Check engine light on gas

[Guy]

I have an NL paj GLX (which I am quite liking) buit the last week or two the check engine light has been comming on whne running on LPG.
Got the fault code read and it is saying the Crank angle sensor is not being read\used.
Works fine on petrol (fault goes away)

Any ideas where to start looking ?

[steverisingsun]

Recheck codes
Oxygen sensor code pops up if the gas is badly out and the proccesor cant correct enough. Or it may flash an injector code if you have no emulator fitted

[Guy]

Will take another look. Thanks.

[date]

I have been told (although I am yet to see evidence of it) that there is a knock sensor fitted to the engine to control the timing of the spark. If so, it may be that because of the different octane rating of the gas, maybe the spark has been pushed out of normal operating range, hence a crank angle sensor fault. Hence it operates normally on petrol.

Does the 'fault' appear when the ambiernt temperature is hot or cold, or is it random. If it happens when the ambient air is cold, maybe the spark has been well advanced by the ECU.

[Guy]

I have been told (although I am yet to see evidence of it) that there is a knock sensor fitted to the engine to control the timing of the spark. If so, it may be that because of the different octane rating of the gas, maybe the spark has been pushed out of normal operating range, hence a crank angle sensor fault. Hence it operates normally on petrol.

Does the 'fault' appear when the ambiernt temperature is hot or cold, or is it random. If it happens when the ambient air is cold, maybe the spark has been well advanced by the ECU.

Occasionlly if you switch back to petrol and onto gas again it goes way. but normally there from startup if it's on gas. Hot or Cold (only had the car a few weeks .. so ambient has been as low as minus 4 and up to about 15-16)

Hmm will pay closer attention to the temp next time it goes off.
If the system was running excessively rich the ecu would advance the spark I am guessing.

[date]

"Occasionlly if you switch back to petrol and onto gas again it goes way. but normally there from startup if it's on gas. Hot or Cold (only had the car a few weeks .. so ambient has been as low as minus 4 and up to about 15-16)

Hmm will pay closer attention to the temp next time it goes off.
If the system was running excessively rich the ecu would advance the spark I am guessing."

I really don't think that the gas mixture should have any significant effect on operating temps. Having said that, if it is too lean, it will run hot and tend to pre-ignite (or ping), but you have to be way too lean to get that happening. I cannot see any logical link between fuel type and a crank angle fault coming up. Fortunately, my NL hasn't done that to me - yet!

As an aside, check your plug leads - try not to disturb them but make sure that they do not cross over each other because they can short out to the adjacent lead and you get BIG backfires. Try to keep them separated from each other and earth as much as possible.

[Guy]

"Occasionlly if you switch back to petrol and onto gas again it goes way. but normally there from startup if it's on gas. Hot or Cold (only had the car a few weeks .. so ambient has been as low as minus 4 and up to about 15-16)

Hmm will pay closer attention to the temp next time it goes off.
If the system was running excessively rich the ecu would advance the spark I am guessing."

I really don't think that the gas mixture should have any significant effect on operating temps. Having said that, if it is too lean, it will run hot and tend to pre-ignite (or ping), but you have to be way too lean to get that happening. I cannot see any logical link between fuel type and a crank angle fault coming up. Fortunately, my NL hasn't done that to me - yet!

As an aside, check your plug leads - try not to disturb them but make sure that they do not cross over each other because they can short out to the adjacent lead and you get BIG backfires. Try to keep them separated from each other and earth as much as possible.

Gas system is quite new ( 8 months old roughly) The gas system, timing belts and plug leads were all replaced about 20,000k's ago so should be good .. but thansk for the heads up will take a look and make sure.

[date]

For what it is worth, my NL Check Engine Light comes on when I switch to petrol (usually as I run out of gas). It will not go out until I throw the clutch in and let the engine fall back to idle, then it goes out and stays out. No idea of what is happening and as long as the light goes out, I am happy. I assume it is something to do with mixtures then - too rich because of the residual amount of gas in the system, along with the petrol coming directly in.

I don't have an emulator in my NL, but do have one in my wife's Magna. The guy who fitted the NL system used a relay to override the Check Engine Light. I wasn't too happy with that, but it seems to go OK so I cannot complain.