roush boost gauge troubleshooting

[corey5988]

I have a Roush installed electric boost gauge on my car. The gauge wasn't working when I got the car. On inspection the wires were fed between the dash trim and the duct work and had been cut right there (don't know if it got pinched on install or what). Anyway, I spliced them back in with the corresponding wire colors (I had one black wire off the gauge pigtail and two off the harness to the electric unit). I unioned the three black (assuming grounds) together and it still doesn't work. I traced the vacuum line from the blower to the electric unit and it seems intact, though it did have tubing over it. I'm at a loss, and this is my first FI car. So I figured maybe it was something obvious. What should I look at and/or test? The illumination is working, btw.

 

[AutoXRacer]

You should have one ground, 12V, and lighting.

Is this the one you have? I have not heard of an electrical boost gauge from ROUSH, unless its a pretty old one.
http://www.americanmuscle.com/roush-boost-20psi-mechanical-black.html

This is the ROUSH install instructions for their latest boost gauge:
http://1.cdn.lib.americanmuscle.com/files/69137-manu.pdf

The difference with an electrical boost gauge is that you'll have a signal wire coming from the sensor (0-5V).

 

[corey5988]

You should have one ground, 12V, and lighting.

For an electronic gauge, not a mechanical gauge? I have around 5 + the ones for lighting.

Edit: It's an '09 Roush GT. I'll grab some pics when I get to the garage.

 

[AutoXRacer]

For an electronic gauge, not a mechanical gauge? I have around 5 + the ones for lighting.

Edit: It's an '09 Roush GT. I'll grab some pics when I get to the garage.

I have an 08 and it came with a mechanical gauge.
Do you have a peak memory option in your gauge?

According to the mechanical gauge install, there should be Red, Black, White, and Blue wires; all for lighting.

 

[corey5988]

Here's some pictures.

To the electrical unit (mounted below fuse box).

 

[corey5988]

Is one of the short studs on the back supposed to be grounded?

 

[AutoXRacer]

Typically,

Red is 12V source
Black is ground
Purple is your sensor signal (0-5V)
You should also have a sensor common ground
And the grey one I have no clue. There could be a wire sending a 0-5V power to the sensor.

Here is a typical Autometer electric boost gauge installation instruction:
http://www.autometer.com/productPDF/0569A.pdf

Seems like you definitely should have 3 wires between your sensor and gauge (I assume 5V power to sensor, common ground, and 0-5V signal), then a switched +12V and ground.

OH!!! HERE YOU GO!!! Exact installation instructions for your gauge!!!
http://www.autometer.com/productPDF/0598A.pdf

 

[corey5988]

So the gauge isn't grounded. I have the two black wires in the gauge pigtail going the black wire in the sender harness. The lighting ground is good, since it's lighting up. So I need to run one of the grounds in the gauge pigtail to the ground for the lighting and I should be good? I'll give that a try and report back. Thanks a lot, I think that will get it.

 

[AutoXRacer]

Be careful, not all blacks are ground!!! Do not ground the wires going to the harness/sensor. Those should be untouched!!

 

[corey5988]

Be careful, not all blacks are ground!!! Do not ground the wires going to the harness/sensor. Those should be untouched!!

There's one black from the sender, which for sure would be a ground between it and the gauge. The gauge has two black, one should be between the gauge and sender and a chassis ground.

 

[corey5988]

That did the trick. Thanks. It does have a peak button and another button as well.

 

[AutoXRacer]

Awesome!!!!!

 

[corey5988]

Checked the gauage again. It's "PEAK" and "WARN".

 

[AutoXRacer]

Nice, wish mine had that... lol