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aka: mOtOrHeAd MiKe
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Discussion Starter · #1 ·
This has developed since the cold weather kicked in. Yeah, this car is temperamental… heavy on the mental.

Basically, the car is searching up and down over and over again. 700-1400-650-1300-710-1410-… and so on. And occasionally the thing will shut off when the RPMs drop low enough.

The IAC has been reset, is kinda low @ 13-14. But it is better than the 45-56 I had before. TPS is at .43v

Is there anyway to tune this out? Or am I looking at a new IAC motor?

PS. The car idles great when cool and idling in gear, kinda like the load. Hmmm….


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Michael Lis

87 Vortec SS -- 12.7 @ 110 w/ 1.9 60' (This car runs 12s on 87 octane)
Click Here To See Specs
87 Turbo T - 1986.99 WE4 Clone -- 13.7 @ 104mph w/2.2 60'
Click Here To See Specs
See the cars here:
Canadian Skunk Works

Originally posted by myclone
I see you have ODed on retardacylin today. Want me to call an ambulance?
 

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Mike, i've been having the same problem as you are. When the car hasn't been started all night and i go out and try and start it in this cold weather, the idle surges up and down all over. It makes the car sound like a lumpy cammed big block. Mine just happened with the cold weather too. wierd.....

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87 T-top GN 235" JE pistons, TA-49, 009's, ported heads,206-206 cam, trans+LT1 MAF,Jim Testa street chip, AFPR, Walbro 307, stock IC, stock exhaust, 275/50/15 nitto's, and bad driver mod.
Best time: [email protected] 104, 15 psi, 1.98 60' yep, i need to tune it
 

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Mike
Reset that IAC closer to 20 in P/N (adjust TPS accordingly)and check for Vac and Exhaust leaks. Jim's and Jay's chips usually have a great idle.

Paul
72 Toyota Celica with a 87 TR drive train

[This message has been edited by Quick Toy (edited October 18, 2002).]
 

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aka: mOtOrHeAd MiKe
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6,603 Posts
Discussion Starter · #4 ·
Originally posted by Quick Toy:
Mike
Reset that IAC closer to 20 in P/N (adjust TPS accordingly)and check for Vac and Exhaust leaks. Jim's and Jay's chips usually have a great idle.
Paul, Do I need to disconnect the IAC when setting it? gnttype.org says so... but I haven't thought it was needed.

Yeah, Jay's chip idles great once the car is all warmed up... I don't think that his chips burned in the Texas heat can cope with the Canadian cold.
J/K.


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Michael Lis

87 Vortec SS -- 12.7 @ 110 w/ 1.9 60' (This car runs 12s on 87 octane)
Click Here To See Specs
87 Turbo T - 1986.99 WE4 Clone -- 13.7 @ 104mph w/2.2 60'
Click Here To See Specs
See the cars here:
Canadian Skunk Works

Originally posted by myclone
I see you have ODed on retardacylin today. Want me to call an ambulance?
 

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1. Ground ALDL diagnostic lead (short the top two rightmost pins in the ALDL connector).
2. Turn on the ignition (but don't start the car).
3. Wait 30 seconds.
4. Leave ignition on and disconnect the IAC connector.
5. Remove the grounding from the ALDL connector.
6. Start the car. The car will probably run rough and may stall. Just restart and try again.
7. Adjust the throttle stop screw to set the idle to 500 RPM +/- 50 RPM.
8. Turn the car off and reconnect the IAC connector.
9. Turn ignition on and adjust TPS to proper settings. (.42-.44 at idle is typical)
10. Repeat procedure until the 500 RPM +/- 50 RPM in step 7 can be maintained while TPS is at proper idle setting

That is one way of doing it.

Joe Lubrant's IAC Setting Procedure:
Put ECM into Diagnostic Mode (jumper the top far right 2 ALDL connector pins) with key on-no start. Disconnect the IAC plug, then turn off key, remove ECM from diagnostic mode (remove ALDL jumper), start engine with scan tool attached, set idle to 650 to 680rpm. When completed shut off engine reconnect IAC plug. Turn key back on and reset TPS to .4v to .42v closed and approx. 4.6v to 4.65v WOT. Then clear ECM by disconnecting the orange wire by battery for a few seconds and reconnect. (finished)
I don't use IAC numbers as a general rule because of some variables with the types of throttle bodies out there. Some of the machining fit on throttle bores & plate sizes leave a little to be desired, and in cases effect by-pass air #s.
The 650 to 680rpm IAC setting is approx 100 rpm below the commanded chip program, and also becomes part of the stall saver.
90% of tip-in or off idle stumbles are mis-adjusted IAC's, the others are normally bad MAF's or air leaks.

Some just play with the throttle stop screw wile monitoring the scan tool... "Every car is different"


Paul
 
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