Engine Starter Engaging When Key Turns to ACC or ON!!

[begNOpardon]

I have a 71 C10, HEI, Powermaster Performance starter. I’m having some electrical issues. My engine is now starting anytime I turn the key either to ON or ACC. if I turn it all the way to START it just grinds badly. Starter is aligned well w/proper gapping and engages/disengages properly. The only way I can start and drive is to pull the brown ACC wire from the back of the ignition switch.

Any help would be appreciated. I feel I’m pull rope from both ends rather than figuring out the simplest ways to find the root cause. Seems like possibly a grounding issue that’s causing a loop but not sure how to find it. Any help, suggestions would be greatly appreciated. Lemme know if you need more specs or images.
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[dmjlambert]

Make sure you only have the purple wire going to the start post on the starter, and don't have other wires such as yellow going to that same post. My 2 cents.

[begNOpardon]

Originally Posted by dmjlambert

Make sure you only have the purple wire going to the start post on the starter, and don't have other wires such as yellow going to that same post. My 2 cents.

Yes, double checked all wiring to starter. Starter is solid.
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[Getter-Done]

Pictures would help us help you.

Is the harness pinched between Transmission and engine?
How old is the Ignition switch?





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[dmjlambert]

I re-read your first post. So with the engine not running, when you turn the key one click to the right the starter starts turning the engine over? You mentioned when you turn the key all the way to start it grinds, does that mean there is a difference between the engine turning over with key in on position, and you get additional sound of grinding adding to that with the key in start position?

I suggest take the purple wire off the starter and connect it to a test light or voltmeter. Connect the negative lead of the voltmeter or test light to ground. See what the test light does in various key positions. Trace the purple wire back from the starter and check the condition of it and make sure it's not connected to anything else and that the insulation is in good condition. You may need to unwrap the wiring harness to do that, and you can re-wrap it with the same tape or buy new non-adhesive vinyl tape. It should go through a neutral safety switch, which makes sure the truck is in neutral or park when starting, and then to the ignition switch. There should be no other wires connected to the purple wire at the neutral safety switch or at the ignition switch.

I don't think the problem is likely to be related to ground in any way.

You can remove the connector from the ignition switch and test it with an ohm meter or test light, to make sure the tang that supplies the purple wire voltage only gives voltage in the start position. It should conduct from the tang the fat red wire connects to, to the tang the purple wire connects to, only in the start position. Picture is from a post by VetteVet

[lousyflyer]

Take the harness connector off and look for signs of excessive heat and melting of the plastic. If it is melted, the switch itself may be damaged.

That's all I got.

[Getter-Done]

Auto or Manuel Transmission?







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[Wrenchbender Ret]

I just had the same thing happen to mine. I had to replace the ign. switch & put a new pigtail on the connector. It is fine now.
George

[lil hoodlum]

Originally Posted by begNOpardon

I have a 71 C10, HEI, Powermaster Performance starter. I’m having some electrical issues. My engine is now starting anytime I turn the key either to ON or ACC. if I turn it all the way to START it just grinds badly. Starter is aligned well w/proper gapping and engages/disengages properly. The only way I can start and drive is to pull the brown ACC wire from the back of the ignition switch.

Any help would be appreciated. I feel I’m pull rope from both ends rather than figuring out the simplest ways to find the root cause. Seems like possibly a grounding issue that’s causing a loop but not sure how to find it. Any help, suggestions would be greatly appreciated. Lemme know if you need more specs or images.
Posted via Mobile Device

Sounds like the ignition switch is going out on you.

By the way, I'm also in Denton, Texas.

O'reillies auto parts carries ignition switches for our truck in stock. I usually have a spare on hand just in case.

[BigBird05]

With your foot on the brake, take the truck out of park and put it in any gear. Now turn the key on. If nothing happens you have a bad ignition switch.

[57taskforce]

You can test the switch with a multi meter/ohm meter as well. You just have to pull the switch and the plug and test for continuity from the power feed tang on the switch to the purple wire tang in the different positions of the key. It should only have continuity with the key in the start position.

I went thru this with my ‘57 and a new aftermarket switch a few years back. Switch tested bad, and was replaced.

[begNOpardon]

Originally Posted by dmjlambert

I re-read your first post. So with the engine not running, when you turn the key one click to the right the starter starts turning the engine over? You mentioned when you turn the key all the way to start it grinds, does that mean there is a difference between the engine turning over with key in on position, and you get additional sound of grinding adding to that with the key in start position?

