View Full Version : Bad injector knocks on diesel, smooth on veg

04-09-2015, 04:46 AM
Just got one of my rental vans back today. On diesel it was knocking like crazy at idle and would stall after revving. Also lots of smoke. Switched it over to veggie oil and all symptoms went away, no knock, no smoke, no stalling. I first thought the band got bad fuel or put gasoline in the diesel tank. I drained the tank and refilled it with diesel from my fuel station. Same exact symptoms, would run smooth on veg, crappy on diesel. Changed the fuel filter, same thing.

Codes that were on there when I got the van back- random multiple misfires and misfire cylinder 2.

After swapping fuel and filter I've decided that injector number 2 has gone bad. The only mystery is why on veg does everything work better. It seems like the smoke is unburnt fuel (white misty diesel smelling). It seems like the injector is dumping more fuel then it should and maybe a slightly different viscosity fuel doesn't do the same? Interesting problem. Now for the fun of pulling an injector!

04-09-2015, 04:51 AM
a friend of mine has an 84 benz 5cyl the car has worn injectors it will barely run on diesel but since the veggie oil is thicker the injectors dont leak as much I guess. it is definitely something to do with the thickness.

04-10-2015, 03:53 PM
ive heard if you are wearing a black t shirt it can cause this. try changing your t shirt to green or yellow and this should rectify your problem.