Misfire on 13B

[Newbie]

Can anybody tell me what to check first?

I developed a misfire at about 6000 RPM, and the first session out, it went away quickly. The next session it lasted the better part of 3 (4 mile lap) laps, then fixed itself. It happened on the straights as well as the turns, and seemed to happen only under load. The third session it did it for a lap then went away. On the final session of the day, all was well until the 5th lap when it started again. This time, it was back firing and did not go away. I pulled into the pits and reved the engine with no load, and it still happened.

My 13B takes forever to start. When it's warm, it fires right up. On my 4th and final session at Road America this weekend, the starter would not engage, but I was able to push start it easily.

I have a fuel pressure gauge, and I was not loosing fuel pressure. Can somebody tell me where to start looking?

Thanks

[seckerich]

You didn't say if it is carb or injection? Sounds like bad plug wires or a crank angle sensor is going south. Check the ground to your coils with a multimeter and check resistance on your wires (should all read the same). Good luck!

[ddewhurst]

A couple years ago I had a situation at Gingerman where at approx 5,000 a 1st gen 12A would cut out & stop runing. It restarted very hard & stoped a couple more times before I finished the lap. I got $hit lucky while trying to restart it in the paddock. I viewed smoke coming off one of the coil plug wire snouts. The snout was cracked & shorting out. These were MSD Blaster coils. Put on a spare coil & everything was fine.

David