Changed IAC, Now Idle Hanging

[dukeentdotcom]

Hey guys,

I did some searching here but didn't find an answer. I did see info on other forums, but so much conflicting info that it leave me wondering what direction to go in.

I've got a 96 explorer block 302, TFS stage 2 cam, explorer intake, accufab TB...

I don't know if any of that really matters, as I had a Professional Products IAC on but changed it since it was rusted to hell. Everytime I pulled rust off, it would rust up completely in a matter of days. idle was good with it. When I would blip the gas pedal it seemed normal to me. The revs were never really fast, but they didn't hang necessarily.

I just put on a brand new Ford OEM IAC, part E7SZ-9F715-A (photo below). Now the idle hangs after I blip the gas at around 1500 for a few seconds before going back to around 950ish where it has always been.

I don't want to waste time and money buying adjustment plate (which I had one of those long ago) unless that happens to be the only way this will be fixed...

Thoughts?

[qikgts]

Disconnect the battery for a bit and reconnect then see if it improves. If not reset the base idle.

[dukeentdotcom]

Disconnect the battery for a bit and reconnect then see if it improves. If not reset the base idle.

Thanks, I'll try that.

I see you're in Rockledge... I'm 30 min north of you!

[qikgts]

Thanks, I'll try that.

I see you're in Rockledge... I'm 30 min north of you!

Give it a whirl... Yep, fine livin' on the Space Coast! lol

Where are you at?

[dukeentdotcom]

Give it a whirl... Yep, fine livin' on the Space Coast! lol

Where are you at?

S Titusville

[qikgts]

Very nice! We should hook up and go for a cruise sometime...

[dukeentdotcom]

Absolutely... I'll PM you

[dukeentdotcom]

So I unplugged the battery overnight. In the morning, connected battery again and started her up. Idle was around 1000. Pressed gas, and still had the hanging idle. I let it run for a few and then decided to take a short ride to see if things would "settle". I drove about 5 min away and stopped at a light, and at that time the idle reached 1250ish at idle. I then went a few more minutes, shut the car off for a few minutes. When I started again, the idle was at 1500ish!

So I unplugged the IAC, and the idle dropped just under 1000. is the IAC supposed to make the idle increase when plugged in?

At any rate, I got home and then later on I adjusted my TPS to about .97 (it was a little over 1 when I first checked it). After doing this the idle was around 1200ish.

I decided to lower the idle using the TB screw, and dropped it to around 750-800ish. I went for another ride and the car had noticeably less power and choked on itself when I tried to get in it in third gear. So obviously I'm not moving in the right direction here lol...

*** edit - reading some more info on this on Corral and it seems I am supposed to set my idle with the IAC unplugged? I will try this tomorrow as it's already dark outside. At least I seem to have the TPS set at the right voltage now...

This is the first time I'm trying to make these adjustments on my own, so pardon the ignorance! lol

[qikgts]

Chris, when you get to mess with this again follow the procedure below.

https://web.archive.org/web/20150505...ic,1031.0.html

[dukeentdotcom]

Gotta love Wayback Machine - thanks I'll try this out tomorrow!

[qikgts]

No problem...

[dukeentdotcom]

Went through the idle reset process, car didn't start. I then figured maybe I adjusted the TB screw improperly. Tried it a couple turns in, then out but still didn't start. This was yesterday.

Came back to it this morning, and without doing anything I was able to start the car. Adjusted the idle with the screw (small adjustment) then went for a ride. Car shut off 5 minutes later and would not start again. Made some roadside adjustments until the car started and I drove back home.

I then did the full reset procedure from the beginning, this time including the cleaning of the TB which was fairly dirty.

readjusted the idle to around 900ish, got the voltage to around 98, went for another ride. Car felt good through all gears, but still a bit of hanging idle...

Damn these cars are temperamental!

[qikgts]

Good deal Chris! Sounds like you have made some solid progress!

Has the car been "tuned" with a chip? How high is the RPM hanging now and when?

[dukeentdotcom]

It has a Bama 4-Bank Eliminator Chip.

The RPM hangs around 1250ish or so for a couple seconds before dropping down to 900-950ish

[qikgts]

I believe the stock programming in the computer will intentionally hang the idle a little bit and for a short (couple of seconds) time to presumably make the power steering easier at low speeds, keep ac blowing cold, etc. Perhaps you never had the issue before because the old IAC was lazy?

Can the tunes be edited? If so, making adjustments to dashpot/idle airflow settings could possibly help. Are the tunes for your specific combo of parts?

An alternative quick and dirty fix, clipping the VSS wire going to the computer, would likely make it go away.

You also may be able to make very slight adjustments to the idle screw and chase it until it behaves better or like you stated in the first post get another adjuster plate on there. The only other thing I can think of but it's likely not going to be worth the effort would be to inspect the 10 pin connectors making sure they are clean and that the pins are tight making good solid connections.

[erratic50]

Restrict the airflow on the IAC circuit.