Hi Guys, what RPM should an 89 5.7 GTA with TPI idle at in park, and in drive? And in park with the AC on and in drive with the AC on? Just curious on this. All I have is the owners manual that came with the car, and I don't see it in there.
Thanks
Mike

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(Gran Turismo Americano) "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber).

 

The car should idle in drive around 750rpm.. Park/neutral doesn't matter. AC doesn't matter either really, so long as it doesn't stall. If the idle in drive is fine, all will follow. heh. There's technical articles on how to set this.

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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

mine idles at about 500, but its also kinda rough.

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88' GTA 350 MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass

 

Mine seems to Idle in drive at about 600 & 700 in park. It s real smooth. I was just curious what the factory Idle was. But as long as it is running good, and not idling too high it is alright. I tuned the car up today, I thought it was running good before the tune up, but man it idles so much better now. If it wasn't for the noise from the flowmaster, you wouldn't even know it was running.
Thanks for the info guys!
Later
Mike


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(Gran Turismo Americano) "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber).

 

Mines idling rough at 500 or just under and the tag under the hood says it should be 600.

Anyone got or know of a good set of instructions for adjusting idling speed for an 84 L69 5.0 4bbl HO??

thanks

 

My 87 305 tpi idles smoothly at 500rpm.

 

my 305 TBI idles at 600 now with my new O2 sensor

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1992 Pontiac Firebird
- 305ci V8 TBI / Automatic Trans / Loaded
- MODS: Edelbrock 14x3 Open Element Air Cleaner, Dual outlet exhaust
1985 Chevy Z28
- 350ci V8 TPI / Automatic Trans / Paid $200 for it
- In the process of restoration!

 

All the idle speed is controlled within the ECM. At normal operating temperatures, the idle when in Drive will be around 600 rpm. If you have a colder T-stat, the temperature will be higher because the engine thinks it is still in "cold start up" mode. This is one of the tables you need to adjust if you go to a colder T-stat.

Also, in Park/Neutral, the ECM will add another 100 rpm and 25 rpm for the AC. All of these parameters can be changed in the ECM. I personally lowered the amount of RPMs to add in P/N to only 50 additional RPM. Makes for a much smoother transition when moving the gear selector and it's much easier on the drivetrain.

When the coolant temperature is below 195*C, there are various "desired RPM" to assist in "cold starting". This is why a colder T-stat like a 160* causes your car to idle higher (around 750 rpm in Drive, +100 P/N, +25 AC; IIRC).

This is if your IAC and TPS are in proper working order and set correctly. People trying to "adjust" their TPS/IAC, especially for this "greater than 4.5 volts to get into WOT sooner BS" generally screw things up and can result in an erratic idle.

 

Thanks or the advice everyone. I think I am right on the money with my Idle Glen91L98GTA. Thanks man
Later
Mike

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(Gran Turismo Americano) "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber).