omega_rugal Posted October 4, 2020 Share Posted October 4, 2020 today i got some free time to work on the MJ, and pulled the spark plugs, 2 thru 5 were clean, they had a thin layer of carbon but could be scratched off easily, below the electrodes were good and whiteish in color... but 1 and 6... they had more carbon build up, it burns lpg so is not gasoline related, all the plugs were dry so is not oil or water getting on the combustion chamber, any ideas? dust? Link to comment Share on other sites More sharing options...
jdog Posted October 4, 2020 Share Posted October 4, 2020 have you changed them since it was converted to lpg? how many miles on the plugs? how much more build up? Link to comment Share on other sites More sharing options...
omega_rugal Posted October 4, 2020 Author Share Posted October 4, 2020 i changed them a month or 2 before the conversion, that was 4 years ago, so almost all of their life have been running on lpg, miles? id unno, the odometer broke long ago carbon buildup in 2-5 was almost non existant, only 1 and 6 had some but nothing that prevented them from firing, it was just there now that i think of it, 1 and 6 are in the opposite sides of the engine, all lpg comes from the throttle body, no fancy multipoint injection, unequal air fuel ratio? if so, shouldn´t the outer cylinders get the LEANER mix? Link to comment Share on other sites More sharing options...
jdog Posted October 4, 2020 Share Posted October 4, 2020 I would say probably uneaqual air/fuel mixture as to why they aren't showing lean you have got me, maybe its only lean during certain times, ie full throttle or high revs Link to comment Share on other sites More sharing options...
cruiser54 Posted October 4, 2020 Share Posted October 4, 2020 Make sure the intake manifold bolts aren't loose. Link to comment Share on other sites More sharing options...
omega_rugal Posted October 5, 2020 Author Share Posted October 5, 2020 the intake feels solid, no loose bolts/nuts, i checked for vacuum leaks today and found none, took out 1 and 6 and they look as clean as yesterday so it may be a long term problem... Quote maybe its only lean during certain times, ie full throttle or high revs due the way my lpg system is rigged, this may be it, thrttole response is a little slow, that may be the lean phase it´s causing trouble... Link to comment Share on other sites More sharing options...
jdog Posted October 5, 2020 Share Posted October 5, 2020 hows the egr system? hoping thats all it was, and they stay nice and clean for ya Link to comment Share on other sites More sharing options...
omega_rugal Posted October 5, 2020 Author Share Posted October 5, 2020 no egr Link to comment Share on other sites More sharing options...
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