Good info to know, but what can be done to fix it? Can you change the rate at which the A/F ratios return to stoich after letting off the gas? Can the injector pulse width be adjusted, or is this an issue with the injector itself? Does it have something to do with the fact that the X takes high impedance injectors? Also, I just have to say that I disagree about the rev hang only occuring when light throttle usage is being applied. The issue also occurs at heavy throttle and it's not just when in gear.

For example, if you have the clutch depressed and rev the car up with a full throttle burst to any rpm, low or high, it takes FOREVER to come back down. In any case, this issue is annoying and needs to get fixed. Where I find the issue most irritating is when I am parking. Every time I engage the clutch and apply gas to get the car moving, as soon as I disengage the clutch and let off the gas, the damn rpms jump up and hang there and it's embaressing. People hear this and probably wonder why I'm revving the car up like that, or maybe they think I'm burning my clutch when I'm not even using the clutch at all.

Hell, add in the fact that this clutch stinks so easily if you slip it even a little bit and this car makes experienced drivers look like noobs. Kind of ironic, actually; this car makes a noob look like a hero around a racetrack, and yet makes an experieced driver look like a noob in daily traffic. I guess I have to see the humor in that...

 

The 05-06 guys have been complaining about the same problem since they rolled off the lot.

https://www.evolutionm.net/forums/ec...per-table.html

I didnt take the time to read the entire thread but it doesnt look they have found a solution.

 

We have tuned this out with the idle stepper adjustments in the 05-06.

There does not appear to be tables yet defined in the Evo X roms.

With the drive by wire throttle on the X, it very well may be able to be tuned out with throttle % modifications in the ECU.

 

thank you for this thread. As mentioned it's only an annoyance at very low speeds. I notice it especially when giving it just a bit of gas while starting to pull forward (so gently engaging the clutch). But then due to traffic or whatever i have to stop immediatelly so i push the clutch back down immediately and the rpms jump to like 2500 3k and hang for several seconds.

It really is kinda annoying, but doesn't have an impact much beyond just very slow moving. Still would be interested to know why.

 

^honestly I think some of that is because of the light flywheel.

 

Uh, no. Lightweight flywheels cause the rpms to drop very quickly once off the gas, which would be the opposite of what's occuring here. Not only that, but the X doesn't have a lightweigth flywheel from the factory, not like an aftermarket true lightweight flywheel, at least. It's ecu programming for sure, or it's something like an idle control valve in conjunction with the ecu.

 

Thank all of you for the information you provided.

Unfortunately for all of you, my car doesn't seem to do it. I drove to the Dynojet at Switzer's tonight and didn't notice it. Then when I got back to the shop I tried to move it around the parking lot and make it happen, again, nothing. Then on the way home I'd throw the clutch in at various times and nothing.

I don't know if it's something we've done without knowing in our base flash that is in the car, if it's because the cams are lopey and could be effecting it. I'm not sure but my car doesn't seem to do it.

 

yeah mine did it today but it was in neutral and i just pressed in the clutch and it started to come back down.

oh and david how do those cams run?

 

Cams work kick *** but the idle is very lopey with them. I'm going to work on tuning that out of it tomorrow and some other stuff on the car.

 

is there anyway to make it not lopey?

 

https://www.evolutionm.net/forums/6531917-post12.html

That's amazing.

 

My 06' Civic SI did something simular to this. The civic however wasn't nearly as bad as my X.

-X

 

Out of curiousity? Are there any changes to the mivec in your tune?

 

Quote:
Originally Posted by toshibakoludo
^honestly I think some of that is because of the light flywheel.

Uh, no. Lightweight flywheels cause the rpms to drop very quickly once off the gas, which would be the opposite of what's occuring here. Not only that, but the X doesn't have a lightweigth flywheel from the factory, not like an aftermarket true lightweight flywheel, at least. It's ecu programming for sure, or it's something like an idle control valve in conjunction with the ecu.
__________________

Um, on second tought this was what I meant. Now that I think about it can be many different things. Maybe not the light flywheel and it is lighter than most cars out there there is no question there.

http://en.wikipedia.org/wiki/Mitsubi...ncer_Evolution
(Even standard components are considered 'tuned' compared to other vehicles. For instance, the flywheel on normal cars weigh about 12-15 kilograms (26-33 pounds), but Evolution flywheels weigh a mere 6 kilograms (13 pounds) for very quick engine response).

I don't want to argue u got a point but you are wrong about the flywheel. Anyways on with possible causes
http://blogs.edmunds.com/roadtests/2...-rev-hang.html

 

yeah i saw your post so i just tried it