Log of test drives | Posts 16+

log

Vehicle scan.

Hi,
At first glance, I can barely make out anything in the logs, except that the rail pressure might be slightly lagging when I apply a little bit of throttle.
The combination of engine speed, throttle position, target pressure, actual pressure, pressure control valve, metering valve, and status bits is already good; perhaps including the deviation of the rail pressure would be beneficial.
It would be helpful if the logs indicated the occurrence of the error (if necessary, the marking can be added manually). Unfortunately, I am unable to process the status bits.

What I notice:
The pre-pressure was measured with a volume of 1000 ml in 30 seconds. In my opinion, it should be at least 1300 ml. The guidelines for the CFFB (presumably a specific system or component) might be a bit strange. For the same engine, vehicle-specific specifications for the return flow rates can be found, for example, for the Audi Q3.
Were the learning values for the dosing unit (metering valve) and the pressure control valve reset after being replaced?
hg
Herbert.

I still need to check the flow rate. As I mentioned earlier, I only performed the pre-pressure test with 4.5 bar and didn't check the flow rate further, since the required pressure was reached.
I reset the learning parameters, but that didn't help.
I'm now going to perform the volume check for the 1300ml and will get back to you.
Best regards,

Hi,
It seems like nothing is happening here anymore. It's a shame, really, because you invest time to help, and then the user just disappears.
"In case of rail pressure problems, always:"
- Autoscan
- Recording of rail data (pressure, status, control parameters, speed, injection quantity, pedal position) at idle, partial load, and full load; also, marking the engine check light on/off.
- Check the pre-charge volume and pressure;
- Completely check the return flow rates of the injectors and the pressure control valve.
hg
Herbert.

Hello Herbert.
I'm currently on vacation, but I'll be addressing the problem next week and resolving it for good.
Best regards,

Hello.
Okay, I've looked into the Sharan again to get to the bottom of this issue.
The tests for the pre-pressure and flow rate.
Everything is done with the original VW tools, specifically the VAS 6551, which is required for the testing process.
Result:
The pre-lift pump G6 achieves a pressure of 4.5 bar, but the amount of fuel that should flow into the measuring cup within the 30-second activation time is completely incorrect.
There were only 100 ml in the measuring cup.

Okay, so let's remove the tank and take a really close look at the pumping unit.

When removing the pump unit, the plastic pipes for the suction pump, supply, and return lines must be disconnected from the quick couplings inside the tank in order to extract the unit from the tank.
During this job, I was already holding the pipe connecting the pump to the hose when I noticed that the fitting on the pump had broken off.

It was clear – there was nothing to fix or repair; a new blower unit was needed.

Okay, so I need to get the parts, install them, and then take it for a test drive.

Okay, I did what was needed, and the car is running again. The problem hasn't reappeared so far, even though I've tested the problematic RPM range multiple times.

What I noticed later was that when I was bleeding the fuel system, I could only hear the faint hum of the pump in the tank. Before, it was louder and accompanied by a distinct splashing sound.
My assumption is that the connection fitting between the booster pump and the suction pump, which pumps the fuel into the reservoir, was already cracked.

Thank you for the feedback!