Mercedes A170 CDI (w168) won't start - P1187

[mbackonja]

Hello everyone,


I have MB A170 CDI 2002. The engine won't start.


I read it with Delphi DS150E and DTC is P1187.
I checked the high-pressure pump through live sensor data and while cranking pressure is about 20 bar and the car won't start. I tried to start the car with start spray and I succeed at that but only for a second or two and engine immediately stop and P1187 error appears. At that moment when the engine starts, I have ~330 bar pressure in rail but engine often immediately stop and the max pressure is about 60-80 bars. Only one or two times I succeed to get ~330 bar. So I'm hoping that pump is OK but something else command ECU to stop the engine ASAP.


The rail pressure regulator was changed and it didn't help.


Any ideas about what else can be a problem or how to fix this problem?

[mercis]

check injektoren

[autoden]

60-80 bar is not enough. Check low pressure from tank. No low pressure = No high pressure.

[mbackonja]

@mercis
Hey, I forgot to mention. I removed inlet manifold so I can perform an injectors leak test. I cannot start the engine so I can't test leakage on idle but while cranking there was no leakage.

@autoden
Yeah, I know, but the pump doesn't have enough time to get ~300 bar because ECU immediately stops the engine once the engine is successfully started with start spray. I mentioned that few times I get motor running for few seconds and then the pressure is ~330 bar. I'm not sure if A170 CDI has the low-pressure pump in the tank? Next to the high-pressure pump, there is a low-pressure pump and it's OK.

[mercis]

you must injektor test,out car

[mihac]

Check fuel flow from injectoren and rail return, at startup. If present, see DRV valve and ijectoren, if not present, see shut-off valve.

[mbackonja]

@mercis,
The only way to perform this is to remove injectors and test on machine because I cannot start the engine, right?

@mihac
By "DRV valve" You mean Rail Pressure Regulator? It's replaced and it isn't a problem... While cranking there is a lot of fuel in return pipe but it's coming from fuel return from high-pressure pump not from common rail and injector return.
Can You tell me where is shut-off valve and how it looks like? Some pictures, please?

[mihac]

At wich points the return flow was measured?
a168 cdi170.jpg

[Pistattaaa]

Hello, because I have exactly the same car with the same problem, can anyone tell me how the problem was solved?