PJF

Hoping some of you LS guru's can help point me in the right direction.

Running a new LS3 crate motor in my truck, I'll throw up a picture just so there is something interesting to look at while I type all this other stuff out.

It's the silver one laying out on the ground.



Running an Aeromotive A1000 Fuel Pump, which is recycling about 2 gallons per minute back in to the tank, so we are installing their fuel pump speed controller to slow down the pump based on RPM input, which needs a clean tach signal to work.

Which is why we are trying to install the MSD 8913 tach driver, recommended by Aeromotive.

Not finding a good wiring diagram on how to install the tach driver on this motor.

MSD's instructions.. :
http://www.msdignition.com/WorkArea/...id=15032386436

It looks like they want us to tap next to each of the coils? run 8 wires back into one?

Is there something closer to the ECU we can tap into to pull this off of.

Maybe I'm totally overly complicating this, any help would be greatly appreciated.

LS3 ECU wiring diagram, or advice on where we should tap the MSD tach driver into...

Thanks all in advance.

oldgoat69

The way I read this is that they want you to tap into a single coil + wire. Do you have a PCM wiring pinout diagram? You should be able to go to the tach signal port for the same type of signal. Someone with more expertise should be able to pipe up as well.

PJF

oldgoat69, thanks - we did find what *looks* to be like the correct wire, it's pink - but it's not working when hooked up to the MSD tach driver if we plug a tachometer on the other side to test with.

I don't have a PCM wiring pinout diagram. I found some online for other LSx motors, but not the LS3. Don't know if they are totally different or not...

sierrac3_s2000

iTrader: (6)

Check out Dakota Digital's website. They have a device that plugs into your OBDII port that gives you a VSS and tach signal to run your gauges. It's plug and play and should give you what you need.

PJF

Reading the instructions, we would fall under the:

Figure 1 - Connecting to a Coil Pack, correct?

Or... is there a single Coil Positive (12 Volt ) supply wire we can tap?

Thanks yall in advance!

PJF

Thanks sierrac3_s2000, I looked into that device, while that could work I have another device that I would like to permanately hook up to the OBDII port, which is why I'm attempting to go the MSD tach driver route.

I even looked into using a Y splitter to get two OBDII ports but it's my understanding trying to run two devices at the same time will likely be problematic.

Thanks though!

rascalking

I'm sure someone will correct me if I'm wrong, but I believe the pink wire is the 12 volt supply to all of the coils. If you're looking for tach signal, you would want to connect to the other wire. And you should be able to find those control wires back at the ECU.

rascalking

Guess I could have looked at the instructions first. You are right but connecting to the pink according to the instructions.

1989GTA

On my E38 ECM I plan on using terminal J1-48 for the tachometer output. For me it has to be activated through the software. When hooked up it is a white wire. People also say to use a 1K ohm pull up resistor connected to 12V when doing this.

PJF

Thanks for the feedback guys.

I found this thread from last year:

https://ls1tech.com/forums/conversio...magic-man.html

Is this diagram relevant for a LS3?

https://ls1tech.com/forums/attachmen...ircuit_fix.jpg

oldgoat69

Just for giggles take a loo at the Autometer website in the tech section. They offer a great database of wiring instructions.