Renault Clio failed emissions test!!!

[v8benji]

Hi All,

This is my first post here so hope somebody can help .

Took my Clio (M reg 1390CC 'RT' model) for an MOT earlier which it failed on various easy-to-fix things, plus emissions, which is not easy for me as I cant see it working therefore I don't understand it!!!

The test printout reads:

Result                                    Diagnosis Limits
                                              Min       Max
Engine Oil Temp             90                 80        -

Fast Idle Test                       FAIL

Engine Speed               2624rpm   PASS    2450       2850
CO Level                   0.73%     FAIL      -        0.30
HC Level                    344ppm   FAIL      -         200
Lambda                      1.00     PASS     0.97      1.03

Second Fast Idle Test                FAIL

Engine Speed               2733rpm   PASS    2450       2850
CO Level                   0.73%     FAIL      -        0.30
HC Level                     65ppm   FAIL      -         200
Lambda                      1.01     PASS     0.97      1.03

Natural Idle Test                    PASS

Engine Speed                825rpm   PASS     750        900
CO Level                    0.25%    PASS      -        0.50

This must be clear as day to many on here, please advise - I would be very grateful - All i've had from the MOT station/garage is that they can start investigating but can't give any idea of price until they've had a bit of a look, for which they want an hourly rate obviously and they don't sound the most trustworthy lot in the world tbh. If someone can hit the nail on the head from this then that would be sound .

cheers in advance all,

Ben

[DaveL485]

I'd stick a CAT on it I think.

[944fan]

The high CO and HC could indicate that you have incomplete combustion, or that your cat (if you have one fitted) is not functioning correctly. Incomplete combustion could indicate a problem with the ignition system, if the car feels ok and is not miss firing then it is probably the cat.

[autopium]

Assuming there is no warning light on the dash I'd agree on the cat.

[smoking ron]

Same as the last few posts assuming the engine is running as should be i,e no misfire, then your def looking at new cat. If running lumpy will need to be looked into and figures are not much help.

[Mr2Mike]

Check the oxygen sensor voltage, it should be switching high (>= 0.8v) and low (<=0.2v) 2 or 3 times a second if the closed loop system is working properly. If this is working normally, then the cat is likely to be dead. If it's stuck high then it's indicating a constant rich mixture, which would rule out the cat as the cause (though it might still be dead from overheating in this case). In this case you'd probably want to check the other sensors, especially coolant temperature.

[jagracer]

Have you serviced the car recently, plugs and air filter would be the first things to check before you go to the hassle of changing the cat.

[Defcon5]

Has it had an extended Italian tune up recently?

[thisisnotaspoon]

changed the air filters recently? Usually a good cheep and cheerfull place to start. Then plugs, leads, coil.

Stick some redex in in the carbs, and a big glug in the petrol tank. Take it for a blast down the motorway keeping the revs high, that'll burn off a lot of crap in the engine and often gets older cars through the MOT. We got an old diesel estate through doing this for three years after it first failed.