I have a 1984 900 GLE (Australian) fuel injected (non turbo). It's been a great car for the 21 years I've owned it and looked after perfectly. Over the last year the engine will intermittently stop. Often happens whilst driving. First it loses power and you are foreced to stop where it will idle only. Press the throttle and it splutters and gasps. Then eventually it won't even idle and stops completely. Repeated attempts to start it don't work. Then all of a sudden after a few minutes to an hour it will start again and run perfectly. Occasionally it will happen from start in the morning but very often after it's warmed up. It may happen more in damp weather but certainlyt doesn't need a big soaking. It has been to my Saab dealer countless times where they can't get it to repeat the problem. They have replaced the fuel pump, fuel filter, plug leads, cold start unit. Can anybody offer any suggestions? Pete
Interesting problem. I don't have an answer but here are some suggestions. I would guess you either have a fuel problem or an electrical problem and the problem is to identify which is the problem. (Does your car have an ordinary distributor with points or one of the fancier electronic gadgets ... beyond my time I am afraid).
Similar experience from my 1979 900 GLE (injection non-turbo but I think a different engine to your 1984 model).
It did not display any of the running problems you have, however, once stopped the engine could refuse to restart when warm. It also happened once or twice with a cold engine.
SAAB suggested at the time (I could not afford to pay them to solve the problem) that the fuel injectors have had it. It would be possible to clean them or replace them, I could afford neither, so I was given a bottle of some cleaning fluid (1 litre) that I added to a full fuel tank. That liquid was supposed to be used once in the lifetime of the car. It kind of worked.
When it would not start with a warm engine it was always fuel starvation (ie. I removed the sparking plugs and they were dry). Since then I have come accross information which pointed to some sensor for warm starting and something to do with fuel evaporation because of the heat of the engine. *If it means something I hope someone else can explain more.*
Once or twice it did not start in cold mornings, removing the sparking plugs showed that the engine was flooded with fuel, hence I suspect(ed) electrical problems.
Other similar(ish) experience from 1983 900 GL(?) twin carb non-turbo.
Eventually the coil went on that car (not sure if your car has a coil). Its effect was to make starting difficult and running weak.
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I can't help with the problems you have when the car is running. But when it does not restart warm or cold remove a sparking plug and if it is covered in fuel, you most likely have an electrical problem like weak spark. Else you have a fuel related problem.
There is my life story with SAABs. Now I let the dealer clean me up ;-)
Check the distributor cap, I ran across a similar problem on a '79 Volvo, the spring loaded center contact had broken so it was arcing intermittantly, took a while to track down. Also check the pickup in the distributor, I've seen those get a broken wire which makes and breaks contact as the vacuum advance mechanism moves.
Does it have an air mass meter? forgive me if that's incredibly stupid, I'm no mechanic!
Our NG900 exhibited very similar symptoms, turned out to be a faulty AMM. Never replaced, just clean up the connector every few months and the problem doesn't come back.
Thanks Charles Electronic ignition (fancier type gadgets.
Injectors were replaced with a (second hand set) some time ago with no problems. If it was injectors I wouldn't expect such a sudden change from go to who and vice versa. I have periodically used injector cleaners.
Thanks James, Al I'll check the under the distributor cap. I guess the tendency for it to happen more in damp weather suggests electrical? Not sure what a AMM is, nor whether mty Saab has one....I'll check.
An AMM is an air mass meter, given the age of the car it's highly unlikely to have one, the Saabs of that year I've seen have been mechanical K-Jet injection.
Well it does sound like the air mass meter to me problem is you dont have one. I would change the dis cap it is cheap enough and also you did not mention plugs were they checked im sure they were. Is your check engine light on saab service can run the codes and find your problem im sure anyway good luck papa
If it's a 1984 C900 it'll have an 8V engine (16V engines didn't come in until 1985 for Australian C900's at least), so there won't be an air-mass meter.
