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Latest IAC adjustment instructions from FiTech turning both front and rear blades

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Couple months ago corresponding with one of the FiTech reps he provided me with a IAC adjustment instructions that I haven't seen before. These ones take into account adjustments of both the front and rear butterflies. There are a few threads going on in regards to adjustment of secondaries. I am copying here the instructions as I received them. I followed this procedure and it worked well. Didn't completely eliminate my fluctuating idle issue but it made an improvement.

 

.... One thing I want to make sure is that the IAC is set correctly and that you were adjusting both throttle blades front and rear using both adjustment throttle screws. It is commonly done that this is set using only the front throttle screw and if it is not set with the back it can create all types of issues. Here is the procedure to do that.

This will be done with the engine off and key does not need to be on.

1. Disconnect the throttle peddle from the throttle body, so we know it is not moving or holding the throttle.

2. Unscrew both front and rear adjustment screws so they just come off of the pivot arm stop.

3. Starting with the front screw, screw the adjustment screw in until it touches the pivot stop and you just see the throttle arm/blades just start to move. Once you see this movement screw the screw in ½ turn (If the engine is pretty stout go ¾-1 turn in)

4. On the rear screw we are going to do the exact same thing, screw the adjustment in until you see it touch and move then go a ½ turn (If the engine is pretty stout go ¾-1 turn in)

5. This will set the blades close enough to start and warm up for final adjustment. We just want the engine to idle, if it is high that is ok until it warms up if it is low and wont idle go in a small amount on both screws until it will idle.

6. Turn the key on do not start, at this point we want to clear the leaned data that the car has learned previously this way we can have a clean slate when we start. Go to Go-EFI Initial Setup then go to Reset Learn, inside reset learn go to Reset IAC Data by switching the 0 to 1 and hit send to ECU. This will erase all leaned data but will not change any of your base settings. Turn the key off for 30 ish seconds.

7. Start engine and let it warm up to 170 degrees F then look at the IAC steps on your dashboard. With the engine running and the temp at or above 170 adjust accordingly. If the IAC is above 10 you will screw in both screws equally until the IAC steps falls below 10 but does not sit on zero. If the IAC steps are staying on Zero and the idle is above the desired setting you will unscrew both screws equally until the IAC jumps back and forth from a number under 10 but not staying on zero and the idle is at your target RPM.

8. While you are making your fine adjustments keep an eye on the TPS value, if it goes above 0 shut the engine off and let it sit for 30-45 seconds. Turn the ignition back on and go into Go-EFI Initial Setup then go to reset TPS Learn, inside reset learn go to Reset TPS Data by switching the 0 to 1 and hit send to ECU. Continue with the throttle blade adjustment.

9. Reconnect the throttle cable/rod.

Normally when the IAC is correct it will jump between 0 and a number under 10 but never sits on 0 and the target/programmed idle RPM is met then the IAC is set. now when you do fire the vehicle up if you have anything on like the fans or anything like that your IAC will move as the draw and the system is increased the IAC will open up to compensate for that draw. Let us know if you have any issues or questions.

Bob, streetperf and 4 other users have reacted to this post.
Bobstreetperfmlrtymejab351wgary.best2011Starquester
1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump

Thank you for this. I found a very helpful youtube video from a bronco guy in Nashville about the FiTech, but his model must only have had front blade adjustment back then? Dunno, but I was in a spot where a 1* turn of the screw went from bouncing between 0-1 and 33.

After trying this and spending time adjusting both blade sets simultaneously, I have it bouncing from 3-7 regularly now. Success!

gary.best2011 has reacted to this post.
gary.best2011

This is a very logical procedure. I wonder why it took Fitech so long to come out with it. My car seems to idle fine setting it the original way. Do you think there is any point resetting it this way?

65 GTO with built 406 Chevy smallblock, Fitech

A lot of people have posted that they have issues with the adjustment of the rear blades. This procedure takes care of it. In my case, even before I followed this procedure, I had an issue where the rear butterflies would stay open slightly in idle, which left the idle high until they finally closed. This was happening because the rear set screw was not topping against the rear blade's rod so it left "play" in the system, which caused the butterflies to stay slightly open in idle.

streetperf has reacted to this post.
streetperf
1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump

Wouldn't you only want to adjust the front screw after both blades are open the same amount?. Don't both blades move insenc when you adjust the front blade?. I thought I read this somewhere.

BOB WENDIG

Kind of, but how do you know for sure they are in sync. For most cases it may be okay just to turn the front screw, but in my case it was out of sync and created a lot of issues with hanging idle. Following this procedure assures they will be synced.

Starquester has reacted to this post.
Starquester
1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump

The other thing I do when setting idle and IAC is set TPS to all zeros while setting. The return to normal.

I just used this procedure today, and finally, got my idle like I want.I have a '74 Camaro, Skip White 383 Stage 2, Fitech Go Classic 600 w/ 50004 Force Fuel Delivery. Thanks for the help, now I think I can say...my build is Completed. Again Thanks 🙂

I hope this works on mine, every since I got it back from fitech because of the fuel relay, I cannot get it to idle,  sometime it just gallops from 1500 to 200 rpm, ir is always running -35 to -38 afr also! It’s also hopeless to get to tech support on the phone,

Tom

When I was talking to their support the other day, he said to only tune the rear blades if you can't get the IAC steps with the front one alone.

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