High idle speed! Please Help!!!

mo_dingo

20+ Year Stangneter :roc</strong><span class=
Aug 26, 2003
3,031
2
58
Tucson, AZ
I just removed my IAC valve to clean it. I soaked it in carb cleaner, and let it dry. I then started the car, and drove around for a while. No problems.

I then removed my k&n air filter from the maf, cleaned it, and put it back on. After I put the filter back on, I immediately started having problems.

My idle speed is anywhere from 2000 - 3000. I can still drive the car, but no matter what I do, the idle speed will not go below 2000.

When I am driving at 40mph, I put it in 4th gear, (5spd), the car continues to accelerate, like I am pushing the gas pedal, when I am not.

I figured this was a vacuum leak, but I only disconnected a few spark plug wires to get access. But I might have disconnected something by accident, without knowing. What could it be? There aren't any vacuum lines in that vacinity.

Anyone know where to look to next??? Thanks!!
Scott
 
dont qoute me on this....but a possibility...could be too much filter oil??...gunked something up???....im pretty sure its reccomended that after oiling a K&N drive it around for a day or something and then clean the MAF cuz you almost always over oil.....maybe try removing the intake arm and cleaning everything out.....make sure nothing is gunked up in the TB....i could be totally wrong but its a suggestion....



Anthony



Edit....and if you dont know how to clean the MAF properly just ask....i will or someone else will tell you...
 
Oh no, I have already cleaned my maf, so I know how to. But thankyou.

I let the filter dry for 3 hours. I would hope that would get the excess out. But who knows. I didn't run the car w/ the new filter till later. So I know the MAF couldn't be the problem. Literally, I started the car, after installing the air filter and connecting the spark plugs, and my idle went crazy. That sounds like someting is disconnected, or my IAC valve took a dump on me.

I can't imagine the MAF making my idle speed go crazy though. Might make me run lean/rich, but not the idle speed.

Thanks for the input. I will take the air tube off, and check the butterfly. If it was stuck open, I could see how this could happen. Definately too much air being taken in.

I know it's something stupid, so please keep the ideas coming. No matter how dumb, please post.
 
UPDATE: I removed my air tube, and started the car. Now, seeing as the air is not going through the MAF, the CEL light comes on. But my idle speed is now normal. The car runs a little rough, but the idle speed is normal now.

What do you think??????
Scott
 
I just got done fighting a war with my IAC. I really didnt think the MAF controlled idle either. Try disconnecting the plug on your IAC and see what happens. Also, have you messed with any of the adjustment screws on the the throttle body???
 
smokediver27 said:
I just got done fighting a war with my IAC. I really didnt think the MAF controlled idle either. Try disconnecting the plug on your IAC and see what happens. Also, have you messed with any of the adjustment screws on the the throttle body???

I tried that, and the car would not stay running. Unless I held down the gas pedal.

So, can I take apart the IAC? I know it is the problem. I think I am going to try something. On the throttle body, there is a hole just before the butterfly valve, and that hole is where the IAC bypasses the butterfly and runs air into the intake manifold.

I am going to put some tape on the hole, so that it is half-covered. If the idle speed drops signifigantly, I will know the IAC valve is stuck open, and I need to replace it. BTW, a long piece of tape so I can hold one end. Who knows what would happen if the tape went into the engine!!!

But if I can take apart the IAC, and fix the problem, I just might do that. Anyone know if you can?

The price of a new one is $69.99. But I might look into getting a junkyard part.
Scott
 
Dingo,

Just a quick FYI, your car should idle (sloppily) without the IAC connected.

Here's what I just had to do to my car, not sure if it will apply to your situation.

First, make sure your idle stop screw hasnt been messed with, to make sure, back it all the way off the throttle, use a feeler gauge, move the screw up to .002 away from the throttle, now give it 1/2 turn. Screw is there just to make sure throttle plate doesnt stick. Next take rubber plug out of top ot throttle body, there should be a screw with an allen head in there, turn it right to decrease idle, left to increase.

Also, do you have any codes/check engine light. ???

I'm real curious as to what the problem is, since i've fought idle off and on since I bought my car in July.

Keep us updated.
 
