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I am working on a 1975 f-100. I took the sick 6cyl. out and put a 400 out of a 1980. BOTH RAN! I have the 400 in and know no spark. I have power at the coil. (I have a 77 also and the brain box from the 80 worked ). I also heard the six cyl. brains are diffrent that is why I used the 80. The wireing looks ok at all the plugs rechecked grounds they seam ok. Everthing looked ok in the dist. did a ohm check for the pick up and that checked ok by the book. I checked seloned at the I ter. and have power there. Cleaned tremanals at coil and check wires looks good. Any checks or Ideas would be helpfull. need to fire this thing up its getting cold to work out side in minn.THANKS
the engine does not care which ignition module you use. the difference is, during certain years, they had different color connectors and wiring. there is a red, yellow and blue module. look for the plastic where the wires enter the module. try whatever came in the truck and it may work, you may have swapped in a different style and although they may plug in, there may be wires that are not hooked up as the wiring in the plugs changed. hawkrod
Check in the Electrical Systems / Wiring forum under the discussion topic No Spark authored by JPT42. There are a number of suggestions for your issue. Good luck!
I had the same problem as you after switching the bodies on my trucks...Everything was checking out o.k.(even had an extra known good module to plug in), but I still couldn't find the problem. I just went out and bought an aftermarket ignition module(MSD, Mallory, Accel...)...took the old module out and hooked up the new one. Problem solved!! Little more expensive, but alot easier than sitting ouside in the cold fighting with it.
Mr. Hawkrod is correct! I was under the impresion there was diffrence between 6& 8. NOT! Went to auto parts store did some checking !1976 and up there are two- blue & yellow in 1975 only grean. thats the color were the wires go into module. I am fired up again thanks everyone :-) & Mr. Hawkrod. I have had over 100 of these type of truck never ran into it befor.