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Richard
02-15-2004, 01:01 AM
I've been experiencing a problem with intermittent high idle for several months now. It probably started when it got really cold here in Pennsylvania, so all damn Winter! Sometimes when the car is sitting at idle, it will rev up to 2,000 rpm on its own. Rarely, jabbing at the throttle a few times will make it come back down, but that doesn't work very often.

So far, I've cleaned the IAC pintle and seat, replaced the PCV valve, and replaced the coolant temperature sensor (Genuine Saturn PCV and new style ECTS). The condition did not change after replacing any of these items.

I have a scan tool, and I seem to get normal readings from the ECTS and IATS (that is, they read the same when the car is cold), throttle position is usually right at 0.0% at idle although after driving for some time it will read 0.4% whether its idling high or not. I don't think I've had the scan tool in place when the idle is abnormally high. So far, no codes have been set.

The car is a 2001 SL1 with an automatic transmission. Intake modifications are an AEM intake, [slightly] bored throttle body, and crankcase ventilation filter.

Any ideas here? People are starting to stare because of my erratic engine behavior at stop lights and I've unwillingly raced people because of it (ok, not really).

Just last Friday it gave me a little surprise. While at a light I had my foot on the brake just enough to stop the car from moving forward at 6-700 RPM. Well, the car decided 700 RPM wasn't fast enough so it revved up to 1,500 or so and lunged forward. I wasn't anywhere near hitting anyone or anything, but this behavior is just unsafe!

Richard
02-16-2004, 12:10 AM
Anyone? Wolfman, you out there?

wolfman
02-16-2004, 02:05 AM
With your modifications it is actually somewhat more difficult to make an accurate assesment. Based on your described symptoms and the list of modifications, my best guess would be that your throttle body butterfly is now not sealing correctly due to your modification. The air leaking past it would explain both the high idle and the lack of a code as the throttle postion sensor is "seeing" a closed throttle but no the air leak. As the IAC sets a "normal" position based on the PCM signal which is in turn based on the TPS "closed" throttle data you wind up with a wonky or high idle that the PCM/IAC cannot compensate for. That would be my guess anyway. I will only add that a high idle is almost always the result of either a sticking throttle plate, IAC valve fault or a vacuum leak or a combination of all three.

Richard
02-16-2004, 03:31 PM
Well I should mention that the t-body had been done long before this problem. Also, I didn't bore around the throttle plate at all, in fact, the plate was left inside when I did it.

Should I check for vacuum leaks? What's the best way to do it?

Is it possible for the IAC to go bad?

Dach
02-17-2004, 08:06 PM
Vacuum hose routing diagram should be under the hood. How's the o-ring for the IAC valve. They need to be lubed up before you put it back together and they are unbelieveably expensive if you crimp it.

Teriyaki7
02-24-2004, 12:05 PM
I have the exact same thing happening with my 98 Saturn SC2. It idles high. When I am stopped at a light and the car is in neutral it idles between 2000-3000ipms, then all of a sudden it will drop down, to wear it should be, then it will start to climb again. If i turn off the engine and restart it all is fine. I am also having trouble then getting it back into first gear.

Let me know if you solve your problem.

I am going to try and replacing a few of the sensors and see what that does. I am going to have a diagnostic test done on friday.

Dach
02-24-2004, 12:14 PM
Originally posted by Teriyaki7
I have the exact same thing happening with my 98 Saturn SC2. It idles high. When I am stopped at a light and the car is in neutral it idles between 2000-3000ipms, then all of a sudden it will drop down, to wear it should be, then it will start to climb again. If i turn off the engine and restart it all is fine. I am also having trouble then getting it back into first gear.

Let me know if you solve your problem.

I am going to try and replacing a few of the sensors and see what that does. I am going to have a diagnostic test done on friday.

I would clean the TB and the IAC before replacing sensors. Generally you'll get a code if the sensor is failing.

