Another IAC Question!

[Slo5Oh89]

Hello, I got a aftermarket IAC idle speed was better around 500 old one would hardly fall under 1K. I looked at the Suging Idle peice and seen where it said to install it upside down!? Or will the computer need time to adjust? Put the old one on it went to 1K and sat there perfect.Any help would be great if it does mean anything I did just reinstall the upper intake and replace the valve cover gaskets. So the battery cable was off for around 3 days.

Once again this message board is great thanks everyone.

 

[lancec2c30]

Is the idle still high? Or just surging now?

 

[Slo5Oh89]

With the new one it is around 500 and surges a little or sometimes a couple hundred. The old stock IAC put it back on and it went to 1K and idle perfect. The old one sticks alot and likes to sit at 3K after ya get off the highway!

 

[lancec2c30]

Try mounting it upside down, it has worked for some people and would only take a minute. But with the old IAC it didn't surge, just sticking idle issues?

 

[HISSIN50]

Where did you get the IAC? For the ones that install upside down, they normally have an instruction sheet included, and that's where it notes the orientation.

Are you clearing the KAM after each installation? If not, it will take awhile for the EEC to learn how the new IAC performs (since the EEC has no clue you installed a part which functions differently per given command/DC).

 

[Slo5Oh89]

Sorry proably dumb question what is the KAM?

lancec2c30

The old one would stick like you get off the highway and it wants to idle at 3K turn engine off then back on and it would stop. The old one did surge a little clean it and it was good to go. But then a few weeks later same problems.

 

[liljoe07]

Posted via Mobile Device

KAM is the Keep Alive Memory. All that is, is the power source to the ECM that's constant hot. Clearing this allows the ECM to relearn its adaptive memory. Basically just unhooking the battery for a few minutes.

I think you need to set the base idle a little higher. If its idling at 500rpms with the IAC pluged in, that's to low. You need to unhook the IAC, set the idle at about 6OO-650, recheck the TPS voltage, then hook the IAC back up. Then reset the KAM. See how that works out for you.

 

[Slo5Oh89]

I reset the KAM ran it again got proably 20 miles on it and still surging with new IAC. Just for a shot I put the old one on again idle was fine still just under 1K. Did I just get a bad IAC and let me guess I should of gotten the Ford replacment part huh?

I also did bump the idle up some with the new IAC over 600. Once again I do want to say I just had the upper intake off a last weekend. Not sure if that helps or not.

 

[Celeb]

You might also try one of these to help trim air going in and out of the IAC

 

[liljoe07]

I reset the KAM ran it again got proably 20 miles on it and still surging with new IAC. Just for a shot I put the old one on again idle was fine still just under 1K. Did I just get a bad IAC and let me guess I should of gotten the Ford replacment part huh?

I also did bump the idle up some with the new IAC over 600. Once again I do want to say I just had the upper intake off a last weekend. Not sure if that helps or not.

When you set the base idle, the IAC needs to be unpluged. So did you set the idle to 600 with the IAC hooked up?

If you run a KOER code test and the RPMS raise, then the IAC is doing its job, and the base idle just needs adjustment.

Follow this and see how it acts afterward

1. Clean TB with carb cleaner and nylon brush (toothbrush size). Engine off, fully open TB blade and spray/brush TB until all gunk and oil residue is cleaned.

2. Allow to dry, or close TB blade and start engine until it clears all carb cleaner fumes/liquid.

3. Let engine idle...if it doesn't, increase idle speed via TB stop screw until engine stays idling on its own.

4. Disconnect IAC valve, if engine dies repeat 3 with IAC disconnected.

5. Set idle speed to the lowest setting possible between 650-850 rpms with IAC disconnected. It is key to use the lowest possible to prevent idle surge, rolling, etc once the IAC is connected as follows.

6. Turn engine off, and reconnect IAC

7. With Ign On Eng Off, check TPS voltage output....if it's between .8vdc - 1.0vdc, it's OK. This voltage check should be done between the Green and Black wires at the TPS side connector as shown in the pic below....(-) terminal of the DVOM on the Black wire and (+) terminal on the Green wire.




8. Disconnect battery (-) for 3-4 minutes.

9. Reconnect battery, start engine, allow it to idle for 2-4 minutes to confirm setup,

10. If idle speed falls too low or stalls, increase idle speed via the TB set screw a little at a time.

11. Turn engine off for 20 seconds, re-start engine and repeat 9 - 11 if required.

12. Reconfirm TPS output is within the .8vdc - 1.0vdc range.......you're done!...

..no need to reset ECM KAM (reset computer) b/c the TPS minimum value used for idle control, is automatically reset by the EEC-IV every time the ign is cycled on-off for 20 seconds-on, and as explained in the next post

13. Allow a 10-20 minute "relearning" period under normal driving conditions (drive cycle).....now you're done.


This is a copy and paste.

 

[HISSIN50]

^^

One note of caution (it's something I feel Joe would have said if he had the time to type up a reply): I would not use Carb cleaner on the TB just in case the coating is still in place. TB cleaner works almost as well anyhow.

And to stress the point, in my experience (as well), one must have the base idle (no IAC function) set as low as possible. The commanded idle is 670-ish and the EEC has a lot easier time adding IAC DC to increase the idle speed than it does trying to lower the physical idle (to try and achieve the commanded idle).

 

[Slo5Oh89]

Once again thanks guys. I did set the idle with the IAC hooked up! I know there are 2 screws on the TB sensor what one do I use for adjustments? And what is a KOER Test? I really think that setting the idle with it unhooked will help thought you had to have it plugged in for engine to run. I will run through this check list this weekend.

 

[liljoe07]

Posted via Mobile Device

My bad on the carb cleaner step. That's usually one step that I skip over, since most cars that I work on are fairly clean, and with aftermarket Throttle body's.

 

[lancec2c30]

Once again thanks guys. I did set the idle with the IAC hooked up! I know there are 2 screws on the TB sensor what one do I use for adjustments? And what is a KOER Test? I really think that setting the idle with it unhooked will help thought you had to have it plugged in for engine to run. I will run through this check list this weekend.

You want to know which screw to adjust the idle with? Or the TPS voltage?

The idle is adjusted with the screw on the back of the throttle body, facing the firewall. Down where the throttle cable attaches.

The KOER test is when you dump the computer codes while the engine is running. "Key On, Engine Running".

The engine will should idle fine with the IAC unhooked, get the engine up to operating temp first.

 

[Slo5Oh89]

I got it to where it will idle good from cold to operationg temp, with the IAC. Is running accessorys such as the front window defroster, A/C, at idle a learning process with computer to. When you run one of them it almost dies, then the idle will surge a little after you turn the accessory off. Then if you turn the key off and start it again idle is great. Any ideas or just drive it a while and it will go away?

 

[HISSIN50]

I got it to where it will idle good from cold to operationg temp, with the IAC. Is running accessorys such as the front window defroster, A/C, at idle a learning process with computer to. When you run one of them it almost dies, then the idle will surge a little after you turn the accessory off. Then if you turn the key off and start it again idle is great. Any ideas or just drive it a while and it will go away?

Something you can try if you like is to let it idle for a couple of minutes with no load. Then shut if off, wait a few minutes and restart it with a load of accessories. Let it idle for a few minutes in this capacity.