Mechanics advice please ?

[TaxiDriver]

I know we have a few mechanics out there so I'm hoping I might pick someone's brains,

I have a 54 plate Petrol 1.8 Mondeo that's just failed MoT on emissions due to excessive Hydrocarbons,

The tester says this is most likely due to failure or blockage of the Catalytic converter, Also a good service, oil change, air filter, plugs along with cat replacement should fix it ?

Only other issue is a coil Spring broken but I don't wanna spend and find I can't get the emissions back to a passable level.

 

If I can't get it sorted out then I'm car less and going to lose my holiday for the second year running, last year was coz I got run over, this year because I can't tow my camping trailer up to Norfolk if I can't get the car fixed as cheap as possible.

[armsid]

servicing should help and cat replacement also try oxygen sensor but these are not cheap without seeing readings and any smoke from exhaust it can be hard to tell could be oil smoke causing high readings sometimes a good blast down the road gets the cat working .short stop start journeys do the cat no good at all many a time i have had to drive a car hard to pass smog test . try plugs filter oil and air cat and oxygen sensor take for a good blast and then ask tester to check after run when engine is really hot not cold as affects outcome of test atb alan

[hodge911]

is there any and I mean any blows on the exhaust as the slightest leak from the exhaust raises the HC .

is there a misfire at low revs as this can increase the HC

HC is unburnt fuel it can be also up if the air filter is very dirty .

before replacing the cat I would change oil and all the filters put a bottle cataclean threw it by putting the bottle in the tank and taking it for a good thrash up motorway keeping the engine revs up .

well that's what I would do

[TaxiDriver]

servicing should help and cat replacement also try oxygen sensor but these are not cheap without seeing readings and any smoke from exhaust it can be hard to tell could be oil smoke causing high readings sometimes a good blast down the road gets the cat working .short stop start journeys do the cat no good at all many a time i have had to drive a car hard to pass smog test . try plugs filter oil and air cat and oxygen sensor take for a good blast and then ask tester to check after run when engine is really hot not cold as affects outcome of test atb alan

Alan,

Cheers, car does get plenty of mixed driving, even around town it's enthusiastic drives well, mpg is on par with what's suggested, no real visible smoke even when thrashed,

[subsonicnat]

It sounds like a sensor mate,what was your reading last time,high,low.?.

A mate had similar problems,Turned out to my best guess after looking at it for 3 hrs..

Changed it,,get an off market one off the Bay,you will have to solder it.

But do a proper job soldering and heat shrink,or it will not work..

Quick Trick,,Like the old engines PULL The leads off one by one,They probably have them on the exhaust as well,,TAKES TIME...

If it runs rough its ok,if no change give it a thought it may be it but carry on and check them all..

As said,if its only a bit over put a cleaner through the Fuel,and give it what for on the motorway or bypass,,,it works wonders..I used to take loads of cars for an MOT For my mate.

Thraped them down the bypass,always seemed to work,,even if it Failed he would take it aout himself and give it another thrashing,,9/10 it would Pass..

Best of Luck.

[TaxiDriver]

Trouble is now it's recorded as failed MOT and MoT has expired,

I can't thrash it up the road after using anything like Cataclean.

It starts and runs perfectly, As I said the mpg is about right given that manufacturers figures are always a tad optimistic.

 

I can get a Cat for approx £80-£90 plus getting it swapped out, air filter is about a £10

Edited June 12, 2017 by TaxiDriver

[Dave-G]

If there is any time left on the original MOT you should be good to use it - I try to get mine done a few days before expiry date.

[hodge911]

you can get a mot done 30 days before the expiry date of the old one and if it passes the 30 days are added on so you can actually have a car with 13 months mot and if it fails you still have a valid mot to run on whilst getting the repairs done

[BrowningB525]

As long as the existing certificate is still valid, you should be able to give if a thrash.

 

If there was a dangerous defect, not so much.

I'd avoid cats that cheap (unless that's a used genuine price) they rarely last.

 

I'd also be more concerned about an o2 sensor or leak than the cat for now. Especially if the co was fine on the test.

[Dellbert]

A new failure cancels the existing time .

was it just hydrocarbon level high or co and lanbda too ?

If just hydrocarboms its likely to be unburnt fuel or engine oil

Is the car regularly serviced ? if not do it all filters new oil and new plugs ,check that all the plugs look the same colour .

