IAC #'s flucuating while cruising?

[rb68rr]

With the cruise control set at 65mph on a very flat road my iac numbers on the Scanmaster will fluctuate anywhere from 71 to 123 and everwhere in between! I have a rough idle and the car studders a lot at all rpm's. I know the oil from my leaking turbo isn't helping any. Is my iac motor bad? Will it cause the car to run bad all the time or just while idleing? Thanks, R.B.

 

[TurboDave]

Originally posted by rb68rr
With the cruise control set at 65mph on a very flat road my iac numbers on the Scanmaster will fluctuate anywhere from 71 to 123 and everwhere in between! I have a rough idle and the car studders a lot at all rpm's. I know the oil from my leaking turbo isn't helping any. Is my iac motor bad? Will it cause the car to run bad all the time or just while idleing? Thanks, R.B.

Well, in the first place it isn't going to tell you much trying to read IAC while driving. IAC is just that, Idle Air Control. Not Driving Air Control.
The fact that you had cruise on didn't help matters because it's always changing the throttle to maintain speed.

Check your IAC at idle, see what the numbers tell you.

Yes, the oil in there will affect air flow, but shouldn't hurt your IAC. Both my cars are still running perfect on their original IAC motors. They seldom go bad, but can be drastically affected by oil and other contaminents in the passage and sealing surfaces.

 

[rb68rr]

Thanks TurboDave. I just didn't know if a malfunctioning iac motor would affect the driveability of a car other than at idle. BTW, my car threw a code 33 tonight. I have the lt-1 maf an translator. What would cause that? Thanks, R.B.

 

[TurboDave]

Originally posted by rb68rr
Thanks TurboDave. I just didn't know if a malfunctioning iac motor would affect the driveability of a car other than at idle. BTW, my car threw a code 33 tonight. I have the lt-1 maf an translator. What would cause that? Thanks, R.B.

A poorly adjusted TPS and/or IAC could be behind your code 33. What does your MAF read at idle??

 

[timstips]

TPS is .44, IAC is .18, and AF is 04 at idle. Sound about right? Thanks, R.B.

 

[timstips]

BTW, i have noticed the AF reading on my Scanmaster go to "ZERO" twice while ideling when I got the hiccup! Thanks, R.B.

 

[timstips]

Any comments?

 

[TurboDave]

Your original readings sounded pretty normal. But the dropouts, could be some kind of electrical glitch. Probably have to go through your system and make sure all connectors are good, good connections, no corrosion, etc.

 

[rb68rr]

Yeah, it's that electrical glitz that's about to make me lose my mind!!!!!!!!!

 

[rb68rr]

The two times I've actually seen the maf reading drop to "zero" on my Scanmaster the car died while ideling. If an lt-1 did actually drop to "zero" would it make the car die? Now, if it can does this mean the lt-1 itself is bad or does it mean there's a short in the wiring from the maf to the ecm? I've never read anywhere on this board where an lt-1 maf has failed. What and how do I check for this? I don't know if backfiring will kill an lt-1 but mine has backfired many, many times! Sorry for all the rambling but man, I'm just about nuts! Thanks, R.B.

 

[randymc1]

I have a good known maf you could try! I don't to much about your transalotor but what does your maf read at full throttle? You can chase this gremlin till the sun don't shine if you don't fix what I would expect to be a bad ground or maybe a crank sensor. Usually the maf work or they don't. Usually the iac counts aren't important off an idle. You need to take the car to a knowledgable mechanic and stop all this posting tomfoolery so you can get on with the fun part which driving a non malfunctioning car. You can do as you wish and I know money and convience are a big issue. I would like to help you , but you have to leave me your car.