MOT Failure any ideas???

Hi Guys,
Been on the forum a few months but first post. Sorry its a problem, looking for some suggestions.
Anyway took the car ('95 4.0se) up for its MOT last Friday.
FAILED;
NSF Lower Shock Bush
OSF Lower Shock Bush
OSR Lower Shock Bush
OSF Upper Ball Joint
Exhaust Emissions co at idle excessive
Exhaust Emissions co at 2nd fast idle excessive
Exhaust Emission Lamda Reading after 2nd fast idle outside specified limits.

So took the car home, ordered some parts which arrived for the Saturday.
Done the ball joint (pig of a job!) and shocks over Sat/Sun.
Raining all day Monday so thought i would give the emissions a miss.
Tuesday gave her a full service.
Wednesday, exhaust manifold gaskets arrived, (as there was a slight blow from the right bank) after a couple of hours managed to get the manifold off (awkward may i add!), turns out it was cracked where the branches come together (hence the blow!). Took it along to a mate who has a fabrication business, and he managed to get it welded up for me. Fitted it, and the blow seems to have dulled.

Anyway to cut a long story short, i was hoping that the fact it was blowing/in need of a service would have brought the emissions down, but not!
Was back in at the MOT station today (independant), they put it on the gas anayliser first to make sure it was ok, before doing the retest. But CO results are just as high. Lambda is fine now though. According to the tester this now comes down to the induction side of things as the lambda readings are ok rules out exhaust?

He tried to rig up what diagnostic equipment he has to get any codes, but obviously would not get anything without Testbook/Rovacom.

Tried phoning local diagnostic places, but NONE have the above. So now booked in to Main Dealer for Thursday (there goes the partial retest) for a half hour diagnostic check.

Do any of you guys in the know, have any suggestions that i could try in the meantime?

you dont say what it is petrol or doosel?

4.0 Petrol, mate

have you looked at maf senser? that would put your co up

I have tried disconneting the plug with the engine running. Then within seconds the car stalls, is this what it should do, other than with the currect software is there any way to check that it is doing it job properly? Also i noticed today that the breather hose from the plenum on the right hand side, was venting to atmosphere. i take it it should go into the right hand rocker, with the little plastic vacuum/oil separater in between? If so, do you have any ideas why anyone would of pulled the hose out and left it to vent?

it may have just not been put on fully maf sounds ok. i would put all pipes on as it should be, was engine warm when you unpluged maf?

The engine was up to temp when i pulled the MAF plug, that was a couple of days ago. i also made sure i gave it a good run this morning before i took it to the garage. I put the breather pipe as it should be today but that hasnt made any difference. If a component/sensor was gone, would the check engine light not be on? Im hopeing that the diagnostic check will shine some light on what the problem is. Even the garage couldnt give me any suggestions.

some times we miss the daft things have you changed the plugs?

I know what you mean mate, spend hours wondering what the problem is then kick yourself when you realise it was something stupid!
But plugs, leads and oil, along with air, fuel, pollen and oil filters have all been changed. In fact the spark plugs have been changed twice, as the first 8 i got were Britpart, and didnt seem to idle right, so i changed them all yesterday for NGKs.

Hi.
Sometimes the ecu's start overfueling for reasons best known to themselves....

Nick.

you can access the engine ecu with any iso 9141-2 compatible scanner, i access mine with my laptop and an elm327 cable bought off ebay. its limited to basic engine stuff but its cheap enough to buy and shows fuel trims, maf and lambda reading. you can also read and clear engine codes!

It's possible the car's had emissions problems before, removing the rocker breather could have been a dodgy attempt to drop the hydrocarbons count if it was sucking in too much oil vapour.

what where all the readings from the second emissions test lambda/hydrocarbons and co this always gives you a good clue as to the fault if its slightly high upto about 0.65% on co and others are within tolerence it will be the cats

The engine ecu will need an adaptive reset if its been tolerating an exhaust leak for a while,they do things for a reason - sucking in air through a crack will have made that bank show a very lean reading to the Oxy sensor.Now its been fixed it would take a long time for the long term trims to get back to a decent reading.

kernowdragon said:

It's possible the car's had emissions problems before, removing the rocker breather could have been a dodgy attempt to drop the hydrocarbons count if it was sucking in too much oil vapour.

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The hydrocarbon counts are ok, the two reading were (Limit) <200ppm (Actual) 103/94ppm.
I have to admit though, i took her for a 100 mile round trip today, and Fuel consumption has went up since refitting the breather, does it sound dodgy to you?

eightinavee said:

The engine ecu will need an adaptive reset if its been tolerating an exhaust leak for a while,they do things for a reason - sucking in air through a crack will have made that bank show a very lean reading to the Oxy sensor.Now its been fixed it would take a long time for the long term trims to get back to a decent reading.

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So hoping that the fault has been fixed. Once connected to testbook, i take it the dealer should be able to do this?
I still think there is a slight blow from somewhere, but manifold has been sorted, new gaskets fitted and manifold to downpipe flange cleaned and pasted.

ian24895 said:

what where all the readings from the second emissions test lambda/hydrocarbons and co this always gives you a good clue as to the fault if its slightly high upto about 0.65% on co and others are within tolerence it will be the cats

Click to expand...

Unfortunately i don't have a second printout for the last emmisions tested, as he didnt log on, so that he could check before he actually retested the car.

The first results are;

Fast Idle Test;
Engine Speed - 2734rpm PASS
CO - 2.89% !!!!! FAIL
HC - 103ppm PASS
\ - 0.947 FAIL


2nd Fast Idle Test;
Engine Speed - 2438rpm PASS
CO - 3.14% !!!!! FAIL
HC - 94ppm PASS
\ - 0.921 FAIL


Natural Idle Test

Engine Speed - 705rpm
CO - 2.41%

Hope this helps. Bought one of them Gunson Gas Testers, yesterday for some fiddling about, but they are useless, so took it back today!

gavbriggs said:

you can access the engine ecu with any iso 9141-2 compatible scanner, i access mine with my laptop and an elm327 cable bought off ebay. its limited to basic engine stuff but its cheap enough to buy and shows fuel trims, maf and lambda reading. you can also read and clear engine codes!

Click to expand...

Might try this, there are a fair few available on ebay.

think i paid about 30 or 40 quid!

Kraig said:

The hydrocarbon counts are ok, the two reading were (Limit) <200ppm (Actual) 103/94ppm.
I have to admit though, i took her for a 100 mile round trip today, and Fuel consumption has went up since refitting the breather, does it sound dodgy to you?

Click to expand...

The indicator of whether the breather was removed to lower the HC reading would be if it has significantly increased since you reconnected it, i.e. the unofficial second test result, if you can remember it?

Your MPG would naturally go up once the manifold was sorted if as suggested in other posts the mixture had been leaned off due to erronous sensor readings. Those same adaptive changes to the fuel/air mix could also now be leading to the high CO readings. An unfortunate side effect of fixing several things at once can be to confuse the issue as you're never quite sure which fix has had what result:doh:.