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View Full Version : high revs after lpg backfire



disco97
20th June 2009, 07:54 PM
Hi Guys
i have searched but cant find anyone with the same problem before :(
i have had gas on my car for 1 week now and its run perfect until i had a backfire this morning (first one) when i started the car it idled rough (but ran fine) which is the first time its done that i got 700 metres down the road and it shuddered 3 times then backfired in a big way then the revs went almost 4000rpm and i had to shut the car down tried it on petrol and still high revs. im taking it back to the gas fitter on monday but any idea why it would run at about 4000rpm or more after a backfire?
it also has some water leaks from the T peice they put in buttheres enough water in the system not to cause this i would assume

hope someone can shed some light on it for me i might invest in a flapper valve while im at it



jeff

langy
20th June 2009, 08:31 PM
The explosion has blown a component out of whack ie either a connector is halfway off or a vacuum pipe or the MAF. ( You can start an engine without the maf but is runs horrible). As to whether or not something is permanently damaged is a long guess. It's not really advisable to use the engine without the MAF. Probably a good idea to wait for Monday's appointment.

mike 90 RR
20th June 2009, 08:58 PM
....and it shuddered 3 times then backfired in a big way ....

and get it "Tilt Trayed" to the mechanic ....

disco97
20th June 2009, 09:16 PM
it will be on a tilt tray trust me no way am i going to add anymore to the stuff they will have to replace. and i could hardly pull her up even jumping on the pedal had to shut it down

p38arover
20th June 2009, 09:17 PM
I think you've blown a hose off and it is running very lean.

It's not uncommon.

buzz66
21st June 2009, 10:36 AM
Could have damaged the air flow meter.
Flapper or hot wire, not sure which engine you have. Worth checking.

ozscott
21st June 2009, 04:36 PM
Mine used to rev its ring off when cold...it all settled down after a new MAF and a few hundred k on it.

Cheers

PS. What type of system do you have...how long since plugs, leads and coil packs changed?

Cheers

PPS. I ask that to see what reason is for backfire

tracker
21st June 2009, 05:23 PM
lpg fitted last week.dyno and tune. plugs leads and dizzy supposed all checked,there seems to be a lot of oil rhs maybe from top of tappet cover.air box took a good hit.throttle does not seem to be closing all the way.

ozscott
21st June 2009, 07:43 PM
....arrgh...dizzy - you have a D1 sorry I assumed D2 for some reason. My 95 on LPG used to backfire until I stopped chasing the lucas dizzy and put an Australian bosch based performance ignitions dizzy in...no more problems.

Cheers