Diagnosing Idle and RPM issue on H2B
06-17-2012, 02:51 PM
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Diagnosing Idle and RPM issue on H2B
Thought I'd repost here since Tech/Misc has really light traffic and it's been all weekend.
Car is a 2000 DX hatchback, H2B swap with H23A and ITR transmission.
I'm having some serious trouble sorting out the idle issue with my car. It really idled just fine before I got my valve cover powder coated, so I'm still trying to sort out what possibly could have changed. I've replaced and cleaned and now returned to the original PCV valve (it's in the valve cover on the h23) and that didn't seem to do anything.
Here's the issue:
When I start it up it idles (AC on) at ~2000rpm and searches a little. once warm it still idles around ~1400-1500 or so and searches a little. AC has a dramatic impact on the idle compensation. Even when the car is at operating temp it still idles around 1500 with the AC on, it really takes a good 30min+ of driving to get the idle to start staying near normal at rest.
And when I downshift the RPMs drop too quickly and sometimes stall the car. Even downshifting the rpms drop well below 1000rpm sometimes while cruising down the road. Most of the time it stalls it's when I'm in first gear coming from a stop and there's more load on the engine than usual. It's like the engine just has major parasitic drag on it is what it feels like.
Took it back to the tuner and he's convinced it's the Omni throttle bodies' lack of a idle screw and probably "poor idle porting." The skunk2 throttle body with the idle screw was a pile of garbage I sent back and got the Omni instead.
Intake air temperatures are ~147 degrees which he says is a bit warm. (Big engine, little engine bay) He suggests extending my Short ram intake to a cold air and moving the intake air temperature sensor to the intake piping and off of the scalding intake manifold that is soaking so much heat. He adjusted the duty cycle on the tune a bit and that really didn't do much, if anything.
My mechanic at Mainstream doesn't think it's the throttle body, he suggests moving the intake air temperature sensor and going from there. He thinks it's puling timing.
Thoughts?
Car is a 2000 DX hatchback, H2B swap with H23A and ITR transmission.
I'm having some serious trouble sorting out the idle issue with my car. It really idled just fine before I got my valve cover powder coated, so I'm still trying to sort out what possibly could have changed. I've replaced and cleaned and now returned to the original PCV valve (it's in the valve cover on the h23) and that didn't seem to do anything.
Here's the issue:
When I start it up it idles (AC on) at ~2000rpm and searches a little. once warm it still idles around ~1400-1500 or so and searches a little. AC has a dramatic impact on the idle compensation. Even when the car is at operating temp it still idles around 1500 with the AC on, it really takes a good 30min+ of driving to get the idle to start staying near normal at rest.
And when I downshift the RPMs drop too quickly and sometimes stall the car. Even downshifting the rpms drop well below 1000rpm sometimes while cruising down the road. Most of the time it stalls it's when I'm in first gear coming from a stop and there's more load on the engine than usual. It's like the engine just has major parasitic drag on it is what it feels like.
Took it back to the tuner and he's convinced it's the Omni throttle bodies' lack of a idle screw and probably "poor idle porting." The skunk2 throttle body with the idle screw was a pile of garbage I sent back and got the Omni instead.
Intake air temperatures are ~147 degrees which he says is a bit warm. (Big engine, little engine bay) He suggests extending my Short ram intake to a cold air and moving the intake air temperature sensor to the intake piping and off of the scalding intake manifold that is soaking so much heat. He adjusted the duty cycle on the tune a bit and that really didn't do much, if anything.
My mechanic at Mainstream doesn't think it's the throttle body, he suggests moving the intake air temperature sensor and going from there. He thinks it's puling timing.
Thoughts?
06-18-2012, 06:37 AM
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Re: Diagnosing Idle and RPM issue on H2B
Ordered a TPS sensor today. Hoping that addresses the problem. Starting to make more sense that it is that.
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