LPG idle mixture

ChrisJC · Post by **ChrisJC** » Mon Jan 29, 2007 1:25 pm

Afternoon all,
I've got an LPG system on my 3.5l flapper EFi. It's got an OMVL vapouriser and a mixer on the plenum inlet. I've also got a vacuum operated flap-opener on the AFM.
The engine is Range Rover spec, but with 10.5:1 P6 pistons.

I also have an in-cab LM-1 wideband lambda sensor.

Now the problem - I seem to be unable to set a stable idle mixture. It can vary from around 20:1 to 12:1 with no real rhyme or reason for it.

Any suggestions as to why that might be would be greatly appreciated - it failed the MOT this morning on idle emmissions, and I know that if I set it up pukka on the drive it will be miles out again when it gets retested.

Thanks,

Chris.

stirlsilver · Post by **stirlsilver** » Tue Jan 30, 2007 10:17 am

I normally have my idle mixture set pretty rich so that it doesn't lean out as I start to accelerate at the lower rpms, but it stays pretty constant. Only things I can think of is a pretty big leak somewhere in your intake or something is coming adrift in your evaporator...

ChrisJC · Post by **ChrisJC** » Wed Jan 31, 2007 8:02 am

Hi,
Good point about a leak - I'll have to check that one out......

Chris.