72wagun Posted May 1, 2009 Report Share Posted May 1, 2009 (edited) First of all, this problem occured because of my lack of knowledge of Datsun wiring, and because of changes I chose to make to the stock setup. I just thought it might be helpful in the future if anyone else does what I did.:) Anyway, I had just gotten my 72 wagon running pretty good. Timing (ign.) was set just right, weber was tunned pretty good. I was finally enjoying driving it, but I noticed this problem. When ever I shifted into 3rd, the engine would either miss, or backfire. At first I thought I was imagining the connection with 3rd gear, but after a while I realized it absolutely was only in 3rd that I had a problem. Long story short, I was doing some searching on the problem, and came across a post on another site with the picture below. This was posted by datzenmike along with some helpful advise that applied to my problem as well. I had changed my dist. over to single points. I just hooked up to one of the points wires from the original dual points. I don't know all the particulars, but it appears that the dual points setup has a retard feature that is connected with 3rd gear. It must just retard one of the sets of points, and it must have been the set I chose. I fixed it temporarily by disconnecting the 3rd gear switch on the tranny. I don't plan on going back to dual points as I'm installing a pertronix. I'd like to remove any unneeded parts of this system, but I'm not sure of the cleanest way to do it, or what I should consider when removing things. I'd also like to avoid major hacking on the stock wiring. I'm waiting for my service manual to arrive, so I don't have full wiring diagrams. Maybe someone with more experience can comment. Here is the diagram that helped me: Edit: I forgot to mention that I'm not sure if General Tech is the best spot for this. I put it here because when I was trying to fix it, I wasn't sure if it was my ignition or carb (should have suspected ignition for backfiring) so I was looking to solutions for both. If it should be in Electrical, maybe a Mod can move it. Edited May 1, 2009 by 72wagun Quote Link to comment
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