Car no longer fast idles on cold starts? - MustangForums.com


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Old 03-10-2017, 04:23 PM   #1
schecterplayer
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Default Car no longer fast idles on cold starts?

Hey everyone! Yet again another question on my trick flow HCI car lol. In my other posts ive asked about the car running really rich. Like eyes burning rich. It never did that before the hci swap. I checked for vacuum leaks religiously, having previously repaired one on my stock setup i knew what the symptoms were. Anyway, the main issue as far as i can tell is that i have a BAMA tune on the car right now and the "Performance Tune" is the biggest offender as far as the rich condition. The "Street Tune" seems much less rich but still not how i remember the car smelling stock with no emissions equipment. SO. That all being said, I am using the stock ecu for now until dyno day. The car smells, acts, idles the best on this tune. The only issue right now is that the car wont go into the normal fast idle like it used to when its cold. It by no means stalls, but it runs slightly rough until up to temp. Idk if this is normal behavior with a cam? I would like it to fast idle for 20 secs or so like it used to.

Last edited by schecterplayer; 03-11-2017 at 06:30 AM.
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Old 03-11-2017, 01:28 PM   #2
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Might be tune related. If the stock ECU is running it fine for now Id just roll with it until you can get it fixed. I wouldn't think you'd have any other issues other than maybe an ECT out of range or air pocket in coolant causing a false reading.
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Old 03-11-2017, 01:57 PM   #3
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Might be tune related. If the stock ECU is running it fine for now Id just roll with it until you can get it fixed. I wouldn't think you'd have any other issues other than maybe an ECT out of range or air pocket in coolant causing a false reading.
hey thanks for the reply. I have replaced the ect when I put the engine together. The weird thing is after I set the base idle, the next morning the car revved up to 1500, then settled down perfectly. Just like stock. It only did that for that one time. Would the ecu be detecting a lean condition because of all the extra air coming in and then trying to compensate causing the rich condition? Once the car was driven it went back to having a rough cold start, like it changed the fuel tables. I'm also thinking possibly a tps issue because I didn't check it when I set the idle.
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Old 03-13-2017, 07:52 AM   #4
88 orangepeel notch
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Definitely sounds like it's tune related going off your discription. Have you pulled codes lately ?
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Old 03-13-2017, 08:50 AM   #5
schecterplayer
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Definitely sounds like it's tune related going off your discription. Have you pulled codes lately ?
only code I have is for the purge canister. Got a pass for koer.
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Old 03-14-2017, 09:53 AM   #6
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Then a good tuner should be able to get her running nice a smooth again. Good luck
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Old 03-14-2017, 10:34 AM   #7
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Then a good tuner should be able to get her running nice a smooth again. Good luck
thanks for the help. I feel pretty lucky. I see all over the place that people are having horrible problems after a hci job and I'm being picky about how it cold starts lol. I really haven't had any issues other than initial idle problems.
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Old 03-15-2017, 05:53 PM   #8
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Just a quick update on my fast idle situation. It's fixed!! I read on the surging idle checklist that doing the base idle reset involves more than just unplugging the iac. I read that you should unplug the spout for timing, the iac, and the tps. I did that. Set idle to about 750. Car idled great at that speed. So I shut the car off. Plugged it all back in, and the car has never idled so good. Just like stock. I checked it today being 40 degrees outside and the car started right up, smoothly went to high idle and returned to base. So the moral of the story is FOLLOW THE SURGING IDLE CHECKLIST RELIGIOUSLY!!!
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Old 03-16-2017, 07:10 AM   #9
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Glad to hear and thanks for the update.

Funny how some simple, overlooked things can cause an issue. Good find....
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