MOT Fail - Emissions 1993 Rev 2 UK N/A

[Mwilkinson]

Hi all,

Well the beater went for an MOT and failed on emissions. Not a single advisory other then this.

But she failed big time!

Fast Idle:

Engine Speed 2350 − 2650 Not checked
CO max 0.300% 4.474 FAIL
HC max 200ppm 142 PASS
Lambda 0.970 − 1.030 0.901 FAIL

Second Fast Idle Test:

Engine Speed 2350 − 2650 Not checked
CO max 0.300% 4.474 FAIL
HC max 200ppm 153 PASS
Lambda 0.970 − 1.030 0.907 FAIL

Natural Idle Test:

Engine Speed 600 − 800 rpm ——— Not checked
CO max 0.500% 4.496% FAIL

Now I should point out the car is decat. I assumed it was a decat friendly garage but I was very wrong. Despite this I still think the CO figures are high.

My plans:

Check for engine codes.


Buy decat pipe.
New plugs
New Lambda
Fuel filter
Oil filter
Engine oil change
Clean air filter and throttle body.

Any suggestions or ideas about what else to look at?

The car has new HT leads, but I will check the cap and rotary arm.

The car runs fine, no misfires, hesitation, pinking etc..

[HughesR1]

Heya mate, sorry to hear about the emissions.

I would pop a cat on and give it a good drive getting it nice and hot and I think you will get through. The 3SGE with decat is never gonna be low emissions unlike the turbo's. You can pick up a cat for £50 and then sell it on.

Also no receipt for it but I fitted a new Lambda I had kicking around for years the week I sold it and I wouldn't have thought that has gone in this amount of time

[Mwilkinson]

Thats good to know ref the lambda.

I will give everything a good refresh with a cat and see how I get on.

The exhaust is leaking somewhere which will also undoubtably impact on the emission levels.

[HughesR1]

Ah yes I remember you saying, that down/midpipe with flexi section was literally brand new 7-8 months ago aswell. Fitted it when I changed the lambda, bought it off a IMOC member and still had the toyota stickers on so wouldn't of thought it was leaking there.

However, never heard of a stock manifold cracking

[Mwilkinson]

I think it's the joint between the exhaust manifold and flexi. The last chap put quite a bit of exhaust paste on the joint.

I will take the whole exhaust off tomorrow and see what I have.

I will make it all work!!!

[ashley]

Looking at those readings I'd say your lambda sensor is shagged

[HughesR1]

Test for error codes before anything, as this guy may well be correct ^

If the lambda has already gone its a fairly easy job IIRC.

[Peter Gidden]

Looking at those readings I'd say your lambda sensor is shagged

+1

[Mwilkinson]

Thanks everyone for your sage advice.

New Toyota Lambda sensor and cat will be ordered. She will also have a thorough service too.

[synXero]

I have a brand new denso (read: Toyota) lambda sensor if you want it. It is no use to me as the beams sensor is different. I believe I paid ballpark £60 for it.

[Mwilkinson]

I have a brand new denso (read: Toyota) lambda sensor if you want it. It is no use to me as the beams sensor is different. I believe I paid ballpark £60 for it.

Tempted. Will that fit a 1993 rev 2 N/A engine?

My concern, if I am honest, is having owned a Supra for 6+ years, that non genuine Lambda sensors tend to fail quickly or not work at all on Toyotas.

I think this is common to many manufacturers. I know Denso make the toyota unit but can you be sure it will work properly?

[synXero]

There was a lengthy discussion on this forum recently about Toyota = Denso. I paid a significant amount for it because much like yourself, I am not a patron of poo.

Anyway it is yours if you want it. Peter Gidden or similar will confirm rev differences. It is certainly for NA engines, I know turbo sensors are different.

[Mwilkinson]

There was a lengthy discussion on this forum recently about Toyota = Denso. I paid a significant amount for it because much like yourself, I am not a patron of poo.

Anyway it is yours if you want it. Peter Gidden or similar will confirm rev differences. It is certainly for NA engines, I know turbo sensors are different.

Much obliged. Will review the recent thread and wait and see what Mr Gidden has to say on the matter.

[TheBaker]

Find a friendly MOT tester.

[Mwilkinson]

Find a friendly MOT tester.

Don't get me wrong. I have considered this, but there is clearly an issue with the engine that needs resolving and that will only get worse if left.