Lisa H.
12-20-2004, 07:40 PM
Hi there! I found this site because I am having problems with my 2001 Saturn SL. And I am having exactly the same problems as everyone above. The idle anywhere between 1500 to 3000 rpm! Maybe coming down to a normal idle when it feels like it, not when I want it to be. My jaw dropped when I read these other people having the same exact issue. If I turn off the car and turn it back on, it's fine for a few minutes.....it will either go up again by itself, or if I tap the gas, it will jump and stay there. I took the car in, and they replaced the idle air control valve and did a fuel system flush. I THOUGHT it fixed it. It was fine for a few weeks and then it did it again. It was spring so the temperatures were getting warmer and it didn't do it all summer....then as soon as it started getting chilly outside.....it really got bad....and it's been bad ever since. Has anyone gotten their problem fixed??? I'm thinking that so many people have had this problem that someone has had to have gotten it right and fixed the thing. If you have managed to get it fixed....what was it? I have an appointment in January....and I have a feeling it's just going to be a guessing game for them. I'd love to go in there and tell them what's wrong!!! I love my Saturn...but this is really frustrating.

Thanks for any help any of you guys can give me. Happy Holidays!
Lisa

kenn3d
12-21-2004, 06:54 PM
Hi there! I found this site because I am having problems with my 2001 Saturn SL. And I am having exactly the same problems as everyone above. The idle anywhere between 1500 to 3000 rpm! Maybe coming down to a normal idle when it feels like it, not when I want it to be. My jaw dropped when I read these other people having the same exact issue. If I turn off the car and turn it back on, it's fine for a few minutes.....it will either go up again by itself, or if I tap the gas, it will jump and stay there. ...Thanks for any help any of you guys can give me. Happy Holidays!
Lisa


Hi Lisa,

Welcome to the board. Yes this high idle thing does seem to be a very common SL problem. My nearly new 2001 SL2 behaves this way also on occasion since the cold weather started. Wolfman is one of our resident experts here, but his advice in this thread may be specific to the original poster's mods. Your symptoms sound a lot like mine and based on advice I've read here I suspect it stems from either the TPS (throttle position sensor) or the ECTS (coolant temp sensor). I'm having mine checked at the dealership next week so I'll let you know what I find out.

Kenn http://webpages.charter.net/kenn3d/DSCI0016.jpg

jdircksen
12-22-2004, 09:47 AM
I'll add myself to the list of people with high idle problems. Mine seems to be different in that it happens when its hot outside, but not cold. And call me weird, but a majority of the problems happened on sunny days, and not cloudy days. :dizzy:

I have spent tons of money trying to fix the problem, only to have
it come back. I first took it to a local mechanic, who replaced the
throttle position sensor (TPS) ($53), engine coolant temperature sensor
($20), and charged $120 in labor. The problem came back a few weeks later.
After paying him for not fixing it, I decided to start looking into fixing
it on my own. I checked for vacuum leaks, cleaned the EGR valve, throttle
body, and idle air control valve. None of those seemed to do the trick. So
I took it to a Saturn dealer. I've had it there 3 times, and paid
$200 in labor for them to run tests. They replaced the idle air control
valve ($80). The problem came back, so I replaced the TPS again ($53). The problem was gone for a month, but started to come back a couple months ago. Lately I have not had a problem with it. I think the problem is induced by hot temperatures, which is why it has not happened at all lately.

I really wish I had access to a diagnositc tool so I could sit down and look at each individual reading without paying Saturn $55/hr to do the same.


Somewhere else I read that this problem may be caused by a leaky intake manifold gasket. Aparently the gasket gets sucked into the engine between a couple cylinders (I forget which ones, sorry). I tested this by spraying brake cleaner down by the gasket, but the sound of my engine did not change.

madpogue
12-22-2004, 06:25 PM
I really wish I had access to a diagnositc tool so I could sit down and look at each individual reading without paying Saturn $55/hr to do the same. Year and model? Is the SES light coming on when you experience the problem? If not, a scan tool probably won't help. If so, you can get a cheapo reader for about $50 at Harbor Freight Tools, or a little more via eBay. This is presuming you have a gen-2 ('96 or later, with OBD II) car. If your car is earlier, thus OBD I), you can read the codes by jumpering a couple of pins on a diagnostic connector with a paper clip; search the forums for more info.

