Ok I've done a lot of searching on this and other forums to get the right combination of problems, but to no avail. I have no power to the coil. When a test light is clipped from the negative terminal of the coil, with it connected, the pointer touching ground, I get no light whatsoever, with the key to the run position. I played with the pick-up on the dist, with no one in the cab, just to see if the inside was clean, and it looked o.k. I know I can also have someone try the key with the cap off the dist to see about spinning, but my guess is no, with no power to the coil. I have a new coil, ignition switch and starter solenoid. I am learning as I go. Yes I have a mulitmeter, just have to learn how to use it. Have owned four or five Fords over the years but this is the first time to tackle a no start condition. So when I turn the key, nothing, no sounds, nothing. I got the engine to turn over but not stay running by running a jumper wire from the positive terminal on the battery to the "s" terminal on the starter solenoid. When I installed the solenoid, I made sure to clean the install surface, and it is tight. I do have headlights that are bright and the brake light comes on only after the key is turned all the way to the start position. Also verified power is reaching ignition switch with the large yellow wire. After replacing my heater core, the no start happened, before it ran perfectly, with no problems. Electronic ignition obviously, 77 F250 351 M 203 transfer case. Thank you for all help.

 

The "s" terminal has power only when the the starter is turning the engine over, as soon as you let the key go to run the power is off. If you are trying to "hot wire" the engine; run a hot wire from the battery to the coil.

 

O.K. thank you

 

The distributor pickup does not affect power to the coil.

It sounds like you're off to a good start. Right now the engine won't even crank - remove the small wire connected to the 'S' post of the starter solenoid and check that it has 12 volts while someone holds the key in START. This should be a RED with BLUE stripe wire.

 

FMC400 Thank you so much for the help. I have seen lots of your replies and they all are very informative, and above all helpful. I did as you asked and I did not get a reading with my multimeter at the "s" terminal with the key turned to the run position. When the key is turned to on, but not all the way to run, I get no lights on in the dash. Although when the key is turned all the way to run, the brake light comes on. I remember before the heater core repair, the key to the on position would light up the brake light. Also I do still have headlights, but no fan on the heat controls. I did replace my voltage regulator, the original was looking pretty tired. So same problem, no spark, no power to the coil. From what I've read the ignition module has nothing to do with the initial spark or power, but is that right? It is original to the truck I think. Can't think of any other details to include. Original wiring but not hacked too bad, except for stereo at some point. But everything ran fine when I parked the truck a month ago, just a leak in the heater core.

 

The ignition module is responsible for switching the coil (to produce spark) at all times, during START or RUN. However, power to the coil is independent of the ignition module as you have read. The ignition module is only responsible for grounding the coil.

It sounds like your ignition switch is bad, or maybe incorrect. If the large YELLOW wire has power, the RED with BLUE stripe wire should have power coming back out with the key in the START position. The other symptoms you describe point to the ignition switch too, although it's odd that it's a new switch.

The BRAKE light should come on about halfway between RUN and START; this is called "prove out." Assuming you have OIL and ALT lights, these should be on with the key in RUN but the engine OFF.

 

Well two more things to include. One my indicator lights do not work, either do the reverse lights, or brake. The other item is a grey wire that goes to a small voltage regulator looking thing on the passenger fender wall, next to the starter solenoid. It has fusible link written on a black rubber coupler that is inline. I suspect this wire has burned thru, so I still need to check it. I have to pull the steering column apart to see about the indicator lights. The brake lights will be another project with the sensor on the pedal, not connected. Luckily I know a very trustworthy mechanic but I am still trying to avoid a tow charge, or him having to travel the crappy road we live on. Also there is much more satisfaction in doing the work myself. I think the module will be my next purchase, but payday is a ways away. What else to check I am stumped. But thank you and I will report my progress.

 

Possibly a bad connection at the plug going into the back of the ignition switch?

Ive had that happen before.

Try unplugging it and check for any wire that may have pulled part way out,then reconnect.Sounds like just a loose connection along the way.

 

Yup that is what I've been looking for forever now, but no success. I will keep at it though, got a lot more time than money, so the search and learning continues.