How to lower exhaust emissions?

[stoneageman]

good day,
my Fiat Punto failed it's MOT on emmisions today. What if anything can I do or change in the engine to lower the emissions? Besides that the car is in very good condition just a couple of small things I can do myself.
Is it the end, surely not! Cheers for any help

 

[freddiemercurystwin]

model, engine size, age, mileage, service history etc?

 

[Avocet]

Also what were the emissions results? In particular, the lambda and CO readings.

 

[stoneageman]

Fiat Punto 60s 1.2 1994 159690km
generally in very good condition, been well looked after. Bit of an oil leak, nothing serious(head gasket).
Results CO ticking over: 0.03% CO with acceleration: 0.54%
lambda: 1.01

 

[Avocet]

First of all, I notice you're in France. Are we talking about a UK MOT test here? (It's just that the French MOT test limits may be different)!

Anyway, assuming it's a UK test, those readings don't look TOO bad. The lambda is fine, as is the COat idle. The "acceleration" CO (which in the UK is called the "Fast Idle" test takes place with the engine held at about 2500RPM. That reading is too high for a UK MOT. I must say I am very suprised that the CO at idle is VERY low (0.03%) are you sure it wasn't 0.3%? Also, the lambda is not usually measured at idle, but at "fast idle".

Anyway, given that the lambda is OK, it means that the car's own computer doesn't think it is running too rich. I would therefore suspect the cat itself. HAve you had the car serviced regularly? You could also check to see if the air filter is clean.

 

[stoneageman]

double checked and yes it is 0.03% CO at idle. yes Iam in France and this is thier 'Cotrole Technique' which is every 2 yrs over here and cost 60 to 70 euros. If you fail you get 2 months to do the work and take a retest at 15 euros. I don't know much about how Englsh MOT's go now but I suppose they're not to different to over here.
I failed on:
1 CO too high
2 handbrake a bit to slack ( was at 13 and should be at18)
3 a headlight that needs slight adjustment.
Not much for 17yr old I thought and jobs I can handle (probably)
What started out as a straight forward tightening of the handbrake cables turned into a 'changing back brakes' job when I discovered that the screw that tightens them was already screwed up to the max. I took the back wheel off to get a better idea of the job in hand and to see what parts I need to order but couldn't get the 'hub' off. Every time I prized it open a bit it was pulled back into place. I presumed this was the cable and decided to stop and check it out here first. If I unscrew the screw that is up to the max, will I be on the road to glory? I've already changed the back brakes on a 405 SRDT Estate (which in my opinion was the best car I ever had) and I kow it's a bit fiddly but not bad with me hands me!
As for the CO emmisions, if I change the s.plugs, leads and air filter will that bring it down enough? I've never played with a cat. before but going for a look on internet
Thanks for any help!

 

[Avocet]

Ok, the handbrake. Yes, slacken the nut off. That's not the way to adk=just a handbrake anyway. You need to slacken if off and then you shoudl be able to take the rear brakes apart. I think they have a self-adjusting mechanism, but I'm not familiar with that model of car. You need to get it so that the rear brakes are adjusted at the rear wheels to the point where the wheels are almost binding a bit but not quite. After that, you take the slack out of the handbrake cable on the adjuster nut. If you don't, the leverage will be all wrong and the handbrake won't be very efficient.

As for the emissions, I don't know what the French limits are. The UK ones are 0.5%CO at idle and 0.3%CO at "fast idle". (about 2500RPM).

Changing the plugs MIGHT help (if you are very close to the limit. Changing the air filter might also help. I'm not sure changing the plug leads will help unless one or more of them are breaking down.

There isn't much to "play" with on a cat. It's just a lump of stuff inyour exhaust. Unfortunately, they are quite expensive too. You could make sure it gets absolutely STINKING hot (they work best when they are hot). If the car only does short runs under low load, a good thrash on an Autoroute might help too.

 

[stoneageman]

Intresting...........I only use this car to go to work. 200 km approx each week and I don't drive fast, ( too many country roads, tractors, sheep etc)
Thanks for your time and advice.

 

[Burnerman]

I guess some of the fuel additives could work but I'm with Avocet here.....I think this one would pass if the cat was at meltdown temperature - I've seen this before, and it passed.
Mind you it may have had something to do with the fact that I was accidentally treading on the sample pipe....
John

 

[Belle427]

it wouldnt hurt to give the engine a service and then a good italian tune up should cure it (or french in your case) !

 

[stoneageman]

thanks for all that.....got what I need to do that service but before I order the parts for the rear brakes..................
Unscrewed the adjusting nut under the handbrake ( that was screwed up as much as possible) got the hub off and found this;

Untitled

• stoneageman
• 3 Jun 2011
• 1

All looks perfectly normal but before I start working and spending, just wondered if its just the cables I need to change? Should I change everthing Thanks for advice!

 

[Burnerman]

All looks ok there - I assume the car has excessive handbrake lever travel?
If so, check that there isn't a snapped cable, and the self adjusters are ok. (That design is fairly reliable, as it happens). If they are both ok then its either new cables you need or drums too - if they are worn over their maximum allowed diameter.
John

 

[stoneageman]

cables are fine. How do I check the self adjusters please?

 

[Burnerman]

The adjusters look like the 'ratchetting quadrant' type, which are behind the left hand shoe, looking at your pic.
Basically if you had the shoes off you would check the pivots of the quadrants for rust / seizure, and also check the knurled surfaces of the quadrant - effectively they move apart when the pedal is pressed, and stay there due to the gripping action of the knurling. All this is fairly obvious with the shoes in your hand, but awkward as hell to describe
If you want to experiment, leave one brake side untouched, with the drum on, and gently press the brake pedal. You should hear the quadrants move apart with a clicking sound. You'll need to reset them afterwards, or the drum won't go back on.
Just a comment concerning the cables - they may look ok, but you can't tell if they have stretched or not.....
John

 

[stoneageman]

Will check 2 morrow............been a long day