W124 1993 220TE MOT Emissions Fail Help

tjamesbo

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CLK430 ,Vito V6 sport ,Jaguar 2.5 X type ,W124's 1993 220TE , 1994 320TE ,Mastercraft X5
Any experts on diagnosing Emissions Problems I scraped through the MOT last year but despite Injector cleaner / Cataclean / OIl Change / Clean Air Filter / MAF cleaned with MAF cleaner / Coolant temperature sensor resistance checked / and a high speed italian tune up on the way and using Dipetane at the MOT it sadly failed as below. The Car drives Well / Idles well / Plugs look OK so I’m looking at the 16 pin diagnostic ( see my other post ) and then possibly checking the o2 lambda sensor voltages and maybe the MAF voltages if I can find the spec values and possibly thinking air leak? or cat has failed?
Any guidance appreciated
Thanks
Boyd
220TE MOT Emissions  Fail .jpeg
 
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Tuercas viejas

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First what is your MAF reading in Mg/Hub?
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Tuercas viejas

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As an aaddendum.
That Indian Fakire Lamdass in the ECM who speaks Lamdah language only! Is saying "You Mr Englishman have too much Oxygen @ 1.31 when I am very happy burning fuel prefectly at 1,00'! ".
You must investigate, look for air leaks first plus how much air is measured going ?
On behalf of Lamdass
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Tuercas viejas

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OK greetings again from Colorado, where once upon a time the New York Times called this state being full of Cornish & Welsh goldminers who were all mixed up with Bushwackers ! :D

So to your E problems .
You have excess oxygen and high hydrocarbons HC's out the tail pipe.
High HC's are the product of unburnt fuel condensing on the relatively cool cylinder walls and being swept out into the "zorst" by scavenging.
So first, a weak mixture diluted by excess air will not allow full flame propagation so you get molecules of unbunt fuel producing i'e HC's all recorded by Lambda (the O2's).
So from "Uz inth trade" ,this statement rings true in advanced diagnostics emission tutorials & State certification as a Master Tech :-

The O2s & the readout are a remarkable tools, beginning with lambda's meaning. Lambda represents the ratio of the amount of oxygen actually present in a combustion chamber compared to the amount that should have been present in order to obtain "perfect" combustion. Thus, when a mixture contains exactly the amount of oxygen required to burn the amount of fuel present, the ratio will be one to one (Ll) and lambda will equal 1.00. If the mixture contains too much oxygen for the amount of fuel (a lean mixture), lambda will be greater than 1.00. If a mixture contains too little oxygen for the amount of fuel (a rich mixture), lambda will be less than 1.00.

So the first thing to look at is inlet manifold depression & air leaks.
All the way from the air filter to the head & manifold joints, gaskets, hoses etc can develop air leaks including injector "O" ring seal at the inlet manifoid and EGR connections where appropriate.
Now here in Yankee Land we use a smoke machine to fill the induction tract with theatrical smoke and look for leaks when the engine is turned off.
You could do the Latin American way of having the engine up to hot running idle, and give suspect areas a spritz with caburetor cleaner. Don't go bloody mad, but listen to a change in engine tone as you lightly spritz a suspect area.
Now its also useful to know what the MAF is doing, but you will need a scanner for this and ask what is the cylinder pumping efficiency.
If the engine internals are worn it won't suck as much air as it should even if turbocharged. So what the MG/Hub reading which is a direct indication of cylinder filling and fuel mapping & correlation. Briefly if the MAF can't read the air flow properly it won't adequately trim the fuel in the short term trims STFT's and working in conconjunctioon with the O2's to produce the long term LTFT's all set by the ECM fuel map.
Now in your case the engine is 2,2 litre or 2200 ccs X it by 1,5 which is the rule of thumb of MG/Hub figures, or 330 by dropping the end zero.
So what is your Mg/Hub figures at idle & 2500 r/m.
MAF reading 330 Mg/hub or what?

Now I see from the failure sheet, the car has a recorded 1/4 million miles.

Is that genuine mileage or has car had a new engine/major repair during that period?

As statement to think about :-
Here's the magic: Lambda is completely unchanged by combustion. Even complete combustion or a total lack of combustion has no effect on lambda! This means we can take our exhaust gas samples at any point in the exhaust stream without having to worry about the effects of the catalytic converter.

