cleaning iac again

[1990LTD]

I'm gonna pull my IAC and clean it again tomorrow. I used throttle plate cleaner last time but I don't have any left, just carb medic in the yellow can from walmart. Can it damage my IAC? Assuming I keep away from the electricals. Obviously not going to drown the thing in it, but I'll probably use a Q tip or something so as to not get more on it than necessary

[1990LTD]

sweet I actually found an unopened can of "air intake cleaner" - just generic stuff but it says it's for throttle bodies so i am guessing it is safe for the iac since it's ON the throttle body

[1990LTD]

cleaned the bejesus out of it. i didn't get some last time judging by what ran out of the iac while i cleaned it. only drove for a little while to burn off whatever intake cleaner is left, don't know if it did anything yet

[85crownHPP]

what's it doing that makes you think the iac is acting up?

[1990LTD]

what's it doing that makes you think the iac is acting up?

I have been having some hesitation coming onto the throttle off of idle, and my idle was not entirely smooth (revving to a few hundred RPM highers and holding it smooths it out and there's very little vibration in comparison). The idle doesn't shake the car apart or anything but it's enough to notice.

[1990LTD]

and, also, it has been recommended by a few people here as the source of my problems

[86VickyLX]

If you still have the hesitation, the egr valve is getting tired. Unplug the vacuum feed, and plug it up, and drive around. The off idle hesitation should go away.

[1990LTD]

noticeable difference when taking my foot off of the throttle completely when at speed, i used to get a bit of a clunk from the rear of the car then it would lose a good bit of momentum immediately, but now the forward momentum seems to taper off. the old IAC gasket was fuckered, too. idle is smoother than it was and you can come on and off the throttle with barely any hesitation.


just unplug the vac line going to the egr valve and plug it up? the hose or where it was plugged? i want to make sure i don't do the wrong one heh, do you have a good underhood shot with it in view? i am going to test it to see if it makes a difference.


what happens when it runs without the EGR valve operating? local emissions laws don't apply to my car, fwiw.

[86VickyLX]

noticeable difference when taking my foot off of the throttle completely when at speed, i used to get a bit of a clunk from the rear of the car then it would lose a good bit of momentum immediately, but now the forward momentum seems to taper off. the old IAC gasket was fuckered, too. idle is smoother than it was and you can come on and off the throttle with barely any hesitation.


just unplug the vac line going to the egr valve and plug it up? the hose or where it was plugged? i want to make sure i don't do the wrong one heh, do you have a good underhood shot with it in view? i am going to test it to see if it makes a difference.


what happens when it runs without the EGR valve operating? local emissions laws don't apply to my car, fwiw.

It won't hurt the car, the NOX readings will be higher. You're plugging the vacuum line. If you haven't touched it yet, it's the green hose on the front of the valve. Plug the green hose with a screw or something. If the problems fixed though, it won't hurt to keep it functional. It keeps combustion temperatures down, and it only comes on when power is not needed (steady cruising speeds etc). It'll lower your mpg slightly but nothing to go crazy over. Unless you're looking for every tenth to help lol.

[1990LTD]

so if it does fix my problem, I can just leave the vac line plugged until I get the chance to pull off the EGR valve and inspect/clean it?

I don't think the hose on mine is green anymore it's either been replaced or is dirty

this one? sorry for stealing gadgets engine bay but it's one of the prettier in my engine bay thread.



EDIT: do you need to disconnect the battery after cleaning the IAC valve? Does the computer need to relearn that?

[gadget73]

yea, thats the EGR line. You can leave it unhooked for a while. It might also be the EGR regulator getting sticky. Mine would slam full open just off idle instead of modulating vacuum. I fixed it by spraying wd40 in the vacuum ports on the regulator.

[1990LTD]

which bit is the regulator?

[1990LTD]

Is the EGR valve an item I can pull off and clean or is it replacement time if plugging that vac line improves things?


Not sure which bit is the regulator that you mentioned gadget, sorry for the n00bage.

[gadget73]

the regulator is the solenoid on the fender that the green line goes to. Either that, or it sits right next to the EGR valve. They moved it sometime around 90 or 91, but I don't remember exactly when.

[1990LTD]

the regulator is the solenoid on the fender that the green line goes to. Either that, or it sits right next to the EGR valve. They moved it sometime around 90 or 91, but I don't remember exactly when.

I will trace it tomorrow and report my findings. What can I plug the line with besides a screw? I don't mean to question you but I don't like the thought of something small and metal potentially getting sucked in there.