So I keep blowing fuses...everything was fine then all of a sudden i'm blowing fuses. I was only using a 40amp fuse and thought I might need to go up to a 60amp so I did and still blew it after only a minute of being on...the autopilot volts display showed 10v then once it blew the fuse it jumped to 12.8v immediately. WTF is going on?

 

How large of a power wire are you using? I'd use a 4awg, for sure.

I'm an audio geek, so I'd also perform the 'big 3'. This entails replacing the positive wire from the alternator to the battery, negative to chassis, and chassis to motor ground.

May even have a bad battery. If your car isn't charging at around 13.8volts, something could be wrong. May also want to replace the alternator pulley with one from NST. The factory pulley has a clutch in it. Weird, I know.

Also check how your compressors are grounded.

 

^^^ check everything he stated and also, are you running water traps, what kind of check valves are you using? When the stock Viair leader hose check valves get even a little moist they seize up, which cause a high amperage restart because you're trying to build pressure against a partially charged tank when the compressor is asked to run. You could have a bad compressor too, possible, not likely, but possible.

 

I spaced those awesome Viair leader hoses. They'll break if you look at them wrong.
However, I do believe the OP is running hardlines. Looks sick! Make sure you do have the check valves. They're required.

 

So I am running 4ga wire with a 60 amp fuse going all the way to the a distribution block and 12ga from the block to the relays...from the relays to the compressors is also 12ga. I checked my check valves (yes I am hardlined and use SMC check valves) the were holding the pressure (145psi) just fine. So I call Lance @ Viair, we double checked my ground it was good. I put a fresh fuse in the holder, drained the tank and turn on the car and the compressors kicked on like normal and filled the tank to 175psi. I then opened the drain to allow the pressure to drop and the compressors to kick back on...at 145psi the compressors kick on my voltage drops to 10v and I pop a 60amp fuse. Odd that it only happens on startup after the tank has been filled to 145+psi. Lance suggested I get a single 80amp relay (battery isolator) and use it with larger wires to everything.

I will be buying one tomorrow but am unsure how to hookup a dual compressor setup with a single relay and the autopilot. Anyone here ever do this?

 

I don't know how the autopilot thing works.

 

Before you put in the relay have your battery load tested. It sounds like you have a voltage drop under load.

 

Man, it still sounds like a high amp restart, like maybe one of those check valves are stuck. I had the crappy Viair leader/checks seize on me and it popped the fuse once, replaced the check, problem solved. The SMCs are a lot better quality. So when you say you're popping a 60 amp fuse, is that shared for both comps or just one? The other part that makes me question the checks, when you drain the tanks and start from zero, no problems, when you restart, boom! You would hold pressure even with a seized check because the compressors have a reed valve in the head just before the outlet that would prevent back bleed. Starting from zero there isn't any starting resistance on the windings as you build pressure in the tank, when you restart at 145psi the piston has to fight to build pressure and your amp draw rises exponentially. I'm curious for sure now.

 

Get an 80 amp fuse and run both compressors off of it, and keep a spare in your tool kit. I always ran the stinger style fuses on my air ride setups and never had a problem

 

It was a bad compressor. I seperated them and the bad one blew a 40amp by itself and the other one has been didnt and it is still going strong. New compressor was sent to me but it has the new head style and with my hardline setup it wouldnt look/work in its current config. Airlift is "trying" to locate me an old style 380c.