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1972 Cadilac Coupe Deville internally regulated alternator upgrade


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Hello everyone, I am having a another problem with my Coupe Deville. I had to replace the old alternator because the old one was out and not charging, could have also been the regulator but I was planning on installing a sound system later so I decided to just replace with 10si 110 amp model. I got everything in but I cant seem to get the car to start with the current configuration. I have my blue wire connected to the 1 position on the alternator and I simply jumped the wire that goes in the number 2 position to the output for the sense wire, however I understand there are better ways to do this which I will do once I get the car running again. I disconnected the external regulator harness and jumped the blue and brown wire. From my understanding the red fusible linked wire that was originally connected to the alternator as well as the white wire are disguarded in this configuration. The car cranks and all electrical accessories work as usual but the car just wont fire I can almost tell that coil is not getting power as it sounds like it is about to fire but doesn't. When I put the red wire  and white wire back how they where originally and plug the external regulator the car fires right up but dies and the lights are very dim, due to double regulation am guessing? Is there a way to wire these cars correctly? I have followed all the info I have found regarding doing this upgrade and the car just wont fire up and it did before. Could it be my coil?, am thinking of changing it out tomorrow to rule that out as it is old. 

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The alternator has nothing to do with starting the car. The car will run off the battery with the alternator completely disconnected. How about rather than guessing and going by ear, you use a voltmeter and figure out exactly what the voltage is at the coil when cranking? Use a spark tester to see if you are actually getting spark at the plugs. And use a timing light to see if the timing is even close to correct (yes a timing light will work while cranking, even if the engine isn't running).

 

Once it runs, fix the alternator wiring correctly before you blow out that new alternator.

 

delco-12si-alternator-wiring-diagram-del

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Thank you for your input, it helped me rule out the bypassing of the external regulator so I have wired up the alternator correctly now. I ended up replacing the coil today as I was going to do it anyways to no luck. I think it is a carb issue as I had done some carb work on it replacing the needle and doing gaskets as they where old. I am going to take a look at that next as that is the other thing I changed since I last ran it.

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5 hours ago, Zodeac said:

I ended up replacing the coil today as I was going to do it anyways to no luck. I think it is a carb issue

 

So again, you plan to simply keep replacing parts until one of them fixes the problem?  The "hundred monkeys with a hundred typewriters" approach is not the best way to find a fix a problem like this. Your time and money to waste, I guess.

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It's easy to check for spark. pull a wire, stick a screwdriver in the end, hold it 3/8 of an inch from something metal, and have someone crank the engine. If there is spark you will get one every 2nd revolution. Make sure you have a good insulated handle. These things pack a wallop.  Ok, you could be more scientific and rig up a gap. 

 is this an HEI system or the seperate coil?

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Hello again everyone, I got the car running again this weekend, and seems to be running better than ever. After some thinking I decided to connect the original ingition switch up and tried it and the car fired right up. This confirmed my suspicion about my push start system turning the car back off the second it fired. Seems I am getting some kind of feedback or intefernce somewhere in the system that is making my push button system not work anymore. So I got myself a diode and installed it into a fuse holder and connected it between my blue and brown wire which are jumped on the old regulator plug. Same thing happened, I decided to connect it to the starter wire on the push start kits harness and it cranks more but seems to cut in and out. So one last try I suspected feedback to the coil and connected it to the wire that feeds power to the coil on the push button kits harness and the car cranks over and fires for couple revolutions then shuts itself back off. 

 

I know I have created this problem for myself but I had my push button kit working before and would like to get it working again with the upgraded alternator. Does anyone know why this could be happening? Somthing to do with the Ingition switch being electronic now. Possibly a ground issue? But the diode seemed to help things. Where could I be getting this feedback from that's telling my push start kit to cut power and shut the car off? I know am not the best at working on these cars but I appreciate all your input really.

