ask the indy first, no point spending on parts you don't need, luckily I have INPA and was able to watch what the lambda was doing before I swapped it out.
M.O.T. emissions - FAIL?
- Thread starter t-tony
- Start date
Just dropped car of with my indy. As no faults showing when diagnostics was run last week, he is now minded that it's the lambda also. That said, the lambda seemed to be working last week but whether it is effective enough. As the garage I bought the car from last year had put on a very cheap cat that was really too small for the engine to get it through a MOT, it is possible that they also put on a cheap lambda. Hopeful for resolution later on today, last date for retest is tomorrow!
ideally he needs to re-set the adaptations too, over a period of time the ecu will make tiny adjustments to fuel trim based on data from sensors, lambda being one of them.
if it has been ineffective the likelihood is the ecu has made adjustments to compensate (or at least try too), these will sort themselves out but maybe not instantly.
your new lambda will just carry on where the last one left off for a while.
don't know how long it would take, it may be fairly quickly, sorry don't know enough on this aspect but I cleared mine straight away just to make sure.
my new cheapo replacement lambda has a duff heat element so it was a case of a quick thrash first then it went through ok.
lesson learned - buy a bosh one with the original part number (being careful not to buy the after cat lambda for E36 as some list them as compatible).
hope this sorts your problem, I know how this feels, anything else is easily rectified but something like this is infuriating and costly.
mine was showing an error but was intermittent.
usually it would only throw an error every 30-50 car starts or there abouts, it took some investigating to pinpoint the lambda.
mine may have been (like yours hopefully) on the edge, near end of life.
if it has been ineffective the likelihood is the ecu has made adjustments to compensate (or at least try too), these will sort themselves out but maybe not instantly.
your new lambda will just carry on where the last one left off for a while.
don't know how long it would take, it may be fairly quickly, sorry don't know enough on this aspect but I cleared mine straight away just to make sure.
my new cheapo replacement lambda has a duff heat element so it was a case of a quick thrash first then it went through ok.
lesson learned - buy a bosh one with the original part number (being careful not to buy the after cat lambda for E36 as some list them as compatible).
hope this sorts your problem, I know how this feels, anything else is easily rectified but something like this is infuriating and costly.
mine was showing an error but was intermittent.
usually it would only throw an error every 30-50 car starts or there abouts, it took some investigating to pinpoint the lambda.
mine may have been (like yours hopefully) on the edge, near end of life.
For Lambda (air/fuel ratio) read Oygen sensor. If the O2 sensor in front of the Cat detects too much Oxygen in the exhaust it prompts the ECU to give more fuel to gain the correct reading which is measured by the O2 sensor fitted after the Cat (increase in fuel consumption) any air leak on the inlet side can have this effect.
Taking the oil temperature with the oil temp. probe on the analyser alters parameters in the machine. Whether or not it changes the unltimate reading is irrelevant, what it means is that you KNOW what the oil temp. was on each test so that you can ACCURATELY decide what difference, if any, has occurred by any repair you have carried out. Otherwise it's total guess work.
Tony.
ps. Please read post #22,
Taking the oil temperature with the oil temp. probe on the analyser alters parameters in the machine. Whether or not it changes the unltimate reading is irrelevant, what it means is that you KNOW what the oil temp. was on each test so that you can ACCURATELY decide what difference, if any, has occurred by any repair you have carried out. Otherwise it's total guess work.
Tony.
ps. Please read post #22,
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I don't think the M44 has a post cat sensor?
I do get a hit rich smell sometimes but it's not regular, could that have somwthijh to do with it?
how did it do while over at t tonys? I seem to recall something about it not getting up to temp (oil)
He couldn't get the co2 down on the mot either Jason.
My saga continues. M44 cat replaced, CO emissions still too high. Lambda sensor replaced, no change. Cat changed again, engine fully warmed up (drove 75 miles and put catoclean in tank, guess what, reading is worse. So car back again with indy. They will now measure the CO level precat (at Lambda sensor position) and compare with exhaust reading. This should determine if it is a fuel injection/MAF type issue or whether the new Powerflow and Eurocarparts cats were not man enough. Hoping it is the former as OEM cat is over £900. If anyone has a known working OEM cat, I might be very interested!
Similar problems with my m44 with crazy readings. Problem with mine was an air leak causing the engine to run rich. Turns out the rubber tubing from the air mass sensor to the engine had some holes either end which would mess up the fuel to air mixture. Take the clamps off and check the areas directly underneath the clamps too. New part on ebay is £13.
wrong post
Hope its something simple like that, but my indy checked the car before the cat was replaced for air leaks and said all was OK. I'm a bit stumped at present!
A bit of an off the wall thought, but, does the fuel make any difference?
RON 95 burns at a lower temperature, the ecu advances ignition so you get a longer burn than you will with 97 or higher. That could easily explain different combustion products.
