Autometer Electronic Tach to RB26 in 240z

[strokerzedd]

I've searched and even posted in the past for the definitive means of hooking up an Autometer Electronic Tach (Phantom II) to and RB26 in 240z (1972). I'm using an AEM 1621u ECU. Some of the info I've cut and pasted from various blogs follows:

 

1.Tach - When you add an Autometer tach you might need to use a tach adapter. For the most part you can just follow the directions, but you do need to find the main power wire to cut so the adapter can intercept the signal and give a good reading to the tach. In the case of the RB it is the main power to the coilpacks.

 

2.Be very careful about using the tach adapter. I actually fried out the 52 ohm resistor in the ECU for the tach signal. I believe the stock Z gauge needs a 12v signal but an Autometer or other aftermarket tach needs a negative pulse, you don't want to use a tach adapter. Basically the tach adapter takes the negative signal and converts it to a 12v signal. Check if your particular Autometer tach needs a 12v as the signal or a ground, cause I'm sure they make both. The instructions should tell you.

 

3. Everyone I met could never get the tach adapter to work their tach. I got part from Summit it's an msd tach translator part #8918 (Toyota Dealership Part Number is 83420-16020. Out of a:

Toyota Camry 2.0 L4 88-91

Toyota Camry 2.0 L4 LE 88-91

Toyota Camry 2.0 L4 Le All Track 88-91

Toyota Camry 2.0 L4 DLX 88-91

Toyota Celica 2.0 L4 GT 86-89

Toyota Celica 2.0 L4ST 87-89

Toyota Celica 2.0 L4 GTS Sport 86-89.

Just tell them you're trying to get your Autometer tach working for your diesel truck and you want the thing that taps on your positive injector wire, it's $30, and you just tap that onto the little two wire plug that's by the ignitor, tap it on the white wire. My tach finally works perfectly. If you wire in an Autometer tach and tap the ecm's tach signal you'll pop the resistor in the ECU!

 

Three different answers. So no definitive answer. Is there someone who has successfully adapted and electronic Autometer Phantom II gauge in a 240z that is running an RB26 with an AEM 1621u? I'm sure someone has and they've found a solution. Please! I made a new gauge pod, so much easier to mount and work on the gauges.

[pat1]

 

this is what I used on my rb20. Worked perfect

[jakeoster]

Can you give me a link to what resistor it is please? There's different watts and what not, I've been trying to figure out how to get mine working for a while with no luck. What is wire 49? is that coming off the coil packs?

Edited July 30, 2010 by jakeoster

[pat1]

 

here is a picture of the resistors

 

pin 49 is a power wire any 12v power will do

Edited July 30, 2010 by pat1

[jakeoster]

Sweet thanks a lot. Like the OP, I've been looking for a definitive answer for this for a while. Hopefully I did not burn up my tach trying to get it to work haha.

[strokerzedd]

 

I followed this diagram but the tach still doesn't move.

[pat1]

I would try a 10k ohm resistor. If that doesn't work check your wiring.It could be possible that your ecu is trashed

[Canadianz]

I used the MSD tach adaptor and used the probe off it to hook onto I belive it was the main power to the coils for a signal. It was a bit tricky to get to work right but it works. The adaptor I used had an alagator clip like end on it that was used to pick up the signal.