Troublesome Mercedes C220 Sport

[onejayster]

Hi to all,

I have an ongoing problem with my 1995 Mercedes C220 Sport Automatic (W202).The problem with the car is that sometimes it can run fine and other times it’s damn dangerous to drive!

Unfortunately, the car has now got to the point of being 75% of the time dangerous and 25% as normal! It’s been gradually getting worse over the last couple of years.

The car will normally start fine (although the exhaust smell is very “petrolley”) if it has not been run for 5 or 6 hours and drive faultlessly. However, if you use it again before the 5 or 6 hours have elapsed it becomes an unpleasant experience. The car will start but sounds more Lada than Mercedes! The idle is eratic, almost dropping to zero rpm but just catching itself before stalling. The exhaust still smells “petrolley” by the way. If you put it in drive or reverse it will sometimes just about move itself but more often than not stall, very annoying backing in and out of spaces on car parks etc!! It’ll restart but still be lumpy!

The car will also stall when coming to a stop at junctions, no warning just dies as the car almost comes to rest. If it doesn’t die it almost does and then when you hit the gas again it’ll stall, not good at roundabouts and junctions, hence saying it is dangerous! Having to shove it back into park before restarting whilst someone bears down on your drivers side is particularly unpleasant!

It doesn’t end there!! When on cruise it’ll be going along seemingly fine at 50 to 70mph but then it’ll just lose power, almost as though you have your foot off the gas (even though you haven’t moved the throttle) but worse, seems to really hang mid cruise but then it picks up a few seconds later and it’s ok again for a few more miles.

Also for info it struggled through it’s emissions this year too.

I’ve done the following so far in a fruitless attempt to fix the problem.

1) New ignition leads

2) New spark plugs

3) Cleaned and rebuilt the throttle body - twice!

4) New Mass Air Flow meter

5) New air filter

6) New lambda probe

Can anybody suggest what to try next other than scrapping the thing as this is not really an option at the moment?!!?

I’m thinking ignition coils or crank angle sensor. I keep thinking i’ve fixed the problem only for it to come back a few days later!! I need some help please from someone with more knowledge than me on this.

If anybody has any advice please please post on this thread or pm me!

Thank very much in advance to anyone who feels they can help!

 

[drivinggod09]

sounds like a fueling problem im sure Television will be able to shed some light on it
bad luck but welcome to the forum

 

[Ian B Walker]

The fuel pressure regulator at the front of the fuel rail has been known to cause either fuel starvation or over fuelling. Might be worth changing it for a known good one.

 

[Xtractorfan]

Have you changed the fuel filter?

 

[television]

Fuel or spark ?

Ignition coils fail99& of the time when warm, something like 10-15 mins the output can drop. I would buy a spark tester (circa £9) and check that there is a good fat spark, you can also hold the plug lead ½ inch from a ground point .

Also where did you buy the MAF,,have you tried running it with it disconnected

Ian mentioned the pressure regulator
http://www.detali.ru/cat/oem_mb2.as...GM=717.417&CT=M&cat=19K&SID=07&SGR=095&SGN=02

Welcome to the forum,,its almost worth going to a Bosch Service Center with injection faults

Your engine relies heavily on the use of sensors for both air and water, have you tested those

http://www.detali.ru/cat/oem_mb2.as...GM=717.417&CT=M&cat=19K&SID=07&SGR=095&SGN=02

 

[onejayster]

Thanks for the replys

drivinggod09 - Thanks for the welcome, I'll look forward to hearing from Television.

Ian B Walker - I shall take a look at the fuel pressure regulator, how would i know if its faulty?

Xtractorfan - No not changed the fuel filter, was advised that it wouldnt be that but ill take a look & there fairly cheap to replace.

 

[onejayster]

Thanks for the reply Television, my old mechanic fitted the MAF (meyle) cured the problem for about 2 days then it started again, i have tried it disconnected but it made no difference!
Ive just come back from a Bosch Service Centre today & they couldnt find anything wrong with any of the pipes & hoses, i took it in for a diagnostic but they didnt have the right equipment for the 38 pin obd.
How would i test the sensors for both the air and water?

 

[television]

Thanks for the reply Television, my old mechanic fitted the MAF (meyle) cured the problem for about 2 days then it started again, i have tried it disconnected but it made no difference!
Ive just come back from a Bosch Service Centre today & they couldnt find anything wrong with any of the pipes & hoses, i took it in for a diagnostic but they didnt have the right equipment for the 38 pin obd.
How would i test the sensors for both the air and water?

They can all be tested with a simple Ohmmeter, and the value measured when both hot and cold. you could take the wires off the air and water ones and shot the wire to ground when the engine is hot.

Most of these things have a value of about 5kΩ at 10-15C dropping when hot to 500Ω to 1kΩ


The links I gave may not open tonight as the server has problems

 

[onejayster]

Thanks Malcolm think ill have to get my brother to help me or ill blow myself up along with the car

 

[television]

The 2 main sensors ar slowly shorted out to ground (engine block) as the car warms up, by taking off the 2 said sensor wires, or just start the car when warm, take a wire from the negative on the battery to ground on the chassis and touch the other end onto each of the 2 sensors in turn, if the engine runs smoother when doing that you have the answer

 

[roofless]

it's worth checking the wiring loom for perished insulation ect but as television says if the maf is not a quality item like bosch it might still be the fault so when it is not running well try unpluging it to see if it's any better

 

[onejayster]

Thanks again malcolm i will get my brother to read this before we start checking the sensors on monday if he's free to help, then i will post up how we got on, fingers crossed!!

Thanks roofless i shall check the wiring loom, i have tried unplugging the MAF and it made no difference.

 

[onejayster]

Hi all,

Just a note to let everyone know how ive got on.

I thought it best to get the car checked by a specialist before i caused more faults with the car my brother had spoken to a mercedes specialist on the MLR website so i checked the website out

www.mercedesservicingwarrington.co.uk

I booked the car in & took it there about 1 hour 30 minute drive WELL WORTH the drive, the place was clean & tidy, the staff were friendly & very helpfull, also good on the price i will use again if i have anymore problems they are that good, especially Shane im sure he knows everything about all types of cars awesome!! They diagnosed the problem & it was the cheap AMM i had put on at my local garage which was faulty, everything else was fine with the car, so anyone reading this & there having the same problems check out the AMM & DONT buy a cheap crappy one the proper AMM's cost around £200 & direct from Mercedes over £300 so go to see a specialist & if your anywhere near MB TECH WARRINGTON i highly recommend taking it there!!

Anyway thanks again to everyone who suggested help with my problem

(AMM = Air Mass Meter also know as the MAF = Mass Air Flow Meter)