W124 E220 coupe FUEL CONSUMPTION/IDLING/EXHAUST,HELP,HELP,HELP!!!

[liiive_o]

HI Everyone

I am a new member here but i have been reading the forums for the past 2 days and have learnt many things, but i still need more clarity regarding my problems.

I have a w124 220 coupe, 1994. I have a big problem with fuel (i think so), currently i am doing 15mpg city drive....this can't be right, right? i had a rattling sound so took it to mechanic and he said i need to replace my cat's...so i went to topgear in hayes,london and had a powerflow exhaust sport exhaust system fitted,but had to de-cat the car,as it required 2 cat's and couldn't afford it at the time,so had straight pipes through.
It improved my performance,but my fuel is still 15mpg...oh and i still hear some rattling sound,friends say it might be the heat shield.

what sort of MPG should i be getting from this car? my dad had a 320 coupe and he says he used to get 20mpg+. what could the problem be?

my other problem is,at traffic lights sometimes,cold or normal temperature,my car starts to idle up to 10rpm...what could this be?idle valve or airflow pipe? Please enlighten me if you can...its bugging me now.

oh...and my passenger seatbelt extender stopped working...any ways of fixing it?

cheers...


heres some pictures of my baby

http://i2.photobucket.com/albums/y21/genuine86/Image000.jpg

http://i2.photobucket.com/albums/y21/genuine86/Image001_2.jpg

http://i2.photobucket.com/albums/y21/genuine86/Image029.jpg


WANTED : WALD OR AMG GEN 2 BODYKIT,FULL OR IN PARTS.

 

[television]

First thing to do is to get the exhaust gas analyzed that will tell you so much.

Any MOT station can do this

 

[rowland75]

Hi.. I have a 94 220 coupe aswell...

I get between 300-400 miles to a tank, depending on style of driving.

Pete

 

[liiive_o]

wow...for 65 pounds...i got 220 miles...and i was driving carefully,i dont do high speeds anyway...and try not to go above 2000 rpm...i treat the car very gently as i know its irreplacable if i mess it up,i have spent alot of money and time on it.

i dont see any difference between E and S fuel wise...just performance on S is better...

something is really wrong then with my car....my exhaust system is brand new stainless steel...from downpipe.

please,any solution/suggestions?

 

[kth286]

liiive_o

get the codes read by Merc specialist that understands older ones and has the tester (blip codes easily availabe).

Lambda probe very important in the feedback loop to ECU for electrical injector pulsing.
On that generation of car, lambda probe considered a replacement item at 100 k miles.

Coolant temp sensor also very important and they do go out of spec. Cheap and easy to replace.

Your exhaust people sound odd saying two cats needed - not to my knowledge.

How was the lambda probe fitted in new exhaust ?????????? Is that the cause of problem perhaps.

Also, has the charcoal filter in wing been replaced at 72000 miles ?????

 

[tjoneill@btconnect.com]

was the consumtion ok before you replaced the exhaust? has a lamda sensor been fitted to new one. I agree with television you need to have the gasses analysed, any mot or quick fit type garage can do it

 

[liiive_o]

i have no idea if theres a new lambda sensor or old 1 is still there,i doubt it though,but have to ask on monday. my car has done 130,000,i bought it at 125,000,so can't tell you if the charcoal filter has been replaced,but if it would help my fuel consumption,i will change it.

my car had twin pipes runnin from downpipe...on each pipe there was a cat apparently,i saw it too, it had this long tube shape and they were right nex to eachother...then the midbox which connected to backbox . i mean the guy had 1 sports cat ready for the job,but he was shocked to see 2 cats there...so had to delay it,going to fit it in on monday...my car won't pass MOT with cat's apparently.

my fuel was very bad even before this new exhaust,my cat was giving out this horrible rattling sound it was definitely gone and rusty. i will have it gass analysed then see what they say...because i remember getting 25-30mpg when we first bought it.


what about the passenger side seatbelt extender?it stopped workin all of a sudden...and the idling problem?although i havent had that problem since new exhaust been bought,touch wood

 

[kth286]

liiive_o

You have got your exhaust totally wrong.

The single CAT is under the front end of car floor, and then connects to the MID box and then connects to the BACK box.

The two "cats" on the two downpies you refer to are NOT cats. Thay are insulation to keep the exhaust gasses hot so that the actual cat (further along) is heated as quickly as possble to become effective and keep down emissions.

That's the extreme detail that Mercedes went to on that generation of car.

 

[liiive_o]

o my god...
if what you are saying is true...the exhaust garage got everything wrong...which is why probably i still hear some sort of rattling like a loose bolt or panel...and probably thrown away my old exhaust system and messed up my new 1, what can i do about it?

so does that mean i still have a cat in my car?i havent replaced the downpipe...jus little bit from above the midbox...have 2 straight pipes running through with no silencer or them insulators then..which connects to midbox then single pipe to backbox....

they ordering me 2 cats for monday apparently...i want to see where he's going to fit them then...

 

[d215yq]

MPG for e220

In city driving not thrashing my e220 coupe I have never got less than 26mpg, nor more than 34mpg - this works out at 380 to 480 miles on a full tank before the refill light comes on.

If the car is idling strangely could it be the oxygen (or sometimes called lambda or mapping) sensor - this will cause a much higher mixture of fuel to go into the engine which will ruin the catalyst and over a long time will destroy the engine, and cause bad fuel economy. Also does the temp gauage work properly - if the iginition system thinks the engine is cold when warm it will also put in a much higher mixture of fuel.

Re the mode on the gearbox, E mode changes gear at the same point as S mode on acceleration so is not actually more economical, E mode just doesnt change down when you accelerate hard and as such can be dangerous as tehre is no power when you need it. The only time I use E mode is on tight b roads where it will always be in the highest gear possible, which allows you to manually change down when you require (before the corner) using 3 and 2 on the stick and you know it wont change down by itself in the middle of the corner and potentially cause the car to skid if you dont hit the kickdown button.

 

[wireman]

The first thing you should do is fit the CAT convertors since they are a legal requirement and you can (and should) get a very large fine for by passing them.

Some of the rattles could be due to saging engine mountings, new ones on mine turned it into a much nicer car to drive with no rattles from the exhaust.