Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure

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Fri 3 Feb 2012 12:07
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - Mondeoman97

My Mk2 97 Mondeo Ghia X 24V just failed its MOT on emissions (fast idle, Lambda and CO). I've also noticed that it's idling badly, can sometimes stall when warm. Ford are saying its the Cats, apparently there are three on the vehicle, 2 precats plus one main cat. I have found aftermarket main cats fairly cheaply on the web, but not the precats. Ford are still checking whether it's all 3 cats that are broken or just one/two of them. Ford want lots of money to replace all three cats (if in fact they all need replacing).
Questions:
1) Do all three cats need to be working to pass emissions testing?
2) If I just replace the back cat, will that work on its own with the others broken?
3) What might have caused the cat or cats to fail (fouled plugs, anything related to poor idle)?
4) Could the Lambda sensors be anything to do with it?
5) Any ideas on where I might source the front cats other than (expensively) from Ford?

Thanks!

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Fri 3 Feb 2012 13:19
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - unthrottled

1.) No. The pre cats exist for cold start purposes. Quite simply they get up to operating temperature faster than the main one. The MOT emissions test is carried out on a warm engine-so the main cat will be fine.

2.) Yes.

3.) MAF, Idle Air control valve or even a vacuum leak could be causing the fouled plugs and the lumpy idle

4.) I doubt it. lambda sensors have the authority to change the fuel trim by about +/-10%. That's enough to fail the MOT but not enough to give a lumpy idle or fouled plugs.

5.) Europarts seem to have one for £75. Is that better than Ford?

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Fri 3 Feb 2012 18:13
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - elekie&a/c doctor

Before getting involved with replacing the cats,I would suggest that the idle and poor running issues need to be sorted first.Any air leaks on induction or breather system will upset the emissions big time.Take a look at the hard plastic breather pipes that run behind the throttle body ,at the rear of the engine.These very often become brittle and fracture.I have owned 4 of these v6 mondeos and they should idle super smooth.Also never changed any cats on any of them,and all had done 150k miles.hth

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Sat 4 Feb 2012 14:13
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - injection doc

cam chains are a week point on V6 and can cause poor idling & Emissons failure.

Investigate why the idle is poor first.

The performance of the cats can be tested with an infared temp probe.

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Mon 6 Feb 2012 10:37
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - Mondeoman97

Thanks for all replies!

Will let you know

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Mon 6 Feb 2012 14:50
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - Mondeoman97

Ford have turned around and said there's a problem with the HEGO sensors and that needs to be fixed first (£440 if you please) before they can see if anything else is wrong. Does this make sense?

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Mon 6 Feb 2012 15:50
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - unthrottled

A HEGO is just a lambda sensor. That's a ridiculous price. I don't see how they can determine if the HEGO is faulty while the engine is lumpy.

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Mon 6 Feb 2012 16:02
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - injection doc

I agree with unthrottled, impossible to diagnose with lunpy running engine.

Sensors can be diagnosed with an ossilliscope , the cat efficency can be diagnosed with an infared thermal sensor & emmsion analyzer.

It sounds like ford will just fit sensors ! then cats then whatever else is wrong ! & a massive bill to follow,

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Mon 6 Feb 2012 16:34
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - jc2

IIRC four HEGO's on that car.

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Mon 6 Feb 2012 16:58
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - unthrottled

Well they can't all have failed! (unless both head gaskets are leaking coolant into the exhaust)

OP-what were the readings for the MOT emissions test?

Lambda, HC and CO

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Mon 6 Feb 2012 20:02
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - sandy56

I will suggest going to a BOSCH service center. I have found them to be helpful AND very knowledgeable before going down the FORD route of replacing everything.

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Tue 7 Feb 2012 09:51
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - Mondeoman97

Again, many thanks all for responses!!

CO HC and Lambda all failed on first fast idle, but passed on second.

1st CO 6.54, HC 209, lambda 0.827

2nd CO 0.20, HC 31, lambda 0.996

CO failed on natural idle 11.24

I don't understand if it can pass one of the tests, why not the others.

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Tue 7 Feb 2012 10:01
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - Mondeoman97

Also, thanks to sandy56 for suggesting Bosch as a place to go for diagnostics.

Injection doc you say "Sensors can be diagnosed with an ossilliscope , the cat efficency can be diagnosed with an infared thermal sensor & emmsion analyzer" where can I go to get these (S London, Surrey, Sussex) other than Ford? Does anyone have any other ideas as to where to get good diagnostics as Ford are being not only slow and fairly clueless but also want to rack up a big bill for me!

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Tue 7 Feb 2012 15:23
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - unthrottled

CO failed on natural idle 11.24

11.24% carbon monoxide! That must be about 50% rich or a lambda of 0.67

The second result seems to suggest that the cat is working.

The first fast idle is also way too rich-but not as bad as the natural idle. I think the values are out of the range of bad HEGOs. Bad MAF? (Mas Air flow Meter)

Any ideas, injection Doc?

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Tue 7 Feb 2012 15:54
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - injection doc

sounds like the first test carried out was before the cats were up to temperature.

The 2nd test where it passes at fast idle indicates the cats are working.

The idle test failure at 11=% is very high ! sensors will not cause mixture to be that high at idle.

I would check cam chains & vacum at idle, also check fuel pressure at idle, may have a dribbley injector causing excess fuel at idle. I would also suggest a live data check to make sure throttle switches are closing of at idle & coolant sensor temp is correct.

Has it had an oil change recently or is the oil contaminated with fuel, also make sure it doesnt have a K&N air filter, these play havoc with mixture issues, especially when inpregnated with oil

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Fri 10 Feb 2012 11:57
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - Mondeoman97

Once again many thanks to all concerned for feedback!

Witrh no Bocsh service centre nearby, I am still looking for a good diagnostics place near me, so all ideas most welcome.

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Tue 28 Feb 2012 18:23
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - Mondeoman97

So took the car to a (not that) nearby Bosch garage. They diagnosed one lambda sensor not working, swapped them over to make sure nothing else was broken, and then found that both worked (possibly had been a loose connection). Cats, MAF etc all appeared fine. Idle now steady as a rock, no hydrocarbon smell at warm idle and it passed MOT.

Thanks to all for advice received!

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Tue 28 Feb 2012 19:50
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - sandy56

Great news

thanks for letting us know the final result.

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Thu 1 Mar 2012 17:18
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - injection doc

Great to hear its fixed.

I would be a little suspicious of the sensors reducing the Co from 11.24% to normal. If the sensor was faulty or disconnected the would of defaulted to around 4% not 11.24%

I would have the fuel trims read in a few hundred ,miles and make sure they are within limits otherwise there is an underlying fault.

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Thu 1 Mar 2012 20:16
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - Mondeoman97

Again, many thanks for the advice.

I will get it checked again as you advise in a month or so.

Cheers!

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Thu 1 Mar 2012 20:44
Ford Mondeo Ghia X 24V Mk2 1997 - Emissions MOT Failure - unthrottled

I think the same. A broken lambda sensor should continue to read rich/lean no matter how much the fuel trim is altered-so the ECM puts limits on how much the fuel trim can be adapted in response to lambda sensor readings.

I'm glad it is sorted, but there must've have been another sensor (probably MAF/CTS that was dirty or shorting/open circuit. Perhaps re-seating the sensors sorted the problem. No need to worry!

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