idle air control valve?????????

[praetorian]

Ok. Here goes. About 2 months ago, my check engine light comes on. After about a day, it goes off. Approx. a week later, it comes on......then it goes off after a day or so. This has been going on for 2 months. The car runs excellent when driven, but at stop lights it idles poorly, almost too low of an idle, the car shimmys and seems to spudder. So I finally went to autozone and got the codes. Mind you I have already changed my PCV, plugs, wires, and cleaned the throtle body with carb and choke cleaner(it was filthy) I get code 0301 and code 0507. (0301--cylinder 1 misfire detected. 0507--IAC system rpm higher than expected.) Now the dude says that 0301 could be wires,plugs,coil or vacuum leak or injector fault or high/low fuel pressure. 0507 could be eng. vacuum leak or idle air control defective or dirty throttle body or connectors or wiring. I realize the common denominator in the two codes is the vacuum thing. But I have a hard time believing that a 4 year old vehicle has bad vacuum lines. To be honest, I really don't know where they all are. I really don't see how code 0507 makes sense because it seems to idle too low rather than too high as the code suggests. I am leaning tward the idle air control valve since the throttle body was filthy. Do you ppl think this could be the culprit? Anyone had a similar experience? I have the haynes manual and it shows the IAC and how to remove it. Should I try it? Is there anything I need to know about removing it? Any suggestions would be greatly appreciated. I CANT STAND IT ANYMORE! ITS DRIVING ME CRAZY!

[drjag]

I just had the same codes appear on my 2002 SL1. Here's my account. The car had been idling rough and sounded like it was misfiring a little. I replaced the plugs (36000mi) which were pretty worn. I then noticed the Service Engine Soon (sns) being on - I don't know if it had been on before since I wasn't paying attention. I brought the car to AutoZone, and code 0301 was in the cars memory. I assume the code appeared because of the worn plugs. I had them clear the code and went on my way. My wife had been mentioning the idle being high for a few weeks now, but the car still drove alright. A soon as I left AutoZone the SNS light appeared again. I returned to AutoZone after doing a little shopping and code 0507 was not in the computer ("IAC sys RPM higher than expected").
My idle in park is high, about 1100-1200rpm, and about 800 in drive. Instead of buying a new part just yet for about $40.00, I'm going to call the dealer and see if the IAC could be the main problem and if so is it still under warranty. If they aren't much help I'll probably just replace it since the cost of the dealer checkout is more than the cost of the part. I am also going to take off the IAC and see how clean it is. I did this on my 97 saturn. It was a little difficult to take off since it's behind the throttle body and the space is a little tight. I think you need a small torx bit and small hands, but it did come off. There was no gasket, only an O-ring that was still in good shape. I'll let you know how it goes with the dealer and cleaning the IAC myself. Hopefully sometime this week. The car still runs pretty good so I'm not in a great rush. drjay

[drjag]

MisSpelling: code 0507 was noW in the computer.

sorry for my poor proof-reading.

[praetorian]

Yeah let me know what they said. I guess that cylinder 1 misfire could need to be cleared since I changed the plugs and wires the other day. It was running fine until on my way home from work tonite the SES light came on again. I have the torx bit wrench so I think I will take the IAC valve out and see if it is dirty. It looks easy to remove, I just wanted to make sure no suprise parts come flying out when I pull it out of the throttle body. My Haynes manual shows the IAC, where it is, and how to clean it, so I'll give it a shot. Just to let ya know, mines a 2000 with 74,000 on her. I can't believe it is anything major, it's still a relitively new car!

[drjag]

I called the dealer about the IAC possibly being the problem with my high idle (on my 2002 SL1), but they only offered I bring the car in for a service check. I took off the IAC and cleaned it with throttle body cleaner (it was a little dirty around the edge, but not bad) and re-installed it. The idle went up to 3000rpm - not good. I did move the plunger a little in and out while cleaning it (it was pretty stiff). It must not have gone back to it's original position. So I took a chance and just bought the IAC from AutoZone for about $40.00. The idle went down to its normally high rpm of 1200-1300 rpm. I guess the IAC is not the problem. I'm going to take off the EGR valve and give it a cleaning. I'll probably need to buy a gasket when re-installing it. I'll let you know how it goes. I also heard somewhere the temperature sensor may be sending the IAC an incorrect signal. First I'll play with the EGR, then check further with the T-sensor. Good Luck

[sierrap615]

saturn rule of thumb - if any thing is wrong(even more so with a wierd idle) change the ECTS

[catesja]

I kept replacing the PCV valve on mine to get the high idle down. Never worked. Then I noticed after a few months that the coolant temperature never got warm enough. The gauge said it was cool but not cold, then it started dropping everytime I drove the car. It would go to about center then drop to almost nothing while driving. So I replaced the coolant temp sensor (this will cause the car to idle high if it senses a cold engine). I also noticed while playing with it after installing the new sensor that the PCV valve tube was flat. It had sucked so hard that it warped the hose. So I went to NAPA and got a replacement hose of a much larger thickness and durability. Now it idles down where it should.

