I had a blowback misfire on LPG the other day (broke the airfilter box!), and scince then have had an engine management light on the dash. This does not seem to have affected the running of the car at all on LPG, but on petrol the idle is a little unsteady. Is there any way to find out what the fault is it is flagging?

Stewart

Should mention this car is a non cat 2.0i prestige with the webber injection system!

Hi Stewart, I thought all 2.0i motors were either Bosch Jetronic (Auto's) or Bosch Motronic (manuals) ?

If you have a Motronic version you should check to see if the air temp sensor that screws into the plastic induction piping hasn't been fried or perhaps the idle govenor (most likely suspect) that pushes into the aluminium inlet manifold or even the throttle potentiometer mounted to the throttle housing. If a Jetronic system check the Manifold absolute pressure sensor hasn't been wrecked during the backfire.

Colin.P

No its definatly Webber Marelli on the ECU, although is very simialar to the Bosch motronic (I had that on my J plate SEi) The idle contreol valve is working fine, as it idles perfectly on LPG, (all the LPG system does is shut the injectors down, idle control and Ignition being left to the original managemnet system), It is possible the throttle pot is damaged, although not sure how to test it!, or of its location.

I think the Marelli system was fitted between the L-jet and the motronic cars, I should mention this car has no Catastrophic convertor

Stewart

Hi Stewart, don't know about your system but on the motronic system, the throttle pot is mounted underneath the throttle housing so that the primary butterfly spindle operates directly on it, just two small screws to remove it but fiddly to get at.

Good luck, Colin.P