As some of you know I have been picking at a rough/choppy start idle. I don't think the IAC stepper motor is working correctly, it appears it try's to raise the idle but kicks back/slips. It's a 1988 I heard they have an issue/recall with the gears being plastic and wearing, I turned the ignition key on and off 3 or 4 times in the video before I crank it over. What do you think???

http://youtu.be/ucNdXgxVczQ?hd=1

 

It definitely doesn't look like it is operating properly. Im not sure what voltage is supposed to be supplies to it but i would check to make sure all your voltages are correct before replacing it.

 

'87-'90 used plastic gears I was told it's a recall but I will see if the manual tells the voltage I'm sure it's 12V based. This would explain why all I have to do is push on the throttle and it smoothens right out (maybe once it reaches a certain RPM?) even after I let off the throttle I am good until the next restart.

By the way I manually shut the engine down at the end of the video.

 

Sorry for the removal of the video...


Since I have no tach I really can't tell where my idle RPMs are at so everything is a guessing game. I think some people are onto something and my idle is turned up so I decided to try and crank it back down...which I'm not sure 100% how to do. I screwed the IAC screw pusher knub way back down/in and I will admit it does shift into and out of gear a bit smoother but still not where I think it should be, and that might not have been the correct way to adjust the idle? Now I am back to it starting up real choppy so I am now thinking possibly the idle was cranked up to compensate something else wrong with the choppy starting issue? It does not idle forward quite as aggressively now, but you can hear the engine idle up a little when I shift from drive into neutral before I backup. Is there a chance the starting issue is just a bad IAC; it works just not that "well" or does not extend fast enough or has lost some reach?

 

i had problems with mine kicking into high idle when coming to a stop so i unplugged it and turned the screw out to the point where it will idle normal(any more in and it wont) and a turn or two just past that point. she idles nice and sounds like shes about to die when coming off the highway but she stays running and i haven't had a problem since

 

That may be whatever is controlling the IAC and not the unit itself.

 

the pcm controls the iac. it uses readings from other sensors to determine the idle speed of the motor and keep close to if not exactly where it was programmed to be at. you can put an aftermarket tach in if you choose to. just tap into the negative side of the ign coil and run a power wire and ground for the gauge and if you want to tap into the dash light wire for lighting the gauge. there is a sticker under the hood that should state where the idle is supposed to be

 

I was not aware that a tach was electrical I thought they were all mechanical, if I can find a really cheap one I will do so. Only reason I say that is because I really have no need for one besides the idle with this crappy 3-speed tranny. I do have future plans of doing up my whole dash with clean looking aftermarket clusters etc, so I would only be tossing the cheap tach in the future anyway.

It deff shifts smoother and is easier to stop with this idle turned down but I get such a choppy startup it sounds like a cammed engine when I start it haha also I figured a high idle might be pissing away gas...I get under 10mpg around town

 

a really cheap one can be had (new) for about $20 at any auto store or even cheaper through craigslist or a rummage sale.

i plan on doing the same thing with my cluster for both my dodge and ford but on my dodge im upgrading to the 2nd gen dash(or 3rd gen if one can be had for cheap)

i have them because i like to see what my rpms are at when im cruising around and to replace any crappy factory gauge. this way i can keep my fuel economy up by keeping my rpms down.

 

I wouldn't want to mount it anywhere that will have to be patched later down the road either when I do all my clusters. It's funny you say that about lower RPMs being better gas mileage I almost find the opposite with my 3-speed non-overdrive, if I keep my RPMs on the higher side of the mid-range I seem to do better; accelerating TOO slow almost works it more...too fast and you dump gas in for limited output (bad ratio).