cascading exhaust problems

[gerard]

Please help. I've been running my '91 2dr 16v 900 for the last few months without a rear resonator. I'm a student, don't drive it very often, and was waiting for good weather to finish the installation. (In short i was procrastinating to save a few bucks )

This weekend i took my car for a long-ish trip to the ski hill 150km away. I was driving pretty fast (120-130 kph) and when i got off the freeway the ‘check engine’ light began blinking at low speeds. I didn't pay much attention it then, then a few kilometers later the light went away and running noise suddenly got a lot louder …

Up until then I had no problems with fumes inside the cabin; the noise and fumes were coming from the back end of the car. (For safety I have still been very careful to run with the windows wide open; this can be cold and noisy). After the incident the noise and fumes came from further up under the car (exhaust manifold - cat) and can be smelt in the cabin.

I'm now very worried. My hope is that the bolts fastening the cat have gotten loose; my fear is that I’ve cracked my manifold. I haven't gotten a good look yet; I’m honestly not exactly sure what to look for. What do you guys think? Could i have done any permanent damage as a direct result on running without a rear resonator?

I did end up having to drive home, albeit a little slower and the windows even open wider. While I had no problem cruising at a constant speed, I found the engine a little erratic whenever i took my foot of the gas or had to accelerate. Please help.

[therealturbofan]

yeah, the advice here is pretty awesome! i guess i'll help however possible... when you say rear resonator, you mean rear muffler right? the one that sits right in front of the rear axle? if so, then i really don't think you'll actually do damage to the engine by not running a muffler... i've had my exhaust fall off twice due to rust (once it broke right behind the cat, then it broke right in front) and it didn't seem to do any damage to the car, but it was absolutely painful to drive it! anyway, good luck, hope you figure it out.

[gerard]

Haven't been driving my car for a few weeks, finally got it on a lift. The O2 sensor rusted out of the downpipe !! It had nothing to do with the rear resonantor. How i hate canadian winters for cars (though the snowboarding aint bad). Curious i drove my car 100k back from the ski hill without an O2 sensor, could i have done any permanent damage to the engine? I know O2 sensors are expensive, does anybody know if i can get one cheap in Canada?

[therealturbofan]

i'll just give you the same answer the moderators always give: go to the online saab pats houses. europarts, saabstore, etc. good luck!

my car sucks... i think a u-joint in my steering is ceasing up... it's very difficult to turn for about 25 degrees of duration almost exactly 180 degrees apart. dad suggested u-joint. i'm pulling it apart this afternoon to see what's up... wish me luck..

[ProfZ]

The detached O2 sensor would have caused your engine to run rich (triggering the check-engine light), but no damage. The sensor might actually still be OK--try getting it out of the (remains of the) fitting that held it in the downpipe.Best bet is to replace the downpipe and the exh. system cat-back; check www.eeuroparts.com for probably the best prices.

[therealturbofan]

or if you're going to go all new from cat back, you may do ok at a local exhaust shop. i went to a small shop that does quite a bit of custom work and he made a custom exhaust for my car (first saab he's ever worked on), 2.5" stainless mandrel bent tubing with a magnaflow muffler and a sweet looking magnaflow tip for like $265. keep in mind that's only cat back, but a complete system would have run me right around $500, including a high-flow cat.

[gerard]

Thanks guys. I lucked and was actually able to find an OE o2-sensor for pretty much the same price as a universal (and in stock!) at a family-owned part shop in downtown toronto. They got me everything (the sensor, downpipe and gaskets) the same day all for under $220 cnd tax incl. That was friday, today i was desperate to get driving and took it to midas down the street where they installed the parts for 1.5 hours labour.

Just got her back and she runs great! Some hesitation/sputtering i used to get on starts is completely gone, and i'm looking forward to the better fuel economy with gas prices pushing 95cents/liter.