Failed MOT on emissions

[besidetheseaside]

Hi Guys, Looking for some more help please
Volvo 2.0 Turbo, B200FT, red block engine, 1993, 217,000 miles.
Surprisingly failed the MOT today on emissions, CO value on fast idle was 0.67 compared to 0.18 last year, limit is 0.20%. MOT guy spotted a very very light misfire (which I had not noticed ) so I am going for the obvious,

4 new plugs ECP list 2 NGK options ???
air filter
oil and filter already changed this month
new lambda sensor ( I have one in stock )
check for vacuum leaks
refit exhaust, very slight blow on back box.

Any further tips on what to check/clean/replace will be gratefully received.
Thanks, Don.

[griston64]

Check leads if misfiring.

[classicswede]

I would do the basics of plugs, leads, cap and rotor as a start.

Monitor the lambda sensor to see what it is doing before considering changing it

[besidetheseaside]

Leads rotor arm and dizzy cap were replaced a few years ago but I will check them and replace if necessary.

[jack taylor]

Hi, The readings on my 1998 V70 were up on last year and it failed ITV [ mot ]
A few people on here reco`d Forte advanced formula gas treatment. I threw a bottle into half a tank about a week before re-test and gave the car an Italian tune-up enroute to the test. Levels had dropped and it passed. Given the price of forte it may be worth a try; nothing to lose. jack

[Laird Scooby]

All items on your list including the new Lambda sensor, given the mileage (217k) there's a fair chance it's the culprit, they only have a service life of 100k miles or 10 years. Cats only last a similar lifetime but can often be recovered with Cataclean or similar (someone mentioned the Forte Advanced Gas Treatment, similar stuff, does similar things) and an Italian Decoke.

Before you start adding the new parts, pull fuse #1 out and leave it out while you add the new parts, replace afterwards before starting. This will erase the fault codes in the ECU memory giving it a "clean slate" to start with so the ECU can take advantage of the new Lambda, air filter, plugs etc and tune the engine for optimal emissions.

May also be worth checking that when the throttle is released, as it returns to idle position it oerates the idle switch in the Throttle Position Switch (TPS). This can be done easily by opening the throttle by hand (engine off) and slowly releasing it and listening for a click from the TPS as it returns to idle position.

Last thing, clean the MAF and make sure there aren't any blockages in it, sometimes with certain air filters there is a layer of foam that disintegrates and blocks the MAF - use carb cleaner or if you can find it, MAF cleaner, squirting it through both ways.

Good luck and keep us posted!

[Dirty Rooster]

I had the same engine, now mine's 1991.

Originally Posted by besidetheseaside

Volvo 2.0 Turbo, B200FT, red block engine, 1993, 217,000 miles.
Surprisingly failed the MOT today on emissions, ...

Last year emissions failed, whipped out the air filter, retested : Pass
No way to explain it, but worth a try.
This year passed with air filter in.

Definitely seal that exhaust blow, such things played havok with my emissions in previous years!

What do the MOT garage guys say about a new CAT maybe?

[besidetheseaside]

Originally Posted by Dirty Rooster

I had the same engine, now mine's 1991.

Last year emissions failed, whipped out the air filter, retested : Pass
No way to explain it, but worth a try.
This year passed with air filter in.

Definitely seal that exhaust blow, such things played havok with my emissions in previous years!

What do the MOT garage guys say about a new CAT maybe?

Cat has been replaced a couple of years ago so should be ok.