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Discussion Starter · #1 ·
Hi everyone,

This is my first post since I've recently purchased my first Saab, a 1994 900 S and am slowly but surely falling in love with the brand. The car is now due for its major 120000km service where I know the belt and spark plugs need to be changed.

There are a few other issues with the car that I would like to gain some perspective on, as well as hear from more experienced owners as to what routine maintenance I should do from this point forward.

1. Car idling problem

The car seems to stall whenever it is in park or neutral (yes it's an automatic, don't bash me). When changing into park the revs slowly drop to about 500 rpm where the car then turns off and enables the check engine light. Whenever I am at a set of lights I leave it in gear to avoid the problem, however if the air conditioner is on it will even do it in this situation. I'm going to mention this to the mechanic when I put it in for servicing on June 9.

2. Frequent braking problem

In general the brakes are fine, but occasionally I have to drive down a very steep road that requires about 20 mins of intermittent moderate to hard braking. After about 5 mins of doing this I get a decent vibration accompanied with noise every time I touch the brakes, which gets worse the longer I keep doing it. The problem then goes away when the hill flattens out and I don't need to use them as much.

I'd say the stalling is the main issue I want to address though. Because this is also the first time I'm sending it to a Saab mechanic I'm wondering if I should get a full check done on the car on the assumption that he isn't doing it already during the major service.

What else should I be doing from here on in to ensure the car is well maintained?

Thanks in advance for any help!
 

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Hi everyone,

This is my first post since I've recently purchased my first Saab, a 1994 900 S and am slowly but surely falling in love with the brand. The car is now due for its major 120000km service where I know the belt and spark plugs need to be changed.

There are a few other issues with the car that I would like to gain some perspective on, as well as hear from more experienced owners as to what routine maintenance I should do from this point forward.

1. Car idling problem

The car seems to stall whenever it is in park or neutral (yes it's an automatic, don't bash me). When changing into park the revs slowly drop to about 500 rpm where the car then turns off and enables the check engine light. Whenever I am at a set of lights I leave it in gear to avoid the problem, however if the air conditioner is on it will even do it in this situation. I'm going to mention this to the mechanic when I put it in for servicing on June 9.

2. Frequent braking problem

In general the brakes are fine, but occasionally I have to drive down a very steep road that requires about 20 mins of intermittent moderate to hard braking. After about 5 mins of doing this I get a decent vibration accompanied with noise every time I touch the brakes, which gets worse the longer I keep doing it. The problem then goes away when the hill flattens out and I don't need to use them as much.


What else should I be doing from here on in to ensure the car is well maintained?

Thanks in advance for any help!

1. My car is funny like this until it's fully warmed up. I think for me it's the IAC valve or the TPS. The car struggles with idling if the heater, heated seats, or head lights are on when cold as it puts a strain on the alternator and the engine won't compensate correctly which *should* be handled by the IAC (meaning the extra load from the alternator is slowing the engine down at idle, and the sensors aren't correcting it by increasing the RPM's to stop from stalling). I'd remove your IAC (it's a big round metal tube about 4" long, in between 2 rubber hoses to the left of the throttle body) and clean it's ports and the moving valve thoroughly with carb cleaner and see if that helps at all. I'd also go through and replace ALL of your vacuum lines 1 by 1 so as to not reattach to the wrong ports. Do the rubber lines going to the turbo and BPC as well. A severe enough vacuum leak can cause hard idle as well as a too lean condition. Even if the lines look OK, there's a chance they're rotted near hotter areas of the engine, or have splits in them, or even they've loosened on the nipple they're attached to which is impossible to detect from a visual inspection. $10 will buy all the vacuum hoses you need. Careful pulling on hoses attached to plastic nipples as there is a 100% chance they'll break, especially with stuff related to the PCV system. Best bet is to get a razor, and score the rubber length-wise several times to get them off. When attaching new hoses, apply a very thin film of 3 in1 oil, WD-40, or similar- sparingly. this will help the new hose glide on. If the car still does it, consider replacing the IAC and/or TPS (throttle position sensor). TPS reads what position the throttle plate is at and is attached to the throttle body. It's possible that it's NOT reading the correct position of the throttle plate at idle, meaning the car thinks it's getting enough "X" amount (when it's not) of air or too much air and is misinterpreting the signal, causing the stalling. Also a good time to clean out the throttlebody. Sometimes too much gunk will build up on the butterfly, causing it to not seat correctly or stick, which can cause drivability issues. TPS is cheaper to replace than the IAC, but I believe there's a specific way for it to be installed, like it has to be set before going in, so read up on it if you decide to replace it, and before trying to remove the old one. Did one years ago and it needed to be manually rotated if I remember correctly before being installed, otherwise car won't read the sensor properly. If the fuel filter is original, consider replacing that too, especially if you run the car low on gas frequently. Do the air filter and spark plugs as well..
Start with air filter, spark plugs, fuel filter, vacuum lines, then clean the IAC and throttle body. If the car still isn't right, try replacing the IAC, then the TPS.