Somewhere else I read that this problem may be caused by a leaky intake manifold gasket. Aparently the gasket gets sucked into the engine between a couple cylinders (I forget which ones, sorry). I tested this by spraying brake cleaner down by the gasket, but the sound of my engine did not change. Again, year and model info would help. IIRC, this is only a problem on '00 (or is it '99?) or later models.

jdircksen
12-24-2004, 02:40 PM
Mine is a '95 SC2. The CEL used to come on, and the code was 22 (TPS voltage high). I can check the codes, but I'd like to spend some time with a diagnostic tool that will tell me what data the sensors are reporting back to the PCM so that if I find a discrepency, I'll have a better idea of which part to replace.

And yeah, I think I read that the leaky intake manifold gasket was on newer SC2's. I can't remember for sure though.

ExoticFish
12-25-2004, 01:22 AM
i've had my 2002 SL2 for a couple weeks. now that it's getting cold when i start the car up it will idle at 1500 - 2000 until the car warms up after 5 minutes or so. is this anything to be concerned about?

NUHeriot34
12-25-2004, 09:20 AM
I also have the same happen to me ExoticFish. On cold days the car will run at around 1500 rpm until it gets a little warmed up. After that it fine. I havent seen it as a problem but just thought it was a little quirk with the car. Should I see this as a problem?

99GreenSC1
12-28-2004, 08:02 AM
I have a 99 SC1 auto and I work overnights so it's extremely cold when I drive my car (MN Winter)...this morning when I left work and the car was warming up (only took a couple minutes), it was idling around 1200 to maybe 1500 RPM's...I don't think that it's a problem, but I am not an expert so don't quote me on that.

My old 92 SL1 does the same thing everyone was talking about at the top of the thread...it does have quite a few problems and 180k on it. It also hasn't had an oil change in a while or the ECTS replaced or anything else...but that will happen when I have time to fix it up and replace the radiator in it. I have used the paper clip in the diagnostic port and it comes up with only one code, but it's the code for everything being fine.

99GreenSC1
12-28-2004, 08:20 AM
I mean not a code that everything is fine, but the #12 code for Diagnostic System Check, which I have just put off as something that isn't too important since it's a car that is just sitting and won't be driven for a while.

Razorbak
12-28-2004, 09:15 AM
i've had my 2002 SL2 for a couple weeks. now that it's getting cold when i start the car up it will idle at 1500 - 2000 until the car warms up after 5 minutes or so. is this anything to be concerned about?

According to wolfman, one of our resident experts, a high idle upon start-up in cold weather is normal...

"Normal" cold start behavior... (http://www.saturnfans.com/forums/showthread.php?t=29789)

kgrunt
12-31-2004, 10:51 AM
I was having idle problems a bit back similar with similar results. One day I had the good fortune (while trying to positively ID which pulley was whining) of hearing a brief "hiss" up toward the injectors. So I grabbed a small piece of vaccuum hose for a stethoscope and went right to the PCV valve thinking that old gooey hose was leaking -- it wasn't. Well the hissing stopped before I could check elsewhere, so I started grabbing hoses. The power brake booster vaccuum hose had a small slit in it right at the inlet where it goes into the intake manifold. Now mind you, standing right in front of it, it only leaked for me when I pushed or bent the hose, however, under various driving conditions, the pressure was probably often times enough to open up
that slit and make the PCM try to figure out how to compensate for the lack of vaccuum (which it has no idea is due to a leak.) And I imagine every time the RPMs would jump during idles at lights or other random stops, my foot was on the brake and the hose would let air escape. Do you notice your brakes feeling different lately? Mine wasn't terribly noticeable over the jump in idle speed, but once I found that leak, I could definitely feel the fade when it'd leak vaccuum.
Long story short...about 5ft. of 1/2" heater hose and a new air check valve and grommet at the brake booster was all it took. I was gonna just cut off the bad 6" of the hose and reclamp it, but under further review, and I've seen it in two other Saturns between 60-140K miles that I've checked their hose on, it was sludged up inside the hose like a clogged PCV valve hose. I went to clean it out some but the sludge was built up too hard at the pre-formed bends in the original hose. The two other SOHC 1.9 cars both were bad too.
So, it seems to me that this Vaccuum line is a somewhat common issue on these cars and may be worth looking at for leaks or clogs, especially if your motor is behaving as if it has a vaccuum issue that won't show itself while you're just looking routinely under the hood.
Hope your solution is cheap and simple like that.