Outer Limits 4x4 Board

hi, got a little problem! i got a backfire through the air flow metre that blew a hole in the air cleaner and blew a few hoses off as well, hooked up all the hoses again but it wont start, after some information on what causes the back fire in the first place as i will need to fix the problem before installing another air flow metre. it's an 86 rangie 3.5lt on gas. any help would be much appreciated, thanks!!!! :?

dont know if this is any help, but i have heard of people fitting some sort of jigger that holds the air flow flap fully open when on gas. wont help with the backfiring but it will stop the destruction to the flow meter when it all goes bang.

a mate of mine has fitted ocky straps to his aircleaner lid instead of clips. when it backfires the lid pops up the re-seats. a beautiful booty fab thing.
relives the pressure and stops things breaking.
Unfortuantly he also has a dent in the bonnet from the lid going balistic

Dont know of any body who has fully stopped the backfire problem.

Simon

It won't start on gas? Maybe check that the hoses are in the right spot..... Far as backfiring, check your plugs, and maybe get it tuned on a gas analyzer.... Very difficult to completely stop backfiring on gas, due to the lower octane rating - it's possible for small particles of carbon in your cylinder to cause preignition, among other things. The best you can really do is keep it tuned right, and good condition plugs....

Your air flow meter shouldn't nescessarily be the cause of not starting - especially if its not starting even on gas - most cars will start without the AFM plugged in, just they'll run rough, and not rev.

The afm has absolutely nothing to do with operation of gas though, its merely in the way - as such, straight gas cars have no AFM, or even carbies.

G`day ,

Some dual fuel systems start on petrol then switch to gas automatically , others are manually switched as in you choose which fuel with the switch .

The norm is for the flap in meter to be twisted when there is a large back fire as yours sounds to be .

I`d suggest you take the pipes off the meter and see if the flap moves , if it`s stuck force it closed , if the flap is twisted the meter is of no use so you can`t do any damage . Then switch it on to petrol and start it , it should idle but may not rev at all . If it starts then get a new/s-hand meter $$$ , fit the meter but only run on petrol .

You will then be able to give it a comp test to check it`s not a mechanical fault , ie == headgasket , valves etc .
If that`s ok , check the whole ignition system , leads , plugs , dis- cap , rotor arm , etc .
If that`s ok check for any air/vacuum leaks or any thing that would cause it to be lean including the gas mixture .

There are many things it could be . I think it will be easier to have it running on petrol first to find the problem . Have it running in the dark with the bonnet up and see how many sparks if any are leaking from leads , caps , etc .

All the best , peter .

Peter Hi again.
If the flapper in a Rangie is the same as the Federal injection, the fuel pump relay is controlled by the opening of the flapper while cranking, ie the fuel pump relay is disabled unless the flapper is slightly open.
So , if you close the flapper , then open it a little bit. You should hear the pump start if you lift the flapper a little
Regards Philip A

G`day Philip .

Yep , seems to me that all the flappers are based on Bosch and though differences . basics are the same .

Got a flapper thats suffered the same fate , when i pushed the vane closed it moved enough to start , have since straightened and freed it up and when time permits will put it back together and try it but don`t hold much hope , also have another with dead spots .
When i`m able to find info on the internal values i`ll make one out of the two but then i may not be as clever as i`d like to be , though it looks possible .

All the best , peter .

thanks to everyone that helped, it up and running again, jammed the flap open and put it back together again running like a gem again. thanks