Idle Hang
Help 🙂 I'm trying to figure out why my idle - which is set @ 800 rpm is fine after start up, but after driving, or increasing the RPM above 2000, the new idle wants to be 1200....in looking at the gauges in Dashboard, the idle target is now 1200ish rpm and TPS is at 0. If I blip the throttle, the target RPM drops back down to around 800 and it idles at around 800....until I bring the RPM back up, the target RPM jumps back up to 1200 until I blip the throttle again......I played with the Decay and it still behaves the same way...where should I be looking to adjust this?
I think that the fact that the idle returns to 800 when you "blip" the throttle - you are slamming the butterflies closed. I'd check for correct throttle cable response.
Do this - remove air cleaner - slowly rev & decelerate & see where your idle falls. Then rev/blip & slam the throttle closed. If your idle returns to 800 with the "blip" then see if you can add a return spring or replace the cable.
Thanks for the suggestion, I did just that...and the same result...TPS is at 0, and the Computer is calling for the 1200 RPM until I blip the throttle...Wouldn't the fact that the computer is calling for (and getting) the higher RPM direct you away from a "mechanical" issue?
Yes - that's odd. Not knowing how long you've had the unit - perhaps you need to reset the (Reset Idle Learn) setting. See below from the Handheld Controller Feature Definitions document.
Reset Idle Learn = The Idle Air Learning can be reset to a default value (16 steps) – by setting this control value to 1, and turning the key off and waiting for the system to completely power down. This can be done if the IAC learned incorrect values from an improper throttle adjustment, or other situation that caused the learning to be wrong.
Have you figured out this problem yet? I have exactly the same issue. Hanging idle till I blip it. TPS is at 0 but idle is high until I blip it.
Thanks
I had this issue and fought it for a long time until I adjusted the rear butterflies. A good test is when the car is idling high, to force close the rear butterflies either directly through the linkage or pushing them close with your finger. What it happened in my case is that the rear butterflies were not being kept closed by the spring. To fix this follow this procedure:
Start 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.
So my issue was the butterflies on the secondaries weren’t centered in there bores. Go to the car get it running and get the rom to hang, then stick your finger or a screwdriver in in the secondaries and push them down (in the closed position) and see if the idle drops. If it does, then the butterflies are hanging on the throttle body itself. To solve it, remove the Unit and loosen the screws holdin the butterflies and adjust them until they don’t rub against the throttle body. That’s what solved my issue.
Quote from tony-muscle on June 29, 2021, 10:02 pmTo fix this follow this procedure:
Very helpful response. I'll give it a shot! Thanks