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  1. #1
    Saab Fan
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    2003 9-5
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    9-5 idles rough & smokes a little after half hour of driving

    I just purchased a 2003 Saab 9-5 (2.3L) cheap, but had to buy it sight unseen because of its location. The Previous Owner (PO) said it started fine but then idled low and rough, and sometimes would not restart easily after warming up. He said it always started easily when cold. Prior to purchase, I had a mechanic go out and check the compression, and he reported it at 180 on all 4 cylinders. He listened to it run, and said it sounded great mechanically. He said he had to run it about 45 minutes (not driving, just running) before it started running rough. Both the PO and mechanic reported the check engine light to be on. Neither the PO nor the mechanic had the means to check the codes.

    On that basis, I suspected a crankshaft position sensor going bad when hot, or other electrical problem. I am new to Saabs, but a competent diagnostician and mechanic, and it was so cheap I thought I'd take a chance. (I understand the risk I was taking was pretty significant, but again, it was so cheap there really wasn't much downside.)

    The car has 86k miles, but the PO has said the engine was swapped out with a used engine in the past 6 months, and not driven much since. He thinks the turbo was rebuilt, but is not sure. The mileage of the used engine is unknown. It is also not certain whether the turbo on it is from the original engine or came with the used engine. I did get a spare turbo with the car, but it is toast. I'm not sure I'm getting the whole story from the PO.

    The car arrived, and I've spent only a few hours on it, changing engine oil (Mobil 1 0w40) & filter (Bosch), and checking the car out. It is in surprisingly good condition overall, and at first I thought the problem must be intermittent, because it drove so good. I've started it several times, and have let it idle for up to 20 minutes. I drove it for 20 minutes when warming it to change the oil, and afterward it drove awesome for about 30 minutes. I saw nothing unusual. Boost builds just as expected, runs all the way to the right edge of yellow under load, and doesn't go into the red. (I didn't drive it hard or run the revs very high.)

    However, after about a half hour of mild driving (some stop and go, some 50mph roads), it started idling rough, and I had to keep my toe in the throttle a little to keep it running when stopped at a light. Exactly as the PO had described. I pulled into a parking lot, and noticed a bit of white smoke drifting with the wind. I rolled down the window and asked a bystander if the car was smoking, and they responded yes. Back at the shop, it was idling rough but kept running in Park, and I got out and looked at the tailpipe. Sure enough, a little white smoke that smells like burning Mobil 1. (I know what burning Mobil 1 smells like from having spilled some on the exhaust manifold of my Chevy truck. ) This perplexed me, because the Saab had not smoked before, nor had the mechanic or PO mentioned any smoke. After letting the car sit a while and cool down, when I restarted there was not the slightest hint of smoke, nor did the exhaust have any burning Mobil 1 smell.

    This leads me to believe that the turbo is leaking oil past the bearing seals. Perhaps leaking on the exhaust side, and the rough idle and check engine light are the result of the oxygen sensor being inundated with hydrocarbons. Or perhaps leaking on the intake side, and the rough running and engine light are from burning oil in combustion. (although this seems unlikely because of the lack of smoke on cool start-up.) I suspect the turbo, and not rings or valve guides, due to the complete absence of smoke until well-warmed, along with the compression report given by the mechanic.

    So, what I'm asking here is:
    a) Does my theory of bad turbo seals sound likely?
    b) Are there other scenarios that would fit these symptoms?
    c) Any other feedback or input?
    d) Suggestions, please! :-)

    Thanks for any input you may have!

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  2. #2
    Saab Enthusiast pisani01's Avatar
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    28 Jul 2014
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    Hey just kicking back at you about your saab. Yes I understand what you are saying about the oil leak at the turbo. I was looking at a diagram that showed oil seepage in the turbo. A little bit of a pain but I would replace it. Never had one blow in a car but sure did in a Ford LT9000 diesle and you wanna talk about white smoke.

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  3. #3
    Saab Fan
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    16 Aug 2014
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    2003 9-5
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    Thank you for the kindness of a reply. Subsequently to posting this question, I have driven the car a substantial period of time, and there is no smoke whatsoever under any conditions. So, I don't know what happened that first day, but it was the first time I had driven the car any distance since buying it. So whatever caused the minor amount of white smoke I was seeing was an anomaly.

