All of a sudden, the engine is running rich - SOLVED
Posted: Tue May 25, 2010 7:01 pm
I'm having trouble with my car going really, really rich at full throttle, and then losing power after it has been running for a short while. It has me completely baffled. MSQ and datalogs attached. In the datalog, around 188990 seconds, is where I start my test. I floor the throttle and it runs up to the 8000 rev limiter, at which point it cuts fuel, and bounces off the limiter. About 10 seconds later, I do the same thing, but it doesn't quite make it to the 8000 limit and then starts to fall off. 30 seconds later, I try the same thing without reaching the limiter. Finally, I use partial throttle, and I'm able to get it up to the 8000 limit again.
This is all with the car standing still, so no load. When I drive it around, I can get one good pull up to the limit, after that, it starts bogging above 4600rpm and is very down on power. The AFR also shows really rich as it loses power. It is acting almost like a plugged fuel filter, except I would expect it to go lean if that was the case.
Here's the really weird part: I used my car in a race 2 weekends ago, and the tune was fine. I was running it over 7600rpm with power, and hitting the limiter all weekend long. The *only* things I changed after the race were the wheels and a bent control arm. All of this bogging started this past Saturday.
Yesterday I checked the fuel pressure and it was too high (43-45psi). This would explain the thing going rich. Today I changed the pressure regulator and re-checked pressure. It is now normal pressure (~38psi, the same as my other Corolla), but still has the same problems. Could the high pressure have damaged anything? I'm using RC Engineering injectors, rated at 43.5psi, so they should be fine.
I suppose I could change my VE table to compensate for whatever has happened, but it was working fine for weeks up until now, and I haven't changed anything in the config. I've even reloaded the msq from before the race to be sure (only differences from the one attached are a spare port output triggering a "shift light" at 7600 instead of 7200, and slightly tweaked warmup enrichments... nothing relevant to this problem). I'm worried that if I lean it out now, then when the gremlin leaves, I'll burn up the motor.
Any ideas? I'm running out of things to try.
This is all with the car standing still, so no load. When I drive it around, I can get one good pull up to the limit, after that, it starts bogging above 4600rpm and is very down on power. The AFR also shows really rich as it loses power. It is acting almost like a plugged fuel filter, except I would expect it to go lean if that was the case.
Here's the really weird part: I used my car in a race 2 weekends ago, and the tune was fine. I was running it over 7600rpm with power, and hitting the limiter all weekend long. The *only* things I changed after the race were the wheels and a bent control arm. All of this bogging started this past Saturday.
Yesterday I checked the fuel pressure and it was too high (43-45psi). This would explain the thing going rich. Today I changed the pressure regulator and re-checked pressure. It is now normal pressure (~38psi, the same as my other Corolla), but still has the same problems. Could the high pressure have damaged anything? I'm using RC Engineering injectors, rated at 43.5psi, so they should be fine.
I suppose I could change my VE table to compensate for whatever has happened, but it was working fine for weeks up until now, and I haven't changed anything in the config. I've even reloaded the msq from before the race to be sure (only differences from the one attached are a spare port output triggering a "shift light" at 7600 instead of 7200, and slightly tweaked warmup enrichments... nothing relevant to this problem). I'm worried that if I lean it out now, then when the gremlin leaves, I'll burn up the motor.
Any ideas? I'm running out of things to try.
