scoobyricht

iTrader: (4)

Hi all

The girlfriends 106 went in for MOT on sat and failed only on emissons. tester said it was missing badly and needed a new set of plugs... so got new plugs and gapped them to 0.9mm. pulled the old ones out and checked the gap, they where all about 1.4mm! upon starting it seemed to idle and sound lovely.

Went back in for a retest today and the tester said it was worse than before.

The readings from the 2nd test are

fast idle1
CO 1.6%
HC 410ppm
Lambda 1.090

Fast idle2
CO 0.92%
HC 340ppm
lambda 1.077

the car was roasting hot going in for the test.
no modifications at all with the standard cat.

What are your thoughts on why the readings are so high and what can be done?


Thanks

Rich

yoza

My mate runs a MOT station, or did until he left the country, he always gave a car that failed its emissions an 'Italian Tune'....which was a 10 minute warp drive, 9 out of 10 times lowers the emissions.

Jamescsti

Shove a rag up the exhaust and do the emissions test then! lol

ALi-B

iTrader: (1)

HC a bit high. So its putting out unburnt fuel (possibly a lean misfire). What was the original test results?

Seeing you say the plugs were well past their sell-by. I'm guess this is a neglected car (poor thing ), so, have you checked any other basic service items?

Air filter? When was that last changed? (If its damp - bin it, and check intake pipe - make sure its not blocked or collapsed- especially the hot air duct from the exhaust manifold).

Intake hoses ok? making a good seal, that includes the vacuum hoses

Plug leads - original? They don't last forever, if its still running a bit lumpy worth checking out. Did you check the connectors? - have they gone green/blue (corroded) - are the rubber boots perished? Is the leads themselves good? any crack, nicked or cut, perishing, corrosion (no matter how minor) bin them (for the sakes of £17).

Exhaust leaking? (especially manifold before the oxygen sensor). It should be an automatic fail anyway, but the tester may have missed it if its minor. Pity the MOT results don't show the oxygen levels, as that would make it easier to spot.

I would like to check the fuel pressure after that, and then you might want to start checking out the sensors and stuff. Obviously by this point things are getting a little more complex to put into a brief post.

Final point to note; if the engine has been running in this state for some time (women - eh? ), then could be a chance that the excess unburnt fuel has killed the catalyst, but at the current moment you need to resolve whats causing those high lambda/High HC readings

scoobyricht

iTrader: (4)

Thanks for the replys people espceially Ali-B. I have changed a few few of the basic service things, plugs, airfilter oil and filter. looks like the plugs i pulled out where originals as are the leads. there is a bolt missing off the exhaust manifold so very possibly blowing.

Its going into a garage next week some time as Im in work all day all week.

Rich

scoobyricht

iTrader: (4)

Turns out the main cause of the high readings is a faulty exhaust valve on number 2 cylinder. there maybe other factors aswell such as lambda and cat but the garage has identified this problem... not sure ehat to do with it now as to repair the valve is going to cost a quoted 500 quid, mostly labour i would expect so i have thought about a recon or good 2nd hand cyl head.

Time to call around some breakers i think.

Rich

ALi-B

iTrader: (1)

I would expect to have the whole cylinder head reconditioned; if one valve is burnt/sticking, likely the others aren't far off, or it was victim to damaged by a previous cambelt failure and somone fitted a new belt was without checking for valve damage

Mind, if you can get a good head from a scrapper, then thats a good option. Plenty of decent written off 106s out there.

Simon K

I would ask around and find a more `forgiving` MOT tester. We all know someone that knows someone etc etc. I tend to use a certain MOT center when Im having a catless JDM supra mot;ed :-)

SBK

scoobyricht

iTrader: (4)

just a little update, After replacing the valves and having a skim the little pug is all back together and running like a dream but still failed on emissions and had a slight miss whilst holding the revs at 2500-3000.

Co 0.9%
Hc 50ppm
Lambda 1.03

Chatted to the bloke who didnt charge me and he said thats one hell of an improvement over the last test, get a new cat and it will sail through.

GMF supply a brand spanker at 54 inc VAT. pretty good.

pretty happy and the Girlfriend owes me loads