Sorry for the double post--the below is on SF, but the issue is still an enigma despite about 50 people viewing the thread. I apologize for the length, but please help!
Hey everybody. I have an 88T that is acting insanely strange. Tonight, I drove 15 miles or so to a movie theater (meeting a friend), and the car performed just great during that trip. When I parked, I let it idle as always. No problems whatsoever. A little over two hours later, I go out and try to start the car. It starts, full ignition and everything, but dies after two seconds or so. At first, I thought "no problem, just some heat soak." Nope. Start it again, give it a good rev; the car dies in the same amount of time, revving notwithstanding. For the time it runs, either idling or revving, it seems to perform just fine. Then it seems as though ignition or fuel just completely disappears. I HAVE NO IDEA WHAT COULD CAUSE THIS. There are no engine codes, and resetting the computer by pulling the EFI fuse didn't change a thing. Unplugging my E-Manage, which is currently zeroed out anyway, and jumpering the AFM KV sensor wire didn't change a thing. I logged a bit of data on the E-Manage, and noticed something strang, but it doesn't explain the problem. I'll post the graph soon, but basically when I start my rev, the KV signal falls through the floor. Then the rev stops, because the engine is stalling (apparently), and the KV signal goes back up--but the RPMs keep dropping, and the AFM follows it to the death. That rev was to about 3700 or so. I tried another to about 1600, and it showed a similar story, but in a slightly different way and obviously on a more compressed scale.
I left something in the car that I need to get the graphs off of this crappy PC laptop, so for now I'll just post a few numbers about the shape of the graph. I'll only talk about the higher rev for now.
The graph looks acceptable for slightly over one second time elapsed. Then, at 2887RPM with a KV reading of 357Hz, the KV starts dropping pretty fast as the revs keep climbing. A fifth of a second later, the revs reach their peak while the KV hits its minimum: 3682RPM at 145Hz. Here, the graphs stay pretty constant for another fifth of a second: the KV immediately levels off, and then starts a very gradual climb, and the story is basically opposite for the RPM. RPM keeps dropping until 2450RPM and 350Hz, which it maintains for a bit over a tenth of a second, and proceeds a comparitively slow death. It takes almost two more seconds for the RPMs to go all the way to zero, which is displayed as a linear decline of RPM and KV. KV hits zero about four fifths of a second before the engine totally dies.
This is damn perplexing to me. I might lable it a bad post-turbo/AFM leak if the car actually idled, but died on a rev. The most unusual part about it is that the car was running flawlessly beforehand. I'm pretty sure it's not heat soak, because I tried starting it many times before calling my sister at 1AM, and revving worked well until the car totally quit.
Please advise!!! Thank any soul with a comment! My modifications are in the image below:
Hey everybody. I have an 88T that is acting insanely strange. Tonight, I drove 15 miles or so to a movie theater (meeting a friend), and the car performed just great during that trip. When I parked, I let it idle as always. No problems whatsoever. A little over two hours later, I go out and try to start the car. It starts, full ignition and everything, but dies after two seconds or so. At first, I thought "no problem, just some heat soak." Nope. Start it again, give it a good rev; the car dies in the same amount of time, revving notwithstanding. For the time it runs, either idling or revving, it seems to perform just fine. Then it seems as though ignition or fuel just completely disappears. I HAVE NO IDEA WHAT COULD CAUSE THIS. There are no engine codes, and resetting the computer by pulling the EFI fuse didn't change a thing. Unplugging my E-Manage, which is currently zeroed out anyway, and jumpering the AFM KV sensor wire didn't change a thing. I logged a bit of data on the E-Manage, and noticed something strang, but it doesn't explain the problem. I'll post the graph soon, but basically when I start my rev, the KV signal falls through the floor. Then the rev stops, because the engine is stalling (apparently), and the KV signal goes back up--but the RPMs keep dropping, and the AFM follows it to the death. That rev was to about 3700 or so. I tried another to about 1600, and it showed a similar story, but in a slightly different way and obviously on a more compressed scale.
I left something in the car that I need to get the graphs off of this crappy PC laptop, so for now I'll just post a few numbers about the shape of the graph. I'll only talk about the higher rev for now.
The graph looks acceptable for slightly over one second time elapsed. Then, at 2887RPM with a KV reading of 357Hz, the KV starts dropping pretty fast as the revs keep climbing. A fifth of a second later, the revs reach their peak while the KV hits its minimum: 3682RPM at 145Hz. Here, the graphs stay pretty constant for another fifth of a second: the KV immediately levels off, and then starts a very gradual climb, and the story is basically opposite for the RPM. RPM keeps dropping until 2450RPM and 350Hz, which it maintains for a bit over a tenth of a second, and proceeds a comparitively slow death. It takes almost two more seconds for the RPMs to go all the way to zero, which is displayed as a linear decline of RPM and KV. KV hits zero about four fifths of a second before the engine totally dies.
This is damn perplexing to me. I might lable it a bad post-turbo/AFM leak if the car actually idled, but died on a rev. The most unusual part about it is that the car was running flawlessly beforehand. I'm pretty sure it's not heat soak, because I tried starting it many times before calling my sister at 1AM, and revving worked well until the car totally quit.
Please advise!!! Thank any soul with a comment! My modifications are in the image below:
