2007 XC90 D5 Not Starting - Diesel Flow Stops
 

Hi All,

Hope you guys had a great weekend. I'm here seeking some advice on my non starting car diesel XC90. I had a broken rocker arm, so I took it out. After putting everything back the car wouldn't start. Double checked the timing on both, camshafts and crankshaft . Engine runs with Easy Start spray though. No error codes detected.

Diesel is not coming out of high pressure pump - Fuel pump sends diesel to the high pressure pump and it would flow continuously. As soon as I tired to start the engine, flow stops and wouldn't pump anymore.

I removed all fuel system related connections like fuel temp sensor, fuel pressure sensor, fuel flow control valve, fuel pressure control valve, (except the pump) and tried to start the car - it threw codes for those sensors. Connected back, cleared the codes. Car didn't start but no more codes.

Could something else causing fuel issue? Please could anyone help where to from?

Attachment 139021

Thanks in advance

Zak

Sorry not been following the threads :o

I know its obvious, and you are getting fuel through, so this may already been checked, but have you checked the filter and the flow valve? oh, and the relays.

Hi and no probes. Thanks for your reply

I did change the fuel filter. Are you referring to the fuel valve on the high pressure pump? I just checked that by unplugging the connector.

Yes checked the relay and its working

Cheers

Hi, yes the the fuel/flow valve on the pump ... not sure the official process for checking it, but it should open and close when the relay switches over as the high pump takes over ... maybe VIDA has something.

Best of luck, hate this type of issue.

Thanks mate

Do you think I should try replacing tank fuel pump and then the valve?

Hi, that's one method, but I'd guess frighteningly expensive, I'd try to get an official Volvo fault finding guide first, assuming you don't have VIDA.

I'm also guessing if you are getting fuel from the tank on the low pressure side, then its not the tank pump so gut says find some way of testing the valve, as something is shutting off the flow as it switches from the low pressure to the high pressure delivery.

If you have another relay, try swapping that as well .... cant hurt.

True that

I'll take the flow control valve (fuel regulator) and check if its working connecting directly to the battery. If that works, then I'd check the motor inside the fuel pump.

I'll keep you posted

Cheers

So..from today's test, flow control valve is working to 12v battery connection. I checked the voltage on the connector is reading around 8V. Diesel also flowing sharply to the valve - please check the video I have uploaded on YT:

https://www.youtube.com/watch?v=bhUFL2myI9c

I think I should take the pump and, dissemble it and check for blocks and worn seals?

Oh and...when I was cranking I checked the rev meter on dashboard and it wouldn't move at all. My understanding is when crankshaft is rotating, rev should move?

Ok so that looks like high pressure, are you getting the same at the fuel rail and the injector feeds ... have you checked the fuel pressure control valve and the fuel pressure sensor on the rail?

The issue here is no fuel getting to common rail, so sensor would not detect anything? Unless we are trying to read air pressure pump is building?

When I checked the flow control valve, without power its fully open, with 12v, it closes and no fuel would flow. So when keys on ECU is wouldn't activate the valve and when excess pressure is detector by sensor, ECU would then send 12v and close it.

If above is correct, then even with a faulty control valve the pump should give some fuel output?