So here's a few things to also consider:-
  • CONVERTER REQUIRES LAMBDA TO BE BETWEEN .98 AND 1.02 TO LIGHT OFF BUT WILL NOT WORK AT PEAK EFFICIENCY UNLESS LAMBDA IS BETWEEN 0.995-1.005
  • HIGH HC READING CAN RESULT IN EXCESSIVE CARBON RESTRICTING THE CONVERTER
  • IF HIGH HC READINGS EXIST ALONG WITH O2 READINGS, (not shown in your case ) A MISFIRE OR CYLINDER IMBALANCE MAY BE INFERRED - THIS MAY CAUSE THE CONVERTER TO OVERHEAT AND THE SHELL TO GLOW RED AND DISCOLOR, RESULTING IN SUBSTRATE MELTDOWN
  • LOWER HC READINGS ARE ALWAYS BETTER FOR ENGINE AND CONVERTER EFFICIENCY.
See what make of all this and ask questions if you need to.
Amistades
Tuercas Viejas
 
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tjamesbo

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Messages
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CLK430 ,Vito V6 sport ,Jaguar 2.5 X type ,W124's 1993 220TE , 1994 320TE ,Mastercraft X5
OK greetings again from Colorado, where once upon a time the New York Times called this state being full of Cornish & Welsh goldminers who were all mixed up with Bushwackers ! :D

So to your E problems .
You have excess oxygen and high hydrocarbons HC's out the tail pipe.
High HC's are the product of unburnt fuel condensing on the relatively cool cylinder walls and being swept out into the "zorst" by scavenging.
So first, a weak mixture diluted by excess air will not allow full flame propagation so you get molecules of unbunt fuel producing i'e HC's all recorded by Lambda (the O2's).
So from "Uz inth trade" ,this statement rings true in advanced diagnostics emission tutorials & State certification as a Master Tech :-

The O2s & the readout are a remarkable tools, beginning with lambda's meaning. Lambda represents the ratio of the amount of oxygen actually present in a combustion chamber compared to the amount that should have been present in order to obtain "perfect" combustion. Thus, when a mixture contains exactly the amount of oxygen required to burn the amount of fuel present, the ratio will be one to one (Ll) and lambda will equal 1.00. If the mixture contains too much oxygen for the amount of fuel (a lean mixture), lambda will be greater than 1.00. If a mixture contains too little oxygen for the amount of fuel (a rich mixture), lambda will be less than 1.00.

So the first thing to look at is inlet manifold depression & air leaks.
All the way from the air filter to the head & manifold joints, gaskets, hoses etc can develop air leaks including injector "O" ring seal at the inlet manifoid and EGR connections where appropriate.
Now here in Yankee Land we use a smoke machine to fill the induction tract with theatrical smoke and look for leaks when the engine is turned off.
You could do the Latin American way of having the engine up to hot running idle, and give suspect areas a spritz with caburetor cleaner. Don't go bloody mad, but listen to a change in engine tone as you lightly spritz a suspect area.
Now its also useful to know what the MAF is doing, but you will need a scanner for this and ask what is the cylinder pumping efficiency.
If the engine internals are worn it won't suck as much air as it should even if turbocharged. So what the MG/Hub reading which is a direct indication of cylinder filling and fuel mapping & correlation. Briefly if the MAF can't read the air flow properly it won't adequately trim the fuel in the short term trims STFT's and working in conconjunctioon with the O2's to produce the long term LTFT's all set by the ECM fuel map.
Now in your case the engine is 2,2 litre or 2200 ccs X it by 1,5 which is the rule of thumb of MG/Hub figures, or 330 by dropping the end zero.
So what is your Mg/Hub figures at idle & 2500 r/m.
MAF reading 330 Mg/hub or what?

Now I see from the failure sheet, the car has a recorded 1/4 million miles.

Is that genuine mileage or has car had a new engine/major repair during that period?

As statement to think about :-
Here's the magic: Lambda is completely unchanged by combustion. Even complete combustion or a total lack of combustion has no effect on lambda! This means we can take our exhaust gas samples at any point in the exhaust stream without having to worry about the effects of the catalytic converter.

