Help! - Tacho output?

[Nizzan]

Hey all, ive recently got a tacho for my Gli (finally) , but one thing im not sure about is where the output is for it? :-/

I understand it has to connect to the ignition coil, but Pinnys have two of them, and they have *several* wires conected . A standard coil has 3 wires, high tension, low tension and the power. Tacho normally connects to low tension.

Any ideas anyone? Please?  :-/

John

[MR.TRX]

on the 2.4 its the green and black striped wire which get plugged in under the coil

[Nizzan]

hmm i tried connecting to that one just then, dont think my car liked it. it tried to turn over but suddenly stopped and all the electrics turned off - was dead :-/. unplugged and reconnected the battery tho and its ok now.

Are the coils the same for the 2.0 and 2.4? twin electronic coils?  

[SSS]

2.4 is single coil. You'd best ask an auto elec for some advice, or search the net.

[Nizzan]

No luck with info on twin spark ignitions on the net.  
Anyone know an auto elec i can ask/email for advice?

[MR.TRX]

the coil nearest to the firewall should be your inlet coil the other one is the exhaust coil.
your tacho (pulse feed) should be connected to the  
- negative coil. (not earth)
to check which one it should be use an volt meter, check for condinuity betwween earth & one of the 2 wires with ignition on only. whichever one has condinuity is the wrong one.
pulse feed comes of the other one, you can also check with a test light on the other wire.
connect clip to earth other end to wire without condinuity the globe should pulsate on/off.


a tacho feeds of negative coil & earth, it sounds like you had one of the wires to positive.
hope i did not confuse you, good luck.

[aussie-gli]

You can actually connect the tacho to the transistor output on the ECU.  The tacho looks for a negative pulse. This can be taken directly from the negative side of the coil or the ecu ouput to the transistors which drive the actual coil.

So either tap into the negative side of the inlet side coil (blue/yellow wire).

OR

connect to pin 18, or 19. (white wire) on the ECU.



I had a biatch of a time tring to get my trx cluster tacho going.  They work differently to aftermarket ones and had to design a circuit to reproduce a TTL pulse from the ECU. Fun and games  :-/

[Nizzan]

Blue and yellow wire! ahh ur a lifesaver. my tacho (digital aftermarket one) can detect RPM sensing directly from the coil or via low voltage signal from the engine mgt computer. so would i be right in saying i wouldnt need to setup a TTL as my tacho can take it direct?

which ones better to hook up to?

(and wheres the ecu located? dont wanna hook up to something else  {excuse my utter ignorance })

P.S. Adams seen my car and told me "You should really have a chat to aussie-gli" hehe, catch up on the birthday cruise if ur going?

John

[aussie-gli]

either connection should work. Your ECU is located underneath ur heater unit in the centre part of the dash.  The connection side is on the passenger side of the car. To get to it remove the kick panel on the passenger side.  If u need a pinout of the ECU let me know and I'll scan it for ya.

[aussie-gli]

I'll be at the cruise  

[Nizzan]

ill try connecting to the coil first. if that dont work, then ecu

p.s. if a connection is wrong, can the coil blow?  

[Nizzan]

its all good, new tacho up and running  

thanx man!

[aussie-gli]

Good stuff!