1973 - 1979 F-100 & Larger F-Series TrucksDiscuss the Dentsides Ford Truck
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NEED HELP . . Start Problems with 79 engine in 55 F250/150
I had put the following in HAMB with zero results. Hopefully some of you can help me out, PLEASE!
I haven't been here in several months as I got real sick last summer and was totally laid up for over 4 months.
I am back to working on my 1955 Yard Horse again, but am having troubles with it currently that I need some help with.
It is an F250 cab and front clip sitting on an 1975 F150 shortened 4x4 Chassis, with a 79 300 6 cyl., out of a 79 F150.
My problem is this: I have it pretty much done, but can't get it to run.
New battery, starter turns good. But when I tried to start it, once I hit the start cycle it wouldn't stop even if I shut the switch off. It was a universal type ign/start switch that I installed. So I tried a different starter solonoid relay switch. That helped to the point of it would shut off when I shut the switch off, but when leaving it on, (not on the start mode), it still kept turning the starter.
I have never had anything happen to me like this before in over 50 years of working on them.
So I bought and installed a new ignition switch and a new Solonoid relay switch and installed them along with a new GROUND wire from the "brain box" control module mounting screw to the engine block.
And it still keeps trying to start even in the ON position, but does shut the starter off when turning the key to off now.
I am really puzzled. I followed the only schematic I could find for the 79 F150 truck. I can't find a COMPLETE schematic for the truck, like for the charging circuit and the starting and ignition circuit. I was surprised there wasn't a schematic in the 78 FORD Truck complete service manuals. I would like the schematics for the charging circuit also.
Anyone know WHERE I can find one and anyone got an idea WHAT the problem is?
I would appreciate any help I can get. I haven't had a snow plow since early December and have been fortunate we haven't had a big snow during that time, but usually March gives us our biggest snow storms and I need to get this done before one hits and i am stuck in here. My driveway is well over 200 feet long and don't want to shovel 12 inches of wet snow for that distance at age 68 with my back the way it is, if you know what I mean.
Try reversing the two small wires that actuate the solenoid. My bet, based on my own recent stupidity, is that this will eliminate your problem. My 79 was doing the exact same thing after I reinstalled the wiring during a frame off restoration. I also bought a new ignition switch and after several hours of troubleshooting without the schematic I figured it out.
I was just out there and tried that and the only difference was that it didn't fire at all. I also have a little red wire that comes from the ignition switch to the start side of the solonoid and I disconnected that and of course NOTHING happened.
I actually spliced into the original 55 wire from the new ignition switch. I just came in from the garage and I am going back out now and try running a whole NEW wire from the start terminal of the ignition switch to the S terminal of the solonoid and see IF that makes any difference at all.
I currently still have the brain box in there from the 77 Ranchero that had the 351W engine. I do have the new one I bought from NAPA for the 79 300 and may put that back in tonight AFTER I try this new wire first and see what happens.
Thanks for trying. Hopefully someone else has had this problem and can be of some help tonight or tomorrow.
Make sure you have your voltage regulator harness connected as well. When I reversed my wires I had a no start situation at first. I traced the power flow through the ignition wires and discovered that the 4-pin connector for the v-reg harness has to be connected to complete the circuit. I put in a jumper wire and all was well. I did not have the harness connected as I am running a one-wire alternator with internal regulator. I am also running an MSD HEI distributor and have the brain box completely removed so I don't think the brain is your problem. Mine works fine without it. Just a thought...
No offense fmtowman, but your advice is pretty far off base - which makes me think the wiring in your situation had been modified from original. You can't remove the ignition module in every setup - his distributor (if it's stock) has a different triggering mechanism than yours.
JimBo - run a test light from the TACH TEST terminal of the coil (negative coil terminal) to clean, unpainted metal on the engine block. You need to keep the coil connected, so you'll need to clip the test light to some exposed metal on the coil horseshoe connector. Climb in the cab and crank the engine over, and the light should BLINK. Post your results and we'll go from there.
Okay, will try that. I just disconnected the start wire as part of it was the orginal 55 going into the harness. And ran a NEW temporary wire, only this time I was back to the starter turning once I tried to start and and wouldn't shut off even with the key off, so had to get down from the truck and run around to where the battery box is and pull off the positive wire. Geez. I am 68 and not easy, especially since I have this truck up on a Hunter Frontend alignment lift which is two feet off the floor.
I will rest a few minutes and go back out and see what happens with your suggestion.
I do have the regulator hooked up. Hopefully it is correct. Like I said can't find any schematics any place so far.
By the way, as far as I know the distributor is stock Ford. I do believe it has been replaced in the past, but not by me. The guy I bought the 79 parts truck from said it hadn't been run in 6 or 7 years. And I have had it for over a year and a half. But all the wiring is not stock as it is a 55 cab and I put all new gauges and switches in except for the 55 headlight switch and heater switch. The starter and alternator are from the 79 F150. I may have to rebuild the carb to, I don't know, but want to find THIS problem first.
I did go back out and checked to see IF I had a test light and I did. So hooked it up to the coil, turned on key and hooked up a remote starter button and the test light did flicker. But when I took my thumbo off the remote button, the starter still kept turning, so I had to pull the battery cable again.
Also, I do not have the original 79 style ignition switch, but rather a universal ign/start switch, so there is no resister wire coming from it, so I have installed an external resistor between the Switch and the coil, for run mode as best as I could figure it out using a schematic I found in a Chiltons Manual.
I can put the NAPA brain box in for the 300 6 cyl., it has the "blue" chip where the wires come out. That is the correct one, right? Only if there is a problem that could destroy it, I don't want to yet.
CL NYE: You mean do the search on here for it? As I tried Google without much results.
The Solonoid SHOULD be grounded as I just put in new plated screws to the firewall. I imagine it is staying hot after I shut it off until I remove the battery cable. I suppose I can disconnect the two wires that go from the S and I terminals on the solonoid and see what happens then. I can't start then, I don't think, but should still turn the starter when it is in start mode. It is almost midnight now, I just got done with supper, so may wait til tomorrow to try that. . . . Electronics . . . UGH!
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