LT8 and stock tach
 

Can't get the stock tach to work. Karack and I slaved over this install for hours. the car runs great but no tach.

Which wire is which as far as the tach is concerned. All I know is that it gets the signal from the trailing coil.

Excuse the lazy post. I just got home from doing the microtech install and it's 5 AM... a little tired...

this is on an S4 TII....

Tach wire is the yellow/blue wire at the trailing coil. This goes to the cluster also through a yellow/blue wire as part of the body harness. It should not have been effected by the install unless the trailing coil connector was totally cut from the harness.

Keep in mind that the LT8 does not seem to fire the trailings during start up so you won't get a tach during cranking.

Thanks Aaron...

I have no tach at all. I don't mind it being non-functional during cranking. but I'd like to have it working anyway...

Thanks. I'm thinking if just patching the wire directly to the tach provided that the body harness connector doesn't work...
I spoke with Icemark over the phone and he suggested just patching it.....

we'll see what happens.

Yeah...I've tried to find that wire in the body harness before but when it's in the car it seems impossible. It disappears into the harness, then only comes back out at the power steering computer (not applicable in my car...) and at the tach. So it's likely easiest to just run a wire directly to the tach.

OK.....so if I look around the PS computer, I should be able to see the wire hanging there?

it should only be a matter of cutting one wire off the 4 pin connector at the trailing coil and connecting it to the one on the microtech. that single wire is part of the body harness so it didn't come on the harness with the microtech. i remember seeing the yellow/blue wire in the connector i just was too tired to look it up. :p:

if you lift out the trailing coil you will see the connected 4 pin connector and the dangling 4 pin connector from the stock harness that is unconnected, take the yellow/blue wire from the dangling connector and splice it into the one that was already connected, the yellow/blue wire on the microtech harness side should just be taped up in the harness and easy to reveal.

w0rd!

thanks for the wire color aaron, wish i could have looked it up that evening but damn that was a long day..

for some reason they never gave me an ignition schematic with my diagrams with the microtech. also i noticed on their website the color wires out of the microtech do not match the schematic colors, i should send them an email to look into it since apparently the MTX8 (which their link goes rather than the LT series wiring diagrams) has different color wires than the LT series.

The colours on the Microtech harness seem to match the manual, but often they reference the colours not on the stock harness, but on the other side of the connector. So for the coils and CAS you need to look at the actual wires coming from the coils/CAS.

For the record, the power steering computer is mounted underneath the steering column. It has a yellow/blue wire which is tach signal.

the wiring color for the coils they have listed on the microtech site now make no sense since they relate to neither the microtech which are all grey wires with color tracers nor the stock harness. the CAS wiring is the same between all series of microtech though so that isn't the issue i had with their diagrams now. for some reason i can't find the LT series ignition wiring diagram anywhere now, it always comes up as the MTX diagram which appears different. i know their links used to be correct but since they redid the site it looks like the links are not correct anymore.

here is what they now link to as the LTX8 ignition diagram, the ignition connector wire colors do not relate to this diagram at all either by plug location or by wire color, the only thing that does relate is the loaction of the trailing wires in the connector.

http://microtechefi.com/pdf/LTX8MAZDA13BTS4-5ign.pdf


perhaps it has always been this way and i just got the wire colors from the microtech section here on the forums, i just wish they would clarify their diagram better since it really is of no use.

Thanks Aaron...

And thanks Ben for doing the install! :bigthumb: