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Discussion Starter #1
Hi everyone,

I would like some help diagnosing my 2003 9-3 SS 2.0T AERO 210 hp, as I have failed to solve a misfiring problem at idle that has been tormenting me form the past months.

Long story short, car misfires at idle, and just at idle, not enough to throw a CEL but bad enough to cause transmission backlash, step on the gas a little bit and car runs perfect. I have already done all of this:

  • New coil packs.
  • New spark plugs.
  • New ionization unit.
  • Replaced all the known to fail vacuum lines.
  • Checked for deteriorated wires or connectors.
  • Cleaned throttle body.
  • Checked and cleaned MAF.
  • Replaced MAP.
  • Replaced EVAP purge valve.
  • Checked that car does not smoke when starting.
  • Camshafts are properly timed.
  • Done a compression test, perfect on every cylinder.
  • Replaced lambda probe.
  • Injectors were replaced 20k miles ago.
Up to this point I'm at a loss about what to do... something to note is that misfiring behavior seems to change depending on what spark plugs are used, whit original SAAB/NGK branded sparks, misfires affect all cylinder but specially 1 and 3. Replace them with NGK 7 normally used in remapped cars, and misfires focus mainly on cylinder 4... Bosch compatible ones? Seems to run better but still misfiring... A part from that, car runs perfectly fine, a bit to easy to stall if you ask me, but take it with a grain of salt...

I don't have a Tech2, so I survive with a BlueDriver, the only thing that looked out of place was the long term fuel trim, showing values between -5.5% and -8.6%

Help guys :( I'm at my wit's end.
 

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Discussion Starter #4
Have you done a fuel pressure test to rule out fuel pressure regulator and fuel pump?
Have you checked your EVAP inlet and outlet hoses for leaks?
Yes, 2.4 at idle 2.9 under load and yes, when I replaced the valve y checked both of them, seem to be perfectly fine, I dont have an smoke machine to check for small leaks, but at least I can guarantee that no major ones are present.
 

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Discussion Starter #5
Is your car remapped?
Im not completly sure about this one, as I bought it months ago, it does pull surprisingly good so I dont discard the possibility, however, this problem was not present at all when I bought it, engine was smooth as silk at idle but It got slowly bad up to this point.
 

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Discussion Starter #8
Are the coil packs original Saab?
Yes, had the yellow top ones, now I mounted the black top Mitsubishi/SAAB ones.

Is there anything else going on with the car? Are you losing coolant? Oil leaks, etc?
It leaks a bit from the vacuum pump. Coolant was replaced when I changed the water pump, its crystal clear for now and level is stable. Out of that, the only odd thing that I found is that if not driven for a week or so, after turning the engine on, oil pressure and ABS lights flash for 1-2 seconds and then switch off.
 

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1. Start checking vacuum lines. Check the one that runs by the oil filter housing (specifically at the check valve) and the T by the oil dipstick. Also fix the 2x vac pump seals.
2. 2003s have 2 O2 sensors. Considering LTFT is off the other might be bad. Was the first one replaced with OEM or cheapie amazon junk?
 

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Follow Diggs advice, but I just want to add this very long shot: Does your Blue Driver scanner show you exhaust gas sensor monitor PIDs for sensor 1? I've had to change my water pump twice and the first time I did it, I didn't seat the Cat properly to the wastegate. It was just slightly off and I didn't realize my mistake until I had to change my water pump a second time. By then I had a scanner and it was showing a small leak for exhaust gas sensor monitor 1 (the O2 sensor before the Cat) and my LTFT was in the negative 5-8% range. After changing the water pump a second time and seating the Cat properly, the LTFTs have since come down to the negative 1-3% range and the scanner no longer shows a value for exhaust gas sensor monitor 1. I can only think that that's what was causing it to run rich, but maybe someone more knowledgeable can weigh in on that.
 

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Discussion Starter #12
1. Start checking vacuum lines. Check the one that runs by the oil filter housing (specifically at the check valve) and the T by the oil dipstick. Also fix the 2x vac pump seals.
2. 2003s have 2 O2 sensors. Considering LTFT is off the other might be bad. Was the first one replaced with OEM or cheapie amazon junk?
The one that goes from the vacuum pump to the intake and over the oil filter was replaced entirely, the T by the dipstick looks good, sprayed it whit carb cleaner serveral times with no effect. About the vacuum pump seals, I read contradictory experiences, some seem to bend when taking them apart and leaking harder after that, so I left it untouched for now... will definitely change them if you recommend doing so.

The lambda probe that I replaced was indeed the first one close to the turbocharger, NTK branded, correct me if I am wrong, but the first one should oscillate while the second one should throw almost constant values right? If that's the case it seems good in the ODB scanner.


Follow Diggs advice, but I just want to add this very long shot: Does your Blue Driver scanner show you exhaust gas sensor monitor PIDs for sensor 1? I've had to change my water pump twice and the first time I did it, I didn't seat the Cat properly to the wastegate. It was just slightly off and I didn't realize my mistake until I had to change my water pump a second time. By then I had a scanner and it was showing a small leak for exhaust gas sensor monitor 1 (the O2 sensor before the Cat) and my LTFT was in the negative 5-8% range. After changing the water pump a second time and seating the Cat properly, the LTFTs have since come down to the negative 1-3% range and the scanner no longer shows a value for exhaust gas sensor monitor 1. I can only think that that's what was causing it to run rich, but maybe someone more knowledgeable can weigh in on that.
I'm not sure I understand here, I still have a picture around, O2 Bank 1 Sensor 1 corresponds to sensor after the turbo right?

268679


post up misfire counts for each cyl...
Sorry, dont have the screenshot, since it was done at the shop with a Delphi scanner, but the values were up to 2000 misfires in cylinder 4 in less than 5 minutes.
 

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2000 after clearing? Yikes.
Replace the seals. It isn't hard. I did it without issue and I'm all thumbs.
 

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The one that goes from the vacuum pump to the intake and over the oil filter was replaced entirely, the T by the dipstick looks good, sprayed it whit carb cleaner serveral times with no effect. About the vacuum pump seals, I read contradictory experiences, some seem to bend when taking them apart and leaking harder after that, so I left it untouched for now... will definitely change them if you recommend doing so.

The lambda probe that I replaced was indeed the first one close to the turbocharger, NTK branded, correct me if I am wrong, but the first one should oscillate while the second one should throw almost constant values right? If that's the case it seems good in the ODB scanner.




I'm not sure I understand here, I still have a picture around, O2 Bank 1 Sensor 1 corresponds to sensor after the turbo right?

View attachment 268679



Sorry, dont have the screenshot, since it was done at the shop with a Delphi scanner, but the values were up to 2000 misfires in cylinder 4 in less than 5 minutes.
Didn't mean to confuse you. Was simply thinking of possibilities since you have negative 5-8% LTFTs - when you change the water pump you have to remove the Cat and when you reinstall it, if you don't properly seat/mate the Cat to the wastegate evenly, it's possible to affect your O2 sensor 1 reading causing the engine to run rich. This happened to me. One nut was tightened down farther than the other two. My scanner shows me PIDs for Exhaust Gas Sensor 1 and after I reseated the Cat evenly the reading zeroed out. Thought your scanner might give you some information on that too. Anyway, there's clearly something else at play here.
 

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Is 4 the furthest along the rail?
 

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I know you said your coils and plugs are new, but you could try swapping the coil and plug from cylinder #4 with another cylinder to see if the misfire follows. That would tell you if something is wrong with the coil and/or plug from cylinder 4.

Dumb question, but I'm going to ask it anway: Are all your plugs gapped properly to spec?
 

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Discussion Starter #17
2000 after clearing? Yikes.
Replace the seals. It isn't hard. I did it without issue and I'm all thumbs.
Yeah... It shakes like a madman at idle... worst part is that the irregular spinning causes knocking in the primary shaft of the transmission, so I literally stay at redlights with the clutch pressed and apply a bit of gas so that the engine is never at idle to avoid unnecessary strain.

