I need help with an Idle issue
Thread Starter
Member
Joined: Nov 2002
Posts: 100
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From: Port Orange Florida
Car: 89 IROC
Engine: 350 CI Tuned Port
Transmission: Automatic
Axle/Gears: 3:45
I need help with an Idle issue
I am having some trouble finding exactly what is causing my problem and would appreciate a nudge in the right direction. I built myself a TBI powered 383 with Vortec style heads and a 213/219 Lingenfelter camshaft. I am running $42. Here is the issue I am having. I start the car, warm it up, and everything is good. It will idle at my targeted 800 RPM. I can turn on the A/C or put it in gear and see the IAC steps increase. When I take it out of gear or turn off the A/C they decay back out as they should. However as soon as I drive the car, at the first stop I can feel the idle has jumped and the engine is pulling in drive. If I take it out of gear it is now idling at 1600 or so RPM and stays that way. The IAC is maxed out at its park of 145. I can shut the car off and restart it and it will be back to the 850 RPM target. Until I drive it again. I pasted and copied all of the stock IAC settings back in as an experiment and it did not change this behavior. I imagine I am looking in the wrong place for this issue and dont know where the right place is. Hopefully someone here does. Thanks Roy
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Joined: Feb 2016
Posts: 62
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From: UT
Car: 84 Corvette Z51 ("The GoCart")
Engine: 350(CFI)
Transmission: Built 700R4 w/3400RPM 9.5in stall
Axle/Gears: 3.07 (D36)
Re: I need help with an Idle issue
I'm still figuring this out my self however i had this problem...
Turned out i needed a heated O2 due to my long tube headers, and then a few learns while idling stabled it right out.
Other than that it also helped to smooth out the low speed ve table, i had some bumps and i needed to raise some low spots and lower the high spots in the rpm and map range.
Turned out i needed a heated O2 due to my long tube headers, and then a few learns while idling stabled it right out.
Other than that it also helped to smooth out the low speed ve table, i had some bumps and i needed to raise some low spots and lower the high spots in the rpm and map range.
Thread Starter
Member
Joined: Nov 2002
Posts: 100
Likes: 0
From: Port Orange Florida
Car: 89 IROC
Engine: 350 CI Tuned Port
Transmission: Automatic
Axle/Gears: 3:45
Re: I need help with an Idle issue
I havent ever done it before but I will give it a go. I have some things shut down right now because I have been working with the blms but here you go.
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From: Chasing Electrons
Car: check
Engine: check
Transmission: check
Re: I need help with an Idle issue
The TPS value is important to having the ECM control the idle speed. As it has to be below a low value to be considered 'in idle.'
Here is a writeup on how the $42 mask handles idle and IAC control:
https://www.thirdgen.org/techbb2/sho...hreadid=308613
RBob.
Here is a writeup on how the $42 mask handles idle and IAC control:
https://www.thirdgen.org/techbb2/sho...hreadid=308613
RBob.
Thread Starter
Member
Joined: Nov 2002
Posts: 100
Likes: 0
From: Port Orange Florida
Car: 89 IROC
Engine: 350 CI Tuned Port
Transmission: Automatic
Axle/Gears: 3:45
Re: I need help with an Idle issue
Well I figured it out and it leaves me feeling like an idiot. The only thing I was right about is that I was looking in the wrong place. Like many of you I drive around with my tuning cable hooked up to my computer. Wellllll apparently at some point a few weeks ago the resistor in my cable got tripped to on putting the car into ALDL mode, and left me chasing a ghost. Let this be a lesson to me.....
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