Testing QA

Can I test the QA with 4 VDC?

If you mean VCDS, yes.
Should be everything you need to know here:
https://www.myturbodiesel.com/wiki/injection-quantity-adjustment-fuel-pump-hammer-mod/

I don’t have VCDS. I meant a static test by providing 4VDC to the QA to verify that it’s functional. 5 VDC should run the QA to 100% travel. I just want to test it to rule it out as a problem. The system isn’t running the QA 0-100-0 on key on.

Instead, measure the voltage at the QA when you turn the key on?

Thank you.
I have a write up in the MKIII thread:
http://forums.tdiclub.com/showthread.php?t=500368
I have 12 VDC at Pin 5 from the ECU, but am also reading a PWM signal of 161 mS pulse width and a Duty Cycle of 98%. No P to P value.
Just verified continuity from IP plug to ECU for pins 5 and 6.
Next step is verifying continuity from ECU plug grounds.
Thought I’d hit the QA with 5 volts DC to at least verify functionality.

Just verified a good ground at the ECU plug to pins 1, 24, and 46, but not Pin 33, listed as Sensor ground. The search continues.

QA current requirements?

Does anyone know the current requirement for the QA?

I tried 1.5 VDC from a D cell battery with no luck. I want to at least verify actuation before condemning they want to keep adjuster

I meant “before condemning the QA”.
Autocorrect..

Got it

Turns out one of the Modulating Piston Displacement Sensor wires was broken to the ECU. Easy fix once I found that.