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[sassanach]

ive have been working on a stag lpg equipped 2.5 omega on a t plate today, and the problem is this,it runs fine on petrol ie all the injector times are identical and the lambda sensors cycle rich/lean etc ,but when you switch over to gas  the injector times on one bank increase by approx.50% and one lambda reads weak and the other reads rich.come on chaps give us a clue

[Omegatoy]

ive have been working on a stag lpg equipped 2.5 omega on a t plate today, and the problem is this,it runs fine on petrol ie all the injector times are identical and the lambda sensors cycle rich/lean etc ,but when you switch over to gas  the injector times on one bank increase by approx.50% and one lambda reads weak and the other reads rich.come on chaps give us a clue

firstly is the lpg filter fairly new??
sounds like the vapouriser is not supplying enough gas for both banks???
could be the diaphragm in the vapouriser got a small split in it??
could be vapouriser not hot enough??
are the gas injectors clean? they are stripable for cleaning
hows that for starters??

[VXL V6]

Only reason I can think for the ECU to add more fuel would be if the Lambda tells the ECU that it's lean?

Does the ECU have two Lambda inputs or is it running from a single input?

[Martin_1962]

I bet the injectors and lambdas are cross linked - ie RH Lambda monitoring LH bank

[Kevin Wood]

Sounds like a cross-linked wiring of the system, as Martin said, or one bank is delivering more gas than the other. Possibly a dodgy injector?

I would try switching cylinders one at a time from petrol to LPG and see if one cylinder in particular causes the injector times to go out of balance. Listen for a misfire as well.

Actually, I wired mine crossed the first time I fired it up on gas and, because this system switches over one cylinder at a time, it stumbled big time when switching from petrol to gas. You get one cylinder getting petrol and LPG, and another getting nothing.

I had approximately 10% imbalance between one bank of injectors and the other on mine. It was the injector rails themselves. Just added 5% fuelling trim to 3 cylinders and pulled 5% from the other 3.

Kevin

[sassanach]

martin imber gets it spot on.cross linked lambda,s you learn something new all the time

[Martin_1962]

martin imber gets it spot on.cross linked lambda,s you learn something new all the time

Good guess

I just thought about it and it was pretty obvious.

Mind you I am a black belt in fixing bugs!