Pressure Switch not working on my EDC (Sandan not York)

Okay what's up guys?I've been asking this on the mazdatruckin site, but mini trucks aren't always their things....

So here's the low down

87 Mazda B2000

Stock engine set up, using my A/C compressor for the tanks (not the popular Yorks)

Sandan Compressor

So the problem is that it won't shut off, usually it hits 140 psi and then i would stop, but since the rebuild i did it goes WAY beyond that, and just keeps running

It went way past 200 psi, so I drained the tanks and for a temp fix i've been letting the tanks open a little to relieve pressure. (dumb i know....)

But yesterday it was idling and it started making a racket and i looked at the comp and it stopped spinning (completely overheated) and so i let it rest and the next day i went to start it up again and no issue, start filling the tanks again (and going past the 140psi mark).

So re-checked my wiring and i found one wire just kind of hanging out, and i have no idea where to put it....it runs to the fire wall and is completely independent from everything else

So i guess what i'm asking (ill post pics) is where this sucker goes. or if there's another way to hook the pressure switch from A/C compressor to get it to shut off at 140 psi again...

Thanks Guys!

--Ryan

You need to wire it the same as you would a single viair:

http://www.viaircorp.com/OnRoad/Schematics/singlec_wd.pdf

If you aren't using a relay the pressure switch will stop working. If I were you I'd replace it when you rewire everything. Mine built up enough pressure to blow apart my water trap, so be carefull.

So with that one wire off the A/C Comp, i'll put a relay and add the new pressure switch??

It's been so long since I did mine I can't remember where all the wires go, there's a switch in the dash, and I think another device behind the grill that has wires going to it. But the one on top should be you positive 12v power source for the comp. Throw 12 volts at it and see if the clutch engages. From there, use know what you do know to back track through the viair wiring diagram to make everything work correctly. Here is some more discussion on it:

http://mazdabscene.com/forums/suspension/using-stock-maz-compressor-for-edc-t1916-120.html

That one lonely wire going to the compressor is the clutch wire, which tells it to turn on/off obviously... but it looks to me like that one lonely wire is hardwired strait to your Ign? If that is correct then it's obvious why it's not shutting off, it's getting constant power as soon as you turn the truck on...

You need to yank all that shit and go back to the drawing board... 1st off, you really don't need a relay on an engine driven compressor. The only reason you need one on a Viair setup is due to the amount of power the compressor requires and you don't want all that juice running through your pressure switch. So now here is how you will need to wire this up...

12V Power -> Fuse -> 1st Post on Pressure Switch... then 2nd Post on Switch -> Compressor

Also, i'd assume that the lil black wire that has no home is coming from the pressure switch, so i'd be watching where that guy is laying at. last thing you need is a fire due to a live wire just laying around under there...

And one last thing... is that a dryer on the INLET side of the compressor? I'm hoping you have one on the outborn side also? I'm not as familiar with the Sandan's, but Yorks have an oil reserve and spit oil as they're pumping, so you need something to catch all that oil coming out and also needs topped off time to time. Does that one have a reserve or does it require a constant flow of oil like a normal AC compressor?

Yeah, mine was a 708 and that looks to be a 508. I bet that is an oilier on the suck side, not a water trap as saidens do need constant oil. For $4, why not put in a relay? My experience is with this makes me wish I would have ran a relay.

Here is how I did mine in my Mazda.

I really like your clean setup you got, and i figured those needed an oiler but that didn't look like any oiler i've ever seen. and I wouldn't argue with running a relay by any means, but i figured in this guys situation he would be a lot better off not trying to learn how to wire a relay until he gets this ironed out first, lol.

And about the oiler, I've heard of guys running the suck side into the PCV valve so it gets constant oil...

Edited: 10/25/2010 11:32:41 PM by MajorDrop