16197427 IAC how to drive closed?

For everything related to using Fuel Injection in an FSJ.
Post Reply
User avatar

Topic author
babywag
Posts: 1217
Joined: Fri Jun 08, 2012 7:29 pm
Location: Land of Fruit Loops & Coconuts

16197427 IAC how to drive closed?

Post by babywag »

How do you drive the IAC closed on the 7427.

The aldl jumper doesn't do it like the 7747.

For the life of me I cannot remember how I did it last time.
-Tony
'88 GW (aka Babywag)
User avatar

JeepsAndGuns
Posts: 168
Joined: Sun Jun 10, 2012 4:12 pm
Location: cullman, AL

Re: 16197427 IAC how to drive closed?

Post by JeepsAndGuns »

I'm pretty sure there is not a way to do it.
If your needing to set your min air, I took a spare tps, taped it in place at the correct .5 volts, I then unplug the one on the engine and plug this one in. I then start and run engine and set the laptop up to where I can see it and adjust the blades till I get the iac counts I want. Took me a couple tries. First time I went too far and had good counts when I set it, but after driving it a day, my iac counts went down to 0. Had to readjust.
79 Cherokee Cheif. MPFI 401, T18/D20, hydroboost, otherwise stock.
93 YJ. 4.0, 5 Speed, SYE, hydroboost, WJ knuckles/brakes, 8.8 rear, OME 2.5in lift, warn M10000 winch. 31x10.50's
99 WJ limited. 4.0, auto, 2wd, stock.
User avatar

Topic author
babywag
Posts: 1217
Joined: Fri Jun 08, 2012 7:29 pm
Location: Land of Fruit Loops & Coconuts

Re: 16197427 IAC how to drive closed?

Post by babywag »

Well I stuffed a rag in there last time I adjusted the TB which seemed to work.

Just wondering what the correct way is.
Seems odd there is no way to close it like the 7747.
-Tony
'88 GW (aka Babywag)
User avatar

sgtpoliteness
Posts: 517
Joined: Sun Sep 30, 2012 5:56 pm
Location: Arvada, CO

Re: 16197427 IAC how to drive closed?

Post by sgtpoliteness »

Per Alldata the procedure is to disconnect the battery for several minutes and then re-connect it. Then, cycle the key to 'on' for 10 seconds. Then, key off and key back to 'on' for 5 seconds.

I just did that upon my initial start up this afternoon for my conversion and it fired right up and idled well. Always within 25-50 rpm of spec.
1977 Cherokee Chief WT w/ 2" lift
360 (originally a 401)/TH400/QT w/ MM part-time
16197427 $OD junkyard TBI set-up
User avatar

Topic author
babywag
Posts: 1217
Joined: Fri Jun 08, 2012 7:29 pm
Location: Land of Fruit Loops & Coconuts

Re: 16197427 IAC how to drive closed?

Post by babywag »

So do you disconnect the IAC before starting then?
Because as soon as you start it the pcm is going to open it up again?

You verified this drives the IAC closed so you can adjust the minimum idle speed
-Tony
'88 GW (aka Babywag)
User avatar

sgtpoliteness
Posts: 517
Joined: Sun Sep 30, 2012 5:56 pm
Location: Arvada, CO

Re: 16197427 IAC how to drive closed?

Post by sgtpoliteness »

No, Alldata (which is the TSM, really) says to leave it connected. The battery disconnect and re-connect simply re-sets basic settings it seems like. Then, the PCM goes through a basic settings procedure with the key cycles. It may be a function of being an almost OBD2 system...I don't know. I'll try to get some more info.
1977 Cherokee Chief WT w/ 2" lift
360 (originally a 401)/TH400/QT w/ MM part-time
16197427 $OD junkyard TBI set-up
User avatar

Bill usn-1
Posts: 188
Joined: Mon Mar 25, 2013 9:23 pm
Location: Whidbey Island, Wa
Contact:

Re: 16197427 IAC how to drive closed?

Post by Bill usn-1 »

What it's referring to is the standard IAC reset that the software does on power off.
Just watch your data log/sensors when you turn the key off.
The ecm stays on for 8 sec, the IAC drives closed and then open back up to the park position.
It does this every time you turn the key off to help the ECM keep track of the IAC position.

This is separate from the initial setup procedures for the early ECM's.
Post Reply