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EBL P4 Cold Idle Adjustment...

Old Feb 8, 2026 | 04:19 PM
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Car: 91 Black Formula KR
Engine: 305 TPI R69/G92
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EBL P4 Cold Idle Adjustment...

EBL P4 Cold Idle Adjustment...I have a 91 Firebird 305 TPI, with Dynamic EFI's EBL P4 ECM.
When I first got it and pluged it in and started the car, I noticed immedieattly that it had a slightly high rev (cuz of starting) but that within a second or 2, it would really drop down the RPM's quite low (much faster than stock ECM) and there wasn't really much of a problem, because I lived in FL at the time...

Now I live in a much colder climate... So it wants to behave the same way, but since the engine is so cold, when it slows down, it's rough, RPM speeding up / slowing down... the warmer it gets the better that smooths out... and when fully warm, idles perfectly.... I have replaced all the sensors (not recently though).

Is there an adjustment I can tune for to just keep the RPM's higher for longer instead ?

Or is there something else I'm missing ?

Thanks!

Raf
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Old Feb 8, 2026 | 04:25 PM
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Re: EBL P4 Cold Idle Adjustment...

The surge sounds like it’s to lean and needs more fuel vs coolant temp for cold start enrichment.
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Old Feb 8, 2026 | 04:41 PM
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luvofjah's Avatar
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From: PNW
Car: 91 Black Formula KR
Engine: 305 TPI R69/G92
Transmission: Astro A5-Pro 5.0-McCleod
Axle/Gears: US Gear 3.42 Eaton True Trac
Re: EBL P4 Cold Idle Adjustment...

Is there a specific control(s) / setting(s) in Tuner Pro to adjust this?
Thanks!
Raf
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Old Feb 8, 2026 | 05:00 PM
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Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: EBL P4 Cold Idle Adjustment...

Open Loop - AFR Multiplier vs CTS

https://web.archive.org/web/20210920...Tune_Intro.php
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Old Feb 8, 2026 | 05:04 PM
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luvofjah's Avatar
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From: PNW
Car: 91 Black Formula KR
Engine: 305 TPI R69/G92
Transmission: Astro A5-Pro 5.0-McCleod
Axle/Gears: US Gear 3.42 Eaton True Trac
Re: EBL P4 Cold Idle Adjustment...

Thanks!
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Old Feb 8, 2026 | 06:01 PM
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: EBL P4 Cold Idle Adjustment...

If you want high rpm
to hang longer you can adjust that in the bin. Should be a target rpm vs coolant temp or iac steps vs coolant temp something to that effect.
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