Using The S12 Tacho?

[Sharas]

I have no prob with the diodes or the $5, but i just dont like the idea of more wires being sliced and resoldered under the hood. To many already.

[Ozchuck]

It'll be fine, just do it

[jeffwins24]

is there any way at all to use the digi dash? what if i we're to rewire it would that work?

[gerrybg]

Try the method and see if the digi tach runs with it!

[dwardle]

Sorry for reviving an old thread, but it's the most appropriate.

I had my SR20det running fantastic in my mk2 s12, then I spliced in 4 diodes, hooked them to a wire to my tach, and now it runs like crap and won't rev at all.

ANY HELP?

[mod_mastaz]

You probably have the diodes running the wrong way. The diodes purpose is to allow electricity to go in one direction only. If you wired it backwards, you pretty much just jumped ignition coils 1-2-3-4 all together and they all spark at once. Fix it before you kill your igniter.

Oh and this method does work with the digidash. Mine has been working for over a 6 months in CA heat and everything. I haven't cracked the diodes or had my car run like shit yet. They are the crappy radioshack ones too.

[dwardle]

They weren't wired the wrong way, strip was towards the tach end.  However I'm wondering if they weren't the right type/size of diode?

The tach was working fine, but the engine was not running at all barely.

[mod_mastaz]

Make sure they aren't contacting BEFORE the diode also. Remember to shrink wrap or wrap it in electrical tape. Does the car run better when the diodes aren't hooked up? Maybe there's an electrical issue not related to the tach.

[dwardle]

Car runs awesome without the diodes hooked up.  I ensured they were fully wrapped so there was NO contact before the diode.  I'm guessing they just weren't strong enough diodes.

[mod_mastaz]

Hrm.. quite possibly. You can try a higher amp/voltage diode and see if that helps.

[dwardle]

My bad, I was using the wrong diodes.  Make sure to use the 1N4004!  Tach works like a dream now along with the rest of the car.  

Getting the diff welded this week sometime so I can stop destroying my spider gears

[Navy_Mech2]

Curtosey of the first page  

Its actually a 1N4004

[chad-s12-drift]

Here's a pic of the ca18det ignitor, the 4 wires that go to the coilpacks from this are the ones you splice 4 diodes onto then join the "cathode" (striped) ends together and join them to one wire which you run to your tacho. There is a light green wire at the back of the tacho, which you cut and join to this wire. You have to remove the instrument panel to get at the connector that has the light green wire in it.
(Value of the diodes is stated in the other post linked further up, you get them from radioshack or similar)

Jeez you guys are lucky its all there spoon fed for you!!

on the ignitor im trying to figure out what side to tap into i noticed on it there is an arrow pointing toward an edge if that arrow is pointed up would i tap into the left clip or right clip or if someone could tell me the wire colors i think both sides had different colors

[mod_mastaz]

Tap into the side before the igniter. That's the signal you need to combine for the stock tach to work. Don't forgot the diodes also!

[Gnome]

Just about to attend to this tacho problem myself after checking into this string many months ago. Let's just say the whole engine transplant has been a major episode with considerable time and frustration getting the ECU sorted and the engine finally back on the road …only to have to do it all over again with a new ca18 rebuild when the former sounded like castanets and was definitely not environmentally friendly. Thanks to those who have provided what seems to be well considered info. I'm no electronics wiz, so I'll be getting a local auto elec to get it done and give him the thread to get him in the zone. I'll post my results, one way or the other.

[Fhu]

Thanks for this thread
My Eur Tacho is alive