G
Guest
Guest
Hi. My FZJ80 VX is dual petrol / LPG.
For a while now it has run badly on petrol but on LPG it's absolutely
AOK. Just changed the petrol filter in the hope it might be that but the
problem is still there so now I need help, well many that know me have
been aware of that for a while but that's another story! ;-)
The problem manifests itself thus:
It'll start fine on petrol, first flick of the key and be OK for a few
seconds.
This bit is hard to describe but here goes; after a few seconds the
engine gives the impression that it's fighting or straining against
something, it's as though some force is grabbing the flywheel and trying
to slow the engine down. It judders, the revs decrease over about 10
seconds down to an indicated 200 or so, it judders some more, almost
stalls and the next second it's as though the invisible hand has let go
and the engine picks back up to a smooth 800 rpm. A couple of seconds
later and the whole process starts over again. If I try and drive it in
this state it feels gutless.
If I switch over to LPG it's 100% OK, idles fine, pulls fine, MPG is
fine (well, same as it ever was anyway!)
I don't think it's ignition related as LPG needs a more precisely timed
and 'hotter' spark to run properly so if it were ignition I would expect
it to run fine on petrol and not on LPG. Can't be air intake or exhaust
related either because it's fine on LPG so it must be fuel
related???????? Injectors? Pump?? Why the cyclical pattern? How can I tell?
Does anyone have any ideas?
Pete
1995 FZJ80 VX Auto
Worcester
England
For a while now it has run badly on petrol but on LPG it's absolutely
AOK. Just changed the petrol filter in the hope it might be that but the
problem is still there so now I need help, well many that know me have
been aware of that for a while but that's another story! ;-)
The problem manifests itself thus:
It'll start fine on petrol, first flick of the key and be OK for a few
seconds.
This bit is hard to describe but here goes; after a few seconds the
engine gives the impression that it's fighting or straining against
something, it's as though some force is grabbing the flywheel and trying
to slow the engine down. It judders, the revs decrease over about 10
seconds down to an indicated 200 or so, it judders some more, almost
stalls and the next second it's as though the invisible hand has let go
and the engine picks back up to a smooth 800 rpm. A couple of seconds
later and the whole process starts over again. If I try and drive it in
this state it feels gutless.
If I switch over to LPG it's 100% OK, idles fine, pulls fine, MPG is
fine (well, same as it ever was anyway!)
I don't think it's ignition related as LPG needs a more precisely timed
and 'hotter' spark to run properly so if it were ignition I would expect
it to run fine on petrol and not on LPG. Can't be air intake or exhaust
related either because it's fine on LPG so it must be fuel
related???????? Injectors? Pump?? Why the cyclical pattern? How can I tell?
Does anyone have any ideas?
Pete
1995 FZJ80 VX Auto
Worcester
England