4g61t.org

Hey guys,
Ive just recently started wiring up all my extra gauges ...
And am currently stuck with my aftermarket tacho.

Ive run the tacho wire from my tacho to pin 109 on my ecu which is ignition pulse detect (tach)
Im runing a 4g61t with a vr 4 ecu

So after hooking the cables up for my tacho the original works, but my aftermarket one does not, it does turn on etc but does not seem to be getting a signal.

Anyone have any ideas ive found some threads on here about tachos not working but not aftermarket.

Any helps appreciated thanks.

Do i need to connect the tacho directly to the coil pack filter by any chance ?

A lot of aftermarket tachs are designed to receive the type of signal generated by a single coil, like on an older car. The signal generated by the DSM ignition is a 12v square wave.

_________________
Early 2000's: 1992 Summit sedan - 14.1 @ 100.9mph w/ 155/80 13s
2012: 1989 Dodge Colt GT Turbo - 14.9 @ 100mph, 10psi/s16G

Im sorry i do not quite follow,
Are you saying there is no way to hook it up?

Edit: the tacho box says its compatible with coil and electronic ignitions,
In the manual it says :quote ( on standard coil ignition* attach wire to negative side of coil.
* on electronic ignition connect the green wire to tachometer pulse output.)

I thougt id be fine hence why i bought it (well i bought it cause it was 30 $ and has a digital volt, water temp and oil press ure plus tacho all in one) but yeah i didnt see a reason why it shouldnt work,
It does say in the manual that some cars have a low tacho signal output and require a tacho adaptor.
Could this be the case?


If i do need to get to the coil filter thingo which is located under the inta,ke, how do i get it out?

Lol well i fixed it... answered my own question...
I found on the pin out diagram a crank angle sensor (rpm) wire which sits right behind the knock sensor on the ecu.
I just figured well this senses rpm output. So i hooked the rpm tacho to it... and like magic it works perfectly no glitches no messing around and easy as

So for anyone having tacho issues hook it to that line ( its the 4th wire from the very right inside row, black wire.. just behind knk sensor on the ecu)

Works like a charm even standard tacho runs of it.

Thanks.

AUS/JDM ECU's have slightly different pin configurations than the USDM models we have here. Wire locations may be a bit off, but it is good to know that you can use that output to get an aftermarket tach to work properly.

I guess i was a little to fast to be satisfied with my work, the tacho works perfectly when slowly reving the engine, but if i put my foot down and rev it fast it can not keep up , the shift light turns on before the needle even gets up there.

Wondering if the tacho is screwed ? Or why would the shift light turn on before the needle gets to desired rpm ?

Edit: Just to clarify, my original tacho now works fine after fixing the wiring to my ignition pulse detect tacho output, the aftermarket tacho is hooked up to my cas output as it didnt work on the pulse detect.
Anyways my original tacho moves way faster than the aftermarket tacho ,the aftermarket shift light ( which is build into the aftermarket tacho) is set to 4000 rpm for testing, the shift light turns on when the original tacho displays 4000 rpm but my aftermarket tachos needle only shows say 3000 rpm and is still moving its basically moving to slow. Unless i rev the engine slowly then it seems accurate.

Not to detract from the conversation about making an after-market tach work...

BUT

If your car came with a tachometer why install an after market unit in tandem with the factory unit? Why not just stick in the shift light and call it a day?

VERY CURIOUS, thanks.

Well the original tacho used to jump around like crazy until i started installing the aftermarket one and found out why, also my tacho is a big 4 in 1 tacho which shows oil pressure, water temp, volts, and rpm plus shift light...
and the main reason i got it is because it was only 30 aud and i cant buy a shift light, volt meter, water temp and oil pressure gauge for that... really it was just a cheapo option
Was thinking of just leaving it but then it would allways bother me to have done a simple thing half assed

Also i rang the manufacturer who said i may need a tacho adapter to get it to work due to low output signal, doesnt make senxe to me as the shift light works as it should... but has anyone ever heard of this?

Here is what they pointed me to http://www.summitracing.com/search/part ... r-adapters
If i do need one which one would it be and why do i need this if i have a tach output?

Sorry for all the questions but id rather learn than break