Help - Economy problem!

[zedmeister]

No, not the country, my CLK320 W208 2002!

When the engine is cold, the economy suddenly starts dropping after starting the engine from 20 odd MPG down to 7 MPG. It never did this before. On a long run it is still giving good economy 30+ as it did before, but short runs from cold seem not to be doing well. This economy problem has just started - does this all point to a bad Oxygen Sensor or something else like plugs?

 

[television]

Its normal my SL500 started yesterday and was showing 5.1 mpg

 

[zedmeister]

Its not normal for my 3.2 - its only just started doing this in 3 years of ownership.

 

[kth286]

The oxygen sensor is not normally effective immediately until it is fully heated up, and indeed your car is probably running on a fixed map intially because of that fact.

 

[dragon]

Its normal my SL500 started yesterday and was showing 5.1 mpg

Oh you got a car similar to Jeremy's GT43.

Get a W202 1.8 at least 30mpg and 40 at motorway driving at 60mph constant speed and admire the countryside.

 

[jibcl500]

Oh you got a car similar to Jeremy's GT43.

Get a W202 1.8 at least 30mpg and 40 at motorway driving at 60mph constant speed and admire the countryside.

Theres no fun in 60mph and 30 mpg, my CL only gives the best part of 10mpg but close to 30 on a constant with CC on.

As for the CLK, when was it last serviced? best get it on diags and see whats going on.

jib

 

[zedmeister]

CLK was last serviced when the car advised in 2007. Its due in 5500 miles. Full MBsh - it was on Star a couple of weeks ago as I needed a setting changed for the Sat Nav. He said he could not spot anything obvious but reset it. As I mentioned before, even when cold, it used to drop to about 15mpg and back up when driving, now its dropping rapidly to 7 or less before coming up. On a long run I still get 30mpg. Seems to be fine when warmed up, even in the city.

 

[zedmeister]

The oxygen sensor is not normally effective immediately until it is fully heated up, and indeed your car is probably running on a fixed map intially because of that fact.

There are 4 oxygen sensors as well

 

[Xtractorfan]

Its quite possible the star episode reset the values..also of late I think we have seen the wettest and coldest autumn since moses was a boy so another factor.. the overall figures should give a fair assessment of true usage..

 

[zedmeister]

Its been doing it for several months now.

 

[dragon]

Theres no fun in 60mph and 30 mpg, my CL only gives the best part of 10mpg but close to 30 on a constant with CC on.

As for the CLK, when was it last serviced? best get it on diags and see whats going on.

jib

I am enjoying all the fun and the ride, it not one of the mistake I made buying one in my life.

If you can afford it why not, I can't stop laughing the way Jeremy picked his fingernails like a naughty boy when questioned by Hamster on the 5mpg GT43.

 

[dragon]

CLK was last serviced when the car advised in 2007. Its due in 5500 miles. Full MBsh - it was on Star a couple of weeks ago as I needed a setting changed for the Sat Nav. He said he could not spot anything obvious but reset it. As I mentioned before, even when cold, it used to drop to about 15mpg and back up when driving, now its dropping rapidly to 7 or less before coming up. On a long run I still get 30mpg. Seems to be fine when warmed up, even in the city.

Was testing my Carsoft just arrived and noticed the petrol control unit fault in the ME diagnostic test with the error code P203F-001 N3/10(ME control unit) Error P0221(Throttle/Petal Position Sensor/Switch B Circuit Range/Performance Problem).

I erased the error and tested it again, the error didn't show up again. If someone will tell me how to rectify this, would be appreciated.

It worthswhile to put it on diagnostic to show up any obvious error codes and act on it.

Problems are bound to show up at bad weather condition because nobody bothers when the weather is good.

 

[zedmeister]

Is there an easy/cheap way of getting the diagnostics yourself?

 

[dragon]

If you are nearby can do it for £30.

 

[zedmeister]

Wanted to know if there is a cheap way of getting a lead & software as it would be handy to have one.

 

[dragon]

If you look hard enough you will find the answer in another thread.

 

[zedmeister]

If you look hard enough you will find the answer in another thread.

Any hints or even a link maybe?

 

[dragon]

Search carsoft or obd