9-3 Aero 2.0T Possible fuel injectors/turbo air input box

[umma08]

Recently purchased a 2010 Aero 2.0T (200 bhp model).

The seller notified of me of stuttering and when i drove the car it was present. The stuttering is intermittent, presenting on medium-high power (i am guessing only when the turbo is engaging). There is no smoke that i can see, and no obvious smells or nasty noises. It sort of feels like the tyres slipping (which would be consistent with uneven power delivery).

Power delivery is smooth probably 90%+ of the time, which is what is strange. I have a 2008 Vector 1.8T also, so can tell the difference/similarities. Obviously something needs fixed though, so am just trying to get a handle on what it might be before i bring it to the mechanic.

The seller says its is either a) fuel injectors or b) the air filter input (which has been changed to a non-stock one), which is then causing an issue with the air/fuel mix. The old filter came with the car, so my first attempt will be to change this.

Could this be the issue? Also, i am guessing that there could be an issue with the turbo itself? i am not sure if that's the case, as it still definitely works, as i can hear it engaging, and also see the pressure bar move on dash. Also, as i said it is intermittent.

If its not to do with the air intake, should i start sourcing new injectors and injector rail/lines, and possibly a fuel pump/regulator?

If it is if the injection unit or something to do with the fuel supply - what part number should i be getting for the fuel injectors?

It is not clear. I know the parts were shared with other cars, so am thinking it may be easier to source GM unit that was used for some other model, such an Opel/Vauxhall Vectra or some sort?

Any help would be much appreciated!

[sgould]

I doubt that it's the air filter.  The airflow is measured after the filter, so the fuelling request will match.

You really need to get the ECU scanned with a Saab Tech2 computer.  It can read a lot more than a standard code reader.  It can pick up missing on a cylinder by cylinder basis.  Once that gets high it should through an engine warning light though. Does the warning light comeon and go out when you first turn on the ignition and start the engine?  There have been cases of it being taped over!

[umma08]

I doubt that it's the air filter.  The airflow is measured after the filter, so the fuelling request will match.

ok that is good to know

You really need to get the ECU scanned with a Saab Tech2 computer. It can read a lot more than a standard code reader. 

I will try and track someone down close that has one, but i am not optimistic (in Southern Ireland).

It can pick up missing on a cylinder by cylinder basis.

do you mean - the Tech2 computer can pick up a misfire on a cylinder per cylinder basis?

Once that gets high it should through an engine warning light though. Does the warning light comeon and go out when you first turn on the ignition and start the engine?  There have been cases of it being taped over!

No - i am pretty sure it doesn't and i don't think the seller would be one to do something like tape over a light.

The car is mint inside and out - he even did things like getting the wheels resprayed in gun metal grey and replacing the leather on the gear stick. He seemed a genuine seller, and was upfront about the issues. The car was also driven down to me - some 200 miles, so the thing is going well, just this strange splutter.

Any other ideas/expertise welcomed.

[sgould]

Yes, the Tech2 can tell you how many misfires there are per cylinder.  A few a quite normal, for example, on the overrun when the fuel is cut back, but the sparks are still firing.   If you have a smart phone there are some apps that might do something similar.  Something like "Torque" for an Android phone, or "Dash Command" for an iPhone.  Used with a bluetooth or wifi transmitter plugged into the OBD connector under the steering wheel, they can provide live information, like engine speed, temps, fuel pressure, etc.  That might be worth a place, the apps are free to try and the connector/transmitter is only a few €€.  Be careful if you get the transmitter, the cheapness will give you an idea of the reliability.  I have a wifi one which works fairly well with the DashCommand on my iPhone.


The engine warning light should light up when you turn on the ignition.  It stays on when the ignition is turned on and then should go off once the engine starts and runs.

[sgould]

There is a known fault that causes a misfire, but, a) I thought it had been fixed by 2010 and b) I think it causes misfire issues when starting cold.  But I'm not sure and it's hearsay.  But the 2.0 petrol in 2007 and a bit later had an issue with badly made inlet valves.  They go soft and wear/leak.  But you need an expert to confirm/diagnose.

[smurkenstein]

Did you consider spark plugs or coil packs? A bad plug can present as a shuddering under hard acceleration in high gear. You'd might see the CEL to flick on/off while its happening.

[umma08]

If you have a smart phone there are some apps that might do something similar.  Something like "Torque" for an Android phone, or "Dash Command" for an iPhone.  Used with a bluetooth or wifi transmitter plugged into the OBD connector under the steering wheel, they can provide live information, like engine speed, temps, fuel pressure, etc.  That might be worth a place, the apps are free to try and the connector/transmitter is only a few €€.  Be careful if you get the transmitter, the cheapness will give you an idea of the reliability.  I have a wifi one which works fairly well with the DashCommand on my iPhone.

Just looked into this - i might give it a whirl - as you definitely seem to get some pretty cool info. never knew these existed. thanks!

The engine warning light should light up when you turn on the ignition.  It stays on when the ignition is turned on and then should go off once the engine starts and runs.

had to go check this right now for my sanity - engine warning light glows bright orange/amber in the on/start position and then turns off once started - so no tape, thank go. would have been seriously disappointed if it was/or bulb removed/turned off!

[umma08]

There is a known fault that causes a misfire, but, a) I thought it had been fixed by 2010 and b) I think it causes misfire issues when starting cold.  But I'm not sure and it's hearsay.  But the 2.0 petrol in 2007 and a bit later had an issue with badly made inlet valves.  They go soft and wear/leak.  But you need an expert to confirm/diagnose.

the car starts not a bother, but will keep the inlet valves in mind for when i speak with the mechanic. i appreciate the guidance, thanks.

