[dico]

Today I started up my 2007 Saab 9-3. It normally starts up right away with no problems. Today when it started the engine was running very rough and had a lot of vibrations. After abuot 10 seconds the RPM died down and the engine eventually quit. I started it up again to find the same vibration. I thought that if I let it run for a couple minutes things may warm up (-10C outside) and the vibration may go away. No such luck. When I put the car in gear (automatic transmission) it felt like the vibration got 3x worse. Putting the car in neutral eased the vibration. Needless to say I didn't drive it anywhere and just left it.

Anyone with any thoughts on what this might be?

Thanks,

Dico

 

[harryO]

Could be that it's only firing on 3 cylinders. Suspect DI? Any CEL?

 

[dico]

I am not sure what "DI" or "CEL" is... can you please clarify.

Update: I tried to start the car again tonight (since the temperature is about 10C warmer) and it wouldn't start. Plenty of power in the battery, just kept turning over at a good clip, just didn't "catch"...

-Dico

 

[SuperSwede66]

Welcome to SaabScene Dico .

DI is the Direct Ignition cassette at the top of the engine. If one coil has broken then that would cause the problem you describe. Very simple to change, just four screw and a connector.

CEL is the Check Engine Light on the dash. If there's a problem the ECU knows about then the CEL should show up. Connecting the car to a computer (Saab use a handheld one called Tech II) should be able to read any fault codes to find out what the problem might be.

Another possible culprit is the CPS (Crankshaft Position Sensor). It tells the ECU where the engine is in its rotation. If that fails you can get poor running until it fails completely and then the engine will just turn over. The ECU doesn't get a signal so it doesn't know the engine is turning. A bit fiddly to change as it sits at the front of the block behind the exhaust manifold (held in by a single T25 screw). I changed mine last year in approx 20 minutes.

When you crank the engine does the rev-counter show anything at all? If it does 'twitch' a little bit then the CPS might be OK. If there's nothing then the CPS is likely to have broken. If you have a multimeter you can check for resistance between pins 1 and 2 on the connector. It's the blue one to the right hand side of the throttle body (looking from the front). It should be 860 Ohms +/-90. Sometimes when they fail they are much higher than that (up to 1,500 Ohms).

It could also be something simple like an air leak. Check the various vacuum hoses for any splits or a loose connection.

 

[harryO]

I am not sure what "DI" or "CEL" is... can you please clarify.

-Dico[/b]

Sorry about that, but SuperSwede has explained it well. Fairly young car to be having these problems. Is it out of warranty?

By the way, ECU is the Engine Control Unit, which does most of the work!

 

[dico]

Thanks for the info!

The CEL is not on and I'll check if the RPM guage moves today.

I am bringing it to a local shop for repair and will print out this thread as it will probably speed them along.

I'll post the findings here.

Thanks again,

Dico

 

[SuperSwede66]

It's worth knowing that you normally don't get a CEL when the CPS starts to play up. The ECU simply does not get a signal telling it that the engine is turning (hence why it won't start). You normally won't have any fault codes either.

If it's the DI playing up then the ECU will normally store some codes (and flash the CEL if the problem gets bad enough). When mine went it showed plenty of misfires on one cylinder with a few on the other three (probably caused by the misfires on the bad cylinder). The CEL flashed a few times briefly.

 

[merve84]

What engine do you have?

 

[dico]

2.0T is what I have (at least, thats what it says on the back of the car)

 

[merve84]

sounds like its misfiring, as said above it could be a coil pack or a burnt out spark plug. best thing is to get someone to look at it to save damaging it further!

 

[dico]

I called the dealership (which is in another province, 3.5 hour away) and I described the issue to them. They were pretty sure it was the plugs and that it didn't sound like a coil. I then called back the local shop and asked them to change the plugs. The local shop is skeptical that its the plugs -- I am hoping it is the plugs as its a long tow for 3.5 hours.

What does the warranty cover? parts and labour?

-Dico

 

[SuperSwede66]

Just make sure they use NGK plugs. They should be BCPR6ES (or BCPR7ES) gapped to 1mm. You can also use the more expensive PFR6H (IIRC) plugs but the BCPR plugs will be fine. Check your handbook for specific recommendations.

Do NOT let them use any other make and they MUST be resistor type plugs (hence BCPR). If they use ordinary plugs then you risk damaging the DI cassette. The DI cassettes were designed with NGK plugs as it senses the combustion through the plugs. If you use a different make then it won't work as intended.

 

[dico]

Thanks for the tip.

I just called them to make sure they're getting the right plugs and they were 1 step ahead of me.

I really hope this is the fix!

-dr

 

[dico]

Hi Folks,

Just an update.... a new set of spark plugs did the trick. She's back to herself. The cost of the plugs here in PEI is $28CDN each.

-dr

 

[SuperSwede66]

:thumbsup:

Thanks for the update and glad she's working well again.

 

[dico]

For you super car geeks.... can you explain what the difference is between a regular spark plug and one of these ones? The old plugs still look like they're gapped properly, I assume that these plugs have some funny business going on inside of them?

-dr

 

[harryO]

Do NOT let them use any other make and they MUST be resistor type plugs (hence BCPR). If they use ordinary plugs then you risk damaging the DI cassette. The DI cassettes were designed with NGK plugs as it senses the combustion through the plugs. If you use a different make then it won't work as intended.[/b]

Pretty basic stuff - it's printed on a label stuck to the underside of the DI. I think that the R (resistance plugs) reduce the energy in the plug and they do not get so hot. Anyway, if you do not use them, the DI coils get very hot causing the oil to leak out leading to failure (from experience!). Sure someone will be along soon to give "chapter and verse".