FD ignition problems during righthand turns
08-03-05, 12:14 PM
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FD ignition problems during righthand turns
I'm posting this here because I have only seen this problem on the track, and I'm hoping another track junkie may recognize these symptoms...
The car is a 1994 stock plus usual reliability mods, ~50k odometer.
On track, during tight mid-speed (30-70mph) right-hand turns, the car severely bogs.
Typically happens after turn-in, when I am rolling the power on.
Power drops off significantly, and RPM (as displayed by the tachometer) drops quickly to 0, and then bounces up and down between 0 & 3000 or so until I straighten out the wheel. From what I can feel, the engine during this time does not appear to be jumping around, it feels like it is smoothly revving down.
The problem appears to get worse as the day goes on and as the car heats up, although that may be unrelated. It does not occur on similar lefthand turns.
Searching has yielded references to rubbing through fenderliners to wires on the other side, and references to bad grounding. I have checked my fender liners, but they appear to be intact (running stock wheels). I have checked engine grounds, also appear to be in good condition.
Seems like it may be some sort of ignition problem, but I don't know where to start looking.
Any ideas of what to investigate? I'm heading to the track tomorrow and then again in about 10 days. Hoping to get some good debugging time in on this...
The car is a 1994 stock plus usual reliability mods, ~50k odometer.
On track, during tight mid-speed (30-70mph) right-hand turns, the car severely bogs.
Typically happens after turn-in, when I am rolling the power on.
Power drops off significantly, and RPM (as displayed by the tachometer) drops quickly to 0, and then bounces up and down between 0 & 3000 or so until I straighten out the wheel. From what I can feel, the engine during this time does not appear to be jumping around, it feels like it is smoothly revving down.
The problem appears to get worse as the day goes on and as the car heats up, although that may be unrelated. It does not occur on similar lefthand turns.
Searching has yielded references to rubbing through fenderliners to wires on the other side, and references to bad grounding. I have checked my fender liners, but they appear to be intact (running stock wheels). I have checked engine grounds, also appear to be in good condition.
Seems like it may be some sort of ignition problem, but I don't know where to start looking.
Any ideas of what to investigate? I'm heading to the track tomorrow and then again in about 10 days. Hoping to get some good debugging time in on this...
08-03-05, 05:23 PM
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If your tach is dropping you are loosing the signal to or from the ECU. I would start where the ignition signal is generated at the crank position sensors and move toward the ECU. I'd also check the ECU carefully especially if it has ever been removed.
09-13-05, 10:57 AM
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In case anyone ever searchs for this problem, the solution in my case was better engine grounding. Likely the engine was losing ground during the turns, and this was causing the ECU to fail (among other things probably) to read the crank angle sensors.
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