Quote:
Originally Posted by cp1joel
Hi Mike,
Good to see that you are hopefully getting to the bottom of your issues. I am looking forward to seeing if this fixes the idle and power issues.
I took the Z out for a drive yesterday and the car ran very well. What was interesting though, was when the A/C was turned on, my rough idle and loss of power seemed to return.
The car started to get sloppy again when stopped at lights and in traffic.
Once the A/C was switched off, it drove a lot better (even with the bigger cams and the run-in tune )
Anyway food for thought.
Cheers
Joel
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Joel,
If u have bigger cams(and I presume u ported top end), the additional load ur putting on motor when turning on A/C is causing the ECM to use a different part of the VE and SA tables. If u haven’t addressed those areas while tuning, its likely they’re inadequate for handling the A/C request. Plus, the bigger cams lower the overall vacuum at idle so u will probably need to increase IAC steps to maintain idle w the additional load. Maybe even SA.
What happens is that the motor starts to oscillate as the ECM tries to maintain idle and stall saver kicks in. The stock tune will have too much compensation for the larger cams and u get a seesaw effect.