I have a '93 pickup with a 22RE. I just bought an Equus 6088 tachometer from Autozone and it seems fairly straightforward to install but I'm a bit lost on where to find the place to hookup the green wire for the ignition coil. I have the downloaded manual and it mentions the "IG-" test probe over and over, so I tried that but got nothing. So I'm thinking I actually need to find the ignition coil, but I don't have the old fashioned ignition coil, it's a Denso "igniter assy" with a big 208 on it (at least I think this is it). Do I need to splice into one of the wires coming out of this thing? Or is there an easier way? Thanks in advance.



Denso igniter assembly 208

 

Welcome to YotaTech.

Where did you find your IG-?

The IG- connector is just next to the Diagnostic port (I'll mention here that the manual clearly warns that if you ground that pin, VERY bad things will happen. You have been warned.) Even though it comes from the igniter on a different wire, that pin has the same signal as the coil drive (what Equus calls the negative side of the ignition coil).

Of course, you do have a coil. It's right next to the igniter (right behind it in your photo).

Are you sure you have the power connections to your new tach correct?

 

Thanks for the welcome. :-)

I'm not too sure of anything these days. I tried a mickey mouse hookup to test it, with the red wire to the positive terminal on the battery and black to a bolt on the frame. I did not hook up the white (back light) wire.

I found the IG- connector next to the diagnostic port as you said, next to the fusebox on the right side. Had a little rubber cover on it. So you're saying it does have same signal that I need?

 

I don't know what you need. (You're the one trying to install a tachometer I've never seen.) The IG- connector drops to ground 3 times per revolution, and that's the signal used by the stock tachometer. What did you use before?

 

Right, how would you know what I need? (a loaded question)...

Here is what I am going off from the directions. I found a thread on this forum that clearly showed a coil like the top part of this diagram (standard ignition coil), but that was a slightly older truck. What I have seems to be the second option ("delco" external coil). So I'm looking for the mysterious "tach terminal" on that diagram.

Equus 6088 tach instructions

What did I use before? You mean, for a tachometer? I never had one before.

 

You said you tried the "-IG test probe" and got nothing. I was trying to figure out what you've done (unsuccessfully) so far.
Here's a drawing (in the FSM) of your coil. http://web.archive.org/web/201212070.../4onvehicl.pdf It's not an old-fashioned "beer-can" coil.

If your -IG connector doesn't work, then either you have a broken wire somewhere, or cutting into your coil harness is also not going to work (it's the same signal). As you can see in your photo, both the igniter and the coil have sealed weather-proof connectors. Do you want to just cut into that and hope some friction tape will keep water out?

Why don't you try the connector supplied for that purpose (remember: don't ground it).

 

So, here is how I hooked my tach up, this is a four wire tach, power, gnd, signal and back light.

using the black wire off the coil plug as my source wire (bottom right looking to the inside of plug)

+12v power and ground were separate from this.
I also verified signal with a digital timing light that had an rpm output


Please ignore ghetto wiring, will be updated in future build thread

 

Thanks for your help so far. Got a chance to take another crack at it. I spliced into the cig lighter positive wire and soldered in the red wire from the tach. I wired the black wire to a bolt under the dash. I'm certain it's getting good (switched) power and ground now. Green wire into the IG- plug, still nothing on the tach.

Thanks for this pic, that verifies something else for me. I checked the continuity from the IG- port to the connector to the coil assembly thingy. It checked out fine, so there is no break. This pic shows the pin where I found connectivity to IG-, looks the same as yours.


I dunno. Is this tach junk?

 

Time to chase the gremlins!

Test light or volt meter to 2x check power and ground, might be bad chassis connection

 

Grab your multi-meter and go to town!

I used the product linked below from AutoMeter in my kid's 22R:
https://www.autometer.com/2-3-4-tach...ini-black.html

The install was straight forward. Power to IGN. fuse, ground under kick panel to "ground bolt", tach. wire to unused plug for sr5 cluster, light wire routed from dimmer.
Does your tach. have a setting for 4, 6, and 8 cylinder engines?

Cheers

 

A (12v incandescent) test light won't help much, but a plain-ole LED with a 1K ohm resistor in series is fast enough to flash on the IG- signal (at 850rpm idle speed, IG- pulls to ground about 29/second - a fast flash, but you should be able to see it.) Remember that LEDs are polarized, so test it from battery + to gnd to verify you have the correct direction.

(We used to say to get your LED from Radio Shack. I'm not sure where one buys LEDs locally anymore. If you're willing to wait a few weeks, something like these https://www.aliexpress.com/item/32951114114.html have integral resistors and run straight from 12v, so they should work.)

 

Do you have any pictures of the tach placement on the dash you can share?