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91 Camaro engine wont shut off when headlights are on.

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Old 08-07-2012, 08:18 PM
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Car: Blue 1991 Camaro RS
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91 Camaro engine wont shut off when headlights are on.

I just keep finding problem after problem! lol. Okay so I have been having problems with my car not wanting to start... My brother got it starting again though.

NOW my new problem is that when my headlights are turned on, I turn the ignition switch back to kill the engine and it just stays running. As soon as I hit the light switch though it dies. I also noticed it idles a lot better when the headlights are turned on with the ignition switch turned off. What the heck??

Apparently the person who had the car before me thought he knew how to work on vehicles. Ive got cut wires hanging here and there. Sigh. One step at a time I guess.

Anyone know whats going on here?
Old 08-07-2012, 09:51 PM
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Re: 91 Camaro engine wont shut off when headlights are on.

Oh dear, sounds like another "the previous owner was a total dumb-a** s*it-head" story.
If the wiring has been hacked up, as you say, then lord only knows how far it goes.
You will need to start tracing wires for the ignition and headlight circuits, which are supposed to be completely separate, btw.

Maybe an aftermarket DRL installation gone wrong (backwards)?

Some diagrams to get you started: light switch, headlight circuit, and more.

Hope this helps.
Lou
Old 08-08-2012, 01:18 AM
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Re: 91 Camaro engine wont shut off when headlights are on.

Originally Posted by BigBadLou
Oh dear, sounds like another "the previous owner was a total dumb-a** s*it-head" story.
If the wiring has been hacked up, as you say, then lord only knows how far it goes.
You will need to start tracing wires for the ignition and headlight circuits, which are supposed to be completely separate, btw.

Maybe an aftermarket DRL installation gone wrong (backwards)?

Some diagrams to get you started: light switch, headlight circuit, and more.

Hope this helps.
Lou

Good lord Im gonna be at this for a month! lol. But I HAVE to save this beautiful car! Thanks for the diagrams.

If I get the problem fixed I will update this post! Thanks again
Old 08-08-2012, 07:44 AM
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Re: 91 Camaro engine wont shut off when headlights are on.

OMG will they ever learn, if they do not know leave it alone.
Old 08-14-2012, 03:43 AM
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Re: 91 Camaro engine wont shut off when headlights are on.

I'm liking Lou's DRL theory... Do the lights come on when the engine is running without the switch pulled? If so, it could be as simple as the DRL circuit they added needing a diode in the trigger wire to actually work right.

What you have sounds like the headlights are back feeding into a hot in run wire, feeding everything on that circuit just like the key was on. I don't have a diagram on hand to tell you what color the wire from the switch would be, but I'm confident that you'll find some aftermarket relay triggered on that. If you want to keep the DRL, splice in a diode with flow away from the switch, before the relay, and cover it with heat shrink, otherwise, just cut it and heat shrink the ends and you should be all set.
Old 08-29-2012, 11:42 AM
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Re: 91 Camaro engine wont shut off when headlights are on.

Originally Posted by Cat Amanigh
I'm liking Lou's DRL theory... Do the lights come on when the engine is running without the switch pulled? If so, it could be as simple as the DRL circuit they added needing a diode in the trigger wire to actually work right.

What you have sounds like the headlights are back feeding into a hot in run wire, feeding everything on that circuit just like the key was on. I don't have a diagram on hand to tell you what color the wire from the switch would be, but I'm confident that you'll find some aftermarket relay triggered on that. If you want to keep the DRL, splice in a diode with flow away from the switch, before the relay, and cover it with heat shrink, otherwise, just cut it and heat shrink the ends and you should be all set.

Actually they do not come on when I start the car. Only when I pull the headlight switch.

1. I start the car, no headlights
2. I switch the headlights on
3. With headlights turned ON, I turn the ignition off.
4. Engine keeps running as long as headlights are on.
5. I turn the headlights off, the engine dies.

I notice that in step 4 the engine idles much smoother when the ignition switch is turned off. Its freakin odd! lol.