I had/am having the same problem(bad idle-not high) with my IAC. Bought a new one, put it on, and with no other changes to anything idled for 15 min then drove down to the gas station and everythings cool, yeah right. After pumping gas I start the car back up and :( the idle shoots to 3000 and won't come down for chit. Limped the car back home removed new IAC put old one back on and went back to where I started. Tried cleaning both old and new and changed nothing(spraying out w/carb cleaner). Going to try yet another IAC. Maybe I just got a bad brand new one. :shrug:
 
I think I figured out the problem. Me spraying carb cleaner toasted my IAC valve.

I tried a trick I thought of earlier. I took a long piece of electrical tape, and blocked the the IAC hole in the TB about 3/4 of the way. I kept the tape long so I could tie it to something. I didn't want that getting sucked into the throttle body. The tape limited the passage of air from the throttle body and into the motor.

Once I had the tape in, I started the car w/ everything hooked up, and the idle sat at 1200 rpm's. That is about 1300 rpm's less than before. So, seeing as I reduced the amount of air the valve could suck in, I lowered the rpm's.

Going to a junkyard on tuesday to get a used one. I'm not paying $70 for a new one from autozone. I looked it over, and I don't think I can take it apart without breaking it. So, new IAC it is.

BTW, the IAC should be the only thing sucking air into the intake when the car is at idle. The butterfly valve is normally closed at idle.

Thanks for your help. I thought I bumped a vacuum line, but I am glad I stuck with the idea that the IAC valve was to blame. I will post back tuesday night when I get the new one on.
Scott
 
sldghmr said:
I had/am having the same problem(bad idle-not high) with my IAC. Bought a new one, put it on, and with no other changes to anything idled for 15 min then drove down to the gas station and everythings cool, yeah right. After pumping gas I start the car back up and :( the idle shoots to 3000 and won't come down for chit. Limped the car back home removed new IAC put old one back on and went back to where I started. Tried cleaning both old and new and changed nothing(spraying out w/carb cleaner). Going to try yet another IAC. Maybe I just got a bad brand new one. :shrug:

Poor idle quality is not a result of the IAC. All it does is control the "amount" of air to enter the engine when the butterfy is closed (at idle speeds). If your idle speed is normal, the IAC is working fine. When the idle shot to 3000, that was your IAC going bad.

You have a seperate issue. When was your last tuneup? Mileage? What sensors have you replaced? Have you tried running check engine codes. Your problem is related to fuel or ignition, not air.

My original problem was my idle speed was too low. It sat around 500-575 most of the time. That is why I tried cleaning the IAC valve. Then I broke it!!! :rlaugh: :doh:
Scott
 
smokediver27 said:
Dingo,

Just a quick FYI, your car should idle (sloppily) without the IAC connected.

I figured that out. If the IAC valve is completely closed, it can't suck in air. And it didn't. It would stall unless I held the throttle open. Which is a good sign my throttle settings are OK

Next take rubber plug out of top ot throttle body, there should be a screw with an allen head in there, turn it right to decrease idle, left to increase.

what does this do??? Does it turn the butterfly valve??? I am confused!!

Also, do you have any codes/check engine light. ???

Only when I disconnected the air intake tube and started the car. The computer doesn't like it when the MAF can't do it's job! :rlaugh:

I'm real curious as to what the problem is, since i've fought idle off and on since I bought my car in July.

What are your idle problems? Speed, running rough, stalling?
Keep us updated.

I will post by tuesday. I am going on a ski trip tomorrow, so I can't work on the car until then.
Scott
 
i have and extra sensor, i bought one and the factory part wasn't bad it turned out to bet he maf in my situation. If you know someone with a car like yours put their fact maf on and seee if it straightens out. You might be suprised.



jason
 
RIO5.0 said:
If you roasted it with Carb cleaner, then whats supposed to be used????

I read the haynes manual, and that is what it says to use. It's also what my uncle & uncle's friend told me to use. So I did. And I broke it! grrrrrrrr.

The only thing that I could think of, other than carb cleaner, would be WD40 to act as a lubricant. But that is just a guess. I have no idea.

I am sure it would have (fully) broken sooner or later; I just shortened it's life. I was already having an idle (rpm wise) issue, so I know it wasn't functioning properly.

What's that old saying? The bottle that broke the barrel??? The hooker that gave you herpes? I can't remember.
Scott