LPG backfire issue

[Greggles_VS]

Hey i started my car on LPG by mistake today and it backfired, running on petrol it was nearly stalling and running very rough, i got it home, checked the MAF and vacuume lines, MAF is fine, only problem i found is the vacuume line under my throttle body was disconnected. Since reconnecting it, it runs on petrol, a little rough, but every time i switch it to LPG the revs drop and the car stalls, what could it be as i dont trust big name mechanics. Cheers

 

[frogsta]

I used to have this problem... I can't really help but is your air filter still intact?

 

[showbags]

Most LPG backfires are due to faulty leads. You'll find 9/10 times replacing the leads will eliminate the problem.

 

[two-bit]

plugs and leads. plugs and leads. can't say it enough. when i got my lpg conversion done stupid me didn't do the plugs, car back fired going up a hill scared the hell out of me, then backfired and stalled did the plugs the next day runs like a dream.

also get the lpg tuned make sure the airbox is back together like the factory and the air filter doesn't smell burnt also there should be a line from the manifold that normally goes to the throttle body , they generally move this to before the lpg mixer to help with backfires as well, so the sensor or something can read it right and put the correct amount of gas in.

 

[Greggles_VS]

Just been outside looking it over again, waiting til next pay to chuck some 9mm leads onto it, just replaced all the sparks with new NGK ones and it ran better. No airbox issues as there is no air box, it has a K&N pod filter (already there when bought it) so luckily box didnt blow. Fixed the line under the throttle body, now have found another line blown off from behind the plenum. Hopefully the 2nd line will fix the gas, and the leads will hopefully help. No burning smell which is good. Just waiting on phone to charge so i have a decent light to find the line attachment behind the plenum so i can reattach it. Will let you's know how i go.

 

[wraith]

There is a leak somewhere. Does your pipe have what looks like a stubby cooler on it? Usually there is some sort of backfire protection on LPG cars.

 

[Greggles_VS]

Just plugged the 2nd vacuume line and now the gas is running, the car isnt running very well, but now ive found fresh oil on the connector between my trans and engine so now looking like may need the head replaced as i have just replaced the thermostat after the car was running between 1/2 to 3/4 temp. Every so often the guage will still jump up to 1/2 or more so lets hope nothing major. cheers for the replies and will see how it goes with new leads.

 

[Greggles_VS]

There is a leak somewhere. Does your pipe have what looks like a stubby cooler on it? Usually there is some sort of backfire protection on LPG cars.

no surprisingly, however word of mouth has been since pod filter is fitted it should prevent the backfiring

 

[wraith]

no surprisingly, however word of mouth has been since pod filter is fitted it should prevent the backfiring

Not true. I fitted a pod after finding the airbox was broken on my VR. Day later backfired and since then have never bothered with LPG.

 

[Greggles_VS]

Was thinking of getting COI with pod in the airbox with a release flap for back pressure