98 Bad Fuel Pressure Leak
Thread Starter
Heel & Toe
Joined: Nov 2019
Posts: 17
Likes: 0
From: Tampa, FL
L98 Bad Fuel Pressure Leak
1989 L98 92k miles
Was thinking if anyone could shed some light for me. I recently replaced my OEM injectors with some Bosch 3 FIC injectors. The first go around I installed them following the instructions given and caused me some massive leaks, leaking on the intake and exhaust. Fuel Pressure dropped from 40psi to 5psi within seconds. I swapped in the old ones and nothing leaked on the outside. Swapped o rings from OEM to bosch injectors and leaked like crazy still.
I got in contact with FIC and they sent me out a new set.(Fantastic Customer Service) I now installed them and there are now no visible leaks but my gauge shows it will prime to 40psi and drop to 20 within 30 seconds. (Checked with mulitple gauges as well). However, before my OEM injectors would prime to 45psi but slowly drop to 10psi in 8 minutes. and the new bosch 3 will prime to 40psi and drop to 20psi in about 30 seconds.
I also replaced the FPR and fuel filter from FIC as well. And the fuel pump is somewhat new. It has less than 4k miles but was replaced in 2012 and ever since it was replaced it was started 3-4 times a month since but not driven just idled.
I am hoping someone could shed some light on my issue for me.
Thank you
Edit: Fuel Pump was just replaced after this post and still have the same issue.
Was thinking if anyone could shed some light for me. I recently replaced my OEM injectors with some Bosch 3 FIC injectors. The first go around I installed them following the instructions given and caused me some massive leaks, leaking on the intake and exhaust. Fuel Pressure dropped from 40psi to 5psi within seconds. I swapped in the old ones and nothing leaked on the outside. Swapped o rings from OEM to bosch injectors and leaked like crazy still.
I got in contact with FIC and they sent me out a new set.(Fantastic Customer Service) I now installed them and there are now no visible leaks but my gauge shows it will prime to 40psi and drop to 20 within 30 seconds. (Checked with mulitple gauges as well). However, before my OEM injectors would prime to 45psi but slowly drop to 10psi in 8 minutes. and the new bosch 3 will prime to 40psi and drop to 20psi in about 30 seconds.
I also replaced the FPR and fuel filter from FIC as well. And the fuel pump is somewhat new. It has less than 4k miles but was replaced in 2012 and ever since it was replaced it was started 3-4 times a month since but not driven just idled.
I am hoping someone could shed some light on my issue for me.
Thank you
Edit: Fuel Pump was just replaced after this post and still have the same issue.
Last edited by JoshWilkerson1; Nov 29, 2019 at 08:58 PM.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
If the old injectors bled down in 8 minutes, and your new injectors bleed down in 20 seconds, it has to be the injectors leaking into the motor or your regulator leaking if you haven't touched anything else. The fuel filter wouldn't affect anything unless you had a puddle under the car. Pull the vacuum hose going to the regulator and sniff around for gas. If looks and smells ok, send back the injectors and check your oil for fuel contamination.
Thread Starter
Heel & Toe
Joined: Nov 2019
Posts: 17
Likes: 0
From: Tampa, FL
If the old injectors bled down in 8 minutes, and your new injectors bleed down in 20 seconds, it has to be the injectors leaking into the motor or your regulator leaking if you haven't touched anything else. The fuel filter wouldn't affect anything unless you had a puddle under the car. Pull the vacuum hose going to the regulator and sniff around for gas. If looks and smells ok, send back the injectors and check your oil for fuel contamination.
I am not sure what to do at this point anymore.
Edit: When idling car runs at 34psi too.
Last edited by JoshWilkerson1; Nov 29, 2019 at 09:05 PM.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
It shouldn't be the fuel pump if it worked before. Pressure bleeds of 3 ways if there are no external leaks, the injectors, regulator or fuel pump. My pressure bleeds down in just a few seconds but I know it's the fuel pump and doesn't hurt anything in my case.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
It shouldn't be the fuel pump if it worked before. Pressure bleeds of 3 ways if there are no external leaks, the injectors, regulator or fuel pump. My pressure bleeds down in just a few seconds but I know it's the fuel pump and doesn't hurt anything in my case.
Thread Starter
Heel & Toe
Joined: Nov 2019
Posts: 17
Likes: 0
From: Tampa, FL
Well. Before the injector change it bled down in 8 minutes. However when I changed the injectors I also changed the FPR as well. Im pretty sure there is not a wrong way to install that regulator. It was tough to put back on it took one person to hold th cap down while i feed one of the screws in and everything lined up. The fuel pump was replaced with a new one my dad bought for this car back in 2012 it was never used. And we tested injectors and none leak. So maybe I installed the FPR wrong or it is faulty?
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
So, crazy idea but maybe more testing and determine where it is leaking from or to?
