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Hi

My car starts without problems when engine is cold or are hot. When engine cool down about 1 minutes or more then it is very hard or impossible to start it again and only way is to wait at least 2 hours to cool down.
With running engine there is no problems. I have checked that fuel is reaching to injectors. I had opportunity to take another similar car, which engine was working and change the camshaft and crankshaft sensor but my car engine did not still start.
Diagnostics checked with running engine common rail pressure and injectors they seemed to be okay. He guessed that problem is due to some electrical thing. He wrote down three errors what computer showed:
1. Solenoid-operated shut-off valve: open circuit
2. Pressure control valve: open circuit
3. Throttel valve actuator: open circuit.


Does anybody have any idea what do check or try?

I had a problem with starting mine when hot and it turned out to be the pressure regulator on the HP pump, it has a filter which clogs and its almost impossible to clear it. Its held on to the pump with two screws, maybe torx or allen type.

Peter

I checked it over and it seemed okay. When I visited diagnostics then he said that common rail pressure is okay with low and high RPM. And therefore he thought that HP pump pressure regulator should be okay.

I would like to help, but I don't recognise those fault descriptions. Have you translated them from another language perhaps?

I imagine No.1 might be the EGR valve?
Description for No.2 suggests the HP pump regulator.
No.3 for a 110 HDi? The only possibility I can thinik of is the air doser, (if fitted).

Do you know if your in-tank lift pump is working every time? (It should run for about 4 seconds every time you turn on the ignition and you should be able to feel the fuel filter swell with the pressure).

I had a faintly similar intermittent electrical problem with a HDi 90 Xsara. The non-starting was due to no power to the lift pump, but when connected to a code reader, the absence of this supply to the ecu was reported as an EGR solenoid valve open circuit as it gave the same symptoms on power-up self-test.

No these faults are wrote straight down by diagnostic guy.

This first one I think should be HP pump shut off valve( so called 3rd piston actuator valve). I checked that voltage are coming to connector but I can´t be sure that valve opens. I turned one injector fuel input pipe a little bit loose to see is fuel reaching there. When I turned ignition on, the pipe were leaking fuel.
This last one should be air doser as you thought. This seems to be not working and it is in open position.

In-tank lift pump is working every time.

The 3rd piston deactivator solenoid needs to be energised to reduce the pump delivery pressure at low engine speeds, (It is energised above 2000 RPM, or something similar). It would be OK to disconnect it temporarily to prove a point - (the go-faster 306 HDi fraternity commonly do this, as far as I can tell, to make more smoke).

Did you manage to, or could you get it connected to the diagnostic unit when it was not starting? This would enable you to see if you had fuel pressure etc.
You need at least 200 bar pressure and a measured cranking speed of at least 60 RPM before it will start.
Be useful to check there is no immobilser problem too.

talabert wrote:I checked it over and it seemed okay. When I visited diagnostics then he said that common rail pressure is okay with low and high RPM. And therefore he thought that HP pump pressure regulator should be okay.

That's OK when the engine is not under load but when it is it demands a much greater fuel flow, if the filter is clogged which is the common problem it might be restricting the flow at large throttle openings. I would think you could check that by having the Lexia running in the car while you are driving.

Peter

If i disconnect 3rd piston actuator valve with running engine then engine shuts down. Some time ago I had problem that after turning off ignition key, engine didn´t stop. Problem was in trailer connector where was short and 3rd piston actuator valve was all time energized.

For two days I didn´t do with car nothing and yesterday I tried how car is acting and now it is working and starting fine in all conditions fine. So I am confused because there is no logic thing what is going on with my car. I believe that soon the problem returns.

Running on was one of the problems that a replacement regulator cured.

Peter

I found that problem is caused by ECU. It seems that some chip on PCB is not working correctly when it is hot and therefore don't let engine to start. I took ECU cover off and now it seems that air is cooling it so much that car is stating at the moment every time. I will experiment it further.

You could try squirting some aerosol freezer on various chips, that should change it instantly if you have found the right one. That's what we did when I repaired TVs for a living.

Peter