Recently I have has a new air mass sensor, new lambda sensor, new spark plugs, new air filter, new catalytic converter, oil change fitted. This has reduced the emissions however the mpg is worse than before, about 12 mpg. (I have based my calculations on £4.50 per gallon, if this is not correct can someone please tell me.)
Does anyone have any suggestions? I have been told that the air mass sensor needs programming, is this right?
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What was that lot fitted to cure? Talk about a scattergun approach!
If the MAF wasn't a genuine dealer-supplied unit; then the odds are that it's both counterfeit and useless.
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12 mpg? Are you serious? You must have a fuel leak, surely? I get 27 mpg from my 3.2 W124 Coupé.
Alternatively . . . I don't understand what the cost of fuel has to do with your calculation of consumption. Fill up the tank, note the mileage, drive until near empty and, on filling up again, check the mileage again. Divide the miles driven between fill-ups by the number of gallons needed to fill up (1 litre = 0.22 gallons). Come back and tell us the result.
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But don't just do it once;do it several times.
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The air mass sensor is made by Bosch, not sure what make lambda sensor is.
These were renewed to reduce lambda emissions for MOT which had failed.
The cat had gone, big hole in it and noisy, was renewed and reduced co emissions for MOT which had failed. MOT has now passed. Spark plugs, air filter and oil were for service.
Before I had the above done my mpg was between 20-25 mpg. It is now 12 I am confident about my calculations. For £20 I got 54 miles. Should have got at least 90.
Can anyone answer my original question, does the air mass sensor have to be calibrated on computer? If so I can go back and ask the garade to recheck.
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MAF calibration needed; no. MAF source?? [All the counterfeits are marked "Bosch" too!]
No connexion between an oxygen sensor [often, wrongly, referred to as a "Lambda probe" by non-professionals] and the calculation of the air-fuel mixture "Lambda point" in an MOT gas-tester.
Non-genuine, or counterfeit components, are the most likely cause of your excessive fuel consumption.
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>>[often, wrongly, referred to as a "Lambda probe" by non-professionals]
Oh no! The shame of it! I've been known to call them lambda sensors!
Although, I don't think it's completely wrong as in the case of referring to dampers as shock absorbers. Or, is it?
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NC
Moot point maybe; but, you're right, "shock absorbers" - never!
They may be a probe; but as they can only report on the oxygen level, I'm sticking to "oxygen sensor."
You'll have noted the number of times an MOT Lambda fail has resulted in the death of a, perfectly sound, oxygen sensor - for the heinous crime of merely telling the truth....
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The air mass sensor is made by Bosch not sure what make lambda sensor is.
How do you know that? There are lots of fakes about. They also have Bosch written on them. Similarly there are loads of variable quality aftermarket lambda/o2 sensors.
I dont know how many sensors are on this model, someone else can say if there are multiple sensors and if there is a sensor in the cat (or if there ought to be but isnt since the replacement for example). Was this work done at a garage that knows mercs or just a fast fit type place?
MAF should be fit and forget, doesnt need to be configured.
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That milage is so bad, that something clearly is not right. The best thing to do is take it to a Bosch centre and they can put it on their comprehensive machine, wire it all up, and find the problem. They should test for a host of variables, including a compression test. Just replacing bits at random will not work and will be very expensive. The starting point is 'what's wrong with the car?'. The next stage is to fix it. Don't do them in reverse order, as some garages do.
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The official MB figures for a 124.022 are over 25 mpg even on city cycle and nearly 33 mpg at 120 kph. Unless you have a very heavy foot or are constantly on stop/start short trips, you should be getting upper 20s at least. Good idea to Bosch it.
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Sounds like a case of "The good,the bad &the Ugly".You have probably taken off some GOOD components,replaced them with BAD imitations and the result is UGLY.A genuine Bosch maf sensor should be around £160 and a lambda sensor either Bosch or NGK o/e quality about £70.Anything else will not work correctly.hth
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