Will change them asap, by the way, one of them is obvious, but the other is inside the pump, right?

Didn't mean to confuse you. Was simply thinking of possibilities since you have negative 5-8% LTFTs - when you change the water pump you have to remove the Cat and when you reinstall it, if you don't properly seat/mate the Cat to the wastegate evenly, it's possible to affect your O2 sensor 1 reading causing the engine to run rich. This happened to me. One nut was tightened down farther than the other two. My scanner shows me PIDs for Exhaust Gas Sensor 1 and after I reseated the Cat evenly the reading zeroed out. Thought your scanner might give you some information on that too. Anyway, there's clearly something else at play here.
No problem, English is not my mother tongue so I get a bit lost with some terms, I am not sure if I took the Cat apart when doing the water pump... I had to drop the engine a bit to remove the timing cover, but will definitely recheck, thanks!

Is 4 the furthest along the rail?
Its the one oposite to fuel pressure regulator if my memory does not trick me.


I know you said your coils and plugs are new, but you could try swapping the coil and plug from cylinder #4 with another cylinder to see if the misfire follows. That would tell you if something is wrong with the coil and/or plug from cylinder 4.

Dumb question, but I'm going to ask it anway: Are all your plugs gapped properly to spec?
Mounted them several times, behavior is constant per spark plug type, I mean, misfires change from mainly c4 to c1 and c3 when going from NGK to Bosch, but between the same type I didn't notice significant differences.

Sure, 1 mm max.


As you can see, I already checked all the obvious and not so obvious things, yet I'm still at square one, so either I mistakenly deemed as good something that is faulty, or there is something else going on here... However, Nordic-machine's question left me worried now... Is there any way to know if the ECU is remapped? And, if there is, Is it possible to restore the original map? ECUs are actually quite expensive, and my car has the stupid SAI system, so second hand ones are scarce... sigh... :(
 

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Yeah... It shakes like a madman at idle... worst part is that the irregular spinning causes knocking in the primary shaft of the transmission, so I literally stay at redlights with the clutch pressed and apply a bit of gas so that the engine is never at idle to avoid unnecessary strain.

Will change them asap, by the way, one of them is obvious, but the other is inside the pump, right?



No problem, English is not my mother tongue so I get a bit lost with some terms, I am not sure if I took the Cat apart when doing the water pump... I had to drop the engine a bit to remove the timing cover, but will definitely recheck, thanks!



Its the one oposite to fuel pressure regulator if my memory does not trick me.




Mounted them several times, behavior is constant per spark plug type, I mean, misfires change from mainly c4 to c1 and c3 when going from NGK to Bosch, but between the same type I didn't notice significant differences.

Sure, 1 mm max.


As you can see, I already checked all the obvious and not so obvious things, yet I'm still at square one, so either I mistakenly deemed as good something that is faulty, or there is something else going on here... However, Nordic-machine's question left me worried now... Is there any way to know if the ECU is remapped? And, if there is, Is it possible to restore the original map? ECUs are actually quite expensive, and my car has the stupid SAI system, so second hand ones are scarce... sigh... :(
Just curious. I know it's off topic, but why did you need to drop the engine a bit to remove the timing cover when changing the water pump? Did you not use the water pump holding tool that bolts to the balance chain gear through the coolant pump cover within the timing cover?
 

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Discussion Starter #19
Just curious. I know it's off topic, but why did you need to drop the engine a bit to remove the timing cover when changing the water pump? Did you not use the water pump holding tool that bolts to the balance chain gear through the coolant pump cover within the timing cover?
No problem, I don't have it fresh, but I didn't change the water pump alone. The famous balance shaft tensioner guide broke, so I replaced everything, chains, guides, sprockets and of course, the water pump. I would swear that I had to drop the engine a bit to be able to get the whole timing cover off. Its very possible that I had to remove the Cat too... and that makes me wonder if disconnecting the second O2 sensor should trigger a significant change if that were the problem?
 
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