I cleaned my IAC while I had the throttle body off. Put it all back together and now I have code 33 MAF, and the engine is running like crap, and my autoxray says that the IAC stepper motor is at 118 steps. It hasn't gotten to closed loop yet, but in closed before I cleaned the motor it was at 92 steps?

Anyone have any clue? My MAF wasn't dropped or anything, and the burnoff and power relays are about a month old.

Thanks
-Paul

 

Did you reset the IAC?

 

You mean reset Minimum air? no, but everything is fine now. I was retarded and didn't plug the big vac line for the brake booster at the back of the plenum in. Runs fine now, idles great and all.

heh... opps

 

That one will get you. Over the summer when i siamesed my intake i was in a hurry putting it back together and fubarred a lower runner gasket while i was putting it on. Left me with a nasty vacuum leak, so bad that the car wouldn't idle below almost 1k RPMs. Being SD though, a vacuum leak is no big deal, and i had to get the car home so i drove it.

A few days later i pulled the whole upper again after work to get it sealed up. Get everything back together, fire it up. WTF it is still idling high.

I almost lost my mind, there was no way i made another giant vacuum leak. Then i found the brake booster line off, got it back on, and all was well.


Anyhow, point is, it happens to the best of it. Thats why we harp on the basics so much. Only you can make sure you didn't screw something up, even something as easy to overlook as one vacuum line or a loose connector. Before anybody else can help you or give advice, you need to double check all the little stuff yourself. Saves everybody a lot of trouble.

edit: Thought i'd add, this is also where having a good sense of how your car works can come in handy as well. I'm just guessing since i'm a SD guy, but is 33 MAF reading low. If i was a MAF guy, first thing that code would tell me is that air was bypassing the MAF. Or like in my case, a strange high idle out of nowhere was obviously a big vacuum leak.
If you understand the basics of how your ECM works, then figuring out posible causes to problems gets alot easier.

not trying to chastise you in particular, just trying to educate the population in general who will be reading through.

 

I very much understand that and I, at very least, enjoy all the input you and many others give, that have a vast array of knowledge far beyond mine.

My xray said code 33, maf sensor too high... so I figured it had something to do with air, and then the booster popped into my head.

I do have a question though, now when I start the car, the rpm goes to about 1500 and slowly creeps down. Is that for not resetting minimum air after removal of the IAC?

 

Wow! I a little surprised you were even able to start it. You would have had a helluve time starting a carbed engine with the booster line open.

As for the higher RPM on startup, the ECM will step the IAC open so the RPM starts out fairly high, then slowly step it down as the CTS warms a bit and an ECM timer elapses.

You should still get the engine to full operating temoperature, then set the minimum air position. Don't forget to check/set the TPS AFTER adjusting minimum air.

BTW - My basically bone stock '86 TPI starts cold at about 1,400 RPM and takes about 30 seconds to creep down to around 950 - always has from day one.