Modded Mustang Forums banner

1 - 20 of 20 Posts

·
Registered
Joined
·
437 Posts
Discussion Starter #1
There should there be a difference in idle with the IAC plugged and unplugged correct? Today i tried to set the idle as stated in the "sticky thread" in this forum, I kept trying it and it would always stay the same. So I took the bottom part (electrical part) off of the IAC and no change in idle. You could touch the plastic part sticking out and the idle would change. I tried mesuring resistance in the electrical part and it didn't show any at all. The IAC is probably the original one from 1993, do you think this coud be causing my surging idle?
 

·
Registered
Joined
·
25 Posts
the serging idle can be caused by either not enough charge to the iac, vacuum leaks, or ur fuel pressure regulator is shot. Thats from my personal experience
 

·
Registered
Joined
·
437 Posts
Discussion Starter #3
I know the FPR is working and as far as vaccum leaks I've searched and searched to no avail. There are 12v going to the IAC but it dosen't seem to be functioning. How can you tell if the IAC is doing it's job or not?
 

·
Registered
Joined
·
74 Posts
When i leave my IAC plugged in it will idle terribly. the rpms will just hang and take forever to go down. but when its unplugged the rpms drop as they should. but when its cold it won't idle very good. so i just leave it unplugged.
 

·
Registered
Joined
·
437 Posts
Discussion Starter #5
Does anyone have any insight or theories to test the IAC???
 

·
Registered
Joined
·
5,029 Posts
Is your car still running really bad?My guess would be the iac is either bad or going bad.But what all is your car still doing?
 

·
Registered
Joined
·
437 Posts
Discussion Starter #8
The idle is still rough, fluxuates between 800-1800 rpms and when you go down the road and stop to turn around the idlw dosen't want to go down and hangs around 2000. Correct me if I'm wrong, but when you unplug the IAC shoudn't you notice a idle difference? I unplugged the electrical part of the IAC and took out the two screws that hold it to the mechanical part and no change at all even though half of the mechanisim was taken off and unplugged.
 

·
Registered
Joined
·
5,029 Posts
The idle is still rough, fluxuates between 800-1800 rpms and when you go down the road and stop to turn around the idlw dosen't want to go down and hangs around 2000. Correct me if I'm wrong, but when you unplug the IAC shoudn't you notice a idle difference? I unplugged the electrical part of the IAC and took out the two screws that hold it to the mechanical part and no change at all even though half of the mechanisim was taken off and unplugged.
MY CAR ALWAYS RAN ROUGHER THAN **** WITH THE IAC UNPLUGGED.SORRY ABOUT THE CAPS
 

·
Registered
Joined
·
685 Posts
have you double checked the timing? I had a suge problem and it turned out to be my timing was a lil off. I tried all kinds of tricks then a last ditch effort I put my light on it and found it to be off
 

·
Registered
Joined
·
437 Posts
Discussion Starter #11
Timing is set at 14-15*
 

·
Registered
Joined
·
2,950 Posts
sounds like it would be good to replace yours
 

·
Registered
Joined
·
437 Posts
Discussion Starter #13
MY CAR ALWAYS RAN ROUGHER THAN **** WITH THE IAC UNPLUGGED.SORRY ABOUT THE CAPS
The car runs and idles the same with pluged in or unpluged, it seems to me that the 15 year old IAC is out of commision.
 

·
Registered
Joined
·
334 Posts
ours runs almost the same without the IAC, just less fluctuation at idle it seems.

didn't really drive it around with it unplugged, just set the idle without it hooked up
 

·
Registered
Joined
·
4,781 Posts
Check you TPS voltage at idle and what kind of MAF do you have? Have you tried cleaning the MAF and IAC...Brakleen works best for me.
 

·
Registered
Joined
·
685 Posts
They are a lil pricey if I remember correct so cleaning first would be a good idea, all kinds of crap came out of mine when I cleaned it
 

·
Registered
Joined
·
437 Posts
Discussion Starter #17
Check you TPS voltage at idle and what kind of MAF do you have? Have you tried cleaning the MAF and IAC...Brakleen works best for me.
I set the TPS voltage at .96 with ignition on engine off. I have a 80mm ford MAF calibrated for 24# injectors. I have clened the MAF and the IAC. What should the TPS voltage be at idle?
 

·
Registered
Joined
·
4,781 Posts
sounds like the TPS is right.

Have you tried clocking the MAF. If the stock bracket is still on it, take it off and throw it out. Then you can freely rotate the MAF. Certain positions will give you better readings that others for whatever reason. Also, what is your fuel pressure set at?
 

·
Registered
Joined
·
437 Posts
Discussion Starter #19
30 psi with vaccum line off and pluged
 

·
Registered
Joined
·
4,781 Posts
That's kinda low for what you have. When you connect the vacuum back up it is going to go down to like 25 or lower. Your computer might be at the limit of the adaptive learning with that fuel pressure. You might start by upping the fuel pressure to 35-40 with the vac off.
 
1 - 20 of 20 Posts
Top