socal73HS30 Posted June 17, 2011 Share Posted June 17, 2011 (edited) Im researching as much about MS and wiring it up before i dive headfirst into my engine bay. My question is, since an IAC valve is optional, how many have used it and is it worth the extra effort to install? I have MS2 pcb3 board. L28et into '72 240z, mostly stock motor. If you used one, let me know why you chose the type you did (stepper or fast idle valve). how did you install it for your application? I already used the search function and couldnt find the information I was looking for. If this topic has been covered, perhaps you would be so kind as to point me out the thread? Thanks! Edited June 17, 2011 by socal73HS30 Quote Link to comment Share on other sites More sharing options...
mobythevan Posted June 20, 2011 Share Posted June 20, 2011 My opinion after having several megasquirt cars for several years is that if you only drag race your car then skip the IAC. If you daily drive it and drive it at night or have AC/eletric fans/windshield wipers/etc then put a stepper IAC on the car. Right now I am setting up GM steppers on 3 different cars and I think it is worth it on a daily driver. Of course I did not have have IAC in the old days of MS1 because the board did not support it. But now that everyone is using MS2 or MS3 I would say everyone should have IAC since both support it. That is my two cents. Quote Link to comment Share on other sites More sharing options...
Derek Posted June 21, 2011 Share Posted June 21, 2011 I have a stepper IAC on my rig and it's the way to go. It's quite civilized! Running MS2 extra. Derek Quote Link to comment Share on other sites More sharing options...
misterZ Posted June 21, 2011 Share Posted June 21, 2011 Didn't think of it when I purchased my MS1 yesterday; I'll have to check if the newer v3.0* PCB supports. Btw--did anyone build there own kit or did you purchase assembled? Just trying to gauge what I got myself into time-wise to solder the board up. Thanks, Quote Link to comment Share on other sites More sharing options...
mobythevan Posted June 23, 2011 Share Posted June 23, 2011 The v3.0 pcb doesn't support the stepper per se. MS2 and MS3 actually have stepper driver ICs on the daughterboards. The v3.0 pcb allows the 4 wires to be connected to the stepper, but you still need to driver IC. Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted June 24, 2011 Share Posted June 24, 2011 (edited) Im researching as much about MS and wiring it up before i dive headfirst into my engine bay. My question is, since an IAC valve is optional, how many have used it and is it worth the extra effort to install? I have MS2 pcb3 board. L28et into '72 240z, mostly stock motor. If you used one, let me know why you chose the type you did (stepper or fast idle valve). how did you install it for your application? I already used the search function and couldnt find the information I was looking for. If this topic has been covered, perhaps you would be so kind as to point me out the thread? Thanks! If your alternator needs extra help around idle, maybe. But that's only if you have A/C, power steering, a large stereo, ... Otherwise, If you need the extra air for cold starts and warmup, just use the thermometer valve. The Z31 has a 12v on-when-car-is-on valve, and I believe the L28's is the same. No need to hook it to MS, just have it powered when the IGN is on. I used just that cold air valve and never had any issues with MSII on my Z31. And it had power steering and A/C. Although now that I think about it it has a separate PS up-idle valve. Edited June 24, 2011 by BLOZ UP Quote Link to comment Share on other sites More sharing options...
letitsnow Posted June 24, 2011 Share Posted June 24, 2011 I don't have an IAC, you can tell it doesn't, but it's plenty drivable. I think it would be worth it, sometimes the idle hunts during stop and go traffic and that bothers me. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted June 24, 2011 Share Posted June 24, 2011 I don't have an IAC, you can tell it doesn't, but it's plenty drivable. I think it would be worth it, sometimes the idle hunts during stop and go traffic and that bothers me. You should be able to tune that out without using an IAC valve - in fact, we usually don't recommend using an IAC valve to fix a hunting idle as it will react too slowly. This can usually be dealt with using fuel and timing. Perhaps it's leaning out from higher IAT readings? Quote Link to comment Share on other sites More sharing options...
jthom5147 Posted June 30, 2011 Share Posted June 30, 2011 (edited) I very much appreciate the input. I hadn't ordered my ms board yet, so I went with a v3.57 instead of a v3.0 so that it is already setup for IAC. Ideally, it sounds like something I want to have, but i will add it later after the engine is in and running (so I don't get distracted from my budget and time constraints) Perhaps those of you that did use a stepper could find some time to take photos of what parts you used and how you setup the solenoid? Please? Matt, do I need to make any modifications to the ms2 v3.57 (aside from the settings that come from your factory as default) board to wire in an stepper IAC? I'm using a relay board, so the stepper would use pins 6-10 on the J20 if my memory serves me right. Thanks Edited June 30, 2011 by jthom5147 Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted June 30, 2011 Share Posted June 30, 2011 No mods should be needed - you can run a stepper IAC off the S1 through S4 relay board terminals. Quote Link to comment Share on other sites More sharing options...
