My car idles at 1400-1500 rpm's when i first start it. It last for 10-15 minutes. The goes down to normal. Wouldn't be a big deal but I'm running no cat into a flowtech afterburner. So its really loud when I start it up. I'd love some advice. Thanks!

 

Okay with some more searching i found out its my iac valve? Where is that? and what do i do to fix the problem? Sorry just trying to learn.

 

You will need to change the calibration (BIN) in the ECM.

The IAC is on the throttle body and is controlled by the ECM.

RBob.

 

If you post your broadcast code the letters on the top of the chip I will take a look at the .bin and see if there were service bulletins.

 

My car also idles high at start up (open loop) until warm then drops down and it goes into "closed loop".I don't know how high but its about twice as high as when warm.
I thought it was supposed to do that,although 10 to 15 min does seem a little excessive.

 

My formula does the same but i checked for air leaks, did not find any.then i changed the IAC still same thing. Then i found out my car used to have an automatic tranny before it was swaped for the manual that's in it now...since there is no more park/neutral switch anymore and the wire is now grounded to the chassis,the stock ECM ''thinks'' the car is always in neutral and that gives me a intermitant code24. I also heard this is why the idle is so high for so long at start up. Now the question is: recalibrate ECM? or change the PROM chip. recalibrate seems a great idea, but how? help

 

A high idle will cause the 24 malf to set. Check for vacuum leaks especially around the tb base gasket.
If you are using the bcc from the automatic get one for a manual trans L03.

 

Disconnect the ECM's P/N wire from ground. For a stick trans that is how it should be, always in drive.

RBob.

 

I second the checking for vacuum leaks as some of the older calibrations do not control the idle speed of a cold engine very effectively. I remember having issues with a 7747 calibration that kept wanting to idle at 1300+ RPM.

The only code in the TBI Formula I just picked up was for idle speed control failure. It had a TBI base gasket leaking and numerous other vacuum leaks.

 

that is pin B10 of the ecm a orange/Blk wire .

 

I did a custom $61 tune for a guy with a 350 and manual trans and he had the same issue no leaks could be found. The only thing I could figure is when the cold start is over and the rpm drops if it is not low enough thats when the ecm does a check for the 24 malf. I think it believes the car is moving but it doesnt detect any vss signal. I got the car to idle real well and the only way I could fix it was disable the 24 malf.

 

Can any one tell me if this is correct.Is the car supposed to run higher rpm's during warm-up ?(open loop)

 

high idle for cold start enrichment.

 

Thanks,
Thats what I thought but wanted conformation.So since this is true why are we trying to "fix" it ?