09-11-2023, 03:45 PM
Those with stage 2 or 3 D1R superchargers have a special adjustable fuel pressure regulator (FPR) that was part of the kit. Mine failed, and I thought it would be useful to inform others that might have the problem what the symptoms were and what to do.
First the car became difficult to start. I had to hold the pedal to the floor and crank for awhile before it would fire. Once it did start, I had to keep the throttle open some for a minute or two to keep it from dying .
Second the idle was not steady. It would rise and fall between about 800 and 1200 rpm with the throttle closed.
Third, I had a very weird feeling power dead spot around 2600 rpm.
Fourth, after starting there was a strong gas smell.
Fifth, heavy black soot in the tailpipe.
Sixth, decreased gas mileage.
For my first troubleshooting I changed the idle regulating valve. I watched a number of YouTube videos that described symptoms like mine that were caused by a bad idle regulating valve. This is a pain to change because you have to take the intake manifold off. After changing this valve, I saw no improvement. I wasn't happy.
I checked all vacuum lines and found no leaks.
More research and thinking about the problem led me to the FPR. I hadn't looked at this at first because the pressure on the fuel rail did not seem to be varying.
I pulled the vacuum hose off the FPR in the garage while the car was idling and sure enough there was raw gas coming out. Bingo. FPR with failed diaphragm. I removed the FPR, took it apart and verified the diaphragm was shot. I contacted Bob/Flash, and he was able to point me to the company that had supplied him the FPRs. A search of their website showed they sold replacement diaphragms. I called them, found they do have these diaphragms in stock, and ordered 2. Some days you get lucky because we are down for the count without a working FPR. There were no identifying marks or labels on the FPR that would have allowed me to locate where to get these.
Here is a link to the site page with the replacement diaphragms. https://www.kirbanperformance.com/replac...tor/p44186
I've attached a picture of my FPR after disassembly. Hopefully there's enough detail to see the sad shape of the rubber diaphragm.
First the car became difficult to start. I had to hold the pedal to the floor and crank for awhile before it would fire. Once it did start, I had to keep the throttle open some for a minute or two to keep it from dying .
Second the idle was not steady. It would rise and fall between about 800 and 1200 rpm with the throttle closed.
Third, I had a very weird feeling power dead spot around 2600 rpm.
Fourth, after starting there was a strong gas smell.
Fifth, heavy black soot in the tailpipe.
Sixth, decreased gas mileage.
For my first troubleshooting I changed the idle regulating valve. I watched a number of YouTube videos that described symptoms like mine that were caused by a bad idle regulating valve. This is a pain to change because you have to take the intake manifold off. After changing this valve, I saw no improvement. I wasn't happy.
I checked all vacuum lines and found no leaks.
More research and thinking about the problem led me to the FPR. I hadn't looked at this at first because the pressure on the fuel rail did not seem to be varying.
I pulled the vacuum hose off the FPR in the garage while the car was idling and sure enough there was raw gas coming out. Bingo. FPR with failed diaphragm. I removed the FPR, took it apart and verified the diaphragm was shot. I contacted Bob/Flash, and he was able to point me to the company that had supplied him the FPRs. A search of their website showed they sold replacement diaphragms. I called them, found they do have these diaphragms in stock, and ordered 2. Some days you get lucky because we are down for the count without a working FPR. There were no identifying marks or labels on the FPR that would have allowed me to locate where to get these.
Here is a link to the site page with the replacement diaphragms. https://www.kirbanperformance.com/replac...tor/p44186
I've attached a picture of my FPR after disassembly. Hopefully there's enough detail to see the sad shape of the rubber diaphragm.
