924Board.org

[Borken]

Hi!
Clever me tried to swap my old rev counter to a fresh one from a 924S. I did not have the same terminals as the old one but one was marked + and the one under it gn (ground?). I tried the signal cable on the other terminals but with no success. I swapped the cables back to to the old rev counter but it´s just as dead as the new one

I no longer have any voltage on the black lead. Of course some of the other meters where dead too, same supply cable i suppose.

The black cable is not fused.

Is my supply cable fried and where do i start looking?

I seems totally intact the little bit that is visible. No fuse box connectors is blackened.

Help!
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Jack of all trades, master of none

[daniel]

From memory -
Black is signal wire
Brown is earth
Pink is switched 12v
_________________
Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet

[edredas]

On the 924S the black wire comes from terminal 87 of the fuel pump relay. If you need to trace the wire, it goes through the firewall and to the 9 pin connector behind the brake booster.


I hope that helps!
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'84 944 -White, Brown interior
'84 944 -Red, Automatic
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, Project Car
'88 924S -Red, Daily Driver

[Borken]

Ok, thanks for the replys!

The car is a 924 N/A 1981

The black wire is fed from 15 and is positive and goes via the main instrument.

Perhaps something burned out in the instrument?

But my fuse box was tampered with so i will install a better one and go from there.
_________________
Jack of all trades, master of none

[edredas]

My mistake, I thought you had a 924S and were just swapping another tach in and trying to trace the power wire back to the source.

I'm not sure how you are connecting the 924S tach in the early car, but it should be mentioned that the wiring is of course different colors. So trying to match green wire to black wire will end up a mess. The black wire is positive for this tach and green is signal.

As for the ground, the 924S tach will not work without the ground plugged in for the bulbs on the back of the case.

I hope that helps!
_________________
'84 944 -White, Brown interior
'84 944 -Red, Automatic
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, Project Car
'88 924S -Red, Daily Driver

[Shurick]

I may be wrong, but 924 tach is different from 924S/944. 924 tach counts pulses from coil negative terminal and 924S is voltage-driven from ECU unit.
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WBR, Shurick
'79 931 -- intercooled K26-3060-6.10 turbo @ 1.2 bar, EFI+EDIS, 951S brakes, stripped interior, 951 look.
'86 924S -- R.I.P.
https://www.instagram.com/ru_pacecar/

[edredas]

The 924S/944 DME sends pulses to the coil and the tach just reads those. These pulses aren't any different than the early cars. A guy once asked me to make his 924S look like an early 924 inside so I swapped the speedo, tach, clock, and oil pressure gauge over from a '77 924. I only had verify the wiring and everything worked perfectly!
_________________
'84 944 -White, Brown interior
'84 944 -Red, Automatic
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, Project Car
'88 924S -Red, Daily Driver

[Ian89C4]

If I remember correctly

924 (non S)

Green - Signal wire from negative side of coil (should be a two wired connector at the coil

Black - 12V

Brown - Ground

I haven't messed with a stock wiring loom in a few years, so where the power comes from I don't exactly recall.

Check you grounds behind the fuse box. There are two "wheels" of them attached the sheet metal behind the fuse box. They are usually very corroded if they haven't been tended to in 30+ years. That may be where your problem is.

Good luck,

Ian
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Ian Edgerly
North Carolina

Current:
1981 924 SCCA/ChampCar Weissach Race Car ("Serenity")
1987 924S ChampCar Endurance Car ("Der Weg")
1980 924 Euro ("Wahala")

[Borken]

Yes that wiring was correct!

I swapped the fuse box and now i believe my electric system works 100%

/janne
_________________
Jack of all trades, master of none

[Ian89C4]

Great!
_________________
Ian Edgerly
North Carolina

Current:
1981 924 SCCA/ChampCar Weissach Race Car ("Serenity")
1987 924S ChampCar Endurance Car ("Der Weg")
1980 924 Euro ("Wahala")