LPG problem, backfiring in 80 series landcruiser

for what its worth......overheard a club member (supposedly a good mechanic with gas experience) talking to a visitor about back-firing on his LPG commodore....."get bigger diameter spark plug leads"

Gas Research replacement throttle body.
More economy, more power, no more back fires and no need for the backfire blow out section.
No vested interest, just all good experience with their product.
Check them out, they're on the web.

Thanks again Tuff60.
With my limited mechanical know how it appears their product might not suit my 80 series EFI motor.
Will ask them that question.

Pedro

If they're not still available they used to make a kit. I have worked on and driven EFI 80's with research kits fitted, never owned an 80 myself.
My EFI V8 60 will be fitted with one when I get back to Aust.
There is a 4WD buff who works there(or did) that knows his way round Toyota's, sorry can't remember his name.

As a gas fitter fitting gas reseach will not fix your backfire problem 99% of all backfiring is from poor spark your need to fit not only bigger leads but spiral core leads which are made for lpg.The best leads available at the moment are ICE ignition leads made locally in Melbourne Call ICE IGNITIONS and speak to MIchael .
Also try and get a spark plug with the same numbers as listed std but remove the R from the listing these have about 4-5k ohms less resistance than R versions eg
NGK BPR5EY then use BP5EY . Do this and your vehicle should be backfire free....

Yes these are known as backfire socks and serve their purpose in small back fire siutuations .A large backfire will in alot of cases destroy the a/f meter on most cars .
Or as on falcons and commodores completly destry the aircleaner box itself...

Petro you need sparkplugs without the R not leads also get the car dynoed to make sure the air fuel ratio is correct should be 15.5-1 cruise and 13-14.1 flat out on the lpg scale as most a/f ratio meters have petrol and lpg scales good luck,....

back fires can come from;

1. improper ignition - plugs / leads / rotor / dist cap / wet plugs or leads
2. 'flame back' - open exhaust valves igniting the mixture while the inlet valve is still open - usually at low speed
3. improper A/Fmixtrure combined with #2

a decent backfire will destroy the mass based air flow meter. Engine may appear to run OK ad revs, but will die at low revs. Hot wire air flow meter will survive better.

Any decent LPG shop should be able supply a sock.

Been there - had the problem :-(

Dave
ENG-TEK

Cabbageoz, I have been to see Scott and he identified an arc on the old ignition leads that probably caused the backfire. He said ignition leads needed to be changed at least every 80000kms and spark plugs every 20000km.

Have booked in for Friday and he will go over set up and components, to see all is working ok.
He did confirm that as my vehicle (80 series) is fitted with Impco LPG the Air Flow meter needs to be close to the engine for maximum performance. This was confirmed by Queensland Manager of Impco.
Where I had been informed by all who have previously seen set up that it was incorrect the above puts a different complexion on whole issue.
Re performance he did see one component which had been fitted upside down and that a "dump valve?" had not been fitted.
Each of these components would affect performance.
Also if the set up had been changed around performance would also have been adversely affected.
Will post again after the job is done on Friday

Pedro