ZR8ED

Car has been driving great lately. I was cleaning up the car on the weekend, and when I was done, the car would startup and the stall right away?? I rechecked the electrical thinking "what did I muck/touch while cleaning the car".
Back to basics.
Pulled a plug wire..I have spark.
I have compression and air coming in, because it will run, and has been running flawlessly for the last week or two.
Swapped dme relay. no change
Checked fuely pump (dme relay 30 and 87b per clark's) fuel pump works fine.
Check the pressure. 40psi with pump on and car turned off. Turn off pump (remove jumper) pressure drops to zero within seconds...oh oh....
Put a pressure guage on the rail reads 36 ish when I get the car to run...BUT spikes to 100psi and car stalls...oh oh

Try again with same results. Darn It looks like the fpr is shot. Ordered a new fpr and a fuel pump check valve as the pressure should not drop to zero in a few seconds.
I hope it gets here soon. Daily driver is now parked in the garage, and the Cab is now on duty until a new part arrives. I hope that works, as I'd rather be working on the cab, than my daily driver.

pontifex4

Is your TPS plugged in?

ZR8ED

Hmm I didn't look specifically at the tps, but will check it out today. It's very helpful to have to 44's side by side for comparisons.
While waiting for the fpr and check valve to arrive, I'm going to jumper the fuel pump in my cab and listen to the pump to compare. The black coupe makes a lot of gurgling sounds on the fuel rail, when I jumper the fuel pump on with the car turned off. Sound is in the area of the fpr. If the cab sounds the same, I'll disregard the sound, but it doesn't sound normal to me.
Weird that the car will start right up at 40psi, and spike to 100+ (pegged the guage) in less than a second, and the car stalls as it spikes. I wonder if the fpr is failing in the closed position causing the pressure to spike instantly?

ilikemy944

Also make sure your AFM is plugged in tightly. Typical unplugged behavior is car starts but dies before settling at idle.

ZR8ED

Thinking of what you guys are suggesting, is making me think that maybe the fpr is ok (except for the leakdown issue which may be separate) Maybe the pressure is spiking due to the car stalling and the injectors stop firing and the pump still pressurizing the system. Kind of like hitting a wall...hmmm

86 951 Driver

Do you hear a loud squeal coming from the rear when your fuel pressure spikes? If it does then your FPR is bad? Do you see a lot of black soot in your tailpipe? Can you rev it up to keep it alive?

ZR8ED

No soot. It won't run long enough. I think the longest I had it running was 3-4seconds. Most starts will start and die within a second.

86 951 Driver

Can you press the gas pedal down to try and keep it alive?

ZR8ED

Touching the gas pedal causes it to die.
Ok. more tests.
I removed the afm etc, and cleaned all the connectors in the area. afm, tps, temp.

Put the fuel pressure gage on the rail again, and started the car. I could see the guage from the cockpit. I started the car again, and it idled for a few seconds. Just before it stumbled and stalled, the fuel pressure gauge pegged. 100psi + It dropped back to zero within 5-6 seconds. While the pressure was reading high, I tried to restart it. No go. I let it drop back to zero, and I got it to start again. The gauge then spiked, and the car stalled. FPR I guess....

86 951 Driver

My car didn't stall when my FPR was bad. It ran really really rough. It didn't have good power and was running bad. I would get a new stock FPR that should fix your issue. Mine would spike the gauge when it went bad except the pump would start to squeal.

ZR8ED

Finally the parts arrived. 15min to install, and the car fired up and ran perfectly. When I shut it off, the fuel pressure does not drop to zero. (I'm typing this while waiting for the leakdown test to finish, but so far it is fine)
Back to dd status for next week.
I'm going to drive it around this weekend to confirm it is reliable. After that, I will change the fuel filter and check valve, and the fuel system should be good for a while.

Thanks!

V2Rocket

wow...read the thread title and thought you meant that RL user "FRPorscheman" had been shot...


glad the problem was resolved quickly lol

mytrplseven

Good going.