micktroup2

I was having starting and idle issues- tough to start, didn't like the A/C being turned on etc...
So, did some research and found myself leaning towards the iac valve. Pulled the throttle body, removed the valve and cleaning it. I didn't pull out the arm or spring, just cleaned it as it was. I cleaned out the TB too- lots of coke and carbon in the passages for the iac.
I reinstalled it and it started first time, idling beautifully at around 850rpms. That's the ticket! Drove it a bit and it ran fine- then I thought 'hang on, I think you are supposed to leave the key 'on' for about 30 seconds before starting so the ECM can relearn it'. So i did that. But the next time I started it, it raced up to 2000 rpms and stayed there! Did I screw something up? Does removing, cleaning and reinstalling require resetting the ECM? Or do I just have a sticking iac valve? Or will it sort itself out just by driving it, unless the iac valve is bad?
Thanks.

Jersey89GTA

iTrader: (1)

Not an IAC expert, actually have to clean mine or replace, I will assess once I see it. Heres what my eng does.

My car is bi polar too during start. When cold starts abit rough then clears out, engine light comes on. After it gets hot restart goes to 2000 r's but drops immediately, no light then. Light stays off till it gets cold again.

Wouldn't hurt to clear the codes on computer and reset, either discon neg bat cable or pull the fuse. I had occaisions when the r's went to 2000 and stayed, I pulled a few vac hoses and it cleared up.

micktroup2

I've got no 'check engine' light indicating codes- the IAC apparently often WON'T show a code. I'll try the battery disconnect anyway... Thanks.

Jersey89GTA

iTrader: (1)

Another thing w/ the IAC, the Pintle distance has to be set to 1 1/8" from the end to the gasket according to the Haynes book.

micktroup2

How do you do that? I tried wiggling it when I had it out but the thing wouldn't move...

BigBadLou

iTrader: (3)

If you did not move the pintle when cleaning, there is no need to adjust the IAC afterwards.
The IAC adjustment procedure applies only if the position IAC has been moved manually or if it is in an unknown position or connected to an unknown ECM.

Mick, did you hit the throttle when the engine was idling at 2000 rpm? Did it help any?
Disconnecting the battery (or just pulling the single Fuel Pump and ECM fuse by the battery) wouldn't hurt.

micktroup2

Hi Lou,

I don't remember hitting the gas when it was at 2000rpm- but I will try it. I tried disconnecting the battery, but it didn't seem to do anything. Pep Boys has a Bosch AIC valve for around $20: this is getting annoying enough I think I will just get a new one. The fact that sometimes it is fine and other times not makes me think the damn thing is just sticking.

Any procedures I need to follow when installing a new one?

BigBadLou

iTrader: (3)

Yes, that is my thinking too that your valve is sticking.

If you install a new one, then you WILL have to follow the IAC reset procedure. You can find it here on TGO in the tech articles section.

micktroup2

I read the article- it seems to refer to adjusting 'minimal air'. Does that proceeding also cover the ECM adjusting the IAC? I take it it happens automatically?

BigBadLou

iTrader: (3)

For the IAC reset, you only need to perform the paper-clip portion of the procedure:
Take the paper clip and open it up and form it into a big "U" shape. Insert the clip ends into the ALDL in the 'A' and 'B' pins.
Turn on the ignition, but don't start the engine. Wait 30 seconds.

Turn off the ignition, remove the paper-clip and you can now start your engine.

micktroup2

I think I will try that first and see how it works with the current IAC. Thanks!

Jersey89GTA

iTrader: (1)

Thanks Lou, I didn't do that either. I removed my plenum earlier, but left the IAC in, going to pull it and clean it.

micktroup2

Hi Lou, did as you suggested and it seems to help, but I still have problems with idle all over the place, so I think my valve is sticking- next stop: a NEW IAC valve. I will let you all know the results...!