So here's a few things to also consider:-
  • CONVERTER REQUIRES LAMBDA TO BE BETWEEN .98 AND 1.02 TO LIGHT OFF BUT WILL NOT WORK AT PEAK EFFICIENCY UNLESS LAMBDA IS BETWEEN 0.995-1.005
  • HIGH HC READING CAN RESULT IN EXCESSIVE CARBON RESTRICTING THE CONVERTER
  • IF HIGH HC READINGS EXIST ALONG WITH O2 READINGS, (not shown in your case ) A MISFIRE OR CYLINDER IMBALANCE MAY BE INFERRED - THIS MAY CAUSE THE CONVERTER TO OVERHEAT AND THE SHELL TO GLOW RED AND DISCOLOR, RESULTING IN SUBSTRATE MELTDOWN
  • LOWER HC READINGS ARE ALWAYS BETTER FOR ENGINE AND CONVERTER EFFICIENCY.
See what make of all this and ask questions if you need to.
Amistades
Tuercas Viejas
Thanks for that very detailed explanation Theres a lot for me to check there but it has to be done to keep these cars alive I'm going to start this weekend what is an Mg Hub Reading ? inlet vacuum ? something on a scanner ?
 

Tuercas viejas

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Lambda sensors also have a limited life span and can cause incorrect fueling when old.
Yes absolutely, but don't change them in isolation & not for the heck of it.
I have seen Bosch O2 (lambda sensors) still working fine after 250,000 mies.
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Tuercas viejas

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Thanks for that very detailed explanation Theres a lot for me to check there but it has to be done to keep these cars alive I'm going to start this weekend what is an Mg Hub Reading ? inlet vacuum ? something on a scanner ?
MG/Hub is the MAF air flow measurement of actual air flow through the unit , either in a metric measurement or in lbs of air being sucked into an engine.--any engine . The ECM needs that info to calculate a fueling map.
Again, as a rule of thumb the engine swept volume multiplied by the factor of 1,5 less the last digit is a quick and simple way to assess how the engine is working.
In short ! Is it an asthmatic dog or Husain Bolt ?
Its usually found on a scanner in the EGR pids .

When I/We see cars like this with high mleages on them the first thing is to base line the engine ,
Check compression figures and cylinder balance, (miss-firing maybe) level of maintenance filtration and condition of the inlet & exhaust system.
Even crankase oil can be heavily contaminated with HC's, from blow by and PCV arrangements which not only allow HC laden air into the induction system but distort tail pipe figures.

Here is a list of possible problems areas and causes for you to investigate, courtesy of Envirotest who are contracted by Colorado State to conduct annual & bi annual emissions test or gasoline (petrol) driven vehicles. As an emissions shop we have to be certified by , the state to be able to "do the knowledge" on E failures.
Maybe this will be useful to you:-
All the best / hasta luego
Tuercas viejas
 
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tjamesbo

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Thanks thats most helpful a lot for me to go through but a very thorough list 👍
 

Tuercas viejas

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Thanks for that very detailed explanation Theres a lot for me to check there but it has to be done to keep these cars alive I'm going to start this weekend what is an Mg Hub Reading ? inlet vacuum ? something on a scanner ?
Just to re-cap.
Finding the Mg/Hub with a suitable scanner can reveal a lot about the vehicle when running at idle & at rated speed under load .
Now let's look at a diesel, say a 2,7 litre Sprinter .
2700cc X 1.5=405 Mg depending upon model spec, & always see 365 to 450 mg/hub at IDLE . (ball park figure based upon wear, tune/remapping etc.)
If its drastically low , first look at the air filter or maybe the inlet hose, maybe the turbo!
In any case "zummuts up" if its drastically out of whack!
Now drive it under full power and observe the Mg/Hub readings
Obviously the engine will be "rocking baby" and drawing in lottsa air, so you should see 1200 to 1250 Mg/hub for this 2,7 litre oil burner . .
If its continually of a low reading across the board or flat lined, its time to look at the MAF unit itself, or maybe the induction system or exhaust flow !........In fact the state of mechanical condition of the engine internals including the turbo should not be overlooked. .

This can be a useful tool when buying a car, or when I am doing a pre-puchase inspection for customer with a MB.--or a Landrover (being an "enfusiast" of both marques)!
This simple test will confirm or debunk boasting claims by the seller, or barefaced lies about the state of the engine!!:eek::oops:
Arfur Daly's ,y Snr Carros Trucos con Carcachas better beware, when doing the knowledge ! :cool:
Amistades
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