you have to get the cam and crank lined up with the dowel pins facing upwards to check timing.. you cant just check it without everything lined up like your picture above.

sounds like it has cams. has it idled higher before? if it idles higher with cams it will hide the lope.

instead of buying a new iac you could of just disconnected your current one and seen how the car responded without it.

 

current one not sure what you mean ?

 

theres a few way of checking if your iac is good, do a quick search i dont have the links. ive had to do it before.

 

Very true, i also think found it now, my car wont start because my fuel pump failed, i think that was the reason i was getting bad idle. Or its just a combination of vacuum leak and the fuel pump going out. Anyways time for a Walbro 255

 

@ Andrew thanx ill do that right now

 

So i changed the iac valve and car was running fine all day now it shuts off and in order to stay on i have to give it gas :/

 

So i bought a used iac valve from another member here on evoM and it went to ****s
As you see the one on the left is the one that's bad i bought it yesterday and installed
it today was fine until about an hour ago.

 

Meh,

So my idle issue returned. A while back I had a horrible idle issue and changed IACV with no effect. Backed out the BISS crew and slowly screwed it back down and the issue went away.

But now a few months later I gave it a hard run and noticed the idle sounding terrible almost like it wants to cut out. I thought it was a pipe loose but the boost was holding fine and all the hoses are good. Adjusted the BISS slightly and it helped but idling slightly over 1000RPM but smooth.

Also noticed now when aircon is on, the idle fluctuates slightly as well... gonna take off my EGR tomorrow and give it a clean and recheck all my hoses...

 

What afr's are you at idle? lopey idle could mean running lean at idle. If the ecu tries to do too much adjusting of the fuel trims it will throw a misfire CEL.

 

That's just it: no CELs coming up even when I test for them in evoscan...

When it warms up, the idle goes rough and the AFRs jump from normal 14.7 area to 12 or 11 then the car runs badly. It jumps to about 15.0 then settles at 14.7 again and starts the cycle again.

-Cleaned my EGR this morning (actually it was already quite clean) made no difference

- all the vacuum hoses and intake hoses are fine

- plugs, coils and wires are fine... tested and in spec

- IACV tested and in spec.

I did replace my 9 MR valve back to the plastic one and strangely enough it helped a bit... but still had the idle issue. I actually had to adjust the BISS... even parking it and adjusting to the 900 recommeneded setting has it idling rough, so i have to set it at about 1000 rpm or so just to get it idling somewhat civil. But with the A/C on the IACV set it to idle rpm and then it just starts doing the same thing again.

Now I had this problem once before and I had to back out my BISS screw fully then slowly screw it in and it actually worked, which possibly led me to believe the screw may have had a leak but I doubt. Then recently redid my timing and also installed a test pipe and it ran fine. But after boosting it hard last night it started idling badly again. I know it isn't timing cause the first time this happened was prior to my timing belt change. it drives fine and everything, so I really don't kow what it is... Don't have a tester for boost leaks and other than that i guess I'll have to get it compression tested. Here's a small video of the issue. Only thing I haven't donw (which I plan to do ) is remove the battery terminal for 10 mins and see.


http://www.youtube.com/watch?v=fFrAB...ature=youtu.be

 

What i also noticed is when on a/c, if I touch the pedal enough for the revs to reach 1000 rpm, the idle smoothens and the afrs go back to 14.7 or so.

Can Idle settings be adjusted through the ecu separately for a/c?

 

did u check the teeth on the iac valve ?

 

The valve actually is fine... it's not worn. plus when I had a newer one from an evo 9 the idle was doing the exact same thing... when you park it in evoscan the car would just go into "ghost cam mode..." the IACV does bring the revs to the programmed section.

Anyway I may have solved it for the moment gonna see how it goes:

- worked the BISS till it was about 1000 rpm where my ratios stay steady once again

- removed battery terminal for a few mins

- Sprayed the "E" line on the throttlebody and line slightly with foaming solvent

- went into ECUflash and raised the idle RPM both for normal and A/C to 952


So far took it for a drive and it has been steady. Gonna drive it for a couple days as is and then reinstall the MR valve and see what happens...


EDIT: So car idles and drives ok, but I realise that ONLY between 700-900 is where my AFRs start jumping and causing the idle to be off: Put the car in all gears and allowed the car to just coast along in each gear; everytime it reached between 700-900 it AFRs would drop to 12s and bounce back and forth to 15s... and then the car would idle really bad. Once it passes that point it idles and runs great.

weird.

 

Reviving:

Question: can fuel pressure or the regulator cause the afrs to jump at idle in the video I posted?

reason I asked is that I went to do a fillup this evening and added some Max44 treatment. I found the car wasn't idling too badly... or maybe it's just me.

Anyway I changed the BISS screw and seal and didn't really find it worse for wear:



The new one is on the right. It did take a little more effort to screw it down compared to the old one but the seal feels ok and it still sticks out a bit... but and the idle sounds ok at the moment... will keep an eye

 

well i did a smoke test a few days ago and found out it was my shaft seals on the throttle plate.