problems with backfiring and stalling on VP!

[-**wHiStLe**-]

tonight i went to drive a friend home, i have a 3.8L Vp exec.
its dual fuel...on gas the engine was 2 bars from the bottom on cold..i took off and the car backfired...i've been told this happens when on gas...but later on the car was idling at 0rpm and it kept stalling like at a t-intersection and around a round-about when i took my foot off the accelerator...is this normal or should i have it looked at? btw it runs fine on petrol it's just the gas.

[Pretender]

Have a look at your Airbox to make sure it is in one piece and still connected to the throttle body. They often blow to pieces when there is a backfire.
If you are lucky it may just need clipping back together.
If the Airbox looks OK open it and check if the airfilter is still complete.
If it is then check all clamps on the intake tubing (airbox to throttle body)and the rubber sections for splits.
It's running rough on gas as there is too much air being drawn into it. Well I would be surprised if that is not the case given the backfire.
With gas you need to ensure the correct plugs are fitted and it is serviced regularly but it can backfire regardless if you open the throttle fully when the motor is cold.

[jabbavx]

I had a VS on gas and this started to happen becasue a coil pack died. It causes backfire and stalling. Maybe have a look at that.

[noah_73]

Do not hesitate to put new leads and plugs in it, it won't solve your problem but it will go a long way to preventing it from happening again. Spark plugs in an LPG vehicle need replacing twice as often as a general rule and once they have been in too long backfiring is a given thing. Lpg shop I used to work at found Bosch plugs were a winner in a Commodre. As for the running rough, could be a million and one things from a vacuum leak to a blown diaphragm in your mixer. Do you know what brand of LPG system is in it?

[xlr8_87]

my airbox was anihilated (sp?) by a backfire! blew a hole in the airbox, and half the piping off, whacked a pod on the end (my theory which was meant to fix it...) ended up blowing the pod off and even more of the piping! hasnt done it in a while though, i think a service (inc. new leads/sparks) fixed it up!

[etower]

Had the same problem with my vp. I put 9mm leads & ngk plugs (bpr6ef-13 they use these on the s/c commodore) for the last 12 months and Iv'e had no back fire or damaged air filter/box. Also had the mixer looked at and had a hose replaced due to it starting to perish, hope this helps

[-**wHiStLe**-]

i don't think i should really blame the car. i was hammering a lil when the engine started to warm up and planted it from a stop and that's when it backfired. so i guess it must have been expected.

[-**wHiStLe**-]

ok my airbox is blown to shit....would a pod with a heatshield around it be a good idea?

[Shifty1]

pod on lpg is a no-no.. stay ith box.. lpg doesnt like a pod at all..

[SlyVR]

yer my air box went pooof ya can ask ppl on the sa cruise LOL, i just got eagle 9mm leads n a new air box, i hope that fixed it, i might get the gas mixer diaphragm checked just to be safe.

Mine blew when i stoped and had to gun it to miss a car cause the revs were low and rough and yer backfired.

[HoZy]

pod on lpg is a no-no.. stay ith box.. lpg doesnt like a pod at all..

LPG loves a POD, Get your LPG tuned while on a dyno, It'll pay off....

Had my POD on now for about 2years.

Cheers
MaT

[xlr8_87]

yah...go the pod
mine's running pod and has been great

also the 9mm Eagle leads seemed to make it run a lot smoother on gas. havnt had a backfire in about 9 months now (none at all with 9mm leads/pod)