2. Sounds like you're overheating the brakes. You've got a couple options here, and I'll list them in no specific order as well as tips to stop from overheating:

A. Drain the old brake fluid out and replace with a high quality that meets Saab's requirements. If they make a synthetic, buy it. This will not only increase the efficiency of the brakes, but should also improve the pedal effort. Best way is to get 4 rubber lines, 4 jars or empty beer bottles. Open the bleeders with the hoses attached and let them drain into the jars. Keep and eye on the brake reservoir and keep topping off. Once the fluid going to a jar is clear/new fluid, tighten the bleeder. After all 4 are done, top off the reservoir and put the lid back on, then test the brakes to make sure they don't have air in the lines.

B. It sounds like you're on the brakes too much. Having driven Semi's before retiring from it after 9 years (and several job injuries later), 1st thing you learn is to stay off the brakes as much as possible as they'll overheat at the drop of hat. Especially when you have a heavy load and steep hill. What I was taught was to apply firm pedal, and slow the truck down to about 10-15 MPH less than the posted speed, then let off the pedal while using a lower gear (for manual trans that means 3rd or 4th depending on your speed, automatic means putting it in 3rd as OD doesn't give enough of a braking effort). Let the vehicle's engine help reduce speed. When the car starts getting to around 5-10 over the posted speed limit, apply a firm pedal and quickly get the car back to 10 MPH below the posted limit then quickly get your foot off the brakes. What this does is gives the rotors and pads time to cool off from the air passing over them in between the times your actually using them. If you follow this to a "T", the brakes will remain efficient while traveling down steep declines and won't over heat. DO NOT ride the brakes! So brake quickly until 10-15 below, remove foot from pedal, coast until speed is gets back over by 10-15 MPH, rinse and repeat. This technique also helps you in case you HAVE to make an emergency stop as the brakes will be much much more able to stop you.

C. Replace your pads with a higher quality pad like ceramic, or go with a better than stock pad, and make sure the rotors are new or are wearing evening without grooves in them OR:

C.1 Consider upgrading the brakes to either Viggen or 9-5 Aero units. I don't know enough about this, but others do or Google it. Getting a slightly larger rotor on the front with better calipers as well as vented rotors on the back, along with what I posted above will go along way with getting your car to handle the steep mountain your driving down ;ol;
 

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Discussion Starter · #3 ·
Thanks for spending the time to write such a detailed reply ;ol;

Just FYI have the 2.5L V6 not the turbo.

Another small question, I seem to have closed the bonnet too hard or something and now cannot open it unless I push up and down on it whilst someone else pulls the release. I'm sure I just have to loosen/tighten something but I'm not that experienced when it comes to hands on things, so this may be a trivial question to some.
 

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2. Frequent braking problem

In general the brakes are fine, but occasionally I have to drive down a very steep road that requires about 20 mins of intermittent moderate to hard braking. After about 5 mins of doing this I get a decent vibration accompanied with noise every time I touch the brakes, which gets worse the longer I keep doing it. The problem then goes away when the hill flattens out and I don't need to use them as much.
You might want to get out and see just how hot the brakes have gotten. Careful, don't touch! The brakes might need servicing (pads, rotors, fluid).

Hmm, is it a rumbling/grinding kind of sound? Does your car have ABS? Maybe it's ABS kicking in for some reason.

The brake rotor size was increased somewhat on the front, and quite a significant amount on the rear, a couple of years after your model year. Since your car is pretty much at the heavy end of the model range, it could just be that the brakes are not enough for your requirements. Unfortunately the easy way to fix this is to get a '97+ model with the bigger brakes, and a manual transmission for downshifting too! Trying to retrofit the bigger brakes (and more sophisticated ABS system on the later cars) is likely more trouble than it's worth.
 
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