6 replies to this topic

[M111OWW]

Ok, it's that time of year again, took the car for its MOT only to find it has failed emissions....

I usually have problems as its a John cooper modded car, and that's with high CO and HC

This time it's reversed, very low CO at 0.01% very low HC 0047ppm but high lambda 1.14..
Have checked exhaust for air leaks...

What could cause it to run lean?
There is a hint of misfire at light throttle cruise too...and next to no soot in the tail pipe..

Any thoughts as I'm stumped?..

It has a Lucas Lambda from mini spares that's only done 1500miles Max, have a gen Bosch on order just in case..

[M111OWW]

Plugged in my crypton ACT and the lambda voltage was stuck at 403mV, wiggling the lambda cable kind of got it working but let go and it returned to 403mV..

Interestingly, when I un plugged it the reader still showed 403mV which I'm hoping is a limp home/pre set figure, however I thought it would be set a little richer..

Pinching each fuel line while wiggling the cable saw it swing to righ and lean but quite slowly.

I'm still within my 12 month warranty with mini spares so back it goes....

I only hope I've not done any serious engine damage running it lean..

[minidaves]

whats  the temp sender saying? 

[M111OWW]

The temp sensor has always read low as there was a resistor fitted as part of the John cooper Si package, the ECU sees 70 degrees when fully warmed up....
I suppose it was a cheats method of making it run a bit rich...

[minidaves]

well it was just a thought, of course has the exhaust got a small hole in it? as that would mess it up just enough

Edited by minidaves, 01 April 2016 - 08:17 PM.

[FlyingScot]

Sounds like the lambda - did you check the heater circuit and relay for the lambda ?

FS

Edited by FlyingScot, 02 April 2016 - 09:27 AM.
Spelling

[M111OWW]

Plugged in an old sensor and it heated up ok, took the manifold out and inspecting the sensor two of the four wires appeared to be loose, as in you can move them in and out of the sensor while the other two were solid..

The relay box checks out good...