OBD Diagnostics & LPG Management conflict?

[Art0ir]

Have a management light on my E46 330ci fitted with gas..

I bought a cheap Autel with the intention of even getting some basic codes to work with.. no luck. Power going to it but couldn't detect the engine module.

Bought INPA, after cocking about with it for a while got it up and running and connected to the car. Can connect to the chassis module, instrument cluster, etc but still not Engine module. ("NO Response" Error).

Figured I may have messed up the installation or my cable is no good.

Plug it into a guy down the road's INPA and same issue. Works fine on his car (E46 320D)

I've read that closed loop LPG systems sometimes piggyback off the OBD and as such take priority over any diagnostic cables connected. Is there any way around this?

[MPShan]

In my experience (certainly in the systems I looked at when I got my car converted) the LPG system uses a seperate ECU which intercepts the signals sent to the petrol injectors and sends it to the gas injector instead.

I have a standalone ECU located under the bonnet for the LPG, that creates & stores it's own fault codes but obviously doesn't illuminate any warnings on the dash.

That's only my personal experience though; I'm interested to hear the outcome of this one. Good luck getting it sorted.

[scotty_d]

MPShan said:

In my experience (certainly in the systems I looked at when I got my car converted) the LPG system uses a seperate ECU which intercepts the signals sent to the petrol injectors and sends it to the gas injector instead.

I have a standalone ECU located under the bonnet for the LPG, that creates & stores it's own fault codes but obviously doesn't illuminate any warnings on the dash.

That's only my personal experience though; I'm interested to hear the outcome of this one. Good luck getting it sorted.

This is what i have just fitted to my dads volvo only last week he had it in his old volvo for 10 years. He bought a similar car but 500cc bigger engine. I had problems with the lamda not being compatible with the ECU due to it operating out with the voltage scale of the ecu- 8v apparently a hand full of volvo use this system. I ended up running a universal 4 wire lamda for the gas system as well as keeping the original for the petrol.

I have never known of a LPG system to work though the OBD

[redgriff500]

Best way is to get someone with the right LPG software to check it out.

I've run loads of LPG cars and some throw random codes - particularly the later ones.

The better kits, correctly installed don't.

However I ran one that threw a limp code every few months... disconnect the batt to reset... ran it like that for 3 yrs with no issue.

[ch427]

can you disconnect the gas wiring and do the check just to confirm it is the issue?