vn S1 manual backfires on gas constantly

[Phat VN]

hey fellas um my vn manual always seems to backfire on a regular basis im getting sick of going through air boxes, and my pod just didnt work blew off all the time. any ideas on wat the hell is going on and wat can i do to fix it thanks

[buzuki]

start with leads coils and plugs, once they're all good get the gas tuned

[camstatic]

I'm not sure about the backfires themselves, but I devised a relatively non-expensive air box saver for a mate's car once... Get a 2" hole saw, and drill a hole in the front of the top half of your air box, and buy a rubber grommet to fit the hole. Always keep a spare grommet in the glove box, and you shouldn't blow up another air box.

[Phat VN]

i would say it just needs a gas tune

[Phat VN]

yeh thats wat my step dad said just haven had time to it but i will do that thanks mate

[social]

stop doing burnouts lol, i knew for one, when i did a vurnout on gas, i blew the airbox...hehe

[levymetal]

there was another about backfiring the other day!

as said above, change your plugs and leads first. old shitty plugs and leads are the number once cause for backfires on lpg.

[STEALTHY™]

You answered your own question in the title.

Gas = backfires!

Just ditch the gas, and use petrol!

[VNexecutive]

You answered your own question in the title.

Gas = backfires!

Just ditch the gas, and use petrol!

maybe he doesnt want to. probably why the car has gas in the first place. obviously what he's saving on petrol he's spending on airbox's though

v6's are prone to it, as already mentioned, leads and spark plugs make a big difference. also cars tend to backfire on gas more when the weather conditions are cold. also have been told by a trustworthy mechanic that cold air intake setups are no good for standard mixer type gas systems. i run a pod filter on mine (so flame me..).

[Phat VN]

i dont do burnouts ( not riding brake just coming out of right hand corners still twins though) i got plugs at home ill do it over the weekend. I would run it on pettie if my fuel pump worked grrrrrrr how much are fuel pumps easy to change GAS IS JUST SO CHEAP but it burns out quicker. would i be losing alot of power running it on gas

[levymetal]

you'll need to get that fuel pump fixed, i like to start my car on petrol then flick it over to gas after a minute of driving or so. i've been told that i don't need to do this, but i've never had any problems so i'll continue to do this for as long as i have lpg powered cars. you need to at least run the car on petrol once a week.

get new leads as well before you change those plugs, your leads are probably rooted.

VNexecutive: i run a CAI setup on my car and have no problems at all, and for the record CAI gives a very worthwhile gain in performance. if anything, i thought hotter temperatures would be more prone to backfires due to higher intake temps and increased resistance in the leads etc... ?

[Phat VN]

ok i will thanks

[VNexecutive]

VNexecutive: i run a CAI setup on my car and have no problems at all, and for the record CAI gives a very worthwhile gain in performance. if anything, i thought hotter temperatures would be more prone to backfires due to higher intake temps and increased resistance in the leads etc... ?

it was just what i was told by the gf's dad (mechanic/gas specialist). also my mate said the same thing (mind you he had gas on a worked I6 ef).
i know cai's give increased performance due to the cold air factor. apparently gas burns easier if the intake temperature is warmer. mine hasnt backfired once since i changed to a pod filter.

[omaz78]

modified air intake box top half
Buy three good quality sink plugs from the hardware shop the one's that are about 8-10 mm thick(the plugs are usually red with a little white plastic thing in the middle with a little metal hook on it) and drill three holes in the top half of the box not too close together though with the big round hole saw drill bits the one's that plumbers use cant remember what size but use the bit closest to the plug so its a good tight fit, jam the plugs in the holes you cut, and get some thin wire (or cable ties) through the little holes in the top of the plugs and connected the wire to front of the car, so if it does backfire through the box it doesnt break the box to pieces and you cant lose the plugs, ive had this in my car for about 2 years and i think its back fired once or twice and worked very well,the plugs come out when it back fires and doesnt break the box, just put the plugs back in whenever it does

