duster3

So I am having a strange problem with my 1973 Plymouth Duster. It has a 340 engine.

~Once I turn the key to start it, then stop turning the key, the engine continues to turn over. It keeps cranking even when Im not trying to start it anymore. But now I have to disconnect the neg. on the battery to stop it from cranking.
I noticed a couple times that upon starting it, the starter would continue to engage for a few seconds after I let go of the key. I took a flashlight and seen a little bit of oil pooled on top of the starter from a very slow leaking valve cover.

Any ideas?? Is it possible to be in the ignition switch? Please help

440roadrunner

Somewhere in the engine bay is the starter relay, looks something like this



Either one of the small push-on terminals gets power from the key in "start." The relay coil must have a ground to work. This is the remaining push-on terminal, which sees ground in park or neutral through the neutral safety switch in an auto car, or goes to ground through the clutch safety switch in a stick car.

The large stud is the battery junction, as well as one contact

The smaller "square" screw goes to the solenoid and is the second contact.

So be prepared in advance for this test. Get your 12V test lamp out, and clipped to a ground. Test that it actually works by touching to the big battery stud on the starter relay, and lay it safely aside. Get the battery clamp ready to remove if need be. In other words, get ready

So--------fiddle with the thing until it sticks "cranking"

While the starter is "stuck cranking" quickly take your meter or test lamp and stick the probe onto the "square" solenoid terminal

If you have power there the problem is probably NOT at the starter, but rather----------

a sticking starter relay

an ignition switch sticking / going bad

a wiring fault

=============================

Now without "jiggling" the relay and with the starter "still stuck" attempt to GENTLY pull one of the "push on" terminals off the relay. It is important to do so without jiggling the relay. In fact you might loosen these push on terminals before this test

Once you get this terminal off, and use your judgement "if you" jiggled the relay----

If the starter keeps going, the most likely cause is the starter relay itself

These are not expensive, and are available at any parts store. They were used from the early 60's into the 80??s and the only difference is the mounting ear

slade

sounds like the bendix gear on the starter is sticking its a common problem

duster3

Hey thanks guys. @440, Im going to try what you suggested with the starter relay and what not. I'd rather not throw parts at it so thank you. I plan on checking what you mentioned tomorrow afternoon and will post if I find anything cool or interesting!
@slade, hopefully its something simple but if the starter needs to be rebuilt, I guess that's not to bad lol

slade

meh install a starter from a magnum there smaller and spin faster

440roadrunner

Yup ^^^^ if the starter is bad ask for one on a mid 90's 5.2 Dakota. These are the newer smaller mini, and they crank like mad. I'm an "old guy" but even I finally threw in the towel and went "mini."

pro-tech

It sounds like the starter solinoid is sticking.. What happens is there is a copper washer inside the starter that when the key is turned it connects the 2 terminals together thus ingaging the starter to turn over the engine..That washer has welded itself to the 2 terminals causing it to continue to turn over until you unhook the battery... In any case if your replace the starter with a 90s 5.2 magnum starter like its been said it will take care of the problem.. when you get this starter it will look totally different but it will fit right in with no problem and you will never buy the old style again... Bill

duster3

Well I started tinkering with the car this afternoon, and started to take off the wires to the starter relay. I made sure they were clean and had a good connection. I started it two different times and it fired right up and the starter stopped when it was supposed to.
~ Also if/when I need a new starter in the future, I will take your guy's word on the 5.2 starter.

Thanks for ALL the advise! ~Sean

TVLynn

KEEP TOOLS handy to disconnect the battery !!!!