BMW 540I Running rough on LPG.

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Joined:Wed Aug 20, 2008 8:00 pm
LPG System:autogas2000
BMW 540I Running rough on LPG.

Post by davidpike56 » Wed Sep 22, 2010 11:00 am

I had my car checked as it was missing slighty when running on LPG, (BMW 540I W Reg.)its a tartini system fitted when i bought the car.on the service it showed it was not firing on one of the cylinders and that a new injector rail would solve the problem.
the car does now run smoother (still not as smooth as when on petrol) but i have a number of problems on LPG which i am hoping to have answered (hopefully)
the car now takes longer to switch to lpg even when the engine has reached normal tempreture.i need to rev the car to approx. 3000 rpm to get it to switch to gas, and quite often it then runs as if its firing on 4 cylinders, i am forced to switch back to petrol as the car would stall if i carried on with LPG.
this can take up to 5 miles before it runs correctly on LPG, whereby previously it would switch after about 2 miles and on LPG any help would be apprieciated.

Joined:Mon Sep 03, 2007 8:48 pm
LPG System:Prins VSI
Car:BMW 540iA Sport
Location:All over the UK

Re: BMW 540I Running rough on LPG.

Post by mak-uk » Wed Sep 22, 2010 10:04 pm

You really need to take it back to whoever fitted the rail for you so they can diagnose the LPG ECU. Could be a number of things (e.g. incorrect switch over paramters or incorrectly plumbed heater hoses).
Site Owner
2001 BMW 540i Auto Sport Saloon
~300 BHP; ~320 ft/lbs, Prins VSI system

Joined:Tue May 17, 2011 10:42 am
LPG System:singlepoint
Car:v6 3.5 shogun

Re: BMW 540I Running rough on LPG.

Post by tubbs » Thu Jul 28, 2011 11:46 am

Kenny i have converted many 540's to lpg without any issues. But yeh i would not run the car on gas until the fault has been sorted. If its got a misfire then it would need to be rectified. It could be many things im afraid as mak says. It could even be a dodgy temp sensor. Hard to say without seeing what its doing on a laptop.

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