Running too lean - Failing Emmissions MOT

[Milesk]

I have a 1.4k super sport engine 1992

 

It had been running a race exhaust with no lambda sensor (running rich) It failed on high Hydro Carbon readings at the SVA test centre

 

I have since replaced with a standard exhasut with Cat and Lambda sensor (now too lean)

 

At the MOT station their Sagem equipment acknowledged that the car had a lambda sensor (its a start) however could not secure satisfactory readings.

 

The CO2 reading was 0 and I have no hydro Carbon reading, it was suggested it may be sucking additional air????

 

I am also being told the ECU has an element of self learning - however I believe it to be now confused as it is running too lean. How can I get the ecu to work correctly - I am pretty confident all sensors are working.

 

If I drive a 100 miles - will the ECU work out that it has a nice new lambda sensor and exhaust and rectify the lean running to normal?

 

ANy ideas?? - Thanks Miles

 

 

[Bilbo]

The CO2 reading was 0 and I have no hydro Carbon reading, it was suggested it may be sucking additional air

 

The garage that does my MOT often moans about that and I am on carbs they just bring the idle up a tad to get a reading. They never seam to work out its the primaries leaking at the joints ❗

 

They always get a reading if I have re-jointed the primaries to the 4 to 1 collection box

 

Might be your problem as well 🤔

 

If the cars been laid up over winter and its not been out then the hydro Carbon reading are high but acceptable.

 

 

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'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬

1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? engineered by Roger King, on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension.

[Rob Walker]

If you can prove that the engine was manufactured/built before 1995 then it is exempt from any emissions testing at SVA and any future MOT.

[Rob Walker]

Bilbo,

 

What is your garage playing at trying to emission test a carbed engine ? Should only be a look at the tailpipe for any smoke.

[Bilbo]

Well since it always passes I never moan but I will if it ever fails. 😬 Normally they get a very good reading anyway and it would be nice to know if that ever changes.

 

---

'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬

1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? engineered by Roger King, on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension.

[Milesk]

I have proof that it is a 1992 engine and it does not need to meet the CAT requirements however it still has to meet certain Hydro Carbon limits.

 

When I had no lambda sensor on the HC were sky high

 

Now with the lambda sensor on it is doing its job however the ecu is I believe screing the figures up and are unable to secure a HC reading.

 

Miles