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High Idle Problem

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Old 12-02-03, 06:16 PM
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High Idle Problem

My car idles at about 2100rpm. I was told that the PFC takes a while to 'learn' the car or something but I've put 700 miles on the car with the PFC and it hasn't changed at all.

We've checked for a vacuum leak, but there isn't one. We checked for an intake leak but can't find anything there either.

With the pedal all the way to the floor the car reads 95.1% throttle (when the throttle was reading 84% with the pedal all the way down the idle was erratic and wavered in between 750 and 1950 and settled at 1350 (where the stick ecu idled) after about 45 seconds).


The timing at idle is 31/31. The PFC is tuned to a base map right now. I would think that it was just tuning but the car tries to drive itself. I can let off the clutch and the car will go by itself and speed up to about 2000rpms without me even touching the gas.

Any ideas would be greatly appreciated.
Old 12-02-03, 06:23 PM
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my guess is your TPS is all out of whack. Search for how to calibrate it, as i am not sure how to do it.

-Zach
Old 12-02-03, 10:05 PM
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it could just be your idle adjustment screw near the throttle body. call jerry and ask em.
Old 12-03-03, 01:43 AM
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High idle may be caused by vaccum leak. last time I need to replace the lower intake manifold gasket and never see this problem again.
Old 12-03-03, 01:34 PM
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Would that cause the timing to be like it is?
Old 12-04-03, 01:05 PM
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And the car to drive itself like it does?
Old 12-04-03, 01:49 PM
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31/31 wow thats alot more timing than i have at idle...

im about 10/5, turn your timing the hell down
Old 12-04-03, 08:11 PM
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I have the same idle problem only without the PFC.

Do a sensor check with the commander.

I believe your timing is at 31 because of the high idle...in other words your timing is not causing the high idle...

If you want I can send you a datalog of what your sensor voltages should be at idle...

just pm me your email address
Old 12-07-03, 05:34 AM
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Any other ideas?
Old 12-07-03, 06:09 AM
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try to check if the throttle cable it too tight. then check the 2 idle adjustment screws and then redo the tps
Old 12-07-03, 04:44 PM
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I just remembered something. My boost gauge is off. I'm not sure if this is common or not but my boost gauge reads 2 psi when the commander crosses from vacuum to boost. And the boost gauge reads 11.5-12 psi when the commander reads .70 kg/cm^2 (10psi). Does that indicate a leak or some sort or does that not mean anything?
Old 12-07-03, 05:01 PM
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well that means that either your boost gauge or your map sensor is inaccurate. What kind of boost gauge are you using...

the map sensor should be into a nipple on the rear of the uim, while the boost gauge should be into one of the two nipples that faces the side of the car on the uim, as per mazda spec.

Its not uncommen for boost gauges to read 2 psi off. Ive seen even the most expensive 300$ gauges read inaccurate.
Old 12-08-03, 12:18 PM
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I just had a chance to compare the datalog that you sent me with my car. Everything looks to be alright except VTA1 and VTA2 voltages. The throttle sensors for full and narrow range. VTA1 on your sheet was .38, mine was .61. VTA2 on your sheet was 0.8, mine was 1.44. These were with the car off and warm. Everything else that was different I was able to account for (temp voltages, switches...).
Old 01-09-04, 03:15 PM
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Are the throttle body coolant lines bypassed? If so, and the Fast Idle Cam wasn't wired open, this would explain the idle problem.

http://www.scuderiaciriani.com/rx7/t...e_removal.html

btw, did you ever get that pressure relief cap installed?
Old 01-10-04, 03:53 AM
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I'm running an ast now, but found a pressure relief cap from a 2nd gen that I think I'm going to use instead.

Thanks for the link I'll try that out.
Old 02-28-04, 11:46 PM
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My car just started doing this. It idles at 3200 rpm! Annoying. I don't see any vacuum leaks. I thought maybe the Power FC had something to do with this. I may adjust the throttle adjustment screw and see what happens?
Old 02-29-04, 03:32 PM
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Found the vacuum leak. It was one of the vacuum taps under the UIM. Had to remove the UIM to ziptie the hoses back on (so they don't pop off again under 15 psi boost). Idle's fine now.
Originally posted by SleepR1
My car just started doing this. It idles at 3200 rpm! Annoying. I don't see any vacuum leaks. I thought maybe the Power FC had something to do with this. I may adjust the throttle adjustment screw and see what happens?
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