The van stalled during running and it never started again.
According to the diagnosis I had no error codes. So I measured the high pressure pump output. It was zero bars.
I had then replaced the low pressure pump along with the high pressure pump. Both new.
The high pressure pump is a Bosch remanufactured. I suspected a bad brand new high pressure pump.
So I send it to be checked on a Bosch stand. The guy told me it was fine.
What bothers me is that he said that he applied 5.0 V pwm signal to the pump regulator and the pump started to put fuel out. He never measured the pressure output. He showed me the flow.
The ECU is EDC16C39.
I scoped the pressure regulator on the car and it is a PWM signal of around 9V. Still no rail pressure.
Now I am wondering if my ECU is bad or if he tested it wrong.
Please help me.
Thank you in advance.
- pressure regulator of the high pressure pump on the car.
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Looking at the capture there may be some connection issues with grounding but that aside you have a duty cycle of around 50% which shows the ECU is sending a command to the pump which would allows some fuel into the pumping chambers to start creating flow. Given you have 0 Bar of pressure I would assume the rail pressure sensor is reading 0.5V or around that value.
Remember that pressure is just resistance to flow and if we have flow without a restriction then you will not create any pressure.
Also worth considering the low pressure side of the fuel system. Is there enough fuel getting up to the fuel pump? Can't create fuel pressure without enough fuel to begin with.
It's worth disconnect the leak of for the common rail and when cranking see if there is any fuel coming out. This could indicate that the mechanical relief valve is stuck open. Equally if there is a pressure regulator solenoid on the rail, or pressure discharge valve, check to see if this is stuck open and allowing fuel to flow straight out of the rail.
Also worth considering the injectors. If any of these are stuck open then the fuel will just pass straight in to the cylinder. Check the oil level for any increase of signs of fuel present.
Lots to check first before calling an ECU.
I don t have another regulator on the rail. It is only the fuel rail pressure sensor.
I checked continuity for the both wires of the pressure regulator to the ECU. And I have continuity. I also checked to see if any of the two wires have continuity to the van ground.
Because you told me I may have a grounding issue. But I don't have continuity to the chassis.
I have also removed the O-ring from the pressure regulator and mounted like a dummy plug back on.
I started having flow from the high pressure pump when cranking.
Now I am in a middle of a dilemma. I don't have any ideea where to go from here.
Any aditional advices will be greatly appreciated.
Apologies for any confusion. With regards to a grounding issue, I meant the measurement not the component so where you have connected the black, ground lead of the test lead.
If you can connect the scope up with a current clamp as if you were performing a relative compression test, include the camshaft sensor and finally connect to the fuel rail pressure sensor. It's a similar test to the engine performance test in the HD and OH guided test section. Have it a 1s/div time base and crank the engine. If you capture this upload it here and we can all take a look to see if anything stands out.
Really though I think you need to focus on a possible leak. Remove the leak off pipe for the high pressure fuel rail and see if there is fuel running out when cranking. If there isn't then I would look at the injectors. Need to be able to build pressure and the only way that happens is if there is a restriction to the fuel flow from the high pressure pump.
Hope this helps
There is no fuel coming out of the high pressure pump as I crank the engine.
I will do the next tests per your advice.
But please take a look at the second capture. The ground falls into the minus area of the diagram. I don't know if this is normal.
- fuel pressure regulator backprobed at the connector
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To clarify there is fuel coming out of the common rail leak off port but not from the leak off on the pump?
Have you also performed an injector leak off test?
Did we confirm the low pressure fuel system was OK? If not, can you supply an external supply of fuel to the high pressure pump?
Is there any sign of metal debris in the fuel filter housing?
Are you able to get a cranking capture of the rail pressure sensor along with a relative compression test (current clamp around the battery cable to the starter motor)?
Given it is a Bosch system you may find that disconnecting the inlet metering valve forces the pump into maximum flow. This will of course throw a fault code but should default the pump. There is the chance that it works in the other way though and closes the inlet to the pumping chambers so will give the same condition you have now.
There are a number of waveforms on the Waveform library for this vehicle which I think would be worth taking a look at. There are a number of cam and crank waveforms that might be worth checking in case the timing has jumped - especially as the vehicle stalled.
As mentioned before, I feel there are still a number of checks to do before calling an ECU.