liquid_helix136

So I checked under the dash, which Im now pretty familiar with after installing Nitrous on the car, and after installing the serial gauge everything looks normal, I have 3 wires grounded to one of the hood release bracket screws and the 2 for the serial gauge to another screw on the same bracket. Gave power to one of 12v ignition sources and that was it.

The next day after I installed the gauge, everything seemed fine until about 5 miles down the road the speedometer went out, and the EPS light came on (which I hear is just a symptom of the speedo not working. But the weird thing is that when I slow down at like a light or something, or turn the car off and back on, the speedo comes back on, and the EPS light and power steering comes back.

Of course I figured I must have messed up something below the dash but all looks in order. I also have a Modifry yellow jacket speedo calibrator for my 4.77 gears, and so I'm worried that this is going out, as I've had it for about 3 years now. But if the yellow jacket was going out I would think that the speedo would just cut out and not work 100% of the time, and not be intermittent/random.

All of my connections / wires are taped up decently, everything SHOULD be insulated well enough for wires to wreak havoc on each other.

My next step is probably going to take the yellow jacket out, hook up the speedometer normally and see if that fixes the problem, but until then, does anyone have any thoughts or ideas?

speakeasy2009

It really seems like a bad ground or something that's lose. Even the slightest vibration can cause these issues if a wire is not properly grounded or shielded even if you made sure the grounds were tight. Who knows maybe one of the grounds I would reseat all the ground wires first and maybe even swap them to other ground positions just to test.

4forall

Also check all the grounds on the engine block. I have heard of speedo problems when a ground was disconnect on the head near the firewall.

liquid_helix136

Thanks for the help guys, I'm probably gonna reground everything and see if that helps. If not I'll uninstall the serial gauge and see if something with that is causing the problems. Since its intermittent I would imagine its a wiring problem somewhere, but I'm no electrical engineer so who knows.

ronnuke

Has similar issues with my Yellow box. My trouble turned out to be loose wires in the terminal block for the yellow box. Tightened them up and has been fine since.

liquid_helix136

So you had the yellow box hooked up to a terminal block? Or are you talking about the yellow box itself?