Mot Fail : Emissions yet again

tenkfeet · Post by **tenkfeet** » Tue Oct 10, 2006 1:14 pm

All is fine accept for the lambda reading limit 0.970-1.030 actual value was 1.179 .

Am I right in thinking first place to look is the flexi pipe in the exhaust ?

Co was 0.00% (limit is o.20ppm)
HC was 15ppm (limit 200ppm )

GregR · Post by **GregR** » Tue Oct 10, 2006 1:18 pm

yup

you do have a cat on don't you....?

tenkfeet · Post by **tenkfeet** » Tue Oct 10, 2006 1:26 pm

GregR wrote:yup

you do have a cat on don't you....?

Thats what the MOT tester asked. It only has had a Lotus sports exhaust fitted my understanding being it still has the cat.

GregR · Post by **GregR** » Tue Oct 10, 2006 1:29 pm

double check mate - it might have one of those silenced de-cat pipe jobbies on it. A cat is easy to spot with the tray off, so I'd say have a butchers before you go down the new flexi route.

If required, there's 2 flexis going at the mo on SELC*CK for not too high a price.

tenkfeet · Post by **tenkfeet** » Tue Oct 10, 2006 2:00 pm

GregR wrote:double check mate - it might have one of those silenced de-cat pipe jobbies on it. A cat is easy to spot with the tray off, so I'd say have a butchers before you go down the new flexi route.

If required, there's 2 flexis going at the mo on SELC*CK for not too high a price.

Trays are off and it has a cat . I cannot feel any blowing around the flexi section .My car has only done 12k miles all be it backwards on numerous occasions . Good spot for the Seloc exhaust cheers .

Stephen · Post by **Stephen** » Tue Oct 10, 2006 2:06 pm

Greg,
Do you still have my cat?

GregR · Post by **GregR** » Tue Oct 10, 2006 5:27 pm

Stephen wrote:Greg,
Do you still have my cat?

Sh!t Stephen - I completely forgot about that!! Yes I do still have your cat, and its still fitted on the car

I'll need to get it up on a ramp to get it off and get mine back in pronto!

Sorry about that mate

tenkfeet · Post by **tenkfeet** » Tue Oct 10, 2006 5:27 pm

I have taken the flexi pipe off and it looks ok bar some discolouration on the top . I filled it with water and there appear to be no leaks ( Not scientific I know ) I suppose it could still leak when heated and under pressure .

Anybody got any suggestions , could the sensors be duff? Or should I just bite the bullet and change the flexi .

mac · Post by **mac** » Tue Oct 10, 2006 5:33 pm

Tenk - If your getting that Lamda reading then I would suspect your post cat one has failed (they only have a 3 or 4 year life span).

Change that and get it re-tested - if it still fails either change the pre-cat one.

HTH

Mac

Stephen · Post by **Stephen** » Tue Oct 10, 2006 5:46 pm

no problem, It's just that it's coming to winter and the spiders need a home

tenkfeet · Post by **tenkfeet** » Tue Oct 10, 2006 9:27 pm

mac wrote:Tenk - If your getting that Lamda reading then I would suspect your post cat one has failed (they only have a 3 or 4 year life span).

Change that and get it re-tested - if it still fails either change the pre-cat one.

HTH

Mac

Cool I will give that a go as the exhaust appears ok .

robin · Post by **robin** » Tue Oct 10, 2006 10:40 pm

tenkfeet wrote:
mac wrote:Tenk - If your getting that Lamda reading then I would suspect your post cat one has failed (they only have a 3 or 4 year life span).

Change that and get it re-tested - if it still fails either change the pre-cat one.

HTH

Mac
Cool I will give that a go as the exhaust appears ok .

Testing the upstream lambda is easy enough with a multi-meter - once it's heated up and with car running you should see an alternating voltage flipping back and forth between near zero and around 1V once a second on two of the wires; the thinner ones; the thick ones are heater wires.

I imagine the same will apply to the post-cat one, except maybe you'll need to blip full throttle to make it pump a load of fuel in to cause that one to toggle?

Anyone actually had experience with testing downstream lambda?

Cheers,
Robin

tenkfeet · Post by **tenkfeet** » Wed Oct 11, 2006 10:00 am

Found this on Seloc Wicki for testing o2 sensors.

http://wiki.seloc.org/index.php/Lambda_sensor

tenkfeet · Post by **tenkfeet** » Fri Oct 20, 2006 2:14 pm

Mac I owe you a couple of beers . Cheers .

I replaced the Post sensor and it has just passed its MOT . They did come to say that it was going to fail then it came good by 0.02 . I think the pre one maybe dodgy but that can wait till next year .

I tested the sensors with a heat gun and multimeter the post sensor would only put out 0.07 volts solid the pre one was 0.7 volts and jumped about as it should .

mac · Post by **mac** » Fri Oct 20, 2006 2:55 pm

Portugese MoFo's - just make mine with that pear ciders stuff this time

Mac