I am having some issues of the car staying running when I put the car into gear. I have a 4.6L twin turbo street car with an ATF Speed Stage IV 4r70w. I just put the transmission in the car. New transmission and converter from ATF Speed. I have a Hurst quarter stick in the car. It is a manual valve body transmission with transbrake, lock up converter, and overdrive. The car doesn't start real well off cold start. Have to give it throttle in order for it to start then it will idle and then want to die and have to still feather the throttle to keep it running for about a minute then it will idle at 1100-1200 RPMS. I would like for it to idle lower around 950 to 1000 but that is the least amount of my concerns at this time. Once the engine has some heat in it I put it into reverse....it goes into reverse just about perfect. Doesn't die or anything funny.....actually about as perfect as it can get. Now going from reverse into 1st it dies as soon as it goes into a forward gear. This is a forward shift pattern valve body so 3rd is before 1st. I have spoken to a couple of guys and both have suggested possibly removing the IAC and retuning the car in the areas that are affected while putting the car into gear. They don't really know any reason to have it other than if it effects something else. My question is this.....

What are the pros and cons of removing the IAC valve on BS3 with a 4.6L Mod motor? This is primarily a street car. Very little track usage. I want to get into the car and drive it but I can't even get out of the driveway without it dying. Very frustrated! LOL.

All suggestions and advice is very appreciated!!

Blake Yount

 

The IAC valve lets the ECU control the idle speed; if you're having idle problems, that would be taking one of your tools to fix them out of the toolbox. I would leave it in.

 

Someone does not know how to use an IAC if that was suggested. There is 100% no reason to do that if you know how to tune one or the system. The mod engine really likes having an iac to get the engine started properly. I would suspect the timing is an issue, idle too hi is a problem, IAC vs blade position isn't correct. there are several other things that can cause your problem but it is all in the tuning. Getting a car to idle properly is harder than tuning the WOT portion of the tune.

 

I have spent hours and hours on my XFI mod motor. With the start up tune. So car will start with out touching the gas.
Do not remove IAC..
Turbonova is correct when he says there is 100% no reason to remove it..

Get your tune sorted out..
And you will be happy in the end

 

IMHO, the #1 reason for stalling when going in gear, (if AFR is even close), is timing, too much, or not enough....