VS Berlina V6 auto on LPG revs to 2000rpm when turned on?

[pjdm1980]

I've recently brought a '95 VS Berlina V6 auto on LPG and when you first turn it on it revs to 2000rpm then 5 seconds later it drops down to 800rpm and is fine to drive but if you have it in neutral and give it a rev it will hold the rpm for 2-3 seconds.
It has brought up the following codes-
Code 57 - Injector Power supply voltage variation (It has a early LPG system that doesn't use a loom off the injector wiring)
Code 76 - Air/Fuel ratio variation between left and right banks (assuming it's a bad O2 sensor)
Which I don't know if it matters as it doesn't have a working fuel pump so starts and runs on LPG?
Thanks for any advice, cheers Pat

[scvs6]

Hey mate,

When my VS Berlina was on gas, it was doing exactly the same thing as what you have described and even had the same codes. I changed nearly every sensor on the engine and had the diagnostic scan tool hooked up to the car constantly and never found what the problem was. I think it was doing it for almost a year, but then I had the LPG system removed and I done an engine conversion. But good luck finding out what causes it.

[strgas]

code 57 is common on LPG fueled commodores due the power cut off to the injectors when on gas so nothing to worry about there
code 76 could be a bad O2 sensor or even a simple air leak or crack in the exhaust upstream of the O2 sensor .

[scvs6]

code 57 is common on LPG fueled commodores due the power cut off to the injectors when on gas so nothing to worry about there
code 76 could be a bad O2 sensor or even a simple air leak or crack in the exhaust upstream of the O2 sensor .

I have been told by a workshop that does LPG conversions that the O2 sensor code will come up as well when the car switches over to gas. I am pretty sure both those codes will come up on any V6 Commodore that has been converted to LPG.