[T6_measured] 01-Engine - Built-in test for Transfer fuel pump

[mmi]

A quick DIY way to test fuel lift pump's basic functionality.

The test takes advantage of engine's fuel high pressure sensor (in fuel rail). Running the lift pump continuosly makes the pressure eventually "leak" through high pressure pump and can be detected by fuel pressure sensor.

As a side product the test gives at least indication of fuel high pressure sensor's plausibility - the raw value (in Volts) and converted value (in kPa). However, as the pressure produced by lift pump barely reaches measurement range - for proper pressure measurement traditional means are still needed.

HOW-TO Run engine's built-in test for Transfer fuel pump​

IGNition ON​

VCDS > Select > Engine > Basic Settings > IDE00459-Test of transfer fuel pump​

Select "Show Measuring Data" (see below)​

A selection window opens to tick the needed measurement data items​

Find and tick the following:​

• IDE00589 Fuel pressure
• IDE07819 Fuel high pressure sensor: unconditioned voltage
• IDE07824 Tank-internal presupply pump 1 bank 1: activation

​

​

Select "Log" (see below)​

Select "Start"​

Log for at least 30 seconds - to get "base level of presssure"​

Start the test by clicking "Go" (below)​

Let the test run for 90 seconds - then "Stop" (below top right)​

​

Let the data logging still to continue for at least 60 seconds.​

The log file is in folder C:\Ross-Tech\VCDS\Logs\....​

---

Below the green is lift pump activation (not scaled - just for timing).
Light blue sensor raw data (barely at low end resolution/sensitivity).
Dark/thick blue calculated sliding average of sensor data.

---

More than happy to create the plots - just attch the logfiles.

 

[mmi]

Reserved.

 

[mmi]

Reserved.

 

[Dellmassive]

Awesome.

Ill get you some data to do a comparison plot from my van.

With a few more data sets we should have a average baseline for known good.

So if others can join in we can get a decent idea 0f what to expect.

Good work @mmi

.

 

[n10n]

More than happy to create the plots - just attch the logfiles.

Fresh data for you, sir!

 

[mmi]

Fresh data for you, sir!

 

[n10n]

View attachment 202589

Thank you!

Now, if only we knew whether higher is better or worse? As in, is my pressure control valve leaking more than yours?

Just joking... probably just my pressure sensor calibration is bit higher as evidenced by the ripple even when lift pump was not on at all

 

[mmi]

Just for comparison - the same measurement as earlier but the pump was driven via VCDS output tests - which cycles the pump on and off every four seconds.

I think it's safe to conclude the pump being on only less than two seconds at a time doesn't produce much useful for naked eye on high pressure sensor.

 

[mmi]

Finally at 6 years VW agreed to replace fuel filter. VW garage tool ODIS uses the procedures below to bleed the the new filter.

Fuel filter bleeding​

(1) Run the pump for 60 seconds:​

VCDS > Select > Engine > Basic Settings > IDE00459-Test of transfer fuel pump​

(2) followed by 30 seconds of cyclic run of the pump​

VCDS >Select > Engine > Output test > Fuel pump electronics​

That's all - start the engine - it starts up immediately - check for leaks