[Markus]

lt1: rough idle/bad throttle response=>ecm changing always open/closed loop!

Hello!
A few days ago I entered the forum with the problem above:


Rough idle/bad throttle response. But the engine (92'Corvette LT 1) starts normal, cold and hot. The rough idle starts after warming up.
Now I used a scanning software and the only thing I noticed was that the engine is always changing between open and closed loop. Could this be normal?
The O2-sensors always have arround 0.5 V. I think this is ok, isn't it?
Last weekend I disconnected the O2 sensors but without any reaction to idling.
Perhaps I could send the data (From TTS Datamaster) to anyone who could handle these data better than me => You're welcome.

 

[camcojb]

Re: lt1: rough idle/bad throttle response=>ecm changing always open/closed loop!

have you tried replacing the O2's? I'd look there first as they don't give feedback until they warm up, and that's when the problem starts.

I see you have headers; they can also cause problems with keeping the O2's hot enough, though that usually happens with long tubes not shorties. Are your O2's the heated type? I would try a pair of those in place of your stock O2's, will solve both problems (if they're bad or if they can't stay "lit")

Jody