idle help

[jden87stang]

Just got a 87 5.0 and it has had a supercharger on it at one time and now it back to factory but i have plans to do a twin turbo or a supercharger. the computer and timing and everything is setup for the super charger so it idles at about 1300 right know. my question is when i rev it up it does not go back to idle quick it slowly goes back down and then it will go back up to about 3k and back down would this be due to the timing and ecu being flashed?

 

[TenorPlayinGuy]

Is there a chip installed? If not then no, the 87 Mustang is a speed density computer, so to set the idle, your gonna want to unplug the IAC on the side of the throttle body, and use the set screw to fiddle with it as best you can. Then restart the car with the IAC installed. The slow response is gonna be either a dirty IAC, or a dirty 10pin connector.

-IAC= Idle Air Controller
-10Pin = those salt and pepper shakers on the back side of the intake. Clean those out, it sometimes helps.

Also check out the Surging Idle thread thats a sticky here. Helps tons setting the idle.

Without knowing too much more about the engines current state and exact specs we can only give info based on OE items on the car. More info and we can help you more.

 

[jden87stang]

that's my problem the guy I bought it from really didn't know anything about so im kinda in the dark also so im thinkin bout just starting over ewwith the whole motor so I know what's in it. any suggestions on twin turbo vs supercharger?

 

[jrichker]

See the "Surging Idle Checklist for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.

The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[jden87stang]

thank you for all the help.

 

[BYRDPE]

Have you looked at the computer to see if a chip is installed? That's the first thing you should do.

Posted via Mobile Device

 

[jden87stang]

no how will i tell and were is the computer located to see?

 

[Mustang5L5]

Passenger side kick panel. The computer is behind it. While you are there, write down any and all part numbers on the label and post them up here

 

[jden87stang]

I had to go back out on work yesterday so i will be bringing the post back up in about 25 days

 

[jden87stang]

A9T is on the computer and is also on the plug part of the computer. How will i be able to tell if it has a chip?

 

[mustangsquared]

there is a port on the bottom...it would be sticking out (normally)

 

[jden87stang]

no chip