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Mondeo Mot Failure Help Please

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Hi, I was hoping somebody could help, I have a Mondeo 2003 1.8 Zetec, a while back I put through an MOT to have it fail, the garage didn't really explain to much on what it failed on just emissions.

I am getting a lot of smoke coming from the exhaust, I have changed the plugs, leads and had a new head gasket put on.

I have copied the failure form out to see if anyone here could shed more light.
Results are below, thanks again for any help.


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What sort of distances do you drive? if its short local ones then carbon and c**p can build up, so when they revs the car up for the emissions it could throw it all out, this may cause high emissions.

May be worth sticking some additive in and giving it a good blast on the motorway before taking it back for retest.

There could be other reasons also, but brains not woken up yet so cant think of any, iom sure other members wil come up with some.

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Hi thanks for the reply, It has had some additives put in the car, can't remember name atm will reply once I find out, I have also tried redex and stem seal revivor.

I don't really drive it far, which is why I have now gone to a fiesta, It was mostly around 10/15 miles a day on average, but I did give it a good drive before taking it for an MOT, still no difference.


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mine failed on high hc's but funny when i brought the car i noticed that the air intake pipe was off cause not realizing why it was off till i put it on and it failed. took it off it passed.

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mine failed on high hc's but funny when i brought the car i noticed that the air intake pipe was off cause not realizing why it was off till i put it on and it failed. took it off it passed.

is your pipe still disconnected?. could be a bad maf sensor?

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failed on high hc and co

on those figures its running slightly rich

whats not really clear about your post is if the plugs/leads and HG were changed before or since this mot

going on assumption it was carried out before...then

could be coolant temp sensor, can explain how to test if necessary

dirty air filter

old oil or wrong grade of engine oil

that would be my first steps.

why was HG changed, what colour smoke and when is it happening

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I took it to one MOT station and the garage said it filled the the building with smoke so they didn't bother going through with an MOT,

they suggested to changed head gasket, and give it oil change (got correct oil from haynes manual for the car), that was done, I then changed air filter, changed plugs and leads also at that time.

Took if for the MOT again but to a different garage (the one posted above in the image) after the failure I then tried the additives and redex, took it back again and still failed.

After all that apart from changing the CAT I am clueless.

The smoke coming from the car looks blue'ish white.

I would be grateful if you could explain about the coolant temp sensor please.


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is it smoking less now than before? and was it blue smoke originally

blue tint to smoke is suggesting burning oil, when head was removed was there a reason found for oil burning? did any of the old plugs show any signs of oil contamination?

a fully working cat will only reduce CO by a max of 0.5/%

if engine has been burning oil then this can damage the cat and oxygen sensor, but they are hardier than people give them credit for [unless it has an aftermarket cat fitted} would be reluctant to condemn it yet as you lambda readings are normal so proves the system is trying to work...but they maybe on sluggish side...i noticed the oil temp measurement was bypassed, it maybe the engine wasnt at its peak temp, which could have improved your figures and indicated that cat/oxy sensors are indeed, ok, but sluggish.

testing the temp sensor is a simple resistence test.

disconnect plug, testing at sensor terminals

should see a reading of approx 28000 ohms on a cold engine, 2500 ohms on a hot engine.

with your mot readings, its the hot temp resistence you need to look closely at...anything above 3500 ohms with engine temp above 80degs could give you a higher CO

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As you can see from the test report your readings are pretty high.


CO readings should be 0.5%

Fast Idle-

CO readings should be 0.3%

HC readings should not exceed 200ppm (parts per million) at any time.

By the sheet your CO reading is 3.24% above maximum at idle and 0.27% and 0.4% at first and second fast idle.

Your HC readings are 220ppm and 76ppm over maximum on both fast idles.

The cause could be anything from these causes-

Bad fuel metering due to a fault at the ECU, duff oxygen sensor, vacuum leaks due to damaged pipes, faulty ignition system (plugs/HT leads/coil pack), the fuel mix is too rich due to a faulty injector or fuel pressure regulator, air injection problems caused by dirty filters/clogged manifolds/catalytic converter, damaged vacuum hoses and purge valves or even a faulty fuel cap.

I believe you said something concerning a faulty temperature sensor? that can be a major cause of high emissions as the engine thinks it's still warming up and will therefore inject more fuel as if an automatic choke was in operation equalling more fuel in the system than needed.

Blue/white smoke usually points to, as stated above, oil in the combustion system, that can be caused by a faulty head gasket or more commonly worn valve seals.

A compression or leak down test may be beneficial, a compression test can be carried out through the spark plug holes using a compression gauge, a leak down test involves either the head being removed and fuel being poured into the upturned cylinder head to see if any valves are leaking or the use of a different pressure gauge, again screwed into the plug holes and compressed air or nitrogen being fed into the cylinders to see if the piston rings are performing correctly.

At the end of it all the problem may simply be a dirty engine which needs a good flush with fuel additives or a Terraclean service which has been proven to reduce emissions drastically (about £100 at participating garages) but if the engine is not 100% then these cleaning products may not help much at all.

At the end of the day I'd recommend the services of a decent garage which should be able to pinpoint your problem far better than I can but I reckon that the fact your emissions are worse at idle than at fast idle strongly point to a idle over-fuelling due to a dodgy temperature sensor.

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is your pipe still disconnected?. could be a bad maf sensor?

yep still disconnected mine hasnt maf sensor its duratec 1.8 early so it comes direct off airbox no sensor.some1 suggested lambda sensor

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