I know this has happened to many out there but I cant tell what was the final fix. I have a 79 f350 with 460. I replaced the ignition switch and solenoid. When I start the engine the starter keeps wanting to start until I turn the key off. I dont have the problem with the starter keep going after the key is off. I thought it would be the ignition because what its doing. Not the case unless the new one is also bad. Could this be the starter? Could it be the key tumbler? Please let me know.

 

Does it actually keep cranking or does it go along for the ride while the engine runs?

If it is the later, chance are the starter drive is hanging up from lack of use.
To rectify this you have to pull the starter ,lubricate the starter drive shaft,use booster cables to actuate the starter drive until it moves freely


If it is cranking while engine runs then you have to figure out why it is still getting power ?

Try removing the wire from the S-terminal after the starter cranks and engine runs.

If it still cranks then you have a starter relay problem.

 

Thanks for the response. The starter keeps running after the engine is running and to stop it I can take the wire off the S terminal or I have to shut the engine off. The starter isnt going along for the ride and I wish it would because that would be easy to fix I think. Not that this is going to be to hard. I can start the truck by jumping from the solenoid and the battery and the starter doesnt have a problem when I do that. Not long ago before I fixed the solenoid and ignition switch we got it to start normally by messing with the solenoid but that did need to be replaced. When I replaced that and tried to start the truck this problem started to happen where the starter kept running after the engine started but I was able to turn it off with the key. Mechanic said the ignition swith was bad so I replaced yesterday with the same issue.

 

Just happened to me it was the relay (soliniod)on the fender.

 

If removing the wire from the S post of the solenoid stops the starter, then there's a problem with the wiring upstream of the solenoid. For whatever reason, voltage is still present at this point when you shut off the key - it could be a bad ignition switch, a short, or misrouted wiring. You can double check by probing for voltage at the end of the pigtail with a voltmeter or test light.

Based on your description, the problem is not the solenoid. All the solenoid does is close the circuit when voltage is present at the relay coil (S post). If the solenoid closes when voltage is applied and lets go when the voltage is taken away, then it works. People are trigger-happy when it comes to replacing solenoids when in fact it's only one component of the system. Just because something is cheap and easy to replace, doesn't mean that's a good way to start troubleshooting. My multimeter has paid for itself ten-fold.

 

Sounds like the ignition switch is the culprit, due to what it does in the quote above.

Most likely if you replace the switch, that will fix it.

Test the wires at the switch. Red/Blue stripe. Should be hot only in start. If it's hot in run, which is highly likely, unplug the connector from the switch and see if the wire goes dead. It should.


EDIT: Just been looking over the wiring diagrams. Unplug the Duraspark-II modules Red/blue stripe, and White connector then try to start the truck. It won't start with it disconnected, but if there is a problem beyond the module it should still continue to crank as before with the switch in run. If the starter does not continue to crank in the run position as it does now, then it could be a shorted DS-II module. Have it tested.


Hope this helps.

 

Yeah I have a new solenoid on the truck and new ignition switch, but I guess its still possbile the new switch is bad. The mechanic at work is going to check for me. I can stop the starter with the key as well as taking off the wire on the S post.

 

81-f150, this weekend I bought a new solenoid again and a new switch just to see if possibly one of them was bad right out of the box but the new ones didnt fix anything. I'm taking them back. This is a 79 so on this ignition switch there is only one main plug that goes into the switch. I cant take anything off. What is the DS-II Module and what does it do?

 

The DS-II module is the ignition module that was stock on your engine.

It has a blue relief grommet on it for 1979. It controls engine spark. Usually located on the left fender apron. Metal in color, rectangular with two connectors coming out of it.


The connector at the ignition switch should be a 8 pin connector. One of them will be empty. And one will have two wires going into one pin. The lock tumbler and the switch are two different things, just incase there is confusion.

The colors of the eight wires are...

1: Red/Light Blue
2 and 3: 2 Red/Green
4: White
5 and 6: Yellow
7: Black/Green
8: Purple/white

Unplug the DS-II module. This will disable the engine, so plug it back in or replace it depending on the tests done.

With the ignition switch in run, test the Red/Blue wire for power at the ignition switch. The red/blue wire coming out of the connector. Leave it plugged into the ignition switch while testing. It should NOT have power in run.

If it does have power do what is said in B:

If it does not have power do what is said in C:

B: disconnect the ignition switch. If the power goes off to the wire, it has to be the ignition switch. If the power stays on, then there is a short in the Red/blue stripe wire.

C: Try to start the truck with the DS-II module unplugged. If the starter still hangs up, and you can stop it with pulling the Red/Blue wire at the solenoid, then the ignition switch is suspect. If it does not hang up, check the DS-II at the parts store for an internal short.

These are the only things that it could be with the information I have to go on.

 

If you had read my post, you would have known not to bother replacing the solenoid.

 

fmc 400 I did read your post and thank you for it.

 

I have had this problem on an old ford car, the starter would engage for some stupid reason as I was driving, the starter heated up and died. I didn't have time to figure it out. I ended up running a push button switch on the "S" wire from the solenoid to somewhere under the dash with easy access, you will have to lengthen the wire to get there. Now you just turn the key to "start" and push the button to get the starter to engage,. As soon as the engine starts, let go of the button, and let the key go to "run". Now the starter won't engage unless you do this. Best part about this is nobody can start your vehicle unless they know this..... Perfect anti-theft device.

 

I want it done right but thanks for the info.

 

On an old car you pop the hood, run a 12 volt wire from battery to coil then hot wire the solenoid. Bust the window and open the door. Buh-bye!

Done and Done and there is no need to mess with any keys, buttons or ignition.

Josh

 

Sorry about the crappy advice, guess that's the farmer coming out in me again.