Idle Rpms

[Acid7711]

Sorry if this has been covered before, but I've been poking around a lot of threads on here and been reading people's idle rpms. People have been saying everything from like 900 down to about 600rpms at idle. Right now, mine idles at about 850-900rpms. Is this too high? What is a good idle rpm to shoot for? I just got the car, so I'm still new and learning. This is for an 89 GT 5-speed btw.

Thanks for your help.

 

[BlueThunder1988]

They're all right... it depends a lot on your combo. FWIW, 900 or so is fine for a stock or near stock car on the street as you'll be spinning the alt and wp a bit faster for better power and cooling at idle.

 

[Acid7711]

Thanks for the fast reply One last question, should my throttle plate be completely closed at idle? On my other car it is, and the idle actuator motor on it controls the idle entirely on it's own. Should it be this way on the Stang as well, or should the throttle plate be cracked just a hair?

After either of these, I know I'd have to adjust the tps accordingly.

 

[CoupedUp]

The throttle butterfly should be pretty much closed (visually) at idle.

The adjustment screw on the bottom of the tb should have a paint mark from the factory (as it is pre-set) ... if the previous owner(s) have tampered with it you should be able to tell. It is possible with age that the paint has disapated for the most part, but you should be able to make out something.

As an average, a 5sp car should be around 700 rpms and an AOD about 850 with all sensors operating properly.

 

[Zero_chance]

Mines at 900 on a good day. She usually starts around 750 but once she gets warm anywhere from 9-11 is "normal" for me.

 

[bluevenom867]

Mines at 900 on a good day. She usually starts around 750 but once she gets warm anywhere from 9-11 is "normal" for me.

Mine is just like that.

 

[bluevenom867]

Zero_chance,you runing a carb?

 

[Acid7711]

Awesome! Thanks so much for the fast replys guys! I love this place

 

[1EVIL88VERT]

Mines at 900 on a good day. She usually starts around 750 but once she gets warm anywhere from 9-11 is "normal" for me.

mine does the same, but once warm stays at 900 all day

 

[Zero_chance]

BlueVenom, Im EFI and (not necessarily) loving it.

 

[Euphoric306]

i set mine to 1000, i think it sounds better that way, and i really never let it sit at idle anyway, unless im at a stoplight or stuck in traffic

 

[bsedwebt70-5.0]

I have heard that 672rpm is stock for a 5spd car - mine idles at 775rpm smooth as silk w/ 16* timing and 42lbs fuel pressure 1.7roller rockers & stock internals