Yes, I could have plotted but it was all just dead flat.
The data as of post#17 would be different...
VW T6 No start but cranking
- Thread starter ghosthd80
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The data as of post#17 would be different...
Yes, they do run. Also would flag a fault if the sensor is disconnected.
Could be a red herring but could be worth investigating...
If the high-pressure fuel pump (HPFP) fuel pressure regulator (N276/N290) on a VW has no power (de-energized), the valve defaults to an open position.
In this open-circuit state, the HPFP cannot build up internal high pressure. Therefore, the fuel pressure in the high-pressure rail will only be equal to the fuel pressure provided by the low-pressure lift pump
Therefore, with only 7.6 volts on terminal 15, perhaps this would cause the regulator to be open and therfore no fuel pressure other than from the lift pump? In saying that according to the block map it is showing "Regulated operation via pressure control valve" so possibly working OK.
Maybe another blockmap as suggested by @mmi will give us more clues.
If the high-pressure fuel pump (HPFP) fuel pressure regulator (N276/N290) on a VW has no power (de-energized), the valve defaults to an open position.
In this open-circuit state, the HPFP cannot build up internal high pressure. Therefore, the fuel pressure in the high-pressure rail will only be equal to the fuel pressure provided by the low-pressure lift pump
Therefore, with only 7.6 volts on terminal 15, perhaps this would cause the regulator to be open and therfore no fuel pressure other than from the lift pump? In saying that according to the block map it is showing "Regulated operation via pressure control valve" so possibly working OK.
Maybe another blockmap as suggested by @mmi will give us more clues.
Id agree. I said that in the post above about the pressure regulator valve.
It definitely needs checking for power..
A wise old mechanic told me once that "pressure is not created by the pump, that just creates flow... It's the resistance to follow that causes the pressure"
Wise words , if the valve is open. Then no pressure, .. defo voltage check required.
.......
Post in thread 'VW T6 No start but cranking' VW T6 No start but cranking
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today i disconnect overflow pipe after fuel regulator for leak off test , all correct !!
Have you managed to get voltage readings at the rail fuel pressure regulator valve yet?
Values,:
Key off?
Key on,,?
Cranking?
Values,:
Key off?
Key on,,?
Cranking?
voltage readings are 0 at the regulator on cranking 0 too
I checked fuel pressure after the HPFP and showing over 300 bar on the gauge but there is nothing at the rail even with injectors pipe connections blocked
I will check wiring to the pressure regulator tomorrow
I checked fuel pressure after the HPFP and showing over 300 bar on the gauge but there is nothing at the rail even with injectors pipe connections blocked
I will check wiring to the pressure regulator tomorrow
Ah, looks like we getting somewhere.
Need to get the wires diagram for the pressure control valve, and where it's fed from.
What's the van spec?. Year etc? Engine code?
Thanks for the log. Below GREEN=good, RED'ish=bad
It seems the ECU tries to drive fuel pressure regulator valve (IDE07822) when cranking as expected.
However, the logged current (IDE05632) should peak to 500-700 mA to build up the pressure when cranked. Now nothing happens. Also at the rest (RPM=0) the current should be about 100 mA.
Is the regulator OEM part? How about trying the old one?
2022-03-14-A
These?
J623 engine computer controls it, looking at that schematic.
Definitely need to check all fuses, in engine bay and SC fuse box.
Definitely need to check all fuses, in engine bay and SC fuse box.
I'm afraid that's not correct for MY17 CXHA engine - seems to be for CFCA engine.
Instead
T6 - 2.0 Diesel EU6 Engine Wiring Diagram - History
@ghosthd80 Please plug just the connector into the old regulator and check IGNITION ON (no crank) with VCDS what you get at:
IDE05632 Fuel pressure regulator valve actual value
IDE07822 Fuel pressure regulator valve: activation
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