Could It Be My Left Side Cat Is Toast?

[4liter]

Multi cylinder misfires with fuel cutoff plus the o2 front sensor code p0153...p1341, p1357, p1355, yesterday it was p0306 now it's p1353 5-8 with coil pack and spark plug swap from L side to R side and I get the same results even after clearing codes. I should've gotten something correct by accident right?.... new intake gaskets and OEM OSV and no air leaks can be detected.

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[Timm]

Could well be - remove the Lambda sensors (physically) and see if that makes a difference - also, a garage can measure the back-pressure at the sensor apertures - more info here:

http://www.meeknet.co.uk/e31/E31_840...l_Throttle.htm

[clarkitect]

Could well be - remove the Lambda sensors (physically) and see if that makes a difference - also, a garage can measure the back-pressure at the sensor apertures - more info here:

http://www.meeknet.co.uk/e31/E31_840...l_Throttle.htm

I thought the problem cats on a TU engine were the ones in the manifolds? Would pulling the O2 sensors in this case only diagnose the secondary cat?

I’m having similar codes and figured it was these manifold cats. If there was a good way to test this I’d be pretty pleased.

[4liter]

Could well be - remove the Lambda sensors (physically) and see if that makes a difference - also, a garage can measure the back-pressure at the sensor apertures - more info here:

http://www.meeknet.co.uk/e31/E31_840...l_Throttle.htm

OK I'll do that tomorrow. Thanks for the link it shows the same symptoms I'm encountering

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[4liter]

If it turns out to be that cat, I'm screwed. I just moved to Cali. I've read about the smog emissions here are SUPER strict...

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[Timm]

I thought the problem cats on a TU engine were the ones in the manifolds? Would pulling the O2 sensors in this case only diagnose the secondary cat?

I’m having similar codes and figured it was these manifold cats. If there was a good way to test this I’d be pretty pleased.

The Lambda sensors are in front (upstream) of both cats.....

[kouks]

If it turns out to be that cat, I'm screwed. I just moved to Cali. I've read about the smog emissions here are SUPER strict...

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No, just replace cats with CA compliant ones and you’ll be fine. I think the Flowmaster ones at Autozone are about $200 each. Have a muffler shop weld them in and you’re good to go.

[Sobek]

If it turns out to be that cat, I'm screwed. I just moved to Cali. I've read about the smog emissions here are SUPER strict...

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Don't sweat it, there are aftermarket cats that aren't too pricey that have worked just fine for members in the past with California emissions requirements. Worry about successfully diagnosing the issue first - we can help you get the right part once you work out exactly what you need

[4liter]

No, just replace cats with CA compliant ones and you’ll be fine. I think the Flowmaster ones at Autozone are about $200 each. Have a muffler shop weld them in and you’re good to go.

Those cats are generally under the car for $200. The one in question go for $800-$1000. Those are on the exhaust manifold. Do they chop, weld and pass here?

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[clarkitect]

The Lambda sensors are in front (upstream) of both cats.....

Thanks! I should have studied the RealOEM diagram more I guess!

I was going to pick up used low mileage pair of cat/manifolds.

[4liter]

Well I've tried to break down the exhaust system to clear out the debris in the cats and noticed that from the manifold, it comes out as a whole and not in sections. The pipe won't come out because the rear is connected so, I can't get to manifold cat. I don't have the space (jack not strong enough to lift higher on to jack stands) to do it...nor do I have a pry bar long enough to break up the material even if I could get the rear cat off. If anyone has removed the exhaust, please chime in. I may be doing something wrong...

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[4liter]

Ahhh skip it...I'm going to check in with a local muffler shop Monday.

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