I just finished installing a heads/cam package and the car would not idle and i got fed up with looking for unplugged sensors and vacuum lines so I took it to a performance shop. The mechanic told me the tune doesnt have a high enough idle and that I should get it re-tuned....He adjusted the screw on the TB to increase the idle and problem solved....Is this something that needs to be corrected in the computer to run how its supposed to or will it be fine as is? I ordered a tune from madz28.com and I don't want to pay the $25 for an update if its not necessary.

 

you need a re-tune buddy.

 

Did the mechanic check the IAC counts and the TPS voltage to insure they were still within spec?

 

it's $25.00, seems like a cheap fix to me - I would think you paid a lot more for someone to tell you that the tune needs to be updated

 

OK so I just picked the car up from the mechanic and adjusting the idle screw definately has not solved the idle problem...it just makes it barely driveable. I unplugged the TPS and no change...then i unplugged the IAC and the car smoothed out alot but it idled at 1500. Is the computer just not compensating for the throttle being opened by the screw because the IAC thinks the throttle should be ain a different position at idle? Also when driving down the road the car jerks real hard back and forth....Really seems like how it ran when the opti was bad.

 

adding heads and a cam changes a LOT of stuff, you NEED a tune.

 

I do have tune from madZ28.com and yes its tuned for the heads and cam and all other mods. The mechanic was saying though that the idle is set too low on the tune. I dont know if I agree becasue its not just and idling problem its at all RPMs

 

I would say hook it up to a scanner and see what all your sensors are telling you when the car is running.

 

No I dont think he did. He hasnt dove real deep into it becasue I was only paying him to do the oil pan gasket.

 

I wouldnt know what to look for but I do have a data cable. If I posted a data log would somone check it out for me?

 

If you open up the blades too far, the IAC motor bottoms out at "0" counts, and there is no way it can control the idle speed. When the TPS position is not indicated at 0%, the PCM may increase the idle speed, by opening up the IAC, since it assumes you have the throttle open.

That's why you don't diddle around with the throttle stop screw without putting a scanner on it to check the IAC counts and the TPS voltage.

What is the programmed idle speed? How did the mechanic know what it is? You can't see the target (programmed) idle speed without a scanner.

 

to add to what Fred has already said..

you want the idle to be around 900. the IAC to be around 50 or so. after you adjust that you then need to check the TPS voltage, if it is not right around .67 volts you need to slot the holes in the sensor and adjust as necessary

 

stop being cheap and get it retuned. heads and cam is a big upgrade. the computer has no idea wtf is going on anymore.

 

you should prolly read the thread

 

Ion did my first tune and he did a very nice job with it. I would imagine that
you have some other issues going on. As stated previously you need to scan
the car and get some real data to base decisions on.