Jesse, check your email please.

 

ttt

 

I’m sure Jesse is very busy because of the new born kids, just be patient with him hell get back with you.. good luck

 

He found time to post about his new mig welder

 

I know,, I even responded to that thread with a few welding tips for him.

 

MIdnight...

Sorry for missing this post that you had....not sure when you posted it with regards to my welding post???? But I have been in and out of the house all weekend - spent most of yesterday delivering my D44 to another forum member in Canada trying to save him a few bucks for on shipping etc. Only got back late yesterday and did not have a chance to check the forum or anything else.

I did get your email and saw that you sent some information on your idle and will respond to it right away...I have about 30 emails from people asking questions about everything from tires to intakes....I try to answer them all as good as well as I can.

talk to you real soon and I will try to walk you through some things to determine the root cause.

 

Just took a look at the data you sent me...granted its only a snapshot in time which is not real useful.....but I would like you to try something...and I am posting this since its probably the #1 things people do wrong with setting their idle.

First I will describe what you want to achieve. What you are looking to get is an airflow of 95% thru the Throttlebody and about 5% thru the IAC. If you let the IAC have too much control it will hunt for idle and fight itself. You just want the IAC there to accomidate VERY small changes. If you have the TB too far closed the ECM will tell the IAC to open to get that desired idle RPM, as a result you will have the IAC controlling too much airflow and when you have a cam in the car the incoming airflow is NOT steady and as a result the IAC will go crazy tying to fix the idle.

OK now that we have that explained...lets try a very easy test...(suggest EVERYONE with an idle that hunts to try this). Simply get the car idling...as it is idling start to screw the throttle body stop screw inward to keep the TB open more. As you do this, you are effectively reducing the control or %airflow the IAC has going thru it. Keep doing this and see if it helps the idle calm down......Does this have an effect??

You see the problem I think many have is simply this. Some of the manuals that you have and I have seen state to set the min idle you should disconnect the IAC and set your idle base at ~600rpms.....now keep in mind that is STOCK configuration with stock cam, intake etc. Then plug back in the IAC, which then raises the idle to STOCK setting of 750...you see the IAC added the extra 100-150rpms...but most of the idle air came thu the throttle body in this situation.

Now lets shift gears and look at the modded up car. With a customized chip you have a raised ECM idle target - lets say 900rpms for this example. Now doing the same instructions as before you set the idle with the IAC off at 600rpm...you plug in the IAC and the ECM says "Hey I need more air".. it then starts to open the IAC to get to that desired 900rpms... when it does get there then you have the lope of the cam which causes the incoming air to pulse...with each pulse the IAC trys to compensate to keep the idle at 900 RPMs...after a while the IAC can't keep up and the idle will get more irratic and eventually the car will stall or drive you nuts.

Does this make sense? Give me some feedback....I have written this many times when people have problems and asked that others be made a sticky...but it seems to fall on deaf ears.

Basically in the nutshell, what you want to do is unplug your IAC...use the screw to set your idle at about 850rpms, then plug back in your IAC to give you the exta 50-100 rpms.

After this is all done and the car is idling better, then you want to go over and loosen your TPS and reset it back to .54v. You done and the car should idle with very little lope- you should have no stalling or anything.

If you do the above and you still have idle problems then you have other issues, perhaps bad plugs, bad timing setting, or a vacuum leak.

And aside from the smoke tricks and other things the #1 easiest and MOST FULLPROOF way to find a vacuum leak is with starter fluid. Get some and simply spray in small quantities around the seams of your intake....it will find the smallest pinholes and you will hear the motor REV and then settle back down when it has sucked in all the fluid...believe me when I say I have tried every other imaginable method, propane, smoke, pressure....NONE of them found what a little spray of starter fluid did. For 5 dollars I used it for YEARS after having my intakes off and found MANY small holes that I thought I had sealed.....

Hope this explination is good and helps you guys....

Give me some feedback if something is not clear.

 

Thanks Jesse, I do understand what you are saying and I will give it a shot today. I appreciate your help very much and I will get back to you later today.
One thing I forgot to include with my scan is the fact that the engine will not maintain it's idle when I put the trans in drive or reverse. It drops about 400 rpm and stays down there until I put it back in park. Do you feel this is because the IAC is already retracted as far as it can? This is the main reason I was thinking a problem with the ECM.

 

MAN!!!! THANK YOU!!!!! I searched for months on this site as well as thirdgen.org and nothing worked until this. You couldnt have explained it any easier or in any better terms. It is very clear now to me and my cars are ALL idleing much better.

I vote again to have this added to the tuning stickie or one made just for this topic since I think about 80% of the C4s are modded!!!!

 

No problem! Glad it helped you out!

 

I wish I knew that earlier...I have been chasing a surging idle since I have had the car.

Hopefully your chip will smooth things out. If not, I now know my next course of action.

 

I'm putting my project back together and I just printed off this thread! Thanks Ski!!

I say we just bump this thread daily until "someone" decides to make it a sticky.

 

I was surprised to see this thread come back. I'm glad it did because I realize I never did let everybody know how my problem idle turned out after Jesse's instructions. His idle correction process completly cured my problems too. Thanks to Jesse my car idles smooth as can be and because of his chip it goes like he11!