Hi everyone,

I'm not a tuner I'm just a driver that bought an evo IX (6speed) and now has problems nobody seem to know.
I currently suffer from two painful problems idle is too high and I have throttle hang.

I brought my car for a tune after installing a FP Green HTA and the tuner says my car has a problem and they can't do anything until it is solved, problem is no one here knows how to fix this except changing everything at random hoping to fix it :/

Those two problems I already had before the tune when the car was stock ! But they had not much impact on driveability before, now with 1000cc injectors a green etc...it's absolutely awful.

1 - my ISC steps will never ever go under 40 steps at idle
whatever I do with the BISS with an idle of 2000rpm I have 40 steps with an idle of 900rpm I have 40 steps...it simply doesn't want to go lower than 40.
I can idle for 1/2 an hour it will stay at 40 steps.

2 - the idle I'm setting while SAS mode is activated has nothing to do with the final one I have in regular idling
(I know how to do it right hot engine,battery etc...)
when I dial in sas mode 850 : i have a stable idle at 1400rpm
when I dial in sas mode 800 : I have 1200rpm
when I dial in sas mode 500 : I have 900rpm
at this point the BISS is unscrewed as far as it can go I cannot go lower than 900rpm and of course always have my 40steps

Do you have any idea what could be causing the steps to stay that high ?
And why there is such a difference bewteen when the SASmode is active and when it's not (+400rpm) ?

- ISCV was changed
- throttle body cleaned
- throttle body shaft seals changed
- throttle body gasket is perfect
- blocked the diverter valve vacuum tubing to make sure there was no leak from the valve (boost sensor was on it too so that's not it either)

p.s.
could it be cam related ? I have GSC S1 cams installed, Would it be possible that they were not correctly installed ?

 

I did not make enough evoscan logs that is clear to me now but I found something fishy...
it may be a coincidence or not ?!?

ISC value at idle on various evoscan logs I had
16.05.09 isc steps=20
21.06.09 isc steps=18
19.07.09 isc steps=14
12.08.09 GSC s1 mivec installation
22.08.09 isc steps=29
23.08.09 isc steps=31
07.09.09 isc steps=40
ISC steps never got lower than 40 since then

 

Did someone tune your ROM with the cam install? It would be good to see the values in the various ISCV tables and idle tables just to be sure nothing was adjusted incorrectly (ie your idle may have been targeted higher, iscv steps adjusted higher, etc)

It sounds like you tried everything mechanical, so it may be tune related?

 

I have the same exact problem. Bringing this up from the grave because I can’t seem to figure out what it is either. Im on speed density rom 88591715. I don’t think I have a vacuum leak. Idle is always high and it idle hunts all the time.

 

Hey SyncdLancer, fellow Miami-an here. I recently had an issue with what is described in this thread. Though my issue I think is due to a bad ISC itself. When unplugging my ISC, the rev hang is completely gone and does not hunt for an idle.

Ordered a cheapo replacement online and will see how it fairs when it arrives. Will be happy if it gives me a year.

 

For some reason on my car the SAS mode doesn't always work correctly so I can turn it on and the idle actually increases, which it should not do if the IACV closes. I replaced the factory EVO IX IACV made by Mikuni with a new Mikuni W0133-1767127, which is $225 from partsgeek. If you can't get the SAS to work properly when activated then you can simply increase the idle using the factory stop, which should force the steps to decrease to lower the idle. You'll just have to keep doing this until your steps are where you want them.

 

Thank you for the information. I’m sure nobody wants to pay dealer price for an iacv just to find out it’s not the problem. I’ve been fortunate with the sas mode but after a little while it will suddenly deactivate. The worst thing about the iacv location are the 3 small nuts that hold it to the tb. They snap off too easy and after snapping 2 I’ve had to improvise with zip ties and silicone to keep it on. At this point I’m looking at swapping the throttle body because my idle still isn’t ideal and I think I might have other issues after going on. I went all over the pipes and tb with leak detector fluid and I’m not getting a single bubble.

 

What’s up Chrispy. Yeah Miami is a tricky place to daily an evo when you aren’t sure if your idle will cooperate at a stop light. I’m hoping to fix a bunch of stuff before Sunday the 20th. The mitsu owners meet is being held in Kissimmee. Hope to see you there man!