I suggest take the purple wire off the starter and connect it to a test light or voltmeter. Connect the negative lead of the voltmeter or test light to ground. See what the test light does in various key positions. Trace the purple wire back from the starter and check the condition of it and make sure it's not connected to anything else and that the insulation is in good condition. You may need to unwrap the wiring harness to do that, and you can re-wrap it with the same tape or buy new non-adhesive vinyl tape. It should go through a neutral safety switch, which makes sure the truck is in neutral or park when starting, and then to the ignition switch. There should be no other wires connected to the purple wire at the neutral safety switch or at the ignition switch.

I don't think the problem is likely to be related to ground in any way.

You can remove the connector from the ignition switch and test it with an ohm meter or test light, to make sure the tang that supplies the purple wire voltage only gives voltage in the start position. It should conduct from the tang the fat red wire connects to, to the tang the purple wire connects to, only in the start position. Picture is from a post by VetteVet

Ignition is brand new and problem existed prior. Also, I have completely eliminated the ignition and problem still persisted. It looks like the neutral safety switch is completely bypassed. I had a light green and dark green wire wires into the purple ignition wire. Seems like PO wired the ignition with possibly the reverse lights that went to the same switch on the column, the neutral switch and reverse switch. I’ve removed those and eliminated the straying problem.

Starter is now GOOD!

Thanks!

However on the wiring diagram the purple ignition wire heads straight to the firewall and then there is another purple/white wire that goes to the neutral safety switch. My ignition/truck does not have the purple/white, only a solid purple. Can that purple be ran directly through the neutral switch or do I need to add a wire (purple/white) from ignition to switch to firewall?
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[begNOpardon]

Originally Posted by Wrenchbender Ret

I just had the same thing happen to mine. I had to replace the ign. switch & put a new pigtail on the connector. It is fine now.
George

Ignition is brand new as that was one of my first thoughts and was a cheap enough change which I needed to have a full matching key set so I did switch out ignition and door locks. But again problem persisted prior and after new ignition and when no ignition was in. Thanks though.
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[begNOpardon]

Originally Posted by lil hoodlum

Sounds like the ignition switch is going out on you.

By the way, I'm also in Denton, Texas.

O'reillies auto parts carries ignition switches for our truck in stock. I usually have a spare on hand just in case.

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Awesome you’re in Denton. See previous replies though, ignition is brand new. Problem half solved. Starter working as should but now dealing with no running lights/brake lights.
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[57taskforce]

Originally Posted by begNOpardon

Ignition is brand new and problem existed prior. Also, I have completely eliminated the ignition and problem still persisted. It looks like the neutral safety switch is completely bypassed. I had a light green and dark green wire wires into the purple ignition wire. Seems like PO wired the ignition with possibly the reverse lights that went to the same switch on the column, the neutral switch and reverse switch. I’ve removed those and eliminated the straying problem.

Starter is now GOOD!

Thanks!

However on the wiring diagram the purple ignition wire heads straight to the firewall and then there is another purple/white wire that goes to the neutral safety switch. My ignition/truck does not have the purple/white, only a solid purple. Can that purple be ran directly through the neutral switch or do I need to add a wire (purple/white) from ignition to switch to firewall?
Posted via Mobile Device

Glad you got it mostly sorted out, few things are more fun than having to sort thru previous owners’ electrical riggings. You might see if you can catch vettevet over on the electrical section of the board. He is the resident electrical expert.

[pjmoreland]

The dashed purple wire on the schematic isn't a separate wire. It is showing alternate wiring for a neutral safety switch inside the cab for an automatic transmission. You can just route your existing purple wire through your neutral safety switch.

[begNOpardon]

Originally Posted by 57taskforce

Glad you got it mostly sorted out, few things are more fun than having to sort thru previous owners’ electrical riggings. You might see if you can catch vettevet over on the electrical section of the board. He is the resident electrical expert.

Thanks, getting there. Yes, I’m having the time of my life haha. I do learn a ton every time I have to go deeper with this truck.

I’ll reach out if I hit a wall.
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[begNOpardon]

Originally Posted by pjmoreland

The dashed purple wire on the schematic isn't a separate wire. It is showing alternate wiring for a neutral safety switch inside the cab for an automatic transmission. You can just route your existing purple wire through your neutral safety switch.

Thanks so much. Exactly what I was looking for. Follow up question though... at the ignition the alternative purple dashed wire shows to be terminating at a different location on the ignition than the solid purple wire. Is that just for clarity and it’s a non-point? Assuming so.
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[JMac11]

Had this happen, Housing was cracked on Neutral Safety Switch. Even more fun was the entire steering column being charged.

[BigBird05]

I am looking at pgs 8-32,8-33 and 8-34 in the 10-30 service manual. The ppl 12 ga wire goes from the ign switch to the neutral safety switch, thru the switch, thru the bulk head connector to the starter. It doesn't change color. It stays ppl all the way to the starter.