Hi all,

My 99Uk went in for the MOT today, and failed on the lambda reading. It has a full decat, dawes (1bar) and Forge VTA. I replaced the centre section with a "special MOT" one But the reading was 0.02 higher than the limit.

MOT man reckoned the lambda might need cleaning. Would this cause it? It had a new one 6 months ago so should be ok. What else would cause it?

I have replaced the original DV which should help.

MB

 

Forge would make it run richer Mark, dunno if that affects it ?

That little garage down Magna rd do all the Chapelgate scoob Mot's and all my interim servicing, sure they would try your car on their emissions tester without charging you for a full mot.

Is the lambda sensor a kosha scoob one or a Halfords special ?

 

Dump Valve will make no difference at idle. A centre section cat should easily have been enough to pass any MOT. A reading of 0.02 out??? If anything I highly doubt his equipment has been calibrated that recently anyway. SOunds like they simply wanted to take more money off you for a re-test

What was the actual reading you refer to anyway?? CO, CO2, ??

 

Cheers Shane, I tried them but they were busy. Might pop along and see if they will do it tomorrow. The place I went to do free re-tests so need to sort something out! Its a Subaru Lambda.

Stevie,

Not sure, Im assuming its the 02 reading, but don't know where they get it from. Must be the probe they stick in the exhaust.

The printout shows all at 2761 RPM (fast idle):

CO level 0.05% pass Max 0.3 %
HC level 5 ppm pass Max 200
Lambda 1.05 Fail Min 0.97 Max 1.03

Any ideas?

MB

 

Just done a search and it all seems to point to a nackered lambda or a leak. Ill tighten it all up tomorrow and maybe clean the sensor. Im sure its ok as its nearly new.

MB

 

Emissions test? Not sure if me car had one of them on its MOT. Maybe it did and I just forgot (or the mot tester did!).

 

1.05 is quite a long way out on lambda. The allowable range is 5 points and you are 2 points out.

Also check your MAF.

 

Who dredged this up?!

Thanks Pete, it scraped through on the lambda eventually, but only just. Would you mind looking at the post in G Technical titled "Fuel Presure Regulators" near the top at the mo.

Reason I ask is, my car has just developed a severe idle prob. Hopefully it will be fixed tom, but not sure what the prob is at the mo.

Its staying open loop for some reason...

MB

 

Hi Mark

That would also point to a deteriorating MAF. With the car on idle, unplug the MAF and see if the idle stabilises.

This test only works on 99-00 cars.

 

Thanks Pete,

It was the MAF, all sorted now

MB

 

 

HUMM...

Thats funny my friend had his my96 wrx wagon MOT'd today and it failed on the **** probe test, he has both cats so he called me to see what mine was saying.
Guess what my96 sti wagon failed also failed, i also have still got both the factory cats.

What do ya think about that?