alright so we got to lookin around on this truck, its an 89 f250 5.8w. i have a couple a other posts about it. we cant get it to start. its got fuel to the rails, but its not getting spark. i bought an inline spark tester and its not getting spark to any plugs or in between the coil and distributor. i checked on both connections, the coil to the wire and the wire to the distrubtor so that wire isn't shorted. i drew up a picture of what i found. both wires that are coming out of the harness, that plug up to the coil, have 12v in run? i dont think this should happen since where they connect is designated - and + i thought maybe the computer wasnt coming on so i checked the relay, refer to picture for voltages but everything looks good, i just dont know what the white and light blue wire is for on the relay, in the haynes it says that there should only be 4 wires and there are 2yellow into the same socket, red black white/blue. also thought maybe the coil is bad but we put in another one and same thing, motor just cranks and cranks but wont fire. any ideas? try another coil?

 

IT WONT LET ME ADD A PIC???

 

The ignition coil gets a pulse from the ignition module mounted on the distributor and these modules are a common failure point, but the problem could also be the pickup inside the distributor. The easiest thing to do is replace the whole distributor but if you do be sure to mark the base of the distributor for alignment and also note where the rotor is pointed and put the replacement back in the exact same way.

 

the truck has a new cap and rotor on it. should the coil have twelve volts on both sides of it? from electronics stand point, that makes little sense. if I ground the negative side of the coil and run a new wire from the module to the coil + side, should it work? how can you tell if the module is bad? do they go bad overnight or are there signs? the truck ran the day before we were working on it. if it is the wiring, which wire coming out of the module is it? going into the the "eec distributor tfi module", haynes shows dark green/yellow wire going from pin 4 on the computer to a suppression resistor, then one wire to the module and one to the coil since its an 89, where is the resistor phyiscally located??