94 SHO ATX will not hold idle

[Arc Angel]

Hello SHO Guru's,
This is a very strange problem. My daily driver 94 SHO ATX, that I have romped on for the past year without any major problems...
I decided it was time to do some routine cleaning (just finished on my newly purchased other 94 SHO ATX, so I thought I'd better take a look at my old one, as well.). I took off the Throttle Body and thoroughly cleaned it inside with Chemtool...it was a mess with black soot/carbon build-up, replaced the small anti-freeze coolant lines, as well as the larger line at the bottom of the throttle body that feeds back under the intake/fuel rail. Cleaned the MAF with MAF cleaner, cleaned out the IAB valve, and the EGR nostrils and valve.
Went to start her up - starts fine, but, it will NOT idle. It just drops down to such a low RPM that it stalls out. Put my foot on the throttle, and keep it at 1000 RPM, and it's fine. Let my foot off, and it just dies again.
Now, the reason I'm posting is that before I got all "Mr. Clean" on it, the darn car ran perfectly. I double checked everything I just worked on, and I'm fairly sure everything is back together correctly. I also did the idle reset proceedure outlines (negative terminal disconnected, foot on the brake, re-start, and turn everything on...still the same). Starts - then dies.
Any suggestions would be GREATLY appreciated. I think I should hav left it alone, with the crud.

Frank

 

[Porkchop]

Sounds like a vac. leak... or a connection was over looked when you were putting everything back together.

If I were to try and narrow it down, I would bet your IAC (Idle air control)

 

[MoSHOTIME]

that's the exact same thing that is happening to me, car was idleing roughly, and throwing an egr code, so i cleaned out the nostrils and whatnot, now I have the exact same symptoms (same car too)

I double checked all my connections and vac lines, as that was my intial thought as well.

I am thinking i screwed up the IAC when i cleaned it...


anyhelp would be greatly appreciated

thanks!

 

[Black '93]

Using carb cleaner on the IAC will ruin it. Time for a new one!

 

[MoSHOTIME]

thanks, that's what i figured, I should have known better, but didn't realize i was getting it in there when cleaning out the nostrils.

 

[Arc Angel]

I'll regret asking...but...is this "IRC" the same as the "IAB"? In short, is it the unit that's mounted in front of the throttle body (across from it) in the intake manifold? If so...yes - I used Chemtool B-12 to clean it off, so I guess I ruined it...
IF this is the case, let me know, and I'll fork out the 74 bucks at Autozone for a new one.
Thanks,
Frank

 

[Arc Angel]

Quick question to go with my last post...checked the codes, and besides the obvious EGR code, one says to check ISC. Is this referring to the same Inlet Air Bypass unit (that I should not have cleaned with Chemtool )?
Thanks again for any help...

Frank

 

[johndallara]

SHO will not idle

sounds like you are on the right track. If its not a simple vacuum leak -- easy to foget a hose -- probably the newly "cleaned" IABP valve (on upper intake opposite throttle body). If you are right, it is an easy swap with an allen wrench, about 5 minutes. Besides, your newly cleaned intake deserves it.

Just don't drop the allen wrench while you are doing the switch. I have had several fun "lost equipment hunts" resulting from a moment of inattention.

Best of luck.

 

[djcannon]

when removing your IAC, i'd recommend placing a powerful magnet near the bolt as you're removing it so it doesn't drop in the middle of the block...have fun getting it out of there if it does. also, the "gasket" won't stick to the IAC since it's made of metal. it can also easily slide down if you don't grab it. i tied a string to mine after the first bolt was removed.

 

[SHO04093]

Dumb question Learning the Lingo

Hey guys Not to be dumb but learning curve here ok. BUt what would the "IAC" And other shor terms you used? Sorry for the dumb question but learning. Thank you very much

 

[SeanMc]

Idle Air Control sometimes called IAB for Idle Air Bypass.

 

[MoSHOTIME]

I stuck an IAC off a regular taurus 3.8 automatic on there and it fixed my issues. (free from P+P, rather than $80 and 3 days to get here from parts store)

Is there any problem in using that one, instead of the "right one"? The only thing i can see that is different is the electrical connector is vertical instead of horizontal...but now ofcourse I get a different code (327) instead of the egr code i was getting...

thanks