Wiring experts, need help (N2MB Wot box and Tach at same time)

[JSkwarek]

Hey guys, need some help. I've been running a N2MB WOT Box for a little while now. No issues. Decided to add a Tachometer to the mix using AutoMeters Tach 9117 Adapter.

Basically, the WOT box and Tach Adapter wire in the same way. Cut the coil wires in half under the BEC solder the red wire to the fusebox side and solder the other wire (orange or black of the red/black pair for WOT Box and Red/Green from the AutoMeter Tach Adapter).

Here's where I run into an issue. If the WOT Box is plugged in, the Tach doesn't work. If I unplug the WOT Box, the Tach works just fine.
Any thoughts?

For those of you that have wired the AM 9117 into your GT500, did you wire another way, other than grabbing the wire at the BEC under the hood?

TIA,
Jason

 

[JSkwarek]

Finally figured it out. This is for people that are searching for this option in the future.

I first spliced into the wires at the WOT Box, instead of the BEC. I then ran a fresh set of wires from the BEC to the Auto Meter Tach Adapter 9117, inside the car at the passenger kick panel. I finally got out the trusty voltage meter and found a drop in voltage at the Auto Meter Tach Adapter. This made me think that adding the length of wire somehow knocked down the input just enough to not get a constant signal that the Tach Adapter needs. I removed the added length of wire and relocated the Tach Adapter near the BEC. Wouldn't you know... Tach works.

In short, don't lengthen the wires on the Tach adapter. Mount it under the hood, or in the wheel well like I did, to keep it hidden. Lengthening the wires will create weird bugs with the Tach adapter.

 

[Mr. Freeze]

Good to know, do you have any pics of the tach installed by any chance?

 

[JSkwarek]

I'll get some pics posted once I get everything buttoned up.

 

[et9secstang]

Ok I hooked tach adapter up and hid it under BEC ,ran wire back to tach works fine but now wot box doesn't work??

 

[et9secstang]

where else can we pull the tach signal, I tried the middle connector on pcm at plug 51 or 52 something like that but no signal, They need hooked up separate on my car, its a 2007, any ideas