catalytic convertors (de cat question)

[djcla]

I have been reading posts about people removing there cat in there cars and have a few questions reagrding the MOT rules. Am i right in thinking a J reg 1992 car has to have a catalytic convertor because i thought AUg 1992 was when the law changed? My other question is without a Cat would the car not fail it's ommisions test in the MOT. Or is there different levels for older cars?

 

[cdickinson]

Mine has a decat and just sailed through the mot with no emissions problems...1990 S2.
Not sure about when the exact date for cats started but I think it is in '92....

 

[Neil Haughey]

Emissions test on a 944 prior to the rule change is 3.0% CO the same as all other 80's clunkers. I don't have a cat on my car or for that matter a working lambda sensor so the CO is set by adjusting the screw in the bottom of the AFM. So even running mega rich the car will sail through the MOT test.

 

[djcla]

just noticed my spelling mistake LOL, I just need to know the year know the reg now then

 

[Diver944]

You are right on the dates, but it's not so much that a K plate onwards HAS to have a cat , but it HAS to pass a more stringent emssions test which is harder to do without the cat

 

[djcla]

I have read on another site it is k reg onwards is that aug 1992 onwards , so j might be ok ?

 

[wibble]

You can buy the regulations off VOSA or ask a MOT centre. I seemed to remember reading somewhere that modern engines these days could pass emmisions without the necessity of a cat, but the regs still apply.

 

[Diver944]

ORIGINAL: djcla

I have read on another site it is k reg onwards is that aug 1992 onwards , so j might be ok ?

Whoops you are right. Aug 1992 was a K plate - I'll amend my original post

 

[zcacogp]

ORIGINAL: Neil Haughey
... the CO is set by adjusting the screw in the bottom of the AFM.

Tell me more ... I have wondered how to adjust the CO on my car several times (it's a smidge high, and always had been), and would like to lean it out a little ...


Oli.

 

[djcla]

is it worth getting some this info in the FAQ , finding very usful indeed

 

[Fen]

It was August 1993 K plate.

 

[Neil Haughey]

ORIGINAL: zcacogp

ORIGINAL: Neil Haughey
... the CO is set by adjusting the screw in the bottom of the AFM.

Tell me more ... I have wondered how to adjust the CO on my car several times (it's a smidge high, and always had been), and would like to lean it out a little ...


Oli.

Only works AFAIK if the lambda sensor is not sending a signal to the ECU. There is a connector at the back of the fuel rail which connects the sensor into the system. On the top left hand corner underneath the AFM is a small blanking plug. You pull or cut that out and it reveals an adjusting screw which you can adjust with an allen key.

If your CO is high it sounds like your sensor is kapput, assuming it has one but I always thought that all UK S2's had catalytic converters. You could either fit a new sensor or set it manually. Word of warning though, I have seen as much as 0.6% variation over time on my car so it really needs the CO setting every few months or several thousand miles.

 

[Fen]

Not all S2s had a cat; it was a no cost delete option in the UK for example.

If you remove the cat from a car that had one you are supposed to bridge 2 pins with a jumper (which is an OPC part) to stop the ECU looking for the lambda signal, but I don't know which pins nor the part number.

 

[egan1]

A regional coding plug or impedance adapter is used to select a map which doesn't use the lambda signal. Pin and part numbers are on FR Wilk's site http://www.motronic.ws/4in1.htm

 

[zcacogp]

Thanks ... mine never had a cat (it's an early S2), and hence no lambda sensor.

I think I need to go looking for that plug. Anyone have any photos of it (or a more detailed description of where it is? It's on the AFM, on the underneath? Do I need to take the AFM off to get to it?)

Mine always has returned slightly high CO readings, and has always struck me as running a smidge rich. I'd like to lean it out a fraction, hence the interest.


Oli.

 

[Neil Haughey]

I had to take mine of to remove the blanking plug bta my car originally had a cat. TBH I want to fix the lambda sensor so the car can tune itself rather then having to fiddle with adjustment.