EML ???

[simone19680]

Hi,
I brought a 2002 mr2 in june, after approx 200 miles the mil light came on with the fault p0420, cat efficiency below threshold bank 1.
I was told it maybe a dirty maf sensor, I have removed this twice and both times cleaned it with carb cleaner, but every 40- 50 miles the mil comes back on with the same fault. As you look into the engine bay the left hand lambda sensor has been replaced before I brought it, the one on the right has small holes in each wire where I presume somone has had a multi meter to it.
I also heeded the precat advice last month and removed them, and it apears to have more torque at lower rev range.
The car purrs like a kitten having done 87,000.
Do I need just to replace the lamda sensor or is there somthing I need to look at first.
Thanks in advance, regards, simon.

[Wabbitkilla]

P0420is nothing to do with the two O2 sensors you see in the manifold.

The sensor responsible for monitoring cat efficiency sits after the main catalyst.
It's down below the left side of the main silencer if you look from above.

Now it could mean the main cat is going duff, or the sensor is going duff.
Or someone has replaced the main cat with a cat-less downpipe.

[simone19680]

Thanks,
The lambda says toyota on it, so I guess that is original, and the cat looks very rusty like thats lived there for a few years. Guess I will buy a sensor and see what happens next. Thanks for your help, regards, simon.

[Wabbitkilla]

Try the cheaper thing first

If it comes to replacing the cat, then it usually works out cheaper to get a workshot cout out the old one and weld in a sports cat as replacement.

[simone19680]

Ok, update,
Took my mr2 to my mates garage whom carried out plenty of tests with a modus reader and spoke to snap on support to run through the values given from all sensors. It appears from the results that all is correct and the cat has packed up and died.
I would like to fit a de cat pipe, as this is better mpg, and performance, and cheaper.
The big question is will it pass emissions next year without a cat fitted. Has anyone done this????
The engine has done 87,000 , runs like a dream and burns no oil.

[topgun]

Ok, update,
Took my mr2 to my mates garage whom carried out plenty of tests with a modus reader and spoke to snap on support to run through the values given from all sensors. It appears from the results that all is correct and the cat has packed up and died.
I would like to fit a de cat pipe, as this is better mpg, and performance, and cheaper.
The big question is will it pass emissions next year without a cat fitted. Has anyone done this????
The engine has done 87,000 , runs like a dream and burns no oil.

This seems to be a common fault on the earlier Mk3s.VC had the same problem so might be best to send him a PM.

[simone19680]

Sorry to be thick but who is vc that had the same problem? and how do I send him a pm?

[topgun]

Sorry to be thick but who is vc that had the same problem? and how do I send him a pm?

VC a woman pretending to be a Man lol,no doubt VC will be on here soon to reply.

[topgun]

And has Tony had this issue? I wasnt aware....

I was aware the precats were breaking up and he got the garage to remove them.

[simone19680]

I had this problem with the light coming on in june, then 400 miles later approx.
Removed pre cats, and cleaned out manifold. EML coming on every 50 ish miles now, and test show that the cat is dead. But what I want to know is do I really need it, which appears to be no, but yes once a year for an mot. But has anyone taken there mr2 for an mot with just a decat pipe fitted and passed the emissions??

[simone19680]

Spoke to 2 guys this evening that have removed damaged cats [frontera] and megan, 1 petrol and 1 diesel, decat pipe for the last 2 mot's and passed emissions.

[vanilla.coffee]

And has Tony had this issue? I wasnt aware....

I was aware the precats were breaking up and he got the garage to remove them.

Tony'c car died of precat failure originally....but I'd assume he had the precats gutted by the time he had the new gear installed?

My car's pre cat was fine. I had them removed when I had the new engine fitted as a precaution.
My car died due to oil pump failure.

[Wabbitkilla]

You'd would be very lucky to pass the emissions test without any cat at all.
The MR2 engine can be tuned with the help of a piggy back to JUST pass, but it's a rare thing.

Get the decat pipe and get a sports cat welded into it - cheaper and better for performance than the oem cat

[ZZW30]

The laws governing catalytic converters came into effect in 1993, cars manufactured and first used on or after 1993 must have a catalytic converter fitted at the factory, however it isn't against the law to remove it, the MOT regulations say nothing about a vehicle having a catalytic converter, they merely set emission levels which have to be achieved if the vehicle is first used after a specific year. Certainly some cars with very efficient engines could achieve the required emission levels without a catalytic converter.

So if your car passes without the cat then it's perfectly fine, but I think you'll find you will require the cat in place, some of us struggle to pass with the cat.. never mind without it. Also.. with a decat pipe I think you will find that you will constantly have the EML showing... someone will correct me if I'm wrong.