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Discussion Starter #1
Anyone ever get the famous check engine light after installing 3inch downpipe and race cat upgrade.

After getting the check engine, had my friend plug in with his analyzer/dianostic handheld, and noticed the front oxygen sensor reading slower than the rear. Clear the alarm, and about 20 minutes or so always comes back.

So far I've brush cleaned the sensor and retightened on the sensor before the cat. Dosen't help. Someone suggested driving it for 2 weeks and it may go away because the cat comes with oil from the factory, and you have to burn it out.

Doesn't add up since the one I'm having problems with is before the cat. Called GenuineSaab, and seems to be common, but fixed when clean retightened....but not for me yet.

Haven't received my stage 3 ECU yet.. Thinking that may solve the problem as the ECU will be programed for the increased exhaust flow.
But want no errors before installing the ECU.
The following upgrades were done on the engine.

aluminum intercooler
tornado spinner after the filter
turbo bypass/diverter
K&N filter
3 inch down pipe with race cat

Expecting a little extra torque if the ECU does as it claims with the current upgrades.

Already moves like a bat out of hell, but can't stand that glaring check engine light.

any ideas.

DC
 

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Huh. My Chrysler tech friend just told me that all OBD II cars turn on the CEL without a cat. But then you have a cat. It's really supposed to be a "catalytic converter efficiency" warning. Or something to that effect. If the converter isn't working 100% as good as the original, depending on how sensitive the computer is, it'll set off the CEL. One some cars even a direct replacement cat can cause the CEL to come on. With other cars it's less sensitive. Maybe the race cat just isn't effective enough?

Really bizzare to have the front slower than the rear though! Supposed to be the other way around! Could be something else though. Keep checkin' stuff. Hope it all works out!
 

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I have had the 3" downpipe fitted - but did not get a CEL, sorry  [/b]
Same here and I have no Cat at all although we only have the one O2 sensor on British cars. I have in fact been swapping between the 3" pipe and original Cat over the last couple of months with out any problems.

Mike
 

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So what DTC did the diagnostics actually get? I'm curious about it.

Also, here's another thing to check. I'm sure you know this, but I'll mention it anyway. The O2 sensor uses the exhaust, as mounted to the turbo and therefore, the engine as its ground. If the mating surface of the sensor is badly rusted or dirty, the ground will be hard to get. Also, since the downpipe is new, it may have already worked its way loose. Make sure the dp is tightened up well. If the dp is stainless, it may need periodic retightening. I seem to have to do mine every couple of months sometimes.
 

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Talked with my Chrysler friend again. He says when any OBD II car is warmed up at idle while it switches between rich and lean it times the delay in the reading for each O2 sensor. The second one (after the cat) is supposed to be a certain percentage slower depending on make, model etc. If they cycle at the same time (or not at all) it throws a part failure warning light. Some cars don't display the light, but it shows up on the scanner tool. Perhaps "some" of the racing cats, for whatever reason, just aren't effective enough for the Saab's electronics? It's a possibility at least.
 

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Discussion Starter #11
Nicked the O2/lambda sensor on removal...replaced it.., and all is good.

Put on that stage 3 Maptune ....and she screams
like a bat out of hell.

What's interesting is...although she has all of the required components for Stage 3..ie.., aluminum intercooler, 3 inch downpipe & race cat, k&n filter, plus a few other goodies.., the car feels like it has turbo lag on a higher degree.

The power is there off the line, but when that boost kicks in....way way above normal (pegging the car's boost needle).., its like turbo lag, and the top end dosen't seem to follow its midrange power/torque as high as I thought it would.

But lot's of surprises so far....

Went to the track on Sunday...Crofton Maryland..., and didn't think she was ready for tryouts just yet.

Some guy in a twin turbo Toy Supra, ran 12's at about 131mph... awesome, considering it was only bolt on's that got him there. He only had a bigger intercooler, air filter, no computer mods, and lot's of nerve to get down the track.

Maybe next year..., but got some head work in mind..., and maybe bigger turbo, injectors, and stage 4 maptune will make me feel better/confident...hmmmm.


DC
 
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