Idle Control Problems
 

Hi Guys

I have seen a bunch of threads about people having issues with the Idle dropping to 500rpm and the car strugging to recover...

Most guys sat that the Idle Control Valve needs to be replaced

Some say it is a Vacuum soleniod somwhere

others say maybe its a boost leak or MAF scaling issue...


Im starting to also think its a Idle Control Valve, can the people who resolved their idle problems - please post their solution...


and also:

Is there a way to bypass the Idle Control Valve and force the idle not to drop say below 900rpm?


thanks
Sal
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All of those could be the culprit. On my setup, Ive scaled the MAF per fuel trims, boost leak tested, replaced the ISCV, and its still there. I can get around the issue happening, it seems like its when my IX bov gets loaded up, then opens (I can hear it flutter), then idle drops.

Adjusting the BISS does bypass the iscv to a certain extent. But if you adjusted so far that it completely bypassed the iscv, the car will likely idle really high and possibly have an uncontrollable idle. would probably throw codes too. not ideal....

Im tossing a buddy's Greddy RS BOV on this afternoon, hoping that will fix the issue. Right now Ive got my idle rpm around 1000 and biss adjusted slightly on the high side. It typically idles around 1100, which is pretty annoying, but seems to have made my issue bearable until I can start troubleshooting mechanical stuff.

smoke test to see if a boost/vacuum leak could be the culprit

You can easily test the ISCV by unscrewing it, leaving the electrical connector plugged in and turning the car to "ON", the valve will click loudly and move in and out as it searches for the correct adjustment to keep the idle correct. If it doesn't move, it's bad, also there is an o-ring that seals it, if that goes bad or is missing that is definitely part of the problem.

I've never seen a way to bypass it and the BISS won't solve an issue with the ISCV.

arent the two relatively the same thing? Just one is static and the other is controlled by the ecu? to the op, I appologize if my response was incorrect. makes sense in my head, but so does alot of other senseless stuff.

SO theres no way to stop the idle from dropping below a certain point using Ecuflash...

I have a hunch its my ICV - I have checked everything else, made sure theres no boost leaks, removed EGR, etc... Will try removing the screw or unplugging it and see what happens.

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since u have the EGR deleted, do you have the 2 nipples on the TB looped w/ a small vac. hose? I just figured out a couple days ago, that these 2 nipples need to be individually capped! I need to do this as well... check this thread
https://www.evolutionm.net/forums/ec...enoids-14.html

GL

I have the same exact same problem, but only when my AC is on. ISC is good, no leaks, all vac lines are attached. A while back I pulled the BISS, cleaned the port and the tip of the BISS (was real cruddy) and cleaned the ISC stepper valve and it idled fine.... for a while. Looks like I have to do it again. You may want to try that if you haven't yet.
Remember, you have to set the BISS when you reinstall it.

My thought was buildup would slowly block the BISS passage/tip to the point that the ISC couldn't bypass enough air to keep the idle raised.

Thats defiantly not gonna help.

nope didnt do that yet either...

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lol.. you arent lying. Just got back in from messing with it. that thing is a POS. :lol: And had no effect on the issue. Figured it was worth a shot. Gotta get my compressor back in working order and boost leak test. I swear Ive tested before with this happening (going on close to 2.5 years) and have had the IC piping on and off several times since then and have leak tested since re-installing. Ive just been running the old school map-maf patch on V5.1 and its been masking the problem (been around a little longer than my screen name implies ;)). Recently trying out V7, and trying to run it normally without the xtra patch and the issue is back. If it isnt a boost leak, Im stumped. If fuel trims are in check, then maf scaling/smoothing is good, correct? Or are there hidden secrets out there that fuel trims wont tell? Any other mechanical problems that it could be? ISCV was replaced about 10k mi ago, all egr lines are intact (by feel of hand).


Mine is fine when rolling to a stop. Its when I try to lug it around the driveway or parking lot (gas, clutch out, move, boost hits close to 0, clutch in, 500 rpm) And that is only after Ive raised the idle, initial iscv steps, and adjusted the BISS. On the "stock" phenem rom, it had no chance of recovering by itself. The boost part is what made me think bov, and it flutters at anything under 3k rpm and goes super rich.

Sub'ed, I'm in a similar situation with my IX; idle drops to 500 and struggles to recover, sometimes it does, sometimes I give it gas to get it back up. Often happens during low-speed maneuvers (ie. parking in reverse).

Are you trying to use 9653 V7 or 9417 V7?

Im using 96530706. The very first time this ever happened was when I switched from the 96940011 to the 96530006 rom.

here is my first post about the issue in '08. Just been running the map-maf patch ever since and its been fine. Im really trying not to load that patch back on the car. I know its just masking the real problem. And I plan to go SD once I get V7 MAF running properly, so Im trying to eliminate any "extra" stuff.
https://www.evolutionm.net/forums/ec...g-my-maps.html

fwiw, Im attempting to use as many "stock" settings (minus timing/fuel obviously) as I can in the phenem rom. The maps in that post are far from what it looks like now.

sal, sorry for the hijack. There really should be an stalling "mega-merge" in the stickies.

Cool - lets keep this thread going and we find somthing that works effectively...

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