Golf V 1.6 LPG P0172

[alessioblaupunkt]

This engine 190000 km has
P0172 System Too Rich (Bank 1)

if you run on gasoline the 1st lambda voltage varies from 0.43V during idle to 0.20V
if you run on lpg the 1st lambda voltage varies from 0.82V during idle to 0V in accelerator cut off condition.

Is it on porpouse that on lpg the voltage is double than petrol?
Is the lpg ecu overfueling?
Does lpg ecu need recalibration?

Engine is ok after dtc reset and after a 10 km trip, 5km gasoline, 5 km lpg.

I will not change lambda, someone told me it costs 500eur and does not solve.

[Meat-Head]

Your country makes lpg

slighly confused, reset and ensure fresh gasoline, hold rpm 2500, 3rd gear for your 5km

then read the codes?!

[alessioblaupunkt]

LPG is imported, dunno where.

Fresh gasoline no way I put, owner will put.
Codes in the future, told the owner to run 2 weeks on gasoline to see if error is the same.
(Car arrived in lpg mode)