Check that pesky ballast resistor!

[Elandan2]

On our recent cross country trek, the motorhome was doing something that I have never experienced before.  The engine was becoming hard to start, I could crank and crank the engine but it wouldn't fire until I released the key.  Sometimes, after cranking with no success, I would let go of the key and the engine would be running!  Of course, eventually, I tracked it down to the ballast resistor.  The funny thing here is that I have never had the primary side of the ballast go, it has always been the secondary side.  That is when the engine fires immediately but quits when you release the key.  After replacing the ballast, the engine immediately fired up and other intermittent problems seem to have disappeared, such as misfires and bogging.  The ballast resistor that was in there had been installed since 1985 and I believe that the part may need to be replaced even if it seems to be working.  Something to think about if you are having strange ignition problems.  Rick

[toddabney]

Strange ingnition problems.....well that hits the nail on the head.i'm going to town and getting 2 ballast resisters.  They seem a bit frail.  I'll let you know if it fixed my SIP   (strange ingnition problem,will now be called SIP,,lol) thanks todd

[ibdilbert01]

Very strange.  Normally when the ballast resistor goes out, the engine will start but stop when you let the key off from the START position.   This is because the starter switch in the START position bypasses the resistor, and the resistor is only used in the RUN position.  When I was running points on mine, I use to buy the "double" ballast resistor, that way I always had a spare already mounted and ready to be used if one failed. 

[toddabney]

well i installed new ballast resistor.....no spark at coil !!!...can those be installed backwards? the wires seem rather twisted. or any other ideas?i have 12 volts to both sides of the new coil when trying to start.there is one volt at the coupler between the distutior and the main wiring harness,unhooked   ,then 0 when i hook them up with key on..... help......todd