GQ/Y60 97 4.2 EFI LPG gas problem

[ablast]

HI all,
My 1997 GQ 4.2 ltr petrol on gas.
The patrol ran out of gas and as it did backfired. Since it backfired it is running like a shaking machine. I've replaced the diagram in the secondary gas unit (not the main gas converter), replaced plugs, leads, checked distributor, replaced the sock that blocks the holes in the joining pipe and made sure the air box is sealed. I had it to a mechanic and they don't know why it is running like a charf cutter either. Need help?

[MB]

How big and bad was the backfire Ablast mate? Our little D21 Navara work runaround on LPG has done some ripper backfires lately coming down hills. Tappits are as noisy as hell now, we think it has stressed the crap out of the valve springs, it's off to the mechanics ASAP.

[threedogs]

did it blow the air cleaner housing off ???

[ranger gus]

Mine backfired completely cut out. Don't know when it happened but we located a crack in our dizzy cap and a massive one in our air box. Replaced what we could but the problems still there. We've narrowed it down to our MAF (unfortunately ours seems completely shot). Try giving yours a clean with proper MAF cleaner. Also give your IAC and throttle valve a bit of carby cleaner. Seems to help a lot of other people with this problem. Good luck!

[dom14]

HI all,
My 1997 GQ 4.2 ltr petrol on gas.
The patrol ran out of gas and as it did backfired. Since it backfired it is running like a shaking machine. I've replaced the diagram in the secondary gas unit (not the main gas converter), replaced plugs, leads, checked distributor, replaced the sock that blocks the holes in the joining pipe and made sure the air box is sealed. I had it to a mechanic and they don't know why it is running like a charf cutter either. Need help?

Is it running badly on LPG or both fuels?
If it is an LPG issue only, then probably focus on the possibility of some gunk getting sucked into the LPG cut off valve/filter just before the LPG converter.
Before that, make sure the backfire hasn't damaged the LPG mixer diaphragm. If the diaphragm is ruptured due to massive backfire, then it's advised the mixer unit is replaced.
Also any damage to the airbox and any air/vacuum leaks can make LPG more sensitive to that than it would for petrol.