Our family has own a 2000 SL1 ever since it was new. As far as idle speed is concerned, the engine seems to have had a mind of its own ever since I started driving it. Occasionally when I throw it into park or neutral, the revs fly up to around 2000 RPM. Seems to only happen after heavy acceleration or freeway driving longer than 25ish minutes.

I thought this might be a problem with our specific car, but when we purchased another SL1 from 2001, I noticed that it does the exact same thing. Same motor, same 4 speed automatic, same everything as far as mechanics go.


I'm no mechanic, being only 19 years old :P but has anyone else had this happen to them? If not, anyone have any solutions?

All input is appreciated!

 

Sounds like some kind of vacuum leak to me. If not that, then perhaps it's time for a good throttle body cleaning. EGR valve sticking due to carbon build up may be a remote possibility too.

 

I hate to sound like the repeat of a broken record but with todays auto's being computer controlled and with an on board diagnostic one of the most important features are the error codes flagged when a problem takes place.
It does not necessarily have to flag a check engine light in order to store error code. Some codes are stored just for the hell of it when a problem takes place that some how or another is not serious enough to need a check engine light.
If I counted right there are 34 problem codes and pages of diagnostic information as to how to interpret the code based on physical things taking place. Depending on the year of the car which if I am correct determines OBDI or OBDII level of on board soft ware you can cause the codes to read out by fiddling with the ignition key or go to some where like O'Rielly's or AutoZone or other places where they will use a scan tool to read them. And not all scan tools can read both types of OBD codes.
Like it or not cars from the middle 80's up are extremely complex in their functioning and it does not make the least bit of difference how you obtained the thing or at what price it came to you at, the complexity did not change and the importance of the knowledge of the codes is even greater if the reason you got it cheap is the previous owner could not afford to fix it.
And maybe you can either.
But trying to guess what the hell is wrong is a good way to spend a lot of money quick. Much like flushing the money down a toilet.
In todays world of driving beater cars you had either be a terrific mechanic or be bucks up and if you are neither learning a bus route is the best bet.
Because they ain't easy to fix.
Have the codes checked and post them or learn how to make them show up fiddling with the key of the ignition.

 

Like Unc says

Get codes ......... Post codes

 

I... haven't spent any money? I was just wondering if this was normal behavior for the engine. regardless, thanks for the input.We recently had our 2001 SL1 in at our local shop; Numerous codes went off, of which most had to do with fluids. The mechanic couldn't find anything that really needs fixing at the moment. The high idle speed doesn't seem to affect performance. Nevertheless, I'll keep you guys updated.

 

Regardless,Nevertheless, you don't have to spend any money to get the codes read either. I'm not sure of any stored codes that have anything to do with fluids, except the one for the blinker fluid.

You came with a question, and we asked you a question and you do not want to help us help you. Your next question is it a common problem. Yes it is on many cars and it can be many things causing it.

Now I have a question. Were the hell did you come up with that username?

 

There are four types of diagnostic trouble codes (DTC).

A type A code with store the DTC and the freeze frame data and turn on the MIL (service engine soon light) on the first detection.

A type B will store the DTC and the freeze frame data but not turn on the MIL on the first detection. If the type B DTC is detected in two consecutive ignition cycles, it will turn on the MIL. A first detection of a type B DTC is retrieved as a pending code.

A type C DTC may turn on the service light while the condition is being met but turn it off when the condition clears up. These are non emission related and the code will be stored.

A type D is also non emissions and is only a failed test. It updates each time that test is run.

Now for some more useful information. I have had a similar problem that appears to be quite common for the SL1 engine. The DTC would be a P0507, high idle, but the conditions required for detection allows it to go undetected for long periods of time. The idle has to be more than 200 rpm's above the programmed engine speed for the conditions, for one minute. If you have a high idle, but don't spend at least a minute at idle, it goes undetected. It went undetected for over 40 k miles for me because our lights rarely sty red for more than 45 seconds.

Thanks to another saturn forum that no longer exists, I found out that the high idle can be caused by a leaking intake manifold gasket around the #1 intake port. The port only has three bolts securing the manifold to the head at this location, the outboard upper corner is not secured. On top of that, there is no bridging between the #1 and #2 ports on the head side so the gasket has no support in this area. Add to that the factory gasket is very flexible so it is easily sucked out of position.

The way to confirm this is to spray something around the gasket at the #1 port while the engine is idling. You can use starter fluid, carburetor/fuel injection cleaner or a light oil like WD40 or even propane. If the gasket is leaking, it will suck in what ever you spray and it will affect the idle in some way. If there is no change in the idle, the gasket is OK, any change means you need a new gasket.

I've changed mine twice, the first time I used another factory gasket, it didn't last any longer than the original (about 60k miles). The second time I used a felpro, which is metal backed and a little stiffer and has lasted over 110k miles so far.

 

No it is not normal behavior, in my limited experience of seeing, driving and working on a few of them I have not see one fluctuate the idle speed and have it be normal.
Yes there are reasons for it. Lots of them. All something wrong.
And whether if affects the performance or not? That probably is a matter of opinion. If it ain't right, wrong generally affects the performance.
My personal Saturn is a 94, purchased used in 96 and has never ever had fluctuating idle.
However with the variety of problems that it did or does have over the years knowing what the codes are is the very first step in eliminating potential problems.
Using the old adage if it ain't broke don't fix it. The codes identify what ain't or is broke.

 

SNIP
Thanks to another saturn forum that no longer exists, I found out that the high idle can be caused by a leaking intake manifold gasket around the #1 intake port.
SNIP
This above is a true statement and applies to any engine. A vacuum leak will cause an idle problem.
Whether it is high or low idle or something that stumbles it is an age old type of problem Loose intake manifold gaskets. Carburetor/throttle body lose parts/ Fuel control problems and the list goes on. A vacuum type leak can be chased down to an offending part by as stated spraying something like WD-40, carburetor cleaner or almost anything the can be sprayed at offending parts to see which if any when sprayed causes the idle speed to change.
It is a diagnostic mode of finding things.
But a vacuum leak is not the only thing that can cause that. Prior to computer control where many engines were using miles of vacuum lines, vacuum leaks caused by failure of the tubing were multiple. What is the highest probability is generally learned through experience. The problem is knowing how to go about diagnosing the problem is important. And on new engines that is a problem that is compounded by engine design, location and the room around it. In some cases the most probable parts are hidden due to the physical location of the engine.
Again, one of the disadvantages of a computer controlled car is the addition of complex electronics to something that is basic. However one of the advantages is the complexity allows some form of on-board system diagnostics. And in many cases trying to guess what is taking place and not bothering to use the on board diagnostics is pretty much a fools errand.
It helps to list as best as you can information that you can put together. It also helps to respond to some one trying to help by trying what was suggested and feed back with it.
There are many good trouble shooters this forum, but we can not reach out and touch and listen and smell. You have to do that and accurately report what you see.

 

They checked codes free of charge when we had the thermostat replaced. As for my username; I really have no clue. but thanks to a youtube video where my username was mentioned; it now has to do with a post black friday condition :S

Sorry if I come across as oblivious. Thanks for the tips and replies! Last time we had it into the shop, the mechanic had 'erased' all the codes :P. I haven't actually had this idle issue since he did so. I'll check the codes if the idle speed starts flying about again. Thanks for the input!