rickrock999

Hi,
Hope I am posting to the right place. I got a Bullet tachometer for my '64 Cutlass.
I am in the process of hooking it up. In the videos I am watching all the tachs have 4 wires but this one only has 3.
Red, Black, and Grey. The grey goes to a lightbulb.
In the videos black goes to ground red goes to power, green goes to the distributor. and White goes to the bulb. But there is no green wire.
I am attaching a pic of the tach and 3 wires. Does the grey wire go to the distributor and run the light bulb?
Appreciate any help

Thank You
Rick

joe_padavano

Well, stop watching videos and read the Chassis Service Manual.

(Sorry, that was too easy)

Those videos are for generic aftermarket tachometers, not a factory one. The CSM has a diagram that shows the grey wire to the bulb connects to the illumination circuit, the black wire is ground, and the red wire goes to the negative terminal on the coil. Done.

rickrock999

Joe,
Thanks for the info. I do have the 1964 Oldsmobile Service Manuals (3 of them anyway) I was looking in No. 4 under Electrical, guess I was looking in the wrong place.
I'll check the Chassis Manual (No. 5) (after looking though didn't see it these books seem to be so random)
Also I contacted the person who sold it to me, who claimed to have tested it who replied that I had to add an extra wire, of course he was super vague about where. (which of course makes no sense)
I'll try hooking it up the way you said
Thanks Again
Rick

joe_padavano

I was actually looking in the 1965 manual, since it was easier for me to reach.

The tach diagram was in the chapter on Instrument Panel and Accessories.

rickrock999

Well...I tried to hook up the tach, using 3 wires. Black to ground, Red to the negative side of the distributor. Grey to the instrument panel light.
Go to start the car and...Nothing. No start, no turnover, no click. Completely Dead. Took the tach out, and still Nothing. No instrument lights.
Tried to jump, didn't work. Checked to see if any wires from distributor came out, didn't see anything.
Not sure what to try now. Anyone got any recommendations?

oldcutlass

Do the headlights turn on?

rickrock999

No Headlights.
No power whatsoever.

oldcutlass

Clean your battery cable ends and battery terminals. Check the voltages at the battery and horn relay power stud.

OLDSter Ralph

What type distributor do you have in the car ? Did you check fuses ? Did you connect to the negative side on the coil ?

oldcutlass

None of this will prevent the car from cranking or the headlights to turn on. There are no fuses or fusible links in the main power or starter circuit. Either the battery is no good, bad or corroded cables, a bad or corroded connection at the horn relay, or the bulkhead connector under the master cylinder is not connected properly.

OLDSter Ralph

You are correct. I was assuming the only change was hooking up the tach. Thank you.

rickrock999

Brand new battery, connections are clean.
Battery is putting out 12v
The only change was hooking up tach.
Never had this problem before. Only tried to hook up tach.
hooked it up to the negative side of the coil.

The car has throttle body injection and electronic ignition, I checked the distributor cap
to see if it had the port for tach but did not, so I guess that means not HEI
I checked all fuses on the fuse block inside car.
I am trying to locate the second fuse block, the one with the relays.
I thought it was on the firewall behind the drivers side.
But I can't even see it if it is there, it is covered by the disc brake assembly and other things. I think.

joe_padavano

OK, once again the mind reading thing isn't working. Unless you tell us what is modified on a car, we have to ***-U-ME that it's stock. The stock tach is designed to work with the stock points ignition system. A GM HEI (and "HEI" means the coil-in-cap GM distributor, it is not a generic name for electronic ignition systems) has a TACH terminal in the cap that emulates the negative terminal of the coil. All bets are off on any other aftermarket electronic ignition system as far as wiring is concerned.

And Eric is correct, you can pull the distributor out of the car and the headlights will still come on. You have a fundamental problem unrelated to the tach. Either your battery cables are bad or you blew a fusible link. Get a voltmeter or test light and trace the wires back from the battery until you find where the voltage stops.

rickrock999

One other thing. I started the car and pulled it out of the garage to hook up tach. So everything was fine before I hooked it up.

rickrock999

Didn't know it mattered. It pretty much matters for everything I see. I bought the car as is so don't know everything about it. I probably blew a fusible link. I was reading another thread where someone had a similar problem and that was what it was.
I don't have any problems with my battery cables.
Thanks for the advise.

oldcutlass

There were no fusible links or fuses on a 65 for main power distribution. You are missing main power and we can't help you as your car is not stock. Your going to have to start tracing your wires from the battery onward. Perhaps some pictures of your battery cable routing to the horn relay and any aux power centers could help.

joe_padavano

^^^THIS.

The reason why we can't help is because we have no idea whatsoever how your car was wired. If it's stock, we can look at the factory wiring diagram and make suggestions. Since it's had major changes made, what else was done that might introduce new and creative failure modes? Does it have a one wire alternator? A "painful" aftermarket wire harness? What exact type of distributor does it have? As Eric correctly notes, photos of how the car is built and wired under the hood would help us understand exactly what you have and let us make useful suggestions.

Assuming, of course, this isn't some LS swap...

rickrock999

Joe & Ralph,
Thanks again for the help.
As my car is now stuck in the driveway, I can't push it back into the garage,
And I am busy with work , I am having it towed to a mechanic I know who is a good guy.
I have AAA so the tow if free.
I'll find out today what happened one way or another I hope. I will remember for next time to ALWAYS
mention the TBI Setup.

rickrock999

Hi,
If anyone is interested. Took my car in. Turned out it was the ignition switch which had somehow come loose.
He was able to fix it temporarily until I get a new one.
I also had a problem with the car intermittently running rough.
He did a system check and determined that my alternator was not putting out the full power.
We changed the alternator (he also redid the wiring to it which was in poor shape and added a new plug ) and regulator.
I also had him change the rubber bushing in the power steering mount which had broken.
He also checked out the tach, which was no good. Getting my money back on it.
Price for everything including parts about $280. and saved me a ton of hassles. Great deal. Car is running much better now.

joe_padavano

The ignition switch has nothing to do with the headlight circuit. You can remove the ignition switch from the car and the headlights will still work.

oldcutlass

I'd say that with all the fumbling with the wiring enabled your main power distribution to start working again. Your issue may or may not return. As Joe stated, the ignition switch would not cause a full power loss to include the headlights.

rickrock999

Makes sense. When he was checking it out he was moving wires around. After he got it started the first time It happened again and he went back and messed with it some more, he said it will OK now so maybe he did something else as well. The switch might have coincidentally also needed replacement. I'll ask him about it when I go back to replace the switch.

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