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If the engine starts then immediately dies, your push start system isn't replicating the separate START and RUN positions of the original switch. On GM cars of this vintage, when the key is in the START position, it provides a full 12v to the ignition coil. In the RUN position, a separate wire provides about 9v to the coil through a resistor. If that second wire isn't properly being powered by your push start system, then the engine will start with the button pushed and immediately die when you release it. I suspect this push start kit was designed for newer cars that came from the factory with an electronic ignition. Newer cars don't use this two wire power to the coil because they don't have points. Put the old switch back and call it good.

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Yes I discovered this about the coil when I was testing for voltage at the coil before a tried the old switch, I have both run and start positions because I can put the car into the run position without starting the car. I had this button working well before I changed my alternator. Wouldn't it have had the same problem before?

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8 hours ago, Zodeac said:

Yes I discovered this about the coil when I was testing for voltage at the coil before a tried the old switch, I have both run and start positions because I can put the car into the run position without starting the car. I had this button working well before I changed my alternator. Wouldn't it have had the same problem before?

 

Nothing about changing the alternator SHOULD have effected the starting circuit. What you actually did we have no way of knowing. A complete understanding of what you've done to the car that is non-stock, along with a wiring diagram for the aftermarket starting system would allow us to provide useful answers. Without that, we're just guessing and assuming. The mind reading thing still isn't working.

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21 hours ago, joe_padavano said:

 

Nothing about changing the alternator SHOULD have effected the starting circuit. What you actually did we have no way of knowing. A complete understanding of what you've done to the car that is non-stock, along with a wiring diagram for the aftermarket starting system would allow us to provide useful answers. Without that, we're just guessing and assuming. The mind reading thing still isn't working.

 

Yes I agree with this, the only thing I have done to the car in terms of aftermarket connect the push start kit harness into the original harness where the ignition switch in the column would go. I assume everything else is stock from the previous owner. The car is repossessed vehicle the the column was all messed up and the key cylinder was drilled out along with all the rest of the locks the car. I will provide the diagram for the push kit, I have to go find where I put it haha. 

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Just wanted to make an update to this issue, I ended up figuring it out yesterday when I had some time to toy with it. Turns out it was a ground loop that was my problem. I simply grounded the push start kits box up too the steering column where the original switch goes and the car fired right up with the push start as before. My carburetor work seemed to fix my issue I was having with that as well. Also I took a look at the steering wheel to see of it was locked as someone had mentioned it before and I had known I might have an issue with that. It appears the pin that locks the wheel was broken or damaged when the key cylinder was drilled out so am all good there. Thank you everyone for your help and input. 

Edited by Zodeac (see edit history)
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On 2/12/2021 at 10:18 AM, Ben Bruce aka First Born said:

 LOL. It's a ground problem. Always a ground problem.. Glad you located the problem. 

 

  Ben

 

I used to work on the GM Technical Assistance line for technicians doing electrical diagnosis to fix cars with electrical problems in the dealerships.  I would guess that more than 1/2 of the "fixes" for cars with electrical issues were bad grounds. 

 

This is especially true of modern cars where there is more than one or two "codes".  If you have a bunch of codes from a module you can almost guarantee that there is a ground problem with the module.   Just my experience.

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I guess I have now learned my lesson when it comes to electrical issues, always check the ground! I am trying to put an aftermarket system with technology at least 30 years newer than the car however. Haha

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26 minutes ago, Zodeac said:

I am trying to put an aftermarket system with technology at least 30 years newer than the car however. Haha

When it comes to old cars there are always two ways to do things:

 

1. Assume that the auto makers knew what they were dong when they built it. Fix what was originally there. repair and replace the parts that were installed when new. 

 

2. Assume that most anything and everything on the car is worthy of being modified and "upgraded" to be on par with the latest technology available. 

 

Fact: it is ALWAYS cheaper, faster and easier to keep a car just as it was originally built.

The replacement parts always fit exactly, no cutting, no drilling, no welding, no modifying. . . (Originality is the ultimate "plug & play")

The installations always match what is shown in the repair manuals. (including wiring diagrams) 

You can easily seek and receive assistance from others because their car is exactly like yours. 

 

The only advantage that modifying has over repairing it as it was, is parts availability.