I am wondering if it has any links to my other problem... Occasionally the car stops firing at all. No spark coming from the distributor. It seems to fix itself after a couple days and will start again.
Old 08-29-2012, 12:42 PM
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Re: 91 Camaro engine wont shut off when headlights are on.

Do you still have the original distributor with the multiple wires (I think 7, but I haven't had the factory unit for a while) on the plastic clip running under the cap?
Old 08-29-2012, 02:41 PM
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Re: 91 Camaro engine wont shut off when headlights are on.

Wonder if the po tried to wire in a thief switch. I remember reading it on a website somewhere. The only way the car would start is if the head lights where on. You could crank on the car all day long but it would not start till you pulled the head light switch and turned them on. It was really easy as I remember only thing you needed was a relay. Wonder if this is what the po tired to do?
Old 08-29-2012, 02:48 PM
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Re: 91 Camaro engine wont shut off when headlights are on.

The only way to find out what's going on really is to start tracing wires (under the dash and under the hood). Without seeing how it's wired up, there is no fixing it.

Sorry, I know that's not what you wanted to hear but that's the best news I can give you. :-(

And for crying out loud, when you do find out what it is, PLEASE tell us. I am dying of curiosity here!

Lou
Old 03-10-2013, 06:59 PM
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Re: 91 Camaro engine wont shut off when headlights are on.

Originally Posted by BigBadLou
The only way to find out what's going on really is to start tracing wires (under the dash and under the hood). Without seeing how it's wired up, there is no fixing it.

Sorry, I know that's not what you wanted to hear but that's the best news I can give you. :-(

And for crying out loud, when you do find out what it is, PLEASE tell us. I am dying of curiosity here!

Lou

Hey all. It's been awhile but I have made some progress. I decided to swap out the entire distributor for a brand new one. I have not had any problems with the car not wanting to start since I put the new one in..

But I have found TWO new problems. One of them is .

Problem #1.. My RPM gauge is reading much higher than it should. It's showing around 3k at idle. I thought it was a distributor problem because someone told me that could do it. But it's still high even with the new one.

Problem # .. Ok so when my headlights are turned on, the car will not shut off. I already knew about this problem but I discovered something new.
With the key turned completely off, or even if there is no key in the ignition, when I turn my headlights on the freakin fuel pump kicks on. I have no idea where to even start with this lol.
Old 03-10-2013, 08:40 PM
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Re: 91 Camaro engine wont shut off when headlights are on.

What about a new wiring harness from a parts car ?

I see many of them in circulation, if you get one for your specific model (unhacked) maybe things will clean up ? Just a thought, good luck trouble shootin that one.
Old 03-10-2013, 10:20 PM
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Re: 91 Camaro engine wont shut off when headlights are on.

For the tachometer, I can tell you that it is very common for them to go out of calibration (by a LOT) and show too high. Mine was showing high as well. You can either fix it yourself (if you are not afraid of electronics and soldering parts on boards), or you can let me know, I can help, I've fixed many of them.

For the lights, have you tried pulling the Fuel Pump relay and turning on the headlights? Does the fuel pump still come on? That would tell us which circuit is causing the trouble, the low-power side or the high-power.

Let us know what you find.
Lou
Old 03-11-2013, 12:10 AM
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Re: 91 Camaro engine wont shut off when headlights are on.

Originally Posted by BigBadLou
For the tachometer, I can tell you that it is very common for them to go out of calibration (by a LOT) and show too high. Mine was showing high as well. You can either fix it yourself (if you are not afraid of electronics and soldering parts on boards), or you can let me know, I can help, I've fixed many of them.

For the lights, have you tried pulling the Fuel Pump relay and turning on the headlights? Does the fuel pump still come on? That would tell us which circuit is causing the trouble, the low-power side or the high-power.

Let us know what you find.
Lou
Thanks for the tips. I'll try it tomorrow. Oh yeah, whoever had the car before me also had the throttle cable and cruise control cables switched around backwards on the throttle body. The throttle was only opening about halfway. That's all fixed now. I still have to figure out which vaccum hoses run to the cruise control box because both of those are unhooked too. Messy car :P I'm getting there though!
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