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Posted: Mon Sep 08, 2008 7:06 pm
by ChrisJC
It's not that there isn't enough vacuum. The restriction caused by the AFM causes the engine to suck too much LPG out of the mixer, so it runs very rich. I proved this with the Lambda sensor + readout that I have in my van.
Chris.
Posted: Mon Sep 08, 2008 7:07 pm
by Dangerdoc
Bodger,
exactly what type of mixer are you using?
If it is not a cylindrical type and it is the flat little bugger that has a small lipped venturi then it must go upstream of the AFM.
Only those of the cylindrical type should be attached to the plenum.
I never thought to ask that Q
Posted: Mon Sep 08, 2008 7:28 pm
by bodger
are yes that would explain it , i have one of those lamba control thingy
and when i did get it running with the AFM jammed open ..it was so rich
that i almost had the power screw right in and still no green light ( lean )
DD , i have one of those round ones that are suposed to be on the plenum but mine is here ....
Posted: Mon Sep 08, 2008 7:47 pm
by Dangerdoc
It's not straightforward in the least.
Getting the mixture right is just as important as setting up the right timing and the extra advance to compensate for the slow flame front of LPG.
The power screw can be turned down but you start to get into all the probs of having to reduce the output screw on the vapouriser as well.
Turning down the Vaps output and balancing with the power screw in the vapour feed pipe should help.
Posted: Tue Sep 09, 2008 3:44 pm
by bodger
Hi DD , i have one of these
http://cgi.ebay.ph/Autogas-Lpg-Lambda-C ... dZViewItem
not bad , i have left the unit with the flashing lights on attached to the unit and fitted to the dash ...
red light =too rich
green light =too lean
i have put it back like the picture for the minute ...ie:
airfliter -- mixer -- AFM -- backfire -- plenum .... etc
and it runs fine ..