Tach problems.

[AtomChurch]

I bought a stock tach for my 510 today! came with the speed-o and the gas/temp gauge as well.

 

but the plug in my 510 is the same as the one on the tach. both are the 3 hole male end. the one in my 510 is black green blue and the one on the tach is black green green. with two extra white wires comming from a different spot.

 

please help me get my tach working !! i searched other threads but didnt see anything that helped.

 

what wires go where?

[AtomChurch]

this is the front of the tach

 

 

this is the back. once I removed the harness with the lights on it there are only four wires.

 

where do these go?

[AtomChurch]

ok with a bit of research I found that the green wire is power and the black wire is ground. and the two white wires are signal wires. but I dont know where they go after that. I found a diagram that says but I don't know what the symbol is in between the two wires.

 

maybe someone else will know. here is the link.

 

http://datsun510.com/photopost/showphoto.php?photo=67&size=big&cat=

 

its wiring for the tach.

[hang_510]

dunno what that symbol is either...

IIRC it needs to be disconnected and each white wire will complete the circuit.=1 goes to the ballast and the other end attaches to the BW wire.

if it doesnt work, swap the wires around

[AtomChurch]

no dice. that didn't work.

 

i wonder what that symbol means?

 

does the tach need its own mini coil?

[]2eDeYe]

Not sure about the 510's or what that symbol is...

Why the 2 wires would go to the same connection doesn't really make sense either...

 

I've installed a few tachs (aftermarket and factory) and found a few similarities.

 

The Green wire usually goes to the Neg - side of the coil. If you hook a test light to that side while the engine is running it will flash. The flash is the dizzy telling the coil to fire. This is the 'signal' your tach uses to calculate RPM. This will come in handy during the testing stage.

 

The Black wire is usually ground. Self explanitory.

 

The Blue wire from the 510 might be for the dash light.

 

All of the wires in the car can easily be tested with a test light to sort out their respective functions.

Then match the Black wires (because I'm sure they are both for ground) and test the Green wires on the tach using the Green wire from the 510 to tell which wire is tach and which is light.

 

That would leave you with the 2 extra white wires which I would think go to your charge and oil sending units.

 

Those 2 would be easier to figure out if I could see where the wires terminate inside the tach housing.

 

Hope that helps :D

[moparvwfreak]

waht it looks like to me is the wire that it feeds off of needs to be clipped and the tach itsself finishes the circuit. thats the only thing i can think of. i have seen that symbol before and if memeory serves it means cut. but thats my opinion though and i am no expert.

[]2eDeYe]

That sorta makes sense.

[hang_510]

waht it looks like to me is the wire that it feeds off of needs to be clipped and the tach itsself finishes the circuit. thats the only thing i can think of. i have seen that symbol before and if memeory serves it means cut.

 

thats what i was trying to say :rolleyes:

 

cut the wire, the white wires connect to each cut end, completeing the circuit through the tach.

 

 

sorry 'bout the lack of clarity, i know what i mean :fu:

[AtomChurch]

is there a way to even see if the tach just works short of hooking it up?

 

does anyone have any experience with hooking a after market tach up to the origonal needle and face?

[AtomChurch]

well I studied that diagram and this is how I hooked it up. I made a adapter for the back of the tach to plug into power.

 

and then I wired the two white wires like this.

 

 

if it still doen't work. does that mean my tach is probably broken?

 

is it worth hacking apart to fix that little tiny wire that probably is the only reason its not working?

 

I like the stock tach too much to just nt have it work. haha. So somthing will happen with it either way.

[AtomChurch]

I also found this page. I'll try to hook it up this way. If anyone has the full article of this dime quarterly is there anyway they could copy the repair section for me? thank you.

 

http://dimequarterly.tierranet.com/articles/tech_tachrepair.html

[datzenmike]

no dice. that didn't work.

 

i wonder what that symbol means?

 

does the tach need its own mini coil?

 

Symbol? Do you mean the two things that look like an SS? That is used to signify a cut in the wire, this way the tach is in series with the ballast resistor and coil.

 

Is there a nut where the two white wires connect to the tach? (picture is blurry) My 620 factory tach quit and I undid and cleaned the contact surfaces on the bolt and tightened the nut back up and ..voila!

[datsunaholic]

The 510 tach is inductive, sorta like a timing light. It's not like your normal aftermarket tach, or like the ones used in Z cars or any other Datsun after 1974. The reason was the dual points, if you fed it like a normal tach (off the negative coil lead) it'd jump to double RPM every time the dual points kicked in.

 

The symbol means "cut". That way the power runs through the tach. Almost like an ammeter.

But unlike an ammeter it doesn't matter which way the white wires were wired. If the car even starts with the white wires hooked up inline that's an indication that at least the inductive setup in the tach isn't burned out. But, something else could still be burned out.

[AtomChurch]

yea, i hooked it up in series with the ballast resitor and the negitive side of the coil. and when I hooked it up with the negative side of the coil I got it to jump up to 3000 when I messed with the POT [variable resistor] but it just stayed at 3 and then fell back down. Ill try cleaning. even if this doesn't work someone will need this information sooner or later.

[AtomChurch]

whats the easiest way to take the tach apart without cutting the plastic?