Cannot figure it out, i swapped the idle air cont valve with another one i had laying around, still does it, didnt want to idle at first and now this, i tried plugging the valve area and it did idle down, but as you might assume, it wont idle for crap trying to drive it, i dont want to convert to carb at this time, so i will use it for a last option, someong give me some help? I checked the TPS and it was about .4 at the idle position but was only 3.4 or so at WOT, i didnt think it would hurt the idle of the vehicle.

 

Well then....a carb and intake might be the answer then....

 

no vac. leaks? everything hooked up? do you have anything that will let you check the IAC values?

 

Couldnt find any leaks, i am going to double check, yep, everything is together, but no, i have no way to check the IAC, just tried plugging the hole IAC in the TB and it idled down.

 

If you can round up an old laptop and Craig Moates scanner cable & software, you can check the IAC Count value and see what's happening.

With a big vacuum leak, the number will be zero as the ECM tries to bring the idle down to the configured RPMs.

Without that, it's just a series of tests to rule out possible causes. Loose TB base and/or failed TB gasket, leaking or disconnected vac hose, failed IAC motor, etc.

 

Depending on application IAC will have a different style pentacle (aka plunger head). Plugging a unit with 'another I had laying around' may not solve original problem, but instead intorduce a uncontrollable vacuum leak. Take a look at your TB and locate stamped part number - when viewed from the engine front it will be on the left vertical boss facing you. Post that number - a matching IAC can be found.

In mean time re-install your original unit and perform IAC reset - this simple procedure can found in technical articles. It may just be that simple.

//RF

 

OK, well, i will e install the original piece and see what happens, but like i said before, i plugged the port area in the throttle body so i could see what would happened and it idles down the more i plugged it off with cloth and idled back up when i removed it.

 

Well, i put the original one back in and the damn thing wont idle, it keeps dying unless i keep throttling it, which is why i swapped it out in the first place, it wont idle...


Man i wish i could six this thing quick so i can drive it...but if i cannot...carb and intake is not that far away, i just need another carb, i have nearly everything else.

 

Before you go carb route you should know that are many other things that must changed and adapted to make you car drivable.

All you may have is a seized up IAC - like I said before the fix maybe only $30 away instead of spending hours swapping intake, dizzy, brackets, fuel pressure regulator and etc to make things works with a carb. Think before you do!

 

Well...my 95 Z28 is carbed...my 89 RS hard top is carbed, my 86 TA is carbed...my 91 RS is carbed...my 90 RS is carbed....hell, i am trying my hardest to keep the POS TBI injection as ALL the other cars have cams and are not a BS stocker, i want to keep it as is for the fuel econemy, but a carb and intak ewill free up power and take a minimal hit on MPG.

The IAC i put on it was working fine when i pulled it off the 86 TA, but it was a TBI injection off of a 92 chevy truck, so even though the first part number is the same the numbers below it are different from the two...

 

Go Carb! My 89 has TBI and im not a big fan of it. got the ole carb in the 87 and its great, and simple. Just sucks having to change everything to make it all work.

 

Trust me, i have done it more times than most have had cars, i am on third gen number 13 i believe with this one, some were carbed but the others ended up that way. I am wanting to keep the EFI, but if the help on this third gen board doesnt help...you know what time it will be.

 

Well, i get paid thursday, how many think it is the IAC? It runs like **** in gear too, could that still be it?

 

Well, lack of help and still nothing after tinkering, it is getting the axe. Carb it is. I did notice it was not revving when i went WOT, it bogs first. So i might check the fuel pressure, then if it is good, it will be converted. I have always had the worst luck with third gen TBI for some reason...go figure.