Yes, sometimes you have to search around and call for the correct part BUT when compared to buying something out of a catalog (with next day delivery) then spending hours and hours getting it to fit and perform as intended, and the time saving quickly disappears. 

 

There are entire populations of car hobbyists who enjoy modifying and adapting and changing. These people have skill sets that have been honed over many years. Some are incredible craftsman. But when you are just starting out and learning auto repair skills, keeping things as they were is always the quickest and cheapest method of making a vehicle operational so that you can enjoy it. 

Edited by m-mman (see edit history)
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Yes I agree that original always fits the best, I have other heavily customized and modified vehicles that I own but are much newer than this caddillic so this era of cars are new to me. I personally enjoy the challenge of modifying things to work if they make sense. In this case the car had its ingition switch drilled out when I got it so it was a fun and cheap project to try and fit the push button. Also a good feeling to know am probably the only one in my area with a car this old equipped with this type of starting setup haha. 

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Find a pre-1955 GM vehicle. Pushbutton starting was common on them. Nothing new under the sun.

 

It was a big deal when Chevrolet finally abandoned pushbutton starting in 1955.

 

I'd have found another steering column but that's just me.

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wow I never knew 1955 had push button starting, was it like a key and button, or just simply a button anyone can push? Wouldn't mind having a vehicle from that era. But personally I am a big into modifying cars and customizing them so it would never stay stock for me. 

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5 hours ago, Zodeac said:

wow I never knew 1955 had push button starting, was it like a key and button, or just simply a button anyone can push? Wouldn't mind having a vehicle from that era. But personally I am a big into modifying cars and customizing them so it would never stay stock for me. 

 

What Glenn isn't telling you is that the "pushbutton" was actually a pedal on the floor that mechanically engaged the starter drive in place of today's starter solenoid. The pedal also closed a switch that applied 12V to the starter motor at the same time to turn it. My 1952 Chevy trucks have that also. Note the little pedal to the right of the accelerator. Yes, there is still a key-operated on/off switch for the ignition.

 

rt_66_25.jpg

 

As for your pushbutton start "upgrade", it's just an electrical switch. Whether the switch is a slide switch that closes when you turn the key or a pushbutton switch that makes contact when pressed with your finger is irrelevant. You apply 12V to the starter solenoid either way. A screwdriver across the terminals on the solenoid does the same thing. Adding complexity is rarely an "upgrade".

Edited by joe_padavano (see edit history)
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Wow I never seen cars that start that way with the little pedal closing the circuit pretty good idea actually. But for me the electronic push button gives the car a key to start as it did not come with any keys what so ever. It also adds some sense of security as it locks the Ingition after 10 seconds. Even if the battery is disconnected and reconnected you still need the rfid key to crank the motor. But of course like you said a screwdriver could accomplish the same thing. But that's any car of this age. 

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2 minutes ago, Zodeac said:

Wow I never seen cars that start that way with the little pedal closing the circuit pretty good idea actually. But for me the electronic push button gives the car a key to start as it did not come with any keys what so ever. It also adds some sense of security as it locks the Ingition after 10 seconds. Even if the battery is disconnected and reconnected you still need the rfid key to crank the motor. But of course like you said a screwdriver could accomplish the same thing. But that's any car of this age. 

 

A new key is trivially easy to cut from the code stamped on the side of the ignition lock. New key and lock sets are still less expensive than your conversion and work the  first time. Also, the ignition locks immediately when you remove the key - not ten seconds later - as does the steering column and shifter. Look, if you want a gee-gaw to play with, have at it. Just don't lie to yourself that there's some magic benefit that makes it better. More complexity means more failure modes, as you've found out.

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Back in the late 80s early 90s the local thieves knew how to crack open that GM tilt column and take a joy ride. I probably did 100+ column repairs back then. Still have lots of the little internal parts. Can do one blindfolded.... Ha! 🤣    Ok, I exaggerate.

 

You can cut a key to match the (not a drilled out one, though) ignition cylinder on these tilt colums, but it is "impossible" to re-key an existing cylinder to match a code. After a while, that key only fit the ignition, so having a new key was not an issue, as all other locks stayed the same anyway.

