Discovery 2 V8 petrol missfire lpg fine

Hi all,

I'm new to the forum and in need of a bit of help!!

I have a discovery 2 V8 (2000) converted to LPG (Landi multipoint).

About 6-8 months ago I had an issue that when running on lpg it would switch back to petrol intermittently and blow the engine management fuse, so once switched off it wouldn't restart. Had the errors read and it showed injector 8 malfunction. So I removed air intake to investigate (changed the leads to Magnacore leads at the same time) and when putting 12V on injector 8 nothing happened so I replaced it and reassembled everything. This cured the problem for the lpg side which now runs perfect. However I still have a very definite misfire whilst running on petrol and over 50mph the vibration is unbearable.

Had the error codes read again a few days ago and showed following errors:

- Cylinder 5 misfire
- Cylinder 8 misfire
- Cylinder 8 injector

My mechanical knowledge is limited and I'm only learning through maintenance but I'm guessing the problem is fuel supply, injector or ecu related as they aren't common with the lpg system. If anyone has any thoughts on what the problem could be or what to check it would be much appreciated.

Thanks.

the petrol injectors are in common with the lpg..the ecu switches them off when on lpg..my first call would be checking the wiring on petrol no.8 injector....

Thanks a lot for the reply. So am I right in saying that the main petrol ecu sends the signals but the lpg ecu decides when the switch the signal to the lpg injectors? So the fault is going to be somewhere between injector 8 itself and the point where it switches?

proberly..