Vauxhall Vivaro 2.0 MY2010 Bosch EDC 16CP33, M9R 780

Happy New Year to all.

Looking for a bit of advice please.

This vehicle was originally booked in due to EML illuminated. I collected vehicle and road tested, drove well except for EML warning light on.

Whilst at idle it suddenly hesitated and then stopped. It will now not start unless you pump the Manual fuel-priming pump continuously.

Retrieved around 21 fault codes and found most sensor and actuator wires have been pierced previously, obviously got some history! Cleared all codes and re-checked to find just two: -

P0380 Permanent – Glowplug circuit A malfunction. This was found to be No 1 glow plug dead short. This was replaced; code cleared and this now tests ok.

P0100 Permanent – MAF sensor circuit a malfunction. All associated wiring tested, fault found to be sensor internally open circuit. Replacement MAF fitted; code cleared and this now tests ok.

I didn’t consider either of these faults to be causing a failure to start but thought I would clear these away to eliminate.

After engine is started by pumping the priming pump continuously, it then stores P0089 – Fuel system pressure regulator 1 performance.

As far as I am aware this system only has the one low pressure transfer pump which is mounted on the back of the HP pump and it is a common problem for the shaft to fail between the two pumps. Removed the low-pressure pump to find the shaft and pump gears all ok. Re-fitted and checked the suction whilst cranking to find this increasing to 15inHg Vac after 5 seconds. Rail pressure sensor initially reads 0.502v and between 1.2v and 1.5v at idle, this varies as I squeeze and release the pump. Live data shows fuel pressure to climb when cranking (if I pump as well but not if I don’t) this rises to around 260 Bar prior to start and then to 350 – 380 at idle. When engine is turned off the fuel pressure decays to around 50 Bar within 5 seconds and down to 20 in around 10 seconds. Is this out of tolerance? Does seem low to me but what can cause this?

The engine will rev up but I can’t pump fast enough! Fuel filter has been changed and flow to and from the tank checked and clear. Fuel leak off is the same from all four injectors and didn’t reach the bottles after two minutes at idle. The leak off from the HP pump is around one litre during the same two minutes at idle, I must admit I have no idea what this should or shouldn’t be.

The pressure control valve on the HP pump varies between 6% and 65% when activated thru scan tool but only varies from 8% to 16% when trying to run engine. I read that if this has the plug disconnected it should force maximum pressure from the HP pump, so I assume this valve must be closed to prevent leak off back to the tank from the output side of the transfer pump and hence max pressure created. And open to allow leak off and low pressure. With this disconnected the pressure still only increases as it did when connected but engine will not start.

Talked to one diesel specialist and he said all pressures and suction was fine but another said he thought they were low. Neither had any other ideas.

So, can anybody with more experience than me give any advice on what else to test and how?

Some data I received said some systems have an electric in tank pump as well, can anybody confirm what this vehicle should have.

Again, some data shows two pressure control valves, one on the pump and one on the rail. This only appears to have the one on the pump, can’t find one on the rail.

The HP pump has a pressure release valve, can anybody tell me what symptoms you get if this fails.

Thanks

Graham