91 Fuel(?) shutoff under full throttle
#1
01-11-2009, 11:39 AM
91 Fuel(?) shutoff under full throttle
Greetings all,
My 91 6spd convert has started having an issue with what seems to be a fuel shutoff under full throttle. The first incident was several days ago when I took it to work. After merging onto the hwy, I pulled out to pass a guy in 5th. I got out and beside him when everything just stopped. No response from the pedal at all. I tried shifting down/up and everything was like I was just off the gas. In neutral, it would idle fine, which leads me to believe that the computer cut me off for some reason. When I looked down right as it happened, I was doing 84mph, so there was no way I overrevved unless something slipped. After about 10-15 frantic seconds, everything came back and drove fine for the rest of the trip and return trip. At one point, I even put it back in 5th and let er rip, with no problem, even accellerating past the previous stall speed.
So, I tried to recreate the problem this morning and was successful, though with slightly different results. This time, it cut me off at about 74mph. When I shifted out, it came back immediately. In the process, I confirmed that the engine would maintain idle. On the way back from the store, I took advantage of the long on-ramp to try again. I revved it up pretty good in all low gears, but 5th killed me again. RPM was 2500. Unfortunately, this one lasted a long time like the original incident, which made merging fairly interesting. I actually paniced slightly and shut the car off and recranked. Everything came back ok and I didn't get run over.
It seems to me like the computer is shutting me down for some reason. At first I had assumed that I had spazzed out and overrevved, but today's experiment pretty well killed that idea (unless a sensor is misreporting). Everything runs fine at partial throttle (so far). I checked for engine codes when I got back, but none were displayed (other than the "I'm ok #12").
Any ideas? The only thing I can think of is bad gas or blocked fuel filter, but that doesn't seem to make sense based on it running well at lower speeds.
Thanks,
SteelBlue91
My 91 6spd convert has started having an issue with what seems to be a fuel shutoff under full throttle. The first incident was several days ago when I took it to work. After merging onto the hwy, I pulled out to pass a guy in 5th. I got out and beside him when everything just stopped. No response from the pedal at all. I tried shifting down/up and everything was like I was just off the gas. In neutral, it would idle fine, which leads me to believe that the computer cut me off for some reason. When I looked down right as it happened, I was doing 84mph, so there was no way I overrevved unless something slipped. After about 10-15 frantic seconds, everything came back and drove fine for the rest of the trip and return trip. At one point, I even put it back in 5th and let er rip, with no problem, even accellerating past the previous stall speed.
So, I tried to recreate the problem this morning and was successful, though with slightly different results. This time, it cut me off at about 74mph. When I shifted out, it came back immediately. In the process, I confirmed that the engine would maintain idle. On the way back from the store, I took advantage of the long on-ramp to try again. I revved it up pretty good in all low gears, but 5th killed me again. RPM was 2500. Unfortunately, this one lasted a long time like the original incident, which made merging fairly interesting. I actually paniced slightly and shut the car off and recranked. Everything came back ok and I didn't get run over.
It seems to me like the computer is shutting me down for some reason. At first I had assumed that I had spazzed out and overrevved, but today's experiment pretty well killed that idea (unless a sensor is misreporting). Everything runs fine at partial throttle (so far). I checked for engine codes when I got back, but none were displayed (other than the "I'm ok #12").
Any ideas? The only thing I can think of is bad gas or blocked fuel filter, but that doesn't seem to make sense based on it running well at lower speeds.
Thanks,
SteelBlue91
#2
01-12-2009, 07:56 AM
RE: 91 Fuel(?) shutoff under full throttle
Noway you could have over revved an L98. The rev lmiter is some where around 10K RPM on an L98. I would attach a fuel pressure gauge to the schrader valve and tape it to your windshield and try to recreate the issue. See what fuel pressure you are getting at the instant the problem is happening and you will at least know if fuel is being cut off or starved at that moment. Its a start.
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