Setting Idle

[ravensfan]

Ok so first I'll say my set up is block is .30 over , gt 40 heads, upper and lower intake ,maf and throttle body
Ok so I had been fighting an idle surge until I change maf sensor to 75.. now the car just won't stay at the idle I set it at, but no surge. I unplug iac , turn idle screw to where I want it, set tps, unplug battery for 15 mins , then plug iac back in.. start it up and it idles where I set it momentarily, then back down way too low , to the moment it sounds like it's going to stall..it's really laboring.. if I stab the gas , it goes up then right back to that again
Any ideas ?

 

[ravensfan]

Also , I wanted to add.
You know how when you start your car and the idle first goes hi , then down some, then down again to the set idle... well mine used to do that. Now, it starts high and just drops to the set idle
Is this signs of iac bad ? How can I check it ? I did replace the iac last year but I do know that doesn't mean it still working. . I also replaced the tps .

 

[mikestang63]

look for the surging idle checklist

 

[ravensfan]

look for the surging idle checklist

The new maf sensor stopped the surging.. but now it just won't hold the idle where I attempt to set it...
Or are u saying that it's still the same parts to fix that too ?

 

[General karthief]

You may have more problems or only masked the original problem, as always check for codes, make sure all your grounds are clean and tight, there are four of them under the hood and one by the computer in the kick panel on the passenger side. Also check for vacuum leaks.

 

[jrichker]

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 200,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

 

[General karthief]

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 200,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

Sorry, thought I made a link for the sic, some days I'm lucky not to get fired. Don't tell noobz

 

[ravensfan]

i have been going thru the idle surge check list, That's why I have a new Iac, and tps, and now a new maf sensor which stopped the surging. But now , it idles to low, I have followed how to set the idle a few times, and everytime, its starts out idling ok, but soon after and at stop signs, the idle drops real low.

 

[General karthief]

Vacuum leak?

 

[ravensfan]

ok, so I have installed the new maf, and the surging stopped, but now the idle wont stay stable. it wont stay where I set it, which I did according to the idle surge check list instructions. So far I have changed the maf, tps, iac, plugs, and today I am going to buy a new egr and fuel pressure regulator because I read that can cause the smell of strong fumes and bad idle.
Does anyone have any ideas if these 2 parts don't fix it ? thanks

 

[ravensfan]

Vacuum leak?

I have been looking for one, have not seen or heard anything yet

 

[ravensfan]

what about the O2's ? would they effect the idle at start up tho ?? I thought they didn't come into play until after the car was warm ?

 

[ravensfan]

is there a way to kinda start over ( clean slate ) on setting the idle ??? I have tried to set the idle so many times with the iac unhooked , and turned the screw so much, IS that what has everything messed up ??

 

[General karthief]

Ok fresh start.
Give us a pic of the engine compartment, lets see if anything jumps out
What codes did you get, or did you not run the codes?

 

[ravensfan]

Ok fresh start.
Give us a pic of the engine compartment, lets see if anything jumps out
What codes did you get, or did you not run the codes?

I got a code 23

 

[ravensfan]

Ok fresh start.
Give us a pic of the engine compartment, lets see if anything jumps out
What codes did you get, or did you not run the codes?

I got a code 23

 

[5.0ttops87]

Throttle position sensor out of range .. check your volts to it?

 

[5.0ttops87]

should be .7 - .98 i believe

 

[5.0ttops87]

is there a way to kinda start over ( clean slate ) on setting the idle ??? I have tried to set the idle so many times with the iac unhooked , and turned the screw so much, IS that what has everything messed up ??

I heard you need to unplug the spout connector and iac to set it? I might be mistaken though

 

[General karthief]

Here is a link to instructions
http://www.stangnet.com/mustang-forums/825424-adjusting-your-tps-0-98v-not-necessary.html