 

Speaking of lock idiocy, anyone else see American Pickers where they whallop a 64 Chevrolet trunk lid with screwdriver and hammer to get the trunk open? IDIOTS!🤬  This in no way applies to the OP, as he bought the car already in this condition.

Edited by Frank DuVal (see edit history)
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45 minutes ago, Frank DuVal said:

You can cut a key to match the (not a drilled out one, though) ignition cylinder on these tilt colums, but it is "impossible" to re-key an existing cylinder to match a code.

 

Not sure what you mean by that, Frank, but I've rekeyed plenty of GM lock cylinders to match specific keys.

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1 hour ago, Frank DuVal said:

Speaking of lock idiocy, anyone else see American Pickers where they whallop a 64 Chevrolet trunk lid with screwdriver and hammer to get the trunk open? IDIOTS!🤬 

 

I did see that, Couldn't believe that scene. Those pickers are smarter than that.

Unfortunately it was just on in the background,

But wasn't this Mikes brother? And I saw the owner watching.

I guess I need to watch that one again and pay attention.

It was a convertible wasn't it?

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Yeah it was a convertible I seen that too haha!, it was a pretty clean car too not sure why they would hit on it like that being so clean. On this caddlic someone tried really hard to get into the trunk because the lock for the trunk looked like it had been beat with a sledge hammer a million times even the hole where the lock sits was a little bent up. I replaced it through now is good as new. 

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6 hours ago, joe_padavano said:

 

A new key is trivially easy to cut from the code stamped on the side of the ignition lock. New key and lock sets are still less expensive than your conversion and work the  first time. Also, the ignition locks immediately when you remove the key - not ten seconds later - as does the steering column and shifter. Look, if you want a gee-gaw to play with, have at it. Just don't lie to yourself that there's some magic benefit that makes it better. More complexity means more failure modes, as you've found out.

Well the orignal cylinder lock is non existent, so I saw it has a opportunity to modernize it with an electronic one. I just think its a cool little thing and it serves its purpose. Not necessarly better but it was for sure cheaper then fixing the column or even getting a new one. I might fix it one day just to lock the steering wheel and shifter with a key because I popped in a new cylinder just to cover the hole. $20 and a lesson in these old electrical systems was worth it to me haha. :)

Edited by Zodeac (see edit history)
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The pedal starter was on trucks.

 

Both light trucks and passenger cars had a keyed switch that had LOCK, OFF, RUN positions. All the switch did was turn ignition power on or off. A dash mounted pushbutton to left of the steering wheel activated the starter motor on cars, pedal next to the gas pedal did it on trucks.

 

Buicks had the starter switch mounted on the throttle linkage. Mash the gas pedal to the floor and Buick would start. I think they actually used that thru 1960.

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you asked if 55 had the push button on cars no it was keyed.a funny thing in the early (55+) gm s if you just turned the switch off and not lock.someone if they knew it was easy to jump in turn the switch and bye bye car.the keys were another thing there was a limited number cut thus my 54 caddy key would start my brothers 55 chev convertible led to some head scratching when filling up 😀 back then it was easy to park back where it was

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54 minutes ago, 54vicky said:

the keys were another thing there was a limited number cut

 

In fact, the number of different GM keys was surprisingly small through the 1966 model year. The Briggs and Stratton locks used only one key blank from 1935 to 1966. Yeah, GM had both octagon and round head keys, but the blanks were the same. You can cut an ignition key on a round blank or a trunk key on an octagon blank and they will work in the lock. Again, this is 1966-older. Worse, the B&S lock cylinders used six tumblers, and each of those six positions could have one of four different height tumblers. Do the math and the theoretical number of different keys over three decades of GM car production was only 4,096 (4 ^ 6). The actual number is even fewer than that, since GM did not use keys where all six tumblers were the same (so the key would just be straight) or keys where there were dramatic jumps in tumbler height (which would cause the key to hang up when inserted or removed). Think about that - less than 4000 different keys for all GM cars built from 1935 to 1966.

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