P229A Fuel Pressure 2, Control limit exceeded - pressure low

[DeviAngel]

Hello again,

Recently my car (W204 C200 2008) started to struggle to start, its acting like it doesn't have fuel. after 5-6 seconds it starts and the first 10 sec is like strugling for fuel.

My OBD scanner shows this 2 faults :

P229A - Fuel Pressure Regulator 2, control limit exceeded - Fuel Pressure Low
P242F - DPF - Blockage/Ash

I've replaced the Fuel Rail Sensor, Fuel Pressure regulator on the Rail and the Pump. I changed the Fuel Filter also...

After that let's say 1-2 minute, the car is running like nothing happened. I also have the P242F fault code but the car doesn't smoke, it runs okay etc...

P.S. I used the updated housing on the High Fuel Pressure pump for the regulator.



I've lost my nervs, I'm like struggling for months while spending 500 euro. Should I try to remove the minus from the battery ?

 

[mersum1es]

measure injector tank line leaks, usually problem starts at cold engine, escalating later...

Have you checked DPF sensor and sensor route to pipe is clear? If all ok, check exhaust back pressure sensor.

 

[DeviAngel]

measure injector tank line leaks, usually problem starts at cold engine, escalating later...

Have you checked DPF sensor and sensor route to pipe is clear? If all ok, check exhaust back pressure sensor.

Adter driving it a little last night the car seems again fine and has a good pul and power. I returned the old rail sensor and changed the fuel filter and now it starts good and runs like before no problem.The RPM is again steady without oscillating and no jerking until now It starts good without problems (tiday morning was cold and it started instantly) no more acting like no fuel is there but the check engine light won't go away.

The errors still stay on. There's no leakage on the injektors i took the cover off and observed them while giving gas. Seems like before they had the peoblem because There's a lot of disel there (old one) and they've changed the injektors (the mercedes benz guy check it last month and told me) and they are coded.

What is funny is the error won't go away even thou the car is okay now and when I start Torque Pro with my OBD reader i get this



The ABS error is my sensor it needs to be replaced I am eaiting for my termin. Now the other greyed out errors I don't know if they are old or no but again the car seems fine.

 

[DeviAngel]

Sooo the weather was cold outside ans the car atarted doing the same thing... i get the PDF error (P242F) and the P2373 pressure low ...

 

[mersum1es]

I repeat myself... measure injector tank line leak when problem is present (VISIBLE leak has nothing to do with tank line leak measurement, use search...). OM651 may need tester to control the pressure, OM646 can do without, you are not stating which one you have (it changes around 2008), your signature is not even stating it would be a diesel but shows a gasser type.

 

[M80]

As above,
if only to eliminate, check the injectors leak off.
Excessive leak off (through the return lines) prevents, or slows, the fuel rail reaching threshold pressure at start up.
Until the ECU sees enough pressure it inhibits the start.

You might even monitor the fuel rail pressure during a start to see if it reaches pressure.

 

[DeviAngel]

I repeat myself... measure injector tank line leak when problem is present (VISIBLE leak has nothing to do with tank line leak measurement, use search...). OM651 may need tester to control the pressure, OM646 can do without, you are not stating which one you have (it changes around 2008), your signature is not even stating it would be a diesel but shows a gasser type.

My bad, sorry. My engine is OM646 C200 CDI.
I am,new ro diagnostic and I don't know how to measure the injector tank line..

As above,
if only to eliminate, check the injectors leak off.
Excessive leak off (through the return lines) prevents, or slows, the fuel rail reaching threshold pressure at start up.
Until the ECU sees enough pressure it inhibits the start.

You might even monitor the fuel rail pressure during a start to see if it reaches pressure.

I am sorry I'm new to diagnostics, how do I check the leak?

Something like this? (Idle)

 

[mersum1es]

Easy way

more pro way

And yes read that pressure when you try to start and it won't fire...

 

[DeviAngel]

Easy way

more pro way

And yes read that pressure when you try to start and it won't fire...

Okay...What I did just right now is this..




I don't know why It says Rail Pressure Regulation uknown status when the regulator is new but...

Thank you for the clarification, I'll try what the guy did in the video.

 

[DeviAngel]

After doing the new diagnose test I hear hissing a lot coming out from the fuel overflow hose. There is no fault code and the car now runs normal. The hissing sound is heard on the first contact whilw the fuel pump is woeking the first 30-60secs. The hissing isncoming out from this part, the T plaaric where the 3 hoses connect.

 

[mersum1es]

You mast clamp the hose coming from tank side like in 2nd video because other system is still feeding tank line. Or do you mean you have a crack in t-piece?

 

[DeviAngel]

You mast clamp the hose coming from tank side like in 2nd video because other system is still feeding tank line. Or do you mean you have a crack in t-piece?

The ignition is just on, engine Off. First 30-60 seconds you can hear air hissing .... The sound is coming from the T Pipe if you hold it with hand the hissing sound (air) is getting quieter but i cant feel air on my hand...

I uploaded the video here

Streamable Video

Watch this video on Streamable.

streamable.com

 

[DeviAngel]

After a long internet seach I found on this forum this old post by a poster @Uncle Benz . I have the identical problem with fuel pressure and this T section. Any advice Uncle Benz, i ordered just the T section and the whole hose with T section. How did you solve it? As I dont want to take everything apart again plus i have a 2500km trip coming up, i have no time...