Scorp1us

When I follow the IAC reset procedure (http://www.gnttype.org/techarea/faq/IACreset.html )
My pintle does not move. I am using A14 (wht/blk) and shorting it to ground. I consistently end up with screwed up idles.

The only thing that seems to matter is the IAC flow % vs temp table:
C : %
-28: 93.8
-16: 89.8
-4:77.0
8: 73.0
20: 64.8
32: 55.1
44: 39.8
56: 30.1
68: 28.1
80: 25.0
92: 25.0
104: 31.3
116: 45.7

If I drop it for whatever cell, then the idle comes down to where it should be, otherwise it seems to always wanting to fully open.

Today, I had an idle of about 1400! but the throttle plate was right, the TPS was right too. 0.56v. It was the pintle. I think the problem is it gets confused on what position it is in and consistently the wrong direction.

Today I substituted another IAC i had (I've been dealing with this a while) that was fully extended. With that in, I set the throttle plate to 525 RPM. I checked the TPS 0.56v, where it was when I started.

There's gotta be something up. Help?

EagleMark

Does your conversion have a harness or TBI unit from a Big Block? There are 2 wires reversed on them? Or check your wiring to ECM.

Scorp1us

Not that I know of. It's an ebay kit and originally came with a 16197427 with a 305 cal on it. I've changed the ECU to a different 16197427 with a 350 cal out of a suburban. I don't think they made a 305 BB?

I tried last night shorting ALDL-B and E5 to ground to do t he pintle extend thing, and no dice. I don't know what to try next. I've done all kinds of web searches.

EagleMark

I have a differant ECM on my test bench right now so can't help there... if you short A and B and turn key on IAC should extend all the way in and seal, then usually buzz. Then you unplug it.

Also with A and B crossed you should be able to see CEL flash codes so this could be a test that A and B are wired correctly.

If it's not, then maybe the IAC is faulty? They do get cruddy in there sometimes you can take it out and hold it pintle side down and clean it out with break clean and blow it out. I then use a light oil. Do not do this pintle side up as liquid can wick into electronics. Also check passages for being clean.

Also I didn't think 16197427 ever had a 305/5.0L engine? 4.3, 5.7 and 7.4 I know of... was the harness from a 4.3 CPI engine that may have differant IAC wiring? just not sure of that?

HTH!

Scorp1us

I have 2 IACs, one new fromt he store they both behave the same way. Either both are broke or they both work.

However, in general operation, it can control the idle I can watch the idle drop as the IAC counts drop, so it is moving. It just never moves into the IAC reset position.

If it helps, I would pay for or send you a 16197427 for you to play with, if you have the time?

EagleMark

I have a few 16197427 ECM and others and appreciate the offer to pay me to help your issue, but that is not necessary, I help others as others have helped me and I always learn more as I go. If my test bench was not in middle of harness rebuild I would look into it for you.

But with your other post of weird data log and even weirder fix there's a good probability something else is wrong and this issue will be resolved as well

Scorp1us

I'm gonna get a new ECU from the u-pick-u-pull JY this weekend...
With all the swapping, I bent some pins and once you do that they are good as dead because that metal doesn't take being bent very long before it snaps.