how to connect freaking pressure switch?! - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Methanol/Water Injection Place to talk about meth/water injection.

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 09-20-2007, 07:31 PM   #1
Elite Member
Thread Starter
iTrader: (24)
 
Join Date: Jun 2007
Location: Sherman Oaks, CA
Posts: 4,481
Total Cats: 3
Default how to connect freaking pressure switch?!

i have basic kit which im going to install today. how the hell do i connect that pressure switch? i remember someone mentioned to me that i need to use an automotive 12v relay but i cant find the diagram :/

can someone help me really quick? it is going in in about 4 hours from now so fast response would be gladly appreciated!
UrbanSoot is offline   Reply With Quote
Old 09-20-2007, 07:44 PM   #2
:(
iTrader: (7)
 
Join Date: Jul 2006
Location: nowhere
Posts: 8,281
Total Cats: 2
Default

OK you take a positive on 1 side and a negative on the other. Then run a vac line to the nipple. The switches themselves are robust enough, to handle the laod of the pump. I run mine direct off the battery from a fused source btw.
magnamx-5 is offline   Reply With Quote
Old 09-20-2007, 07:52 PM   #3
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,326
Total Cats: 1,926
Default

Assuming you have a Devil's Own base kit (you didn't specify mfg.), you follow the diagram on Page 4 of the instructions.
Joe Perez is online now   Reply With Quote
Old 09-20-2007, 07:52 PM   #4
Elite Member
Thread Starter
iTrader: (24)
 
Join Date: Jun 2007
Location: Sherman Oaks, CA
Posts: 4,481
Total Cats: 3
Default

so there are 3 wires on that switch:
ign +12v
neg -12v
pump +12v

right?
UrbanSoot is offline   Reply With Quote
Old 09-20-2007, 07:53 PM   #5
Elite Member
Thread Starter
iTrader: (24)
 
Join Date: Jun 2007
Location: Sherman Oaks, CA
Posts: 4,481
Total Cats: 3
Default

Quote:
Originally Posted by Joe Perez View Post
Assuming you have a Devil's Own base kit (you didn't specify mfg.), you follow the diagram on Page 4 of the instructions.
that relay is a piece i didnt get with my kit for some reason.
UrbanSoot is offline   Reply With Quote
Old 09-20-2007, 07:58 PM   #6
Elite Member
Thread Starter
iTrader: (24)
 
Join Date: Jun 2007
Location: Sherman Oaks, CA
Posts: 4,481
Total Cats: 3
Default

gotcha... so i should connect pressure switch inline into +12v wire going from pump. do i need to pump fuse between switch and pump or between switch and +12v ign?
UrbanSoot is offline   Reply With Quote
Old 09-20-2007, 08:15 PM   #7
:(
iTrader: (7)
 
Join Date: Jul 2006
Location: nowhere
Posts: 8,281
Total Cats: 2
Default

No but i like to run one the pump is like 8 amps max i think but just incase i get a short, the 15 amp fuse will blow. And not my pump Between the 12V source and the pump.
magnamx-5 is offline   Reply With Quote
Old 09-20-2007, 08:21 PM   #8
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,326
Total Cats: 1,926
Default

Quote:
so there are 3 wires on that switch:
ign +12v
neg -12v
pump +12v

right?
No.






Notice that the three terminals on the switch are labeled NC, NO, and COM. That's Normally Closed, Normally Open, and Common.

When the switch is at rest (not under pressure, the "normal" state) the COM terminal is connected to the NC terminal. We don't care about this condition, so ignore the NC terminal altogether. Nothing goes to it.

When the switch is under pressure, COM is connected to NO. That's the contact we care about.

Now, if you chose to wire this direct (no relay) then connect a line from the battery, through a fuse, to the NO terminal. Then a line from the COM terminal to the pump red wire. Then ground the pump black wire. Know that in this configuration, when the switch fails from the load of the pump welding the contacts together, the pump will run endlessly until you pull out the fuse.


If you chose to run the relay (which you should) then do the following:

From a fused, switched +12 source (such as the feed to the radio) run a wire to terminal 86 of the relay (the coil + terminal). Run a wire from relay terminal 85 (coil -) to the NO terminal on the switch. Run a wire from the COM terminal of the switch to ground. Now, run a line from the battery, through a fuse, and to terminal 30 of the relay (the COM contact of the relay's internal switch). Last, run ye olde wire from relay terminal 87 (the NO contact of the relay's internal switch) to the red wire on the pump, and ground the pump's black wire.


Note that you can pick up a common 20A automotive relay at any auto parts store.

Note that I have deliberately reversed the polarity of the switch (COM vs. NO) relative to the Devils' Own diagram. If you wire it their way, the switches' unprotected NC terminal will have +12 on it whenever the car is not in boost. I consider this a slightly dangerous condition.
Joe Perez is online now   Reply With Quote
Old 09-20-2007, 08:37 PM   #9
Elite Member
Thread Starter
iTrader: (24)
 
Join Date: Jun 2007
Location: Sherman Oaks, CA
Posts: 4,481
Total Cats: 3
Default

thanks a bunch!
i will pick up a relay on my way home. it seems like the only way to go.
UrbanSoot is offline   Reply With Quote
Old 09-24-2007, 11:55 AM   #10
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,326
Total Cats: 1,926
Default

Update? C'mon, tell us everything.
Joe Perez is online now   Reply With Quote
Old 09-24-2007, 01:27 PM   #11
:(
iTrader: (7)
 
Join Date: Jul 2006
Location: nowhere
Posts: 8,281
Total Cats: 2
Default

yes urban do tell we are dieng to see the results
magnamx-5 is offline   Reply With Quote
Old 09-24-2007, 06:41 PM   #12
Senior Member
iTrader: (6)
 
Join Date: Mar 2005
Location: Sammamish, Washington
Posts: 1,396
Total Cats: 0
Default

If you purchased the kit through me I need to refund you for the relay you bought. Sorry about that not being included. The kits have so many pieces that stuff doesn't get put in every once in a while.
Kelly is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 Yesterday 09:00 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Bizarre connection issue? nick470 MEGAsquirt 1 09-30-2015 11:32 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 01:53 AM.