Vitara JLX 4dr Auto Tacho Not Working

[rupal]

Hi,

I have a 1991 Suzuki Vitara JLX 4dr (Auto Transmission) G16B 16v EFI, and the Tachometer does not work, the car seems to run fine but the needle just stays at its lowest position. I have checked all the connectors around the Dizzy, Ignition Coil & Noise Suppressor & the connections seem to be good... I also removed the Instrument Cluster & checked all the connectors on the back of it.

Any idea's what the problem might be ?

Cheers...

[fixkick]

its bad that tachometer if the brown wire, tachometer line goes dead or funky you get stalled engine or at the least CEL glows and DTC #42.
the tach has 3 wires, 12v , ground and signal. brown is signal.
pin A1 (y1) is tach input to ECU, (ECu just monitors this pin)
page 11.
http://www.fixkick.com/look/91-complete.pdf
then page 16 same pdf, see B9 dead to cluster B6 is power, and b8 is ground

or a1
here
http://www.fixkick.com/ECU/8v-tbi-schematic91to95.jpg

[rupal]

Ok,

So i measured the resistance between the Black wire (Pin 8) to ground & am getting 0 ohms.

Then i tested the resistance between the Ignition Coil & the Noise Suppressor (Brown/White cable) & i got 0 ohms.

I then tested the resistance between the brown wire (Pin 9) on the connector which goes into the Tacho on the Instrument panel, To the brown wire connected to the Noise Suppressor & am also getting 0 ohms...

And when i measure the voltage on the 12v wire (Pin 6) going into the tacho on the back of the Instrument panel to Ground i get 14v.

So it looks like there is no break in any of those wires.
But the Tacho still does not work.

[fixkick]

all good. this is an alternating current signal, the tacho is dead, if brown wire dies, the EFI kills injections.
your tach is dead. or its screws at rear of the cluster head flex-PC card, are corroded.
the ECu sees a 50v pulse. (a scope only works here) see pulse here.

http://www.fixkick.com/look/ECU-secrets/...ge_30.html

how i clean them is here.
http://www.fixkick.com/sensors/speedo/sl...ge_15.html
and your tacho pins are on left side
seen
here
left center screws
http://www.fixkick.com/sensors/speedo/sl...age_6.html

my 91 had no tacho.
so i bought 3 used heads off fleabay and made one good head with tacho.
the screws on the left are tacho screws. the car rust the copper is bare (suzuki bad act there)
http://www.fixkick.com/sensors/speedo/sl...age_6.html