I found replacement IACs from calling different shops. The IAC I have currently came from AMS. I would just try that first or there are places on the internet that sell parts at whole sale prices versus the dealer raping price. I fixed this problem by getting a check valve and a friend of mine fixed his using a solenoid valve. They do the same thing but the solenoid valve can be programed because it is electric.

 

Ouch, I get mine for $280 from the dealership. I have a friend that works there, and I've bought so many replacement parts for my car that even the sales manager hooks me up now

 

Haha ye I get good discounts from the service people but not from the parts department. I guess I'll have to shop around..

 

With the snow kit I had on my evo I ran 60+ gallons through it at about 50% and never had an issue but I have heard of others with this issue...

 

I believe you can clean the iac and if that doesn't work then you'll have to buy a new.

I tried the solenoid valves, however, running 100% meth is recommended for them because it causes the valves to swell up and reduce flow.(recommended for 50/50meth/water use) I have a plastic check valve which last me about 4-6 months..

 

Evoryder, I got a nickel plated check valve from coolingmist.com for 40 and it has lasted for a year on my friends car. i have had mine for about 3 months and I haven't had any problems with it. If you are running 100% meth I would look into something like that. Meth + plastics= corrosion

 

i was going to add that in my prior post...i didn't want to ramble on too much i did see the check valve on coolingmists site for awhile...i wasted my money on the snow unit not knowing they are pretty much useless with 100%...will be ordering their setup today or tomorrow. Thanks for the info

 

I bought a used plenum assy with a throttle body, all the solenoids, and stepper for $200. Look in the FS section.

Or just place a rubber o-ring at the end of the servo valve blocking flow, disconnect the connector, and set idle with the BISS. Never been happier.

Try a smaller nozzle too

 

you said replace the o-ring within the valve that's going bad? You got specs on the o-ring or do i have to size it? I might do 2 smaller nozzles...right now i have x1 625ml/min...might do x2 375ml/min nozzles. Once I get this issue resolved I will redo the checkvalves and piping along with relocating the battery.

 

It doesn't have to be spec tolerant, just any material capable of staying on the tip of the servo valve and blocking any flow, methanol resistant would be good.

Make sure it's fairly soft too just in case it gets sucked into the engine

I just sliced a 4mm wide peice off of a 12mm OD/9mm ID nalgene tubing and stretched it over the tip of the stepper just enough to seal it.

You wont have any step for cold starts, AC, and power steering pressure activation, but I never really cared for the stock cold and AC idle characteristics in the first place.

 

so it's basically gonna idle at what ever rpm you set and not the adjusted rpm levels like normal? Does one have to replace the iac valve first or this bypasses it?

 

I replaced the o ring and cleaned the valve out last summer. It didn't make a difference. I guess I just have to purchase one if my car wants to idle fine on startup. The car runs fine once it gets warm, its just a little annoying at times. No codes either.

Also, turning the idle screw won't do anything or compensate, correct?

 

If anything I would have a tuner tweak your idle map. I have messed with it myself in dealing with this problem the only thing is what is it that you are actually adjusting? I adjusted mine by quarter turns to set the idle by turning the car off and on and letting it warm up and settle down at the desired idle.

 

I have yet to change the o-ring. And mine has started doing the funky idle only on long cold starts...like you said. Goes away once warmed up.

 

Got the POP too. That little pop killed my servo. Methanol backfire ate it up. I recently replaced my IAC servo. I've run 100% meth for 2 years on a 625ml nozzle without incident. I actually cleaned the servo not too long ago and it was fine. An imperfection where my new meth bung was recently welded caused the meth to pool, which lead to the backfire in my intake manifold.

I have the new IAC installed. My idle is set to 1000 rpms on the ECU, but it was at 1500 until I screwed the BISS/SAS all the way down. Now, it's at 1100 rpms with the BISS all the way in. TPS is at 0.0% off, 12.9% at idle and runs to 100% when I floor it.

Is there a way for me to adjust the throttle so that the SAS doesn't have to be all the way down? I'd like to adjust my idle down to 1000 rpms, but there is no more room to travel on my speed adjustment screw.