Bad Things [Archive] - SaabCentral Forums

: Bad Things


Zippy
3rd January 2003, 02:38 PM
Hi.
I was coming home last night in the bitter cold, and odd things started to happen to my poor '91 N/A 9000s.
It started up fine, but as I was in a bit of a rush, I didn't let the engine warm up a second as I sometimes do when it's brutally cold. The first indication that something had gone wrong, was that the car stalled at the first light I stopped at for no apparent reason. I simply dismissed it, started her up again, revved her a couple of times and went on my way. After that, I was coasting down a hill in neutral (as it is a manual) and I noticed my idle was swinging around, going anywhere from 700-1300 rpm for no reason, before it finally just stalled again. After that I gently limped the car home, but I noticed that I had to keep giving it gas (even in neutral) or else the revs would get so low that the engine would stall again.
So far, the engine's been great to me, which is why this caught me completely off-guard. Any ideas on what the cause might be?

P.S. As you might have guessed, with problems like this, the "check engine" indicator came on a few times. Also the radiator level indicator came on a few times as well, and I noticed the engine temperature was also going up and down.

Zippy
4th January 2003, 09:57 AM
Ok, so I drove around again, and it seems that this only happens when the enging has warmed up, when the engine is cold, the idle still bobs around a tad, but not too much and the car doies not stall as a result when the engine is cold.
Any ideas yet, or am I going to have to visit my dear technician?

BillJ
4th January 2003, 01:03 PM
Zippy, it sounds like it might be a sticking idle control valve. See here (http://www.saab9000.com/procedures/fuel/iac.html) for a cleaning procedure. Your valve is probably in a different position, but the principle is the same. If you can't find it, I believe it was under the inlet manifold on some models.

Another possibility is a leak somewhere in the induction system, but I'm not sure that would account for the idle speed increasing sometimes.

lawrence
5th January 2003, 06:52 PM
Zip,
Actually, having an intake tract air leak could well be contributing to your problem. If there is secondary air being introducted into the intake tract somewhere after the AMM, your ECU is trying to compensate for the out-of-wack air/fuel ratio. This might account for a variation in idle speed, along with mushy throttle response. While your engine is cold, it is receiving a richer mixture, and this probably evens the playing field a bit, as far as the ECU is concerned; after the engine has warmed up, it is expected to do with a much leaner mixture. Additional air, at this point, is much more critical; your oxygen sensor is telling the ECU you're running lean, while the AMM is telling the ECU you're not pushing enough quantity of air through it to justify the additional fuel - end result: ECU confusion.
I once had a secondary air hose (mounted to the front side of the intake manifold - belive it goes to the charcoal canister) split at the point where is pushes onto the plastic "L" fitting in the manifold. Aside from hissing like a snake (even my wife heard it, so it had to be bad), it produced very similar symptoms. Check to see if, with the engine running, you can hear any undue hissing.
Cleaning the AIC is always a good idea, but I don't think it is the exclusive culprit here.

Zippy
7th January 2003, 02:04 PM
I'll check it out.
I'm still driving it around for short trips, as its fine most of the time, but the problems begin if i push thye engine a bit. yesterday she revved herself up to 2500 for no apparent reason at a stop light while in neutral.
I'm looking into this later today and I'll keep you guys posted on what it actually was.

P.S. THANK YOU FOR ALL THE INFO!

9000s_91
10th January 2003, 03:11 PM
I'm having some problems that might lend some help. Sounds like you could have a Mass Air Meter going out. I don't think you have an IAC valve on a 91. I think they did away with those, although it wouldn't be the first time I was wrong.

I have a 91 9000s, and I looked yesterday for an IAC just to see (as an 89 I once owned had to be cleaned often), and I didn't see one. Let me know if you figure your problem out, and you'll help us both out.

tom

Miles
13th January 2003, 11:48 PM
I have an '89 9000s - is the IAC in more or less the same position as shown in the saab9000.com page (which shows a turbo)? I had a quick look before I went to work this a.m. (didn't take anything apart), but I didn't see it right away.

Steve Brown
14th January 2003, 03:34 AM
I had similar problems a little while ago, when we had a cold but extremely damp day here in Hong Kong. Drove the car to work, no problems. Then the cold fog rolled in and the drive home ended with a towing-home. The car started staggering when it got up to OT, this got worse and worse until I couldn't take it any more.
After a bit of pondering, I took out the airflow meter (it's between the air-cleaner and the turbo) Accumulated crud on the wires had got damp and was causing the meter to send erroneous signals which caused the problems. I cleaned it by squirting CRC Contact Cleaner (it leaves NO residue, I use it for cleaning inside computers) through it. That shifted no end of muck. Stuck the meter back in and the car ran very sweetly!
It's a very cheap and quick procedure, so why not try it?
Steve

Zippy
15th January 2003, 12:09 PM
:roll: ok so youll all laugh at me, on the way to my friends garage to take a look under the hood, the "check oil" light came on and my engine strted dying a lot, as soon as i got a litre of oil in the car, all the problems disappeared. :o
Past that, I just checked/cleaned off the air filter and she runs decently again.

Always remeber to check your oil frequently kids, and don't do drugs. :nono;