    I have subsequently had a factory-trained Saab mechanic read the codes with the factory tool. Here are the codes he found:
    P1251 (1) Limp mode
    P1312 (2) Combustion Detection 1&2
    P1334 (4) Combustion Detection 3&4
    P1231 (1) TPS 1&2
    P0340 Cam Sensor

    Some of these codes could also be anomlies, as the PO had let the car sit for many months, and several times jump started the car because of a bad battery.

    But in any event, the Saab mechanic said the low turbo boost would be because of the Limp mode being active. In regard to the low, rough idle, he said he would first replace the throttle body, and then reset the codes and see what happens. He suspects it went into Limp mode because the Throttle Position Sensors were not reading consistently, which could also cause the idling problem.

    Other than the low idle and low boost, the car drives very nicely.

    I found a used throttle body from an individual who removed it from his perfect-running 9-5 because his transmission failed and he was parting out the car. So I will try that first.

    Now that I have the codes, and the opinion of one Saab mechanic, I would love to hear other opinions, given the codes that he read.

    Thanks!

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  4. #4
    Frank
    Administrator nordwulf's Avatar
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    previous: 2006 9-3, 2001-06 9-5, 2011 9-4X
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    Before replacing the throttle body, you can also try to clean it first and see if that makes a difference.
    http://saabworld.net/f9/9-5-throttle-body-29618/

    P1312 and P1334 usually indicate the need for a new DIC. What's the condition of the spark plugs? If there is no maintenance record, start with replacing those and make sure they are the correct NGK plugs.
    http://saabworld.net/f144/spark-plug...ication-27621/

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  5. #5
    Saab Fan
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    Ok, just an update on my issue. Further diagnosis has me convinced that the system tests the Limp mode solenoid on either shut down or startup, and I think my linkage must be misaligned or sticky, because it got to the point that the problem was repeatable: When it wouldn't start I could feel a stickiness in the throttle. Checking the TB, the throttles were not locked together as they would be in Limp mode, but I could feel a definite drag. I would have to manually put it into limp mode by moving both the drive-by-wire throttle that the cable is connected to, and the knurled manual throttle, until they locked together into Limp mode, and then the stickiness would go away. It would then start in Limp mode. Also, I could then reset the Limp mode, and it would start and run perfectly until the next time I shut it off. Then upon trying to restart, I would have to repeat the whole process.

    So, to sum it up, it would start and idle low and rough when in Limp mode, or it would start and run perfectly if I reset Limp mode, until next time I turned it off. Then it would not start at all until I allowed it to go all the way into Limp mode by manually fiddling with the throttles. It was like when it shut down or tried to restart, it would fire the Limp mode solenoid as a test, and when the solenoid wouldn't complete its cycle of travel, the system set the solenoid to Limp status, and my fiddling with the throttles would finally allow it to engage. I know I'm not describing this as well as I'd like, and I'm not even sure the system works as I am describing, but the symptoms fit what I am ineptly trying to describe.

    Anyway, I suspect a thorough cleaning would have fixed it, but I found a used TB on eBay from a 2002 9-5 owner who was parting his car out because his transmission cratered. He assured me his car was running perfectly when that happened, so I felt reasonably comfortable in buying it, especially when we negotiated a low price. It came in and I did some minor cleanup prior to installation, but it looked almost new compared to mine.
    I've only driven it a few miles, but so far it's perfect. I stopped and restarted it several times, and everything works as it should. Well - almost everything - the cruise control didn't work before, and I hoped the new TB would fix it. It didn't fix the cruise, so I've got some diagnostic to do there.

    Thank you each for your input. I hope my experience helps someone else diagnose a similar problem.

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  6. #6
    Frank
    Administrator nordwulf's Avatar
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    previous: 2006 9-3, 2001-06 9-5, 2011 9-4X
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    Quote Originally Posted by pj1 View Post
    I found a used TB on eBay from a 2002 9-5 owner who was parting his car out because his transmission cratered. He assured me his car was running perfectly when that happened, so I felt reasonably comfortable in buying it, especially when we negotiated a low price.
    Here is another 2002 9-5 with a failed transmission being parted out. http://saabworld.net/f222/2002-9-5-linear-30594/
    Coincidence? I think not!

    Glad to hear you got it sorted out and hopefully it will last. But it sure sounds like the TB was the problem.

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  7. #7
    Saab Fan
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    That's the guy! Your link takes you to the guy I got the TB from, in Fredericksburg, Virginia. Very helpful fellow.

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