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Ignition problem?

Ive had a reoccurring problem with the key in my truck. You can turn the key to the on position and everything works as needed then you try to start the truck and nothing still power but you just cant start the truck with a key. right now i have a switch which is jumping the starter solenoid. Whaat is everyones thoughts? Oh. and sometimes the starter will stay engaged could this have to do with the ignition?smilieFordlogo
 

dustybumpers

don't play well w others
Starter run on is usually caused by a bad ground. Clean your battery cables on both ends.

Check and make sure there is a wire on the S terminal of the solenoid

A bad ground will shorten the life of a solenoid, you may need to replace it.
 
Thanks that explains it!! the bad ground i need a new ground cable.. right now its grounded to the exhaust manifold where do you reccomend it to be grounded to? and I just put a new solenoid on 4th one!!! free replacement though!
 

primetime

sawmill slave
I`m leaning towards starter relay. That would be what causes the starter to stay engaged. Sometimes they stick, which causes the starter to keep running. When that happens you can swat them with an end wrench and they will usually disengage. But you should get a new one.

First thing though is to get a test light or multi meter. Take off the red/w blue stripe wire, and while the key is in the crank position make sure it has power. If you have power than I would change the starter relay.

If you don`t have power at the red/blue wire with the key in the crank position, than I would move down to the neutral safety switch on the trans (if you have an auto). You should have power in on one, and power out on the other. Good luck.
 
Im going to have to lean towards the neutral safety switch cause sometimes it will work and other tiimes it wont would this be reasonable?
 

primetime

sawmill slave
Thanks that explains it!! the bad ground i need a new ground cable.. right now its grounded to the exhaust manifold where do you reccomend it to be grounded to?

:headbang: Forgot about the ground. I know better to. Run your ground directly to the block. MAKE SURE you have a ground from the body to the engine to the frame to the battery.
 

dustybumpers

don't play well w others
Thanks that explains it!! the bad ground i need a new ground cable.. right now its grounded to the exhaust manifold where do you reccomend it to be grounded to? and I just put a new solenoid on 4th one!!! free replacement though!

Frrom the factory they were bolted to the side of the block, by the motor mount.Make sure you clean everything to bare metal for a good connection.
Some people ground to the bolt on the starter. that works pretty good.

Don't forget to ground your body too, usually the new cable has a 10 ga wire coming off it, on the battery end. You can add a length of wire, and ground it some where on the core support
 

fatherdoug

Tonto Papadapolous
On the 351M/400 there is a dedicated bolt hole for grounding the negative post of the battery to the block. I looked to see if the engine diagram indicated what size bolt was used, but the diagram doesn't show that bolt.

The hole is directly below the alternator at the bottom of the block.
 

DNFXDLI

The Token Canadian
Staff member
79_Truck_00714.JPG
 
The engine start circuit runs through the Neutral start switch which is located in different spots depending on year and type of Trans

The 'Engine keeps cranking' situation is because of power continuing to the S terminal of the relay
This can happen after trying to start an engine with a dead battery. The small amount of power from a low battery can actually WELD the contacts related to the S terminal of the relay.Always use a freshly charged battery when trying to start an engine.Once this has happened, any attempt to start the engine will be met with a NON-stop cranking of the starter

There are other reasons but your issue doesn't qualify

StarterCrankCircuit-1.jpg


DSIIandDSIIIIgnitionModulatorTest.jpg
 
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Put on a ground wire to the starter bolt and the truck fired right up!! the ignigtion still didnt work though still using the push button start for now! thanks for all the help!!
 

DNFXDLI

The Token Canadian
Staff member

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