What fuel is everyone running for their pass/fail on the emissions test?
RON 95 burns at a lower temperature, the ecu advances ignition so you get a longer burn than you will with 97 or higher. That could easily explain different combustion products.
What fuel is everyone running for their pass/fail on the emissions test?
The M.O.T. emissions test is supposed to cover any commonly available fuels so I can't see that being an issue Ian.
Tony.
ps. My suspicions are aimed at the heater element of the O2 sensor assuming it's a 4 wire connector.
Tony.
ps. My suspicions are aimed at the heater element of the O2 sensor assuming it's a 4 wire connector.
Was just a thought that different fuel will burn slightly differently. If you’re close to or on the margin it could be sufficient to push emissions over.
The reality is there’s so many variables, but, if the feedback loop isn’t working due to a faulty sensor then problems will only get magnified.
one of the main issues I believe to be the main cause of M44 fail is the valve sealing, I have run the smoothness test on inpa on 5 different M44 and they all suffer with the same issue.
you get a random misfire which swaps cylinders, hardly noticeable (except on idle, then everyone says yeh lumpy M44 are always like that).
I think maybe there is un-burnt fuel from a low compression stroke getting into the exhaust, after watching mine on the test there was a just audible mis then the readings would rise, but you would need hearing tuned like mine to notice it.
I get the rough start, these issues I believe are all linked.
it may not be ianmc problem, but im convinced its mine.
you get a random misfire which swaps cylinders, hardly noticeable (except on idle, then everyone says yeh lumpy M44 are always like that).
I think maybe there is un-burnt fuel from a low compression stroke getting into the exhaust, after watching mine on the test there was a just audible mis then the readings would rise, but you would need hearing tuned like mine to notice it.
I get the rough start, these issues I believe are all linked.
it may not be ianmc problem, but im convinced its mine.
Resolution to MOT Emissions fail at last.
RMFD BMW cat fitted, emissions now excellent, CO 0.02 (limit 0.20), HC 51 (limit 200), Lambda 0.996 (limit 1.03). Even better, CO Idle was minus 0.01 (yep, minus) (Limit 0.30). Last time readings were 0.51, 51 (same), 0.996 (same), 0.710 respectively.
MOT passed easily!
My hard won experience of cats over recent weeks is:
1. The new aftermarket cats I have had installed and tested for emissions (powerflow and Eurocarparts supplied) do not work on the M44 - other opinions may be available, but this is my first hand experience.
2. The surcharge price levied by BMW is similar to the cost of the new aftermarket cats mentioned above, which likely tells something.
3. The BMW cat is physically over three times the size of the aftermarket ones. I believe that the aftermarket cats are not type approved.
4. The car sounds better (less tinny) and performs noticeably more smoothly with the OEM cat.
My recommendation to anyone buying a M44 (may also apply to others) is to check that the car has an OEM cat fitted. My car was sold to me with a new MOT a year ago as part of the deal. A cheap aftermarket cat had been fitted to get it through the MOT as it had failed at first attempt last year, according to the MOT history. I chose not to speculate further on this!!!
Happy (if poorer) days!
RMFD BMW cat fitted, emissions now excellent, CO 0.02 (limit 0.20), HC 51 (limit 200), Lambda 0.996 (limit 1.03). Even better, CO Idle was minus 0.01 (yep, minus) (Limit 0.30). Last time readings were 0.51, 51 (same), 0.996 (same), 0.710 respectively.
MOT passed easily!
My hard won experience of cats over recent weeks is:
1. The new aftermarket cats I have had installed and tested for emissions (powerflow and Eurocarparts supplied) do not work on the M44 - other opinions may be available, but this is my first hand experience.
2. The surcharge price levied by BMW is similar to the cost of the new aftermarket cats mentioned above, which likely tells something.
3. The BMW cat is physically over three times the size of the aftermarket ones. I believe that the aftermarket cats are not type approved.
4. The car sounds better (less tinny) and performs noticeably more smoothly with the OEM cat.
My recommendation to anyone buying a M44 (may also apply to others) is to check that the car has an OEM cat fitted. My car was sold to me with a new MOT a year ago as part of the deal. A cheap aftermarket cat had been fitted to get it through the MOT as it had failed at first attempt last year, according to the MOT history. I chose not to speculate further on this!!!
Happy (if poorer) days!
Doesn't need to be type approved for older cars and this is how these companies can sell under sized shoddy crap which will usually outlast their warrant . . . . . just.
You get what you (or the previous owner) pay/paid for.
Tony.
You get what you (or the previous owner) pay/paid for.
Tony.
You are right of course about getting what you pay for Tony, except I have effectively purchased three new cats in the last few weeks and only the OEM one worked. Fortunately, I had the funds to buy the OEM one but, as the cost was approaching the price of a reasonable Z3, others may struggle, hence the warning.
Absolutely Ian.
Tony.
Tony.