Danny2569

Hi everyone, long time listener first time poster.

I drive a w203 2002 C200 Kompressor Sedan, I'll set the scene. Vehicle had crank no start issues roughly 6mnths ago, swapped out the CPS (Crank Position Sensor) and car has been running sweet ever since. About 3 weeks ago the car did it's first crank no start since, feeling frustrated I just assumed it was the CPS again. The next day I tried to start it and it ran, thought cool the problem has fixed itself. About a week went by and it produced the same crank no start, this time it was early in the day so I began checking through whether the car had fuel pressure etc. found that the car had no pressure whatsoever at the schrader valve. I checked the relevant fuses (Fuse no.4 off the top of my head?) and then finally swapped the fuel pump relay that I assumed was faulty for the horn relay (these are interchangeable to my knowledge) and the car fired up. I was convinced all this week that the car was fixed and it was just the fuel pump relay had gone bad but this morning I had the same thing happen, noted that there was no audible noise from the fuel pump. I went out and got a voltmeter to check around the electronics and the fuel pump to see what was getting power and what wasn't and then this afternoon, low and behold, the thing starts again and runs beautifully. I am at a loss.

Has anyone had any similar symptoms or experiences with this kind of thing previously? Anything I may have missed?

Thanks again for your time,
Danny.

slammer111

I'd suspect the fuel pump is on its way out. What's your mileage?

Danny2569

Thanks for the reply slammer, car is just about to break 250,000kms. Would a fuel pump randomly die and come back to life like that?

I'll order one anyways, could be worth doing as preventative maintenance maybe?

slammer111

Depends on the failure mode, but intermittent failures aren't uncommon for electrical stuff. Could be something as simple as temperature or orientation that can cause a broken wire to lose contact or suddenly regain contact.

The relays aren't known for failing at all.

Both my buddy (same car as me) and I had ours fail at around the 200-225k km mark. For both of us the pumps just suddenly died one day. I know that's not what you're seeing, but in any case it sounds like you're overdue for a failure.

While I'm on this topic, change out the fuel filter if you haven't done so already. The service interval is around 120k iirc.

Danny2569

Alrighty if they're that prone to failure then I'll change it out regardless, thanks for the advice.

I changed the fuel filter out about 5 days ago and got to drive it for a few days before it died again.

I'll let you guys know how the pump transplant goes!

Danny2569

So after what feels like an eternity waiting on parts I got to replace the: Fuel Pump Part #:0 986 580 184, Fuel Level Sender Unit Part #:0 986 580 343, and I ordered 2 new seals for each of the parts as this was recommended by the Mercedes tech. Car started up after I gave it a few turns to get some fuel pressure through the lines so all seems to be well. Given the information I'd recommend anyone thinking about doing the fuel pump to do the fuel level sender unit (The part under the opposite side of the back seat) at the same time regardless of its condition.

Time will tell if this is ultimately the fix to the crank no start problem in the first place but here's hoping

Thanks for your help Slammer, and on another note, is there anything else you would recommend taking a look at on a car with the kilometres mine has (245kish km's) that typically fails around this mark?


Thanks again,
Dan.

slammer111

No worries, glad to hear your car is running again.

You have the M111 engine which I don't know too much about, so I can't give much information unfortunately. However, other members can probably chime in.

- cam magnet sensor leaking (the M111 has 1 of these things iirc) - replace the sensor and o-ring
- spark plugs, ignition coils

As for non engine related things to look into, (there are links in the W203 forum) off the top of my head,

- Valeo radiator mixing coolant with transmission fluid (if your radiator is a Behr then you'll be fine) - requires radiator replacement before you destroy your transmission
- coolant change, transmission change - good time to check if you have the leaky radiator
- HVAC stepper motors and plastic linkage arms (really nasty job, there's a sticky for this one)
- front suspension control arms and bushings
- engine mounts (2 in the front, 1 behind the transmission) which I'm 99% sure are completely collapsed at your mileage, as well as the 2 corresponding flex discs (service life 300k km)
- transmission pilot bushing - fluid wicks up the wiring and into the TCU, which makes the car shift funny
- turn signal stalk collar spinning around loosely - open up the steering column and glue the collar in place
- timing chain - some say it's sure to fail, but I'm still on my original chain with no problems

Will add more if anything comes to mind.

Danny2569

Awesome, thanks for the heads up!

I think I have the M271 Engine in mine but, I'm sure a lot of these problems carryover anyways. Eye balling doing the valve cover gasket and checking the timing chain slack next but the list is ever growing.

Thanks again for your help Slammer

Danny2569

Just an update for anyone that comes across this thread in future.
What may be a premature update but I'll probably post again in a few months or so, the car seems to be %100 again. I've been running around the past week or so with no failures and confident the car will start every time. My recommendations, even if the car is not currently experiencing problems, replace the fuel pump and level sender unit as a whole at around the 15-20 year old mark. This is depending on what you want from the car but I plan on driving mine for as long as it will run without big issues so it was worth replacing for me.

Now I'm tackling the leaky brake vacuum pump at the rear of the motor, but thanks to this page, shouldn't be a big deal.

Thanks again Slammer and the many other threads I searched for information.