C180 Fuel Consumption

[pmerrill]

I'm wondering what other people are experiencing with C180 fuel consumption. I've just started checking mine and it's not that great BUT I only drive it from the burbs into Sydney (total about 15 kms in and 15 kms back) through morning and evening traffic up and down hills as well. Specs are:

C180 (Apr 1994)
Shell Optimax RON 98
last reading 12.35 liters/100 kms
132,000 kms on the odometer
no A/C turned on as its just turned spring

I've changed the air cleaner and did the plugs this weekend. I noted that all the plugs had a bit of dry carbon black on them, which normally indicates too rich a mixture. I'm wondering whether I might need the lambda sensor checked or the injectors cleaned?

Any comparisons out there or ideas on improving fuel economy?

[nokia8860]

Looks like youre on the right track. Regular items such as sparkplugs & wires, air filters, fuel filters, check of your pcv are items usally needing replacement.

An O2 sensor going south could be a reason why youre running rich. Take it to a qualified shop to have that checked out.

To see what other C180 are running try MBClub UK since most members of this site are from the states where the 1.8 was not an option.

[pmerrill]

Originally posted by nokia8860
Looks like youre on the right track. Regular items such as sparkplugs & wires, air filters, fuel filters, check of your pcv are items usally needing replacement.

An O2 sensor going south could be a reason why youre running rich. Take it to a qualified shop to have that checked out.

To see what other C180 are running try MBClub UK since most members of this site are from the states where the 1.8 was not an option.

Couple of quick questions. check of your pcv?, what 's that?

Where might the O2 sensor be located? I assume you are talking the lambda sensor which is located on the exhaust system manifold? That is something I need to check but that's next weekend's work.

I've now driven 1/2 a week with the new plugs and it seems to have made a difference. I noted that the old plugs were gapped at 1mm where the spec is 0.8mm, so someone in the past screwed up! I suspect it was the Merc shop as that was the last place the car was serviced. It was 1.0 after 1997 but 0.8 before. I'll see what happens when I get to the next tank.

Thanks for the input.

[1998K]

Originally posted by pmerrill
Couple of quick questions. check of your pcv?, what 's that?

Where might the O2 sensor be located? I assume you are talking the lambda sensor which is located on the exhaust system manifold? That is something I need to check but that's next weekend's work.

I've now driven 1/2 a week with the new plugs and it seems to have made a difference. I noted that the old plugs were gapped at 1mm where the spec is 0.8mm, so someone in the past screwed up! I suspect it was the Merc shop as that was the last place the car was serviced. It was 1.0 after 1997 but 0.8 before. I'll see what happens when I get to the next tank.

Thanks for the input.

I've an Haynes Manual that does cover only 4-cylinder model, no kompressor, they say 1,0 mm gap, without any difference to model year.

To avoid misunderstanding, also because mine is a Kompressor, I bought new spark plug directly to the Dealership, it's a Bosch part number that correspond top the small metal plate in engine front bay. Mine are with 3 electrode that, as per Bosch indication do not require gap adjustment.

My suggestion, look if your spark plug correspond to that metal plate (near the radiator).

Hi

[pmerrill]

Originally posted by 1998K
I've an Haynes Manual that does cover only 4-cylinder model, no kompressor, they say 1,0 mm gap, without any difference to model year.

To avoid misunderstanding, also because mine is a Kompressor, I bought new spark plug directly to the Dealership, it's a Bosch part number that correspond top the small metal plate in engine front bay. Mine are with 3 electrode that, as per Bosch indication do not require gap adjustment.

My suggestion, look if your spark plug correspond to that metal plate (near the radiator).

Hi

I don't seem to have a plate but if you look at either www.ngk.com.au or bosch web site itself and look up the required part for an April 94 model, they indicate that the gap is 0.8mm. So I assumed that since both agree, then 0.8mm it is.

[1998K]

Originally posted by pmerrill
I don't seem to have a plate but if you look at either www.ngk.com.au or bosch web site itself and look up the required part for an April 94 model, they indicate that the gap is 0.8mm. So I assumed that since both agree, then 0.8mm it is.

OK:) Bosch web site state that their new spark plug do not require adjustment. So, if they are 0.8 as stated by your mechanic, you are double sure.

Hi

[pmerrill]

Originally posted by 1998K
OK:) Bosch web site state that their new spark plug do not require adjustment. So, if they are 0.8 as stated by your mechanic, you are double sure.

Hi

According to my feeler gauges, the 0.8mm has lots of play, once I added a number of the smaller gauges I it got tight at 0.99mm. I suspect that a "lazy" mechanic thought C180 in pretty good condition, looks like a late model, I need to make sure the gap is 1.0mm which was true after 1997.

At the 1/2 tank mark now and I've put on 240kms in city driving. It's it keeps that up the consumption will be around 11 l/100kms. Better than the 12.35 that I am getting now. What I believe now is that the lambda sensor might be carbonized so that it's not reading O2 very well and make the fuel consumption poor. Next time it's up on the hoist I'll check it out.

[1998K]

Only for your information on consumption, and as comparison, mine is a W202 C200 Kompressor that is a 1998cc , special kompressol model for Italian and also other few Country (i.e. Portugal), it have basically same performances of C230 K, mine have 192 Cv and ab. 28.5 Kgm torque.

Consumption are less than 10% (l/100 Km) as average value. Often below 9.0 %.

Your C180 have to consume less, lambda sensor is a way to check, also MAS (but normally if do not work well there should be other problem) and as suggested O2 sensor, fuel filter, a good mechanical check may be necessary.

:(

[pmerrill]

Originally posted by 1998K
Only for your information on consumption, and as comparison, mine is a W202 C200 Kompressor that is a 1998cc , special kompressol model for Italian and also other few Country (i.e. Portugal), it have basically same performances of C230 K, mine have 192 Cv and ab. 28.5 Kgm torque.

Consumption are less than 10% (l/100 Km) as average value. Often below 9.0 %.

Your C180 have to consume less, lambda sensor is a way to check, also MAS (but normally if do not work well there should be other problem) and as suggested O2 sensor, fuel filter, a good mechanical check may be necessary.

:(

I believe the O2 sensor might be the next thing. I'm lucky (perhaps?) in that my Apr 1994 model does NOT have a MAS. I only have an air temperature sensor on the air intake. As to the fuel filter, that's actually before the engine, so I'm not sure why a bad fuel filter would affect the fuel consumption? What's the logic there, contamination of the fuel?

[1998K]

Originally posted by pmerrill
I believe the O2 sensor might be the next thing. I'm lucky (perhaps?) in that my Apr 1994 model does NOT have a MAS. I only have an air temperature sensor on the air intake. As to the fuel filter, that's actually before the engine, so I'm not sure why a bad fuel filter would affect the fuel consumption? What's the logic there, contamination of the fuel?

Sorry probably you are perfectly right, in any case I really suggest a visit to a good mechanic.:)

as far as MAS, probably you are better without it.:)