Author Topic: Stock AE86 Rev counter  (Read 19693 times)

Offline Will

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Stock AE86 Rev counter
« on: April 15, 2008, 10:29:35 am »
Has any one got the Vems rev output working with the stock Rev counter?
If so where can I find the wire I need to connect to the dash on the AE86 loom?
Had a good look about on the various AE86 sites but can't find much info.

Thanks

Offline rob@vems.co.uk

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Re: Stock AE86 Rev counter
« Reply #1 on: April 15, 2008, 05:30:44 pm »
try taking a wire with a 12v feed and a 300R to  1K resistor, and the AE86 revcounter wire and bang them off each other to see if you get any movement on the rpm - the quicker you make and break the connection the more the RPM needle should move.

If theres no movement its because the tacho needs more of a voltage kick, and we'll need to work that out when you've done the 12v test.

It might be worth using your diode pair connected to coil 3&4's ground wires. like you did with the coilpack from before...

Rob

Offline Will

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Re: Stock AE86 Rev counter
« Reply #2 on: April 15, 2008, 06:10:01 pm »
I never got round to doing that Diode method as I don't know where the wire in the loom (car side etc) is for the speedo. I know its meant to be down the left hand side passenger foot well area where that relay board is, other than that no idea really?

Offline rob@vems.co.uk

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Re: Stock AE86 Rev counter
« Reply #3 on: April 15, 2008, 06:18:43 pm »
Well eitherway you're going to need to find it for this one ;)

Rob

Offline irishtwincam

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Re: Stock AE86 Rev counter
« Reply #4 on: April 17, 2008, 09:00:23 am »
Black with orange stripes, coming out of plugs by the stock ecu.
If its an early model, its on the bulkhead connector that splits in two behind the intake/engine.
Same colour scheme.

Offline Denmark

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Re: Stock AE86 Rev counter
« Reply #5 on: April 17, 2008, 04:09:25 pm »
Yep ,its indeed the black with orangestribe,
On mine i found the wire in the bulkhead plug,
but i never got it working great,
Mine would work fine up to around 4krpm, and it would then just fall to zero again,
That could probbely had been fixed pretty easy, but i never got around to do it.

It did not bother me much ,as after 4krpm i better hold on to the steering wheel, when it broke traction, pretty easyly  ;D

http://www.vems.hu/wiki/index.php?page=MembersPage%2FSkassa


/Skassa
working on the boxer

Offline Will

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Re: Stock AE86 Rev counter
« Reply #6 on: April 20, 2008, 07:44:28 pm »
Did you use any pullup resistors or just straight from vems to the black/orange wire?

Offline rob@vems.co.uk

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Re: Stock AE86 Rev counter
« Reply #7 on: April 20, 2008, 10:08:38 pm »
VEMS doesnt kick out a voltage, so the pull-up will be needed - if its enough of a voltage, personally I think its worth driving the tacho from the negative wire on one of your coils.

Offline Will

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Re: Stock AE86 Rev counter
« Reply #8 on: April 20, 2008, 10:34:30 pm »
Will give that a try then, atleast I think I have the right dash wire.

Offline Will

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Re: Stock AE86 Rev counter
« Reply #9 on: May 01, 2008, 07:32:29 pm »
The diode method doesn't work, but 12v direct on wire works, so how do I do the pull up resistor or do i just connect 12v the taco/ecu wire?

Offline gunni

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Re: Stock AE86 Rev counter
« Reply #10 on: May 01, 2008, 09:57:09 pm »
12v - resistor - tacho wire.

Offline Will

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Re: Stock AE86 Rev counter
« Reply #11 on: May 01, 2008, 10:08:22 pm »
12v - resistor - tacho wire.

Where does the ECu wire go in that lot? Before the 12v wire?

Offline rob@vems.co.uk

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Re: Stock AE86 Rev counter
« Reply #12 on: May 01, 2008, 10:49:15 pm »
Tacho wire to the ECU.  12V via the Resistor to the Tacho wire to "pull" the tacho voltage up towards 12v.

When the ECU's tacho channel is closed the tacho sees 12V, when the ECU opens the channel the current flows to ground and the tacho sees 0V.

Offline Will

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Re: Stock AE86 Rev counter
« Reply #13 on: May 02, 2008, 12:19:37 am »
Ok thanks, is there a rule of thumb of what resistor to use? Or just try one? Like 330Ohm

Offline Will

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Re: Stock AE86 Rev counter
« Reply #14 on: May 02, 2008, 12:23:21 am »
Can I share the 12v that goes to the relays turning the ECU on and off, or will the tacho wire from the ECU make the power relays turn off?