Put some cataclean or similar in the fuel (concentrated) and when you take it for a booked mot (legal to do) drive it like youve stolen it and get it hot .

You could ask the garage to check the lambdas (if they know how)

[TaxiDriver]

Delbert,

The tester mentioned a good service including the oil & filters but I didn't understand how oil in the sump/engine effects emissions out of the exhaust

Surely IF it was burning oil it'd be smoking like a wotsit ?

 

Car isn't serviced at all engine wise other than refilling consumables like washer bottle and checking the oil level and brake fluid and power steering levels.

[fortune]

Several people have suggested thrashing it up the road. Be careful of this. A. You could wreck the motor. B. You don't need to be driving it at a hundred miles an hour and have an accident or get done for speeding ect. Do the filters, oil ect and​ Get it hot on the drive or wherever and give it a series of high RPM runs (without going into the red) do the filters. If it runs a bit lumpy on tick over, see if you can raise the idle a bit if possible. It only needs a bit of uneven running to really raise the emissions. Ask if they can do an emission test without mot testing When you take it in and make sure that it is well hot. Drive it in a low gear with high RPM. If the test Is 10 o'clock take it in at 10 o'clock so that it doesn't sit there and get cold. All as per post #2. Just don't stack it up the road or no holiday.

Edited June 12, 2017 by fortune

[hodge911]

Several people have suggested thrashing it up the road. Be careful of this. A. You could wreck the motor. B. You don't need to be driving it at a hundred miles an hour and have an accident or get done for speeding ect. Do the filters, oil ect and​ Get it hot on the drive or wherever and give it a series of high RPM runs (without going into the red) do the filters. If it runs a bit lumpy on tick over, see if you can raise the idle a bit if possible. It only needs a bit of uneven running to really raise the emissions. Ask if they can do an emission test without mot testing When you take it in and make sure that it is well hot. Drive it in a low gear with high RPM. If the test Is 10 o'clock take it in at 10 o'clock so that it doesn't sit there and get cold. All as per post #2. Just don't stack it up the road or no holiday.

to clarify my statement .

I have used the word thrash as a figure of speech and apologise if its been taken in the wrong context , what I mean is take it for at least a 10 mile trip at an elevated rpm to what yo would normally be doing at 70mph

so if in top gear at 70mph your engine is 3/3500 rpm come down a gear for a couple of mile at a time so your doing about 4/5000 rpm this will increase the temp slightly along with a slightly higher fuel pressure ect and help reduce the emissions .

i.m.o letting it sit idling to get hot may cause hot spots on the combustion chambers of the head / pistons [ we had a trade mag circulated round the m.o.t stations by vosa informing against long periods of idle to reach required temp for emission tests]

Edited June 12, 2017 by hodge911

[rovercoupe]

Do you know how much it failed on? I cannot reccomend it but if it was close then a service and do the mot without the air filter in might get it through. I wouldnt do it on a expensive car but its been known to work on a car that has nothing to lose.

[hodge911]

A new failure cancels the existing time .

was it just hydrocarbon level high or co and lanbda too ?

If just hydrocarboms its likely to be unburnt fuel or engine oil

Is the car regularly serviced ? if not do it all filters new oil and new plugs ,check that all the plugs look the same colour .

Put some cataclean or similar in the fuel (concentrated) and when you take it for a booked mot (legal to do) drive it like youve stolen it and get it hot .

You could ask the garage to check the lambdas (if they know how)

taken from vosa website so I would say as your vehicle only failed on emissions it is not in a dangerous condition and will be fine to take for a drive with some cataclean in it as long as your old one is still got date on it

Driving a vehicle that’s failed

You can take your vehicle away if your MOT certificate is still valid.

If your MOT has run out you can take your vehicle to:

• have the failed defects fixed
• a pre-arranged MOT test appointment

In both cases, your vehicle still needs to meet the minimum standards of roadworthiness at all times or you can be fined.

You can be fined up to £2,500, be banned from driving and get 3 penalty points for driving a vehicle in a dangerous condition.

[TaxiDriver]

Do you know how much it failed on? I cannot reccomend it but if it was close then a service and do the mot without the air filter in might get it through. I wouldnt do it on a expensive car but its been known to work on a car that has nothing to lose.

