Difference between commanded and actual TP at idle.
07-21-2013, 01:09 PM
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Difference between commanded and actual TP at idle. I've got a car with a GMPP LS3 engine and controller, and it's got an idle problem. If it was a cable-operated car, I'd call it a sticky throttle.
Most of the time, the car idles high - 1100-1300 rpm. Occasionally, it will settle down into the desired 800 rpm. But fairly rarely, and without any rhyme or reason I can figure out.
Looking at my HPTuners logs, it looks like there's a fair difference between the commanded ETC TPS and the throttle position. The former will read around 10% with the high idle while the latter sits at 22%. When things work, the throttle position drops down to 16% or so and the car idles properly.
When it does settle down, the first time I blip the throttle it hangs high again.
There's no vacuum leak and I've tried a couple of different (known good) throttle bodies and pedals. Any ideas where to look?
Most of the time, the car idles high - 1100-1300 rpm. Occasionally, it will settle down into the desired 800 rpm. But fairly rarely, and without any rhyme or reason I can figure out.
Looking at my HPTuners logs, it looks like there's a fair difference between the commanded ETC TPS and the throttle position. The former will read around 10% with the high idle while the latter sits at 22%. When things work, the throttle position drops down to 16% or so and the car idles properly.
When it does settle down, the first time I blip the throttle it hangs high again.
There's no vacuum leak and I've tried a couple of different (known good) throttle bodies and pedals. Any ideas where to look?