Now I have other problems like the chime not working and the rear defogger switch seeming to not want to work.

[sierrap615]

radio memory and the chime use the same fuse, its not uncommon for this fuse to blow, if the radio doesn't work too, there you go

[Lucas1]

You, my friend, have a vacuum leak. Very common on SOHC saturn motors. the leak develops between the #1 & #2 intake runners @ the cylinder head. Replace the intake manifold gasket.
Thats why you don't go to autozone to get your car diagnosed. If those guys knew how to fix cars, they wouldnt be worknig at autozone for $8.00 an hour!!!!!!!!!!!!!

[catesja]

If you were referring to me as the vaccuum leak, that wasn't the case. Had the car checked for leaks and none occured. The problem was the hose was worn out and a poor design that it had 2 45 degree bends in less than 3 inches.

By the way I did get the chime to work and it wasn't the fuse. And evidently the rear defogger switch is dependent on the chime module working also. I got a replacement module and plugged it in and the chime worked and the rear defogger.

On to my next item in it is the passenger headlight rattling like crazy when the idle is about 2000rpm. I am thinking that it is time for a new motor mount for that side.

[drjag]

Originally Posted by Lucas1

You, my friend, have a vacuum leak. Very common on SOHC saturn motors. the leak develops between the #1 & #2 intake runners @ the cylinder head. Replace the intake manifold gasket.
Thats why you don't go to autozone to get your car diagnosed. If those guys knew how to fix cars, they wouldnt be worknig at autozone for $8.00 an hour!!!!!!!!!!!!!

Lucas you are so right! I just picked up my car from a repair shop -
where they marked the spot where there is a vacuum leak at the intake manifold. And guess what - it's around the #1/2 cylinder ports. They did repair some leaking o-rings at the injectors. They sprayed carb cleaner at the base of the injectors, and it effected the idle right away. I'm hoping what they fixed really was a problem, at the injectors, and wasn't overspray on the manifold (where the problem was all along?)

I replaced the ECTS, because it was cheap, but it didn't do anything.
I've had (still have) the high idle problem with my 02 SL1. Need to decide whether to bring it in to a shop or do it myself. I'm going to check with Saturn if this is covered under some type of warranty. (I'm out of my mileage period).

Would replacing the gasket be enough, or could the manifold be warped? Suggestions? drjag

[sierrap615]

the gasket likes to be sucked into the intake ports by itself, if there is any warpage, its by chance.

[bobenhotep]

my sl1 had a problem where it would race up on idle after the engine got most of the way warm, then it would turn on the serv eng soon light. i checked the codes, and it said idle too high blah blah... as a last ditch thing ( i was broke at the time) i adjusted the idle stop on the tb butterfly. it worked! all i did was knock out the plug and adjust the butterfly just open enough not to stick at idle. this might help, i dunno. it wont cost anything, though

[sierrap615]

Originally Posted by bobenhotep

my sl1 had a problem where it would race up on idle after the engine got most of the way warm, then it would turn on the serv eng soon light. i checked the codes, and it said idle too high blah blah... as a last ditch thing ( i was broke at the time) i adjusted the idle stop on the tb butterfly. it worked! all i did was knock out the plug and adjust the butterfly just open enough not to stick at idle. this might help, i dunno. it wont cost anything, though

if you do do that you have to be very careful, if you adjust it to low, it can get stuck and you have to kick the pedal to open it back up

[drjag]

Originally Posted by sierrap615

the gasket likes to be sucked into the intake ports by itself, if there is any warpage, its by chance.

I just came out from my garage after putting on a new intake manifold gasket (a moderate amount of work for the unskilled), and the car runs great. Idle, when fully warm, in now 700 rpm, about 600-700 in drive.
The old intake manifold had been sucked in a little at the #1 intake port (passenger side of engine). There are 8 studs that are obvious, but one bolt behind the power steering pump. When I finally discovered this bolt and went to loosen it, it was barely tight - that's where the gasket problem was. The gasket wasn't ripped, just buckled enough to leak in air. If the idle changes when you spray carb or throttle body cleaner around the intake manifold gasket, then you know the problem is with the gasket or the o-rings at the injectors. I hope this helps. drjag