[Blown V6 Hatch]

modified air intake box top half
Buy three good quality sink plugs from the hardware shop the one's that are about 8-10 mm thick(the plugs are usually red with a little white plastic thing in the middle with a little metal hook on it) and drill three holes in the top half of the box not too close together though with the big round hole saw drill bits the one's that plumbers use cant remember what size but use the bit closest to the plug so its a good tight fit, jam the plugs in the holes you cut, and get some thin wire (or cable ties) through the little holes in the top of the plugs and connected the wire to front of the car, so if it does backfire through the box it doesnt break the box to pieces and you cant lose the plugs, ive had this in my car for about 2 years and i think its back fired once or twice and worked very well,the plugs come out when it back fires and doesnt break the box, just put the plugs back in whenever it does

Wouldnt you be better off just fixing the backfiring issue properly?? I'm not a fan of LPG by any stretch of the imagination, however it shouldn't back fire providing:

Plugs & leads are in good nick/replaced regularly
O2 sensor is replaced every 40,000 odd k's
Gas system is kept in tune
Gas system is a good quality unit (if there is such a thing lol)

If you have backfiring on gas, one of those things will be the cause.....If all else fails just pull the gas system off like i did and be happy ever after.

[omaz78]

Wouldnt you be better off just fixing the backfiring issue properly?? I'm not a fan of LPG by any stretch of the imagination, however it shouldn't back fire providing:

Plugs & leads are in good nick/replaced regularly
O2 sensor is replaced every 40,000 odd k's
Gas system is kept in tune
Gas system is a good quality unit (if there is such a thing lol)

If you have backfiring on gas, one of those things will be the cause.....If all else fails just pull the gas system off like i did and be happy ever after.

Im not saying do this to fix the problem its just a precaution,
sometimes gas does backfire for no reason eg; starting on gas does sometimes....
ive got one of those stupid auto gas changeover things it changes from petrol to gas when you do so many revs and it never starts on gas, i had a problem a couple of years ago and it was just plugs and leads and i still use this just in case..........

[VQXTC]

when your doing the plugs just remember to gap them to around 1.0mm.........believe me it makes a difference.......

cheers

[Phat VN]

ok thanks i will gap them tooo hopefully it will fix it otherwise have to buy new leads to very very tight on money c how we go

[VQXTC]

Let me know how it goes....

cheers

[SUSVN]

vn manual on gas waste of time, they will always back fire unless you basicaly flat change, as the v6's have a wasted spark ignition system, the only other way to stop it is get rid of the gas completely.

you need to keep the revs up when changing gears, this will eliminate the back fire issue to some extent, the autos dont have this problem as you dont back off the accelerator when you change gears so the tb stays open

[DavoVP]

not realy true, i have a vp manual, doesnt back fire when i change gears................ infact it never has, its only backfired on start up, and the odd occasion when im realy loading it up but thats only if i feather the accelerator hehe

i did go through a stage where itd backfire if you didnt take off like a grany then when it was over 1.5k u could flog it floor it abuse it, no worries, a good tune saughted that out quickly.

[crazywog]

id say try strong hoze clampz on ur pod filter , if not take air box and pod filter of and get a good hose clamp and stick a stocking over the end, guarenteed this wont backfire and wont let dirt/bugs of the kind in trust me mymate had the same problem with his and fixed it with that exact procedure. try that and let me knw how u go thnx mate

[Phat VN]

mate that is a really good idea y didn i think of that ( maximum air going in) MEANS MORE POWER hahahah i will do that tonight catcha

[andyli]

You answered your own question in the title.

Gas = backfires!

Just ditch the gas, and use petrol!

you are right. the mixed convertion of gas got lots of backfire, they say the injection one is the one to go, but once again, too expensive. but there are more and more car with the samll lpg tag. 4.4 each for the spark plugs and 55 for the lead, then the coil pack, normally 50 for the set, but you have to look carefully to get a good one. that are the things to check first, as they say.

[Phat VN]

hey evry 1 i bout new leads 8mm bosch performance $55 and new plugs came with the car NGK and new filter. it has only backfired once and that was this morning but runs heaps better buying a new memcal chip soon so that = more power and yeh thanks heaps u guys