Hello everybody.

Problem car is a C200 CDI S203 85kW (year 2002), manual 6 speed gearbox.
It all started something like this:
Long cranking periods until engine fired up regardless if the engine was hot or cold. I have changed the battery, diesel fuel filter, air filter, glow plugs, oil and oil filter. The service reset counter has been reseted. The car didn't change in the way it was acting, still you'd have to crank the engine 5-10 seconds to start it.

At this point I bought all fuel lines that are in the engine compartment, brand new OEM ones.

Now it seems that when engine was cold it started a little bit better but when engine was hot still long crank times were present until it fired up.

Besides this 2-3 times it behaved strange, meaning if I was to start it with a hot engine it would start but then it would stop again. In order to fire it up again the engine needed even longer cranking times.

Now I was set on taking down the high pressure diesel fuel pump and change overhaul it with a brand new repair kit. I have disassembled it and reassembled it in reverse order of disassembly. Now the cold starts were OK, much better in comparison to previous behavior. On the other side when starting the engine with hot engine it maintained same nasty behavior (5-10 seconds cranking time).

After installing the high pressure fuel pump I took the car out for a spin, it was ok-ish sort off.... engine stopped while driving a few times.... I thought it is because of the fact that the fuel lines still had some air in them because of a not finished priming sequence... On the way back to the garage on the onboard computer I saw EPC - Electronic Power control - visit workshop.

After doing some more online forum reading and youtube videos related to the matter I ordered the low pressure fuel pump and the DRV (fuel pressure regulator). Until these new parts came I decided to take of EGR, intake manifold and give them a good cleanup. I found out that the intake flaps were in pretty bad shape. I made some blocking rings out of stainless steel and threaded the hole where the flaps bolt was present. Then were the new bolts were threaded in I tack welded a steel stick to avoid unscrewing them because of the vibration. Gasket silicone was used on the thread for a complete seal to prevent boost loss if any would have occurred. Also the rod connecting the 4 flaps wasn't even connected anymore and the 4th flap was blocked closed.... 1st 2nd and 3rd were only half present.... Small electrical engine was left in place and plugged to avoid getting errors.

I installed everything in revers order of disassembly... managed to start the car after 2-3 long cranks (normal behavior in this case because it took some time until it sucked some diesel from the fuel filter).

It ran fine for 1 minute or 2. Then it stopped by itself.

I have checked the following:

Feed line from gas tank to fuel filter -> clear without any obstructions and pressure was constant so no leaks
Fuel line from engine back to fuel tank -> same good situation
I took a manual pump to draw fuel from tank to fuel filter -> fuel was present just after low pressure pump, fuel was present just after high pressure fuel pump and fuel was also present in fuel return lines on injector return rail.

I decided to stop here, as I had no more ideas of what to do.
P.S. - no errors present in Star diagnosis aside of the low pressure on high pressure fuel rail. That one was deleted and it didn't appeared again. It was because of the fact that I had to take off also the high pressure fuel rail while doing the intake manifold job.

If I made some typing mistakes or bad English skills I am sorry. English is not my native language and I am also tired after a full week.

Maybe someone has an idea of what I should do or had a similar situation.

 

When the EPC light came on there should have been some fault code stored, you have to keep a record of the codes before you erase them and print the freeze frame data. There are several components that can cause your problem and while it definitely needed the egr clean and swirl port flap mods I don't think either of them can cause the hard start or stalling problem. The in tank fuel pump and the pressure control valve are high on the list of suspects when low rail pressure codes are stored, as is the quantity control valve on the front of the high pressure pump. Parts are expensive so diagnosis is important unless you have access to good used parts that can be "test fitted". If you have SDS system you can graph the actual values and try to catch the glitch but keep in mind that the quantity control valve is held open at 100 percent during engine start and pressure is controlled by the rail pressure regulator for around 10 seconds after start, if the pressure in the rail fails to increase the engine will not start. Pressure can fail to rise high enough to start the engine for several reasons,1)not enough fuel volume from tank,2)not enough fuel getting into high pressure pump due to faulty quantity control valve,3)not enough pressure rise due to faulty rail pressure regulator,4)high pressure pump internal leaks or wear(keep in mind you may not be able to see the wear with naked eye). After the engine starts the quantity control valve does most of the pressure control and the rail pressure regulator is held in a almost closed position. There are guided test programs for all these in SDS,"list of guided tests".

 

Hello guys.

Managed to start the bloody thing.

Manual hand priming was not successful so this led me to think I don't have enough fuel in the tank.

Checked first the left side of the thank where A2034705194 is present. Enough fuel there. On top of A2034705194 I saw present 2 connectors for fuel (from gas tank to engine and from engine to gas tank) and 1 electrica connector with 3 wires (I guess it's from the fuel level, or does it have something to do with an in tank fuel pump!?).
On the right side of the fuel tank where A2034705094 is present there was very little fuel. How come fuel doesn't go from one side to other side of the tank!?

I then put 20 liters of diesel in tank and hand primed the system. Put everything together and it started very good.

So, main question:

Do I or don't I have a in tank fuel pump? I don't hear any buzz or something like that.

Car VIN is WDB2032041F268067. Engine is 611962 with production number 30 537920