Electrical Nightmare
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Electrical Nightmare
1978 F150 400 auto 4x4, problem #1 engine will not fire until key is released to run position, also it has a tendency to run backwards? as a lot of smoke (white/grey) comes back out the carb. #2 Starter is hanging but is not the solinoid, do Ford aftermarket starters need to be shimmed? Last summer had resistor wire smoke and has been replaced by a porcelan resister mounted to firewall. Ideas welcome.
Jim
Jim
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Whatever smoked the resistor wire probably also smoked the hot in START wire also. Get your wiring fixed properly. The porcelain ballast resistor may not be the right resistance value. Unless it is connected properly the wire connectors will fail from the heat. Standard crimp connectors can not be used. High temp connectors are available for that application. No shim is required for the starter.
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electrical nightmare
I have the correct ohm resistor also the ignitionwire from the switch to the resistor has been changed now the hot I take it is the ign wire. What would make it want to run when I go from start to run is it possible I have the wires crossed? Although that would make it want to crank when in the run position. I most likely will remove all the wires as I need only start, ign and lighting circuit as this is my plow truck.
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There are two wires to power up the ignition system and coil. Depending on what fried the wires both of them may be gone. You have fixed the RUN wiring with the resistor but there is also a hot in START wire.
You need a 1.3 to 1.4 Ohm resistor for the primary coil feed in RUN.
You need a 1.3 to 1.4 Ohm resistor for the primary coil feed in RUN.
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Did that already will try all ides in the morning when I can get the darn thing in the garage.
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You can jump the coil and DS-II box power leads direct from the battery and crank the starter to see if it starts. Otherwise just check for power at the coil and the DS-II power lead while cranking. You need power both places to get the truck to start. You can also have the DS-II box tested at the parts store for free. Sometimes the start side of the circuit goes bad.
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Would this cause the let go of key and engine starts, trhis truck has been a bundle of difficulties since I put the new cab on as it used to snort thru the tailpipe when the road was ruff but it always restarted. I am thinking the best is to find a wire harness for the cab.
Thanks
Thanks
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From: Alabama
yes it will, cause as soon as you let of the key it goes to run position and the motor is still spinning just enough for it to catch. And once in run the dist. powers up. You are most likely not getting power to the ign. when in crank mode.
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Problem # 1. It's seems like the ignition module is not getting Positive "+" feed to the module during when key is in the starting position.
Test for the ignition module, there will be a red wire and a white wire at the harness to this ignition module. Verify the red wire has positive "+" power with the key in the on position. And then verify the the white wire has positive "+" power with the key in the start position.
When the key is in the start position, The module gets its power from the Starter Solinoid at the terminal marked "I" on Solinoid, verify you have this wire connected.
And verify you got power at this terminal marked "I" when your key is in the start position.
Check the timing of the engine.
https://www.ford-trucks.com/user_gal...=94669&width=2
Problem # 2. A bad starter would cause the starter to hang up. Replace with the correct stater for your engine and transmission (year, make and model).
A wrong starter or worn starter on engine would cause grinding at the flex plate.
Verify with the starter removed from engine, that the teeth on flex plate are not worn down or chipped. Replace flex plate if the teeth on flex plate are damaged.
Test for the ignition module, there will be a red wire and a white wire at the harness to this ignition module. Verify the red wire has positive "+" power with the key in the on position. And then verify the the white wire has positive "+" power with the key in the start position.
When the key is in the start position, The module gets its power from the Starter Solinoid at the terminal marked "I" on Solinoid, verify you have this wire connected.
And verify you got power at this terminal marked "I" when your key is in the start position.
Check the timing of the engine.
https://www.ford-trucks.com/user_gal...=94669&width=2
Problem # 2. A bad starter would cause the starter to hang up. Replace with the correct stater for your engine and transmission (year, make and model).
A wrong starter or worn starter on engine would cause grinding at the flex plate.
Verify with the starter removed from engine, that the teeth on flex plate are not worn down or chipped. Replace flex plate if the teeth on flex plate are damaged.
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I suspect that engine is a high miler & the timing is so far out that this is a major cause of your problems,
Do a timing gear to chain stretch test see how bad the timing set is.
You have to make sure all the mechanical parts are within their parameters before making minor adjustments.
Do a timing gear to chain stretch test see how bad the timing set is.
You have to make sure all the mechanical parts are within their parameters before making minor adjustments.