Jersey89GTA

iTrader: (1)

Please report back on the new IAC results, I replaced alot of the electronic crap this year but skipped the IAC, probably due.

micktroup2

Idle seems a little less erratic- haven't replaced the IAC valve yet- but it still climbs up to around 1500 after starting. Makes it a joy to drop into gear!! And now it just flashed the dreaded 'code 32'! Any suggestions?

micktroup2

By the way- it is a 4 pin plug: this is going to sound like a really stupid question, so go ahead and laugh all you want- but I tightened the valve down when I installed it after cleaning so that it was back the way I thought it should be- can plugging the wire back in incorrectly make a difference? You could conceivably plug the lead back in any one of 4 ways..

Jersey89GTA

iTrader: (1)

There should be a lift tab on one side that locks it, the reciever side should have a little nub it locks onto ...?? good question tho, I'll have to mark mine when I do mine.

Looking at the Chilton book, sayes once reinstalled "NEW IAC" you have to calibrate it.

Depress the accelerator pedal Slightly
Start engine for 5 seconds - turn off.
Wait 10 seconds, then start car and let it run ... check for proper idle.
Done.

Keep in mind they always require disconnect neg batt cable prior to any work, so this will clear the memory. This is necessary when recalibrating.

Code 32 is the stupid EGR.

BigBadLou

iTrader: (3)

I would hope that the square IAC plug has some kind of an index in it to prevent it from being plugged in the wrong way. I am not close to my car to check.
So of course make sure the plug is in the right way.
If you had removed the TB before, please make sure that all vacuum lines are reconnected. Including the EGR vacuum source line that connects to the bottom of the TB. Also check that the line is not broken or cracked.

micktroup2

There's SUPPOSED to be a clip on the plug that goes over a tab on the valve. My clip is long gone and there are TWO tabs on the valve(???). Jeez GM, could you design SOMETHING that is a) accessible, b) LOGICAL and c) connects in only one way?? I swear, if these cars weren't sexy to look at, would we spend this much time keeping them running? My old Chevelle I could tune with a timing light and a screwdriver...

BigBadLou

iTrader: (3)

Hehe, I know exactly what you mean.
That's why I recently started saying: "It's a Chevy, get used to it".

Tuned Performance

iTrader: (92)

Delphi 12015798 this need to be installed correctly for the ecm to control the two iac coils.
http://www.ebay.com/itm/Delphi-12015...45bcea&vxp=mtr

micktroup2

Did some cleaning of the valve connector- found that the lead was hooked up correctly. The other tab was a piece of dirt! I may replace the pigtail too- looks like it was replaced once before. Could be a loose connection on one of the butt connectors maybe... It starts easier, as I said, at around 750-800 rpms when cold, then steadily climbs toward 2000 or so as it warms up.

BigBadLou

iTrader: (3)

Did you check the air hose connections, especially the one on the bottom of the throttle body?

micktroup2

I did. The one on the bottom seems fine, as does the evap line. To be honest, the tube from the passenger valve cover to the TB has a cracked end that has been taped. I need a new one, but can't find one. I think the tape is holding- another PO hack job!- but could that be the problem?

BigBadLou

iTrader: (3)

Unlikely. That is pre-TB air source so it does not affect the pressure in the manifold (and the idle) but it would account for code 32.

micktroup2

And yet it feeds into the TB- interesting... I have a bunch of vacuum line caps. I think I will cap each port in turn and see if that helps me track down the bugger that is causing the problem!

Tuned Performance

iTrader: (92)

http://item.mobileweb.ebay.com/viewi...d=160792998139
The PVC vent will not affect your idle quality or starting it sound like you need to check compression fuel pressure and ohm the injectors.

micktroup2

That's not it- but thanks for the help! I will check the injectors in the morning.

micktroup2

Why couldn't it be... a carb, a distributor and a stinky exhaust?!??! God DAMN you California with your 'ooh, save the planet!' crap... SCREW the planet and screw YOU, Al Gore- I want to go fast and get REALLY crappy gas mileage!!

titus78

Amen to that!