Can someone tell me what an "air mass meter" is? What does it look like, where does it sit and what does it do? I'm not sure if my Saab has one or not. I've not heard of it before so I think I don't have one. It is the 8 valve motor. Unfortunately the car is mainly driven by my daughter and has only faulted when she has been in it so I have been unable to investigate the problem when it actually happens. I have just been out in it now and it has behaved as though no problem. But yesterday it broke down and wouldn't restart for about an hour! I even tried a fine spray of water over the distributor cap and leads to the coil in case the "wet weather" suspicion is relevant. But it didn't miss a beat. Pete
You don't have one, K-Jet uses a mechanical airflow sensor, and air mass meter is an electronic airflow sensor used in the newer LH-JetTronic fuel system. It measures the cooling effect of airflow on a hot wire to determine airflow, works very well but pricey to replace when they fail.
It's exactly what the name implies; it measures the mass of air being sucked into the engine, so the ECU will know how much fuel to inject. There's a fixed (stoichiometric) 14.6:1 air:fuel ratio.
Somewhat like a venturi in a carburetor, but with a heated platinum wire inside it.
Between the air filter and the throttle plate
The platinum wire is heated to a constant 100deg C. The passing air flow cools it and changes its resistance, from the change the ECU can calculate the mass of the airflow.
Only on 16 valve engines. 8v engines have another type of airflow sensor; a large baffle plate. Its movement directly controls the fuel pressure in the fuel distributor
It's exactly what the name implies; it measures the mass of air being sucked into the engine, so the ECU will know how much fuel to inject. There's a fixed (stoichiometric) 14.6:1 air:fuel ratio.
Somewhat like a venturi in a carburetor, but with a heated platinum wire inside it.
Between the air filter and the throttle plate
The platinum wire is heated to a constant 100deg C. The passing air flow cools it and changes its resistance, from the change the ECU can calculate the mass of the airflow.
Only on 16 valve engines. 8v engines have another type of airflow sensor; a large baffle plate. Its movement directly controls the fuel pressure in the fuel distributor
in article nJ_we.10445$ snipped-for-privacy@news-server.bigpond.net.au, pmg at snipped-for-privacy@email.com wrote on 30/06/2005 23:53:
It does sound like a combination of dampness and ignition. You didn't say explicitly, but I suspect it to be that little bit after about 5 minutes of starting from cold when the engine starts to shut off parts of the cold start system, but before the car is fully warmed up. Dampness will exacerbate the problem.
I see we can discount a clogged fuel filter as the problem, since that has been replaced. I would begin with replacing the other cheap bits, too, such as spark plugs (only use NGK and BP6ES should be right for your car), air filter, rotor arm and distributor cap. A Bosch arm and a Lucas cap are my preferred parts, but they're not as touchy as spark plugs if you use a more generic brand. Perhaps the ignition coil, too, although that is unlikely.
Which part of the cold start unit was replaced? The thermo-time switch is the usual culprit when cold starting is difficult. That should be located between the intake runners on top of the block between cylinders 2 & 3. That's the bit that controls the whole cold start system. With the car cold, remove the plug and connect a test lamp in series. The lamp should light. If not, you've got a wiring problem or the switch is broken.
Test the cold start injector by removing the plug and connecting a multimeter. You will get voltage when cranking the car.
Likewise, the warm-up regulator (the unit with two fuel lines near the thermostat) can be checked by removing the fuel pump relay and bridging terminals 30 & 87. Quickly check for voltage, which should be at least
11.5V.
If the idle drops very low during this problematic period (which I suspect it does), the auxiliary air valve is likely to be the problem. This unit supplies more air into the system during warm-up. If it's broken, you'll be experiencing a very rich mixture during warm-up. Again, with a cold car, remove the fuel pump relay and bridge terminals 30 & 87. Switch the ignition on and look through the valve. It should be open when cold and close after about 5 minutes by the thermo-time switch. While you're there, remove the unit from the car and clean it through with carburettor cleaner and then a little lubricating oil, like WD-40.
Good luck,
Paul
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