[Orangebean]

95 4.6 HSE with OMVL R90 Millenium closed loop system.
The car has sensed that it's annual MOT inspection is coming on Friday and has thrown me a few random last minute faults to deal with. Have sorted the sudden appearance of ABS Fault/ Traction Failure (wheel sensor air gap) but the LPG system is showing what I think to be a rudimentary fault code.
When driving on LPG, at random, the orange "you are running/ switching to LPG" light will flash. The red "you are running on petrol" light stays off. No apparent difference to performance and when I pull over to do a sniff of the exhaust test I'm definitely running on gas!
The orange light will continue to flash until I switch the vehicle off, even if I select to run on petrol. It does switch to petrol, red light comes on, runs on petrol (another exhaust sniff), but the orange light continues to flash with petrol selected.
Plugged in diagnostics to the LPG ECU and can't see anything out of the ordinary, but can't actually replicate the fault when static as the car needs to be driving and the cable's not long enough to have the laptop visible in the cabin when driving.
Thoughts anyone?

 

[Gilbertd]

Slow flash on the orange LED means it's detected a fault. There's only 3 faults it can detect, lambda not working, lambda lean for too long and lambda rich for too long. I've never been able to find out how long is too long but do know that I can bring the lambda lean for too long error up on a very long downhill stretch of the A8 in the south of France where it is coasting with no throttle for a long time. The flashing will clear after it has been switched off and back on again unless the fault is still there. In the software, go to the diagnostic menu and it will show you which one has come up, click on clear faults and then try it again. With it running normally, is the lambda bar flicking from red to green or is it stuck at one end? It might be that the stepper is sticking a bit when cold so isn't moving (even though it is being told to move) so the mixture is out one way or another initially. Carb cleaner and/or WD40 will sort that.

 

[Orangebean]

Hello Gilbertd!
I'll give the stepper a blast. Cold starting has been a bit hit and miss since fitting the new vapouriser.
Does the ECU diagnostics software report what the stepper is actually doing (ie from the feedback loop) or just what the ECU is demanding of the stepper? Reason I ask is, when troubleshooting the random cold start, the indicated stepper position stays stubbornly on zero, hence no gas = no start!

 

[Gilbertd]

Hmm, staying on zero, not known that one before except when running on petrol. I think there may be some sort of feedback as I have seen the software show the stepper being progressively opened up and then it will jump back down again and have another go.

The Leonardo/Millenium can sometimes get confused, especially after a jump start for instance. Usually that means it won't change over even though everything else looks fine but you've nothing to lose by giving it a go. In which case, go through each screen and make a note of what everything is set at. Then go into, I think it is the File menu and there is a button marked ECU reset. Do a reset then go through the other screens and set the values back to what they were and try it then.

 

[Orangebean]

According to the diagnostics, it's lambda inoperative and lambda too lean. Amazing that it runs at all on gas in that case! Just given the stepper a shot of throttle body cleaner so I'll see what happens...
If it is the lambda sensor, I'm guessing I could fit any generic 4 wire (haven't looked- it might be a 3) 0-1v sensor, or would you recommend buying the slightly inflated OMVL badged (probably generic) one?

 

[Gilbertd]

Assuming you've got an additional 0-1V one to drive the LPG system, yes, you can fit a generic. But, the ones from the Chinese Universal Lambda Sensor Company that you can pick up on eBay for about £15 last a year if you are lucky. I fitted an NTK that was intended for a Ford of some description that had the correct thread and chopped the Ford plug off so I could connect that. Then I hit a bit of flooded motorway at about 60 mph (in the dark, it just looked like a puddle but was over a foot deep!) and filling it full of water didn't do it a lot of good. Out of interest, I connected the Leo to one of the standard P38 5-0V ones and changed the setting in the software to 5-0V Type A and it works perfectly and there's two of those so you've always got a spare in case the one you are using dies.