Can Changing Converter Fix Emission Problems?

[jqzhang]

Hi,

Hope all is well with you guys.

My 1991 LS400 cannot pass inspection. I bought a oxy. sensor from Ebay and replaced the old one since I had a trouble code indicating the sensor on the right bank had failed. It did not work: check engine light still on; another code tells me the fuel mixture is lean.

I suspect the converters be gone because the exhaust really smells. I'm planning to buy a universal one that is cheap. In case it did not work, I'd only lose about $50. Would you think a bad oxy. sensor can cause bad smell of exhaust? I doubt it.

I read some reviews. It looks like people change converters just to quiet down the noise instead of improving the emission. I'm confused. Noises come from bad exhaust pipes or mufflers, not converters.

What would you think? BTW, the car has about 159K miles on it; newly rebuilt starter; 2 year old of radiator; another symptom: occasional missing when engine is hot, not very frequent; it may have something to do with lean mixture of the fuel, maybe converters.

Thanks in advance.

[billydpowell]

you dont need us guessing at all the different possibilities that could cause your problems, have a professional check it and tell you what it needs and then maybe we can offer some suggestions.

[jaswood]

Hi,

Hope all is well with you guys.

My 1991 LS400 cannot pass inspection. I bought a oxy. sensor from Ebay and replaced the old one since I had a trouble code indicating the sensor on the right bank had failed. It did not work: check engine light still on; another code tells me the fuel mixture is lean.

I suspect the converters be gone because the exhaust really smells. I'm planning to buy a universal one that is cheap. In case it did not work, I'd only lose about $50. Would you think a bad oxy. sensor can cause bad smell of exhaust? I doubt it.

I read some reviews. It looks like people change converters just to quiet down the noise instead of improving the emission. I'm confused. Noises come from bad exhaust pipes or mufflers, not converters.

What would you think? BTW, the car has about 159K miles on it; newly rebuilt starter; 2 year old of radiator; another symptom: occasional missing when engine is hot, not very frequent; it may have something to do with lean mixture of the fuel, maybe converters.

Thanks in advance.

Clean the MAF/IAT sensor elements.

[jqzhang]

Thanks Jaswood for the valuble tips. I'll certainly follow what you said and check it out.

Have a good one.

[SRK]

You might be premature in thanking Jaswood, as the early LS's use an optical MAF sensor, not a hot wire type. Cleaning is not required, nor advised.

[jqzhang]

You probably right about it. But my question still is if replacement of the converters can make the exhaust smell better. I don't think they are clogged because there is no hesitation as long as the engine warmed up.

Thanks.

[jqzhang]

One more question. I changed the plugs about a couple of years ago using Bosch. I heard something negative about those plugs (I was trying to get some NGKs but they were out of stock).

So what's so bad about Bosch plugs?

Thanks in advance.

[billydpowell]

My 94 LS failed emissions and the code was converters, I bought two off ebay, put them on and it passed.

SO, your question... Can Changing Converter Fix Emission Problems? YES.... it did mine

[miss1lee]

My 94 LS failed emissions and the code was converters, I bought two off ebay, put them on and it passed.

SO, your question... Can Changing Converter Fix Emission Problems? YES.... it did mine

Did you take it to a shop to get the converters replaced or did you replace them yourself? If you've done it yourself, was it simple?

[curiousB]

I had a low converter code (P0430) and all it turned out to be was a pipe leak after the primary converter and before the secondary one. I spend a few weeks figuring it out and swapped parts that were never a problem. Cost to fix in the end, a bit of welding.... see the whole saga in the thread below.

I wouldn't rush out and swap parts prematurely.

It would be better if you posted the ECU codes that caused the car to fail or was it a failure by exhaust probe measurement?

http://us.lexusownersclub.com/forums/index.php?showtopic=70886&st=0&p=440638&hl=p0430&fromsearch=1entry440638

[billydpowell]

I done it myself, Simple? it was just work...... all work is hard when you are almost 78!!!.... twisted off 3 studs.