[umma08]

Did you consider spark plugs or coil packs? A bad plug can present as a shuddering under hard acceleration in high gear. You'd might see the CEL to flick on/off while its happening.

the seller changed all plugs at his last service - and i have the receipt for the work.

i think he thought it may be that as well. the coil was not replaced though, so that could be it and will also say that to the mechanic.

wouldn't a bad plug/coil cause misfiring all the time though that one could hear? i had that on my last car before the Saabs, and it was very noticeable through the rev range.

CEL is check engine light? engine fault light, correct? i haven't seen that - and have been keeping an eye out.

[sgould]

CEL is the "check engine" light.  If it's working, that's good!

If you have basic code reader, or a smart phone one, there are "faults" that are decided by the car's software.  As misfires are normal, it's the number of them that needs assessing before a check engine light happens.  The manufacturer sets these limits.  There's three limits on a Saab.  The best is "no problem".  The worst is a "big fault" with a check engine light. But in between there is a "Pending fault" which doesn't give a check engine light, but this level of problem can be read by a code reader.

While thinking about this, have you checked the small rubber vacuum pipes around the turbo? They degrade and leak.  New silicone ones would not be a huge expense. The other common(ish) fault is the boost control valve.

Have a look at www.saabwisonline.com  for diagrams and details from the official Saab workshop manual.

[smurkenstein]

wouldn't a bad plug/coil cause misfiring all the time though that one could hear? i had that on my last car before the Saabs, and it was very noticeable through the rev range.

CEL is check engine light? engine fault light, correct? i haven't seen that - and have been keeping an eye out.

It could present all the time but when I had the problem it was only under high output in high gear. My problem was a cracked plug but a failing coil pack can have exactly the same effect. Engine light flashed during the misfires but didn't stay on. Coil packs used to be a common failure on the forums but iirc it was more with the v6 engines. That's right about CML/EML, engine light etc - it shows as a yellow engine pictogram near the dials. I can't remember exactly but I seem to recall some engine faults are also displayed on the saab information display with a cog symbol.

If you get the right code scanner as sgould suggests it should be able to report which cylinder is misfiring. If it does turn out to be coil packs, you can try replacing the one for the effected cylinder and not have to replace all four which can be pricey. And its right misfires are detected and stored but not reported but need to hit a certain reporting level to trip the light. Good luck.

[umma08]

CEL is the "check engine" light.  If it's working, that's good!

If you have basic code reader, or a smart phone one, there are "faults" that are decided by the car's software.  As misfires are normal, it's the number of them that needs assessing before a check engine light happens.  The manufacturer sets these limits.  There's three limits on a Saab.  The best is "no problem".  The worst is a "big fault" with a check engine light. But in between there is a "Pending fault" which doesn't give a check engine light, but this level of problem can be read by a code reader.

While thinking about this, have you checked the small rubber vacuum pipes around the turbo? They degrade and leak.  New silicone ones would not be a huge expense. The other common(ish) fault is the boost control valve.

Have a look at www.saabwisonline.com  for diagrams and details from the official Saab workshop manual.

this is some really solid information - really helpful, thank you. i have looked for any leaks, and couldn't find anything obvious. i plan to ask mechanic to do a full check for leaks anyway (which he usually does anyway on first presentation of the car to him).

i also thought about the boost control valve, as that is sort of like what it feels like - i.e not a smooth delivery of the power at high pressure.

i'll pass on all the info to the mechanic who will also look for codes, and then go from there. will update next week when i know more. fingers crossed it's something simple (am pretty sure it is).

[umma08]

wouldn't a bad plug/coil cause misfiring all the time though that one could hear? i had that on my last car before the Saabs, and it was very noticeable through the rev range.

CEL is check engine light? engine fault light, correct? i haven't seen that - and have been keeping an eye out.

It could present all the time but when I had the problem it was only under high output in high gear. My problem was a cracked plug but a failing coil pack can have exactly the same effect. Engine light flashed during the misfires but didn't stay on. Coil packs used to be a common failure on the forums but iirc it was more with the v6 engines. That's right about CML/EML, engine light etc - it shows as a yellow engine pictogram near the dials. I can't remember exactly but I seem to recall some engine faults are also displayed on the saab information display with a cog symbol.

If you get the right code scanner as sgould suggests it should be able to report which cylinder is misfiring. If it does turn out to be coil packs, you can try replacing the one for the effected cylinder and not have to replace all four which can be pricey. And its right misfires are detected and stored but not reported but need to hit a certain reporting level to trip the light. Good luck.

thanks for the good luck! will know better next week. fingers crossed....!

[sgould]

The boost control valve is identical to another one nearby, but only on the outside. They are not interchangeable. The internal workings are different.

[umma08]

Well the mechanic did a full check over and service.

Changed the air filter back to the original (no more boy racer sound - which i sort of miss if i am honest).

He says that nothing is showing on the computer at all - and he was pretty confident that the computer would show something if it was present. He has a Bosch model, which he says is pretty state of the art. He also ran it through the Opel/Vauxhall checks, and these also showed nothing (not sure if that is sound logic or not).

The air filter change has definitely reduced the incidence rate of the hesitancy, but it is definitely still there.

I am gonna try and find a TechII computer that i can plug it into, or perhaps a Saab specialist to have a look over the next month or two. There is none i know near where i live, so have to travel to the capital.

To be fair, i do trust the mechanic - and he says that the car is pretty solid all round, has plenty of power, and is not making any significant rattles, or noises. he goes by the opinion that if nothing is broken - don't try and fix it.

Turbo boost issues/errors would show up on the computer wouldn't they? Surely they would?