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I put a Honda Civic tach in my 240

Signal from Microsquirt.

This. I figured I could get the signal I needed anyway because of MS, but as you can see in the picture of the laptop it was pretty straight forward.

The original signal on the civic comes from the distributor, as well as most honda's since at least the late 80's, so if you don't have MS, it probably wouldn't be difficult to do this.

It uses a square wave, 5 or 12v. The original tach used a flyback voltage spike from the coil. At least I think that's what it's called. Most modern cars have been using a square wave for decades, so their tachs integrate nicely with aftermarket engine management.

or this I guess.

Trying to get the signal from the coil like the 240 originally does probably wouldn't work, which is why I didn't try it.
 
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Thanks I was wondering about that signal. That may be something to do when some type of the squirt family of injection is installed on my turbo. Looks great in there. My interior is blue in my turbo so it would be a nice little blue touch.
 
If it went in without a 'resistor' adjustment, it's likely set up for a 12V signal just as the VDO tach was. When I hooked up the LS ecu output (5V) to the stock Volvo/VDO tach without any adjustment, it read WAY low. Had to "T" in another 12V connection through a 1000 ohm resistor.

Don't know my Civic nomenclature -- what year did the tach come out of?
 
If it went in without a 'resistor' adjustment, it's likely set up for a 12V signal just as the VDO tach was. When I hooked up the LS ecu output (5V) to the stock Volvo/VDO tach without any adjustment, it read WAY low. Had to "T" in another 12V connection through a 1000 ohm resistor.

Don't know my Civic nomenclature -- what year did the tach come out of?

ek civic is 96 - 00. I believe the EG civic, 92 - 95, also has the same size gauges.

And yeah, the tach output wire from MS is going straight into the signal in the tach, nothing in between.
 
Nice work. Inspiring. My 240 wagon hasn't had a working tach since I bought it. My 244 has one, though, so I'll probably just pilfer that, however this (or similar) could be a good drop in for that car, at that point. Thanks for sharing it :-)
 
Civic Tach Info

Old thread, but wanted to add some info for anyone else interested in trying this.

EG tachs (92-95) use a tach signal from the distributor (Ignition Control Module).

For EK tachs, 96-98 also use a signal from the distributor.

99-00 EK tachs use the square wave signal from the ECU.

DC2 Integras might have the same transition period (94-98 for Distributor, 99-01 for 5V square wave)

My Integra tach is from a 96.

I've tested a DC2 Integra and EG tach on a 240 by wiring the Signal to the Negative terminal on the coil. Both worked without issue. (The EG tach needed some adjustment, read a little low).

From what I can tell, the EG and early EK tachometers can handle using the signal off the negative Terminal on the coil, without issue. Not sure about the later EK tachs.

Don't have one to test (and possibly fry).

The Integra tach is too big to fit in the Tach/Clock section of a 84+ 240 cluster.
Unfortunately, it's roughly the same size as the Speedometer.
Might be nice for a custom cluster, like a STACK style.

<iframe src="https://drive.google.com/file/d/1RmuG8_lsr9tUHicjF9YcPscAv3j5-WHb/preview" width="640" height="480" allow="autoplay"></iframe>

Really liked the response and sweep vs the EG tach I ended up installing for a friend's Wagon (Part #: HR 0143-013)

<iframe src="https://drive.google.com/file/d/1ubSTbIOuuCIZtwTpPC-z2E4hHWY0kt2o/preview" width="640" height="480" allow="autoplay"></iframe>

Though the EG tach worked and looks cool (9k rpm), I'd say use an EK tacho if you don't mind the Blue.

The shape of the Gauge face requires more trimming to fit the 240 cluster vs the OP's EK tach.

<iframe src="https://drive.google.com/file/d/1PsbgJEu9Yv2kqkmXAK1tAYC-35xLq6DI/preview" width="640" height="480" allow="autoplay"></iframe>

Also, the location of the EG tacho PCB makes it a bit tough to fit. It's mounted off center towards the top of the gauge, so it touches the opening in the top of the Gauge Cluster PCB.

<iframe src="https://drive.google.com/file/d/1_bEMpm_8PJ_e_ZfdfACilTWmfHphVZK3/preview" width="640" height="480" allow="autoplay"></iframe>

<iframe src="https://drive.google.com/file/d/1dlEPg9TJkf2wRk_JgxtnG0oL8hxG8fRp/preview" width="640" height="480" allow="autoplay"></iframe>

Required some clearancing with the dremel, as well and trimming the tachometer PCB edges. Still, is a friction fit. But, it does work.

Power and Ground are taken from the pins that used to power the 240 Clock.
Then add a wire to the TA on the Tacho, and run it to the Red/White wire that's not plugged into anything behind the dash (on 86+ 240s).

The 85 Wagon I put this tach in required me to run a wire through the firewall. Pretty easy. The grommet for the throttle cable has plenty of give and the wire is easy to see/pull through when the cluster is removed.

<iframe src="https://drive.google.com/file/d/1sp7xQ2-2YIw5TywAZ596treoMuj7TBY5/preview" width="640" height="480" allow="autoplay"></iframe>

<iframe src="https://drive.google.com/file/d/1lTF8Fj1HLD0uxLxoSJIGsnaGbLHISDKA/preview" width="640" height="480" allow="autoplay"></iframe>
 
Old thread, but wanted to add some info for anyone else interested in trying this.

EG tachs (92-95) use a tach signal from the distributor (Ignition Control Module).

For EK tachs, 96-98 also use a signal from the distributor.

99-00 EK tachs use the square wave signal from the ECU.

DC2 Integras might have the same transition period (94-98 for Distributor, 99-01 for 5V square wave)

I've tested a DC2 Integra and EG tach on a 240 by wiring the Signal to the Negative terminal on the coil. Both worked without issue. (The EG tach needed some adjustment, read a little low).

I didn't know there was a difference. I just bought an EK tach because it was cheap on Ebay. I wanted an EG as I think they look better, but went with the cheaper option. So I'm not actually sure what year Civic it came out of. But it does use the tachout from MS, which I believe is a 5V square wave.

Also, the location of the EG tacho PCB makes it a bit tough to fit. It's mounted off center towards the top of the gauge, so it touches the opening in the top of the Gauge Cluster PCB.

Required some clearancing with the dremel, as well and trimming the tachometer PCB edges. Still, is a friction fit. But, it does work.

Yeah, had to trim the cluster with the EK tach as well, as its also off center.


Being able to run the early tachs from the signal from the coil is good to know.
 
I didn't know there was a difference. I just bought an EK tach because it was cheap on Ebay. I wanted an EG as I think they look better, but went with the cheaper option. So I'm not actually sure what year Civic it came out of. But it does use the tachout from MS, which I believe is a 5V square wave.

It's possible the late tachs are also capable of handling the Coil - signal. But, I don't have one to test, and the ones I've found on Ebay cost more than I'm willing to potentially destroy.

I also don't have a setup that produces a 5V Square wave to see if these older tachs can read it with any accuracy.

If I do come across a car I can test that with, I'll update the thread.

Yeah, had to trim the cluster with the EK tach as well, as its also off center.


Being able to run the early tachs from the signal from the coil is good to know.

Thanks for starting this thread and documenting your install.
Would've never known it could work without you showing it was possible.

If you look at the pic of the EG tach running you can actually see the gauge face is slightly offset down & left. The PCB is still being pressed on by the 240 Cluster PCB, when everything is assembled.

So, will have to figure out how to get that little bit more clearance at the top.
 
The black on the honda gauge seems to match the cluster plastic better than the original gauges, if only there were matching faces for the other gauges. Looks pretty sick
 
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