jthom5147 Posted June 30, 2011 Share Posted June 30, 2011 Perfect, thank you Matt. Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted June 30, 2011 Share Posted June 30, 2011 (edited) I don't have an IAC, you can tell it doesn't, but it's plenty drivable. I think it would be worth it, sometimes the idle hunts during stop and go traffic and that bothers me. I'm not running an IAC at all on mine either - the only issue is at startup on super cold mornings. I don't mind not having it, just depends if you want to put in the work. I personally don't mind a lumpy idle at cold start, and I definitely didn't want that gawdy IAC on my shaved manifold Snow - I read Matt's idle tuning article, and using his methods for spark and VE at the lower regions of the map really cleaned up my idle, and no more hunting. Have you read it/played with it yet? Edited June 30, 2011 by FlatBlack Quote Link to comment Share on other sites More sharing options...
twofouroh Posted July 7, 2011 Share Posted July 7, 2011 (edited) I'm not running my IAC yet, but I will be. I want it so I don't need separate solutions for all of the various idle-up conditions. I found two that you could look at for your needs: #1 is the IAC off of a VQ35 - it's on the bottom of the throttle body, but can be removed if you fab a plate with the in and out air bungs in it. Pros, it can move a lot of air, it has a water heating passage to prevent ice-up, and it has a temp compensator(can be disabled). Cons - fabbing the new back plate with bungs. #2 is the IAC off a VQ30 or 33, can't remember which. It is bolted to the top of the intake manifold, and has a tan/brown plastic cap at one end with 3 screws with white paint across them. Pros - it is self contained and has in and out hose bungs already, it can be bolted on wherever you want to put it. Cons - it doesn't appear to move as much air as the 35 model, and it doesn' have a temp compensator or a water passage. Both are the usual Nissan 6-wire type, but just ignore the center wires to make them work like the 4 wire (MS) kind. It took me much longer to hook the wires up to the MS than it did to get them working, it's monkey simple if you follow the MS how-to directions. The only downside is that it uses 4 wires in the harness, but I didn't need them for anything else, so no problem for me. Just remember to set the pulse width even if they work first try, and to set the power mode to 'when moving only'. They are not the kind that drifts when off, and they (and the stepper chip) will get hot if they're set to 'always on'. Edited July 7, 2011 by twofouroh Quote Link to comment Share on other sites More sharing options...
jthom5147 Posted July 7, 2011 Share Posted July 7, 2011 That is very good info, thanks. Quote Link to comment Share on other sites More sharing options...
jthom5147 Posted July 7, 2011 Share Posted July 7, 2011 Is this like what you're talking about? http://cgi.ebay.com/ebaymotors/Nissan-Maxima-Infiniti-I30-Idle-Air-Control-Valve-IAC-/160541351315?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3AMaxima&hash=item2561029d93 Quote Link to comment Share on other sites More sharing options...
akeboshi Posted September 29, 2011 Share Posted September 29, 2011 ive been driving mine without an iac since i installed ms. ive just been tuning idle with the idle stop screw. just to give you a backround on my preference for car creature comfort, i dont have or need interior gauges or dash, no a/c radio, anything and i can bear without all that stuff but honestly not having an iac f@%king sucks. im ALWAYS turing the idle stop as i can never get it right. its close enough but very annoying. doesnt want to hold idle till its warm then it idles too hight blah blah..... anyways i think if you can afford it you should get an iac setup. im about to add it to my ride after i install edis which is soon. marcus Quote Link to comment Share on other sites More sharing options...
motomanmike Posted November 17, 2012 Share Posted November 17, 2012 Really thinking about this one. We've had a huge swing in weather here the past 2 weeks. It was 70 last sunday and tonight its about 38 degrees. Really driving me nuts trying to tune this car right but I did drive it some tonight. Good information. Quote Link to comment Share on other sites More sharing options...
FricFrac Posted November 22, 2012 Share Posted November 22, 2012 Some of the 280ZXs have an idle air bypass that has a bimetal valve in it. It uses both coolant and electronically heated control. I just used the electronic hookup as I found the hot water doesn't regulate as well. Quote Link to comment Share on other sites More sharing options...
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