It's never previously been an issue at all, in fact last year the tester commented on the good emissions level which was why it hadn't occurred to me it might be any issue this year.

I figure a dirty/blocked air filter would restrict air intake thereby affecting the air/fuel ratio giving a stronger fuel content ?

I think I'll do an oil & filter change, see if I can cobble enough together to change the Cat' and speak to the garage about an emissions check before I fork out on coil springs.

[TaxiDriver]

@ Hodge911

 

Thanks, It could be argued that it is dangerous/unroadworthy as it also has a broken front coil Spring (heaven knows how long it's been like that)

Edited June 12, 2017 by TaxiDriver

[ferguson_tom]

I would have a chat to your MOT inspector and see if he can put it on the emission testers as soon as you arrive and take the long route there to get in really hot. Not sure if it works with petrols but i know a few older lorries that always have to be rather warm to pass the MOT. If its only just over take it to another test station, supposidley the testers are calibrated but i know an MOT station where if it doesnt pass on one they try it on the other and more often than not they go through. If it passes the emissions it will then fail on the spring but you can then get that done as they will only inspect that when they re-mot it rather than doing a full test.

[db135]

If you can get them to put a decent computer on get them to go on live data with the engine running the up stream lambda should be switching and down stream lambda should be a steady 0.83volt if the lower lambda is switching to the cat is goosed

[Dellbert]

Delbert,

The tester mentioned a good service including the oil & filters but I didn't understand how oil in the sump/engine effects emissions out of the exhaust

Surely IF it was burning oil it'd be smoking like a wotsit ?

 

Car isn't serviced at all engine wise other than refilling consumables like washer bottle and checking the oil level and brake fluid and power steering levels.

Most modern oils are synthetic so the old smoking engine thing is reduced ,do a proper service and drive it hard to the mot (ie hold it in the gears longer etc) but your old mot is now void and except for taking it for repair and retest the car is illegal to drive or park on the road .

[HAYBURN]

You really need to see the full readings to get a better idea, as above if you haven't done an oil change you should add an oil flush

to the oil and don't thrash it, drive normally get engine to full temp. change oil,oil filter,air filter. you may also have a engine misfire and

not know..

 

how high is the hc reading..think the max is 200 parts per million

[gustaff]

what are the print out readings if co and hc readings are high and lambda is ok the catalyst is not working if the co and hc are within limits and lambda high exhaust leak after cat some where if co out hc ok and lambda low possibly lambda sensor umpteen scenariaos post print out results and car age

[TaxiDriver]

how high is the hc reading..think the max is 200 parts per million

'Fast Idle Test the 'actual value' was 504ppm (max limit is 200)

2nd Fast Idle test. 'Actual value was 731ppm (Max limit is 200)

[TaxiDriver]

what are the print out readings if co and hc readings are high and lambda is ok the catalyst is not working if the co and hc are within limits and lambda high exhaust leak after cat some where if co out hc ok and lambda low possibly lambda sensor umpteen scenariaos post print out results and car age

Car is Late 2004 with 146437 miles recorded.

FAST IDLE TEST.

CO %vol Max limit 0.300 Actual 0.988 Fail

HC ppm vol. Max limit 200. Actual 504. Fail

Lambda. 0.950 -----1.090 max. Actual 0.956 Pass

 

2nd Fast Idle Test

CO %vol. Max 0.300 Actual 3.455 fail

HC ppm vol Max 200 Actual 731 Fail

Lambda. 09.50-------1.090 max Actual 0.874 Fail

 

Natural idle Max 0.500 Actual 0.225. Pass

[gustaff]

Car is Late 2004 with 146437 miles recorded.

FAST IDLE TEST.

CO %vol Max limit 0.300 Actual 0.988 Fail

HC ppm vol. Max limit 200. Actual 504. Fail

Lambda. 0.950 -----1.090 max. Actual 0.956 Pass

 

2nd Fast Idle Test

CO %vol. Max 0.300 Actual 3.455 fail

HC ppm vol Max 200 Actual 731 Fail

Lambda. 09.50-------1.090 max Actual 0.874 Fail

 

Natural idle Max 0.500 Actual 0.225. Pass

possible air leak induction side or a bad injector as hc a mile out looks like lambda sensor over enriching to compensate