Megasquirt install questions - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 10-04-2012, 09:56 PM   #1
Elite Member
Thread Starter
iTrader: (8)
 
Ryan_G's Avatar
 
Join Date: Jan 2012
Location: Tampa, Florida
Posts: 2,579
Total Cats: 155
Default Megasquirt install questions

I am finally going to get around to installing my reverant eMS2 this weekend and I have a few questions that I need to clear up before I dive in. Keep in mind that, if any of this sounds simple or comes across as ignorant it is because when it comes to wiring and such, I am ignorant and still tying to learn.

1. I am going to use Add-A-Circuit to get switched power from the fuse box underneath the dash. My question is if I can run both my electronic boost/wideband gauge and my LC-1 off of one of these things or if I will need two?

2. Which fuses on that box are switched power?

3. For the GM boost solenoid am I able to wire it to the stock boost solenoid connection for my MSM or will I have to run one of the wires all the way to the MS under the dash somehow? (I assume reverant will have to answer this one because I am not sure how he set up the harness that came with the unit.)

4. What is the best grounding point that I can use under the dash?

5. I plan to use the internal boost sensor in the MS to send a signal to my boost gauge. Rev provided two blank output wires on the MS harness. How do I program this output to send the boost reading to the gauge?

Thanks in advance to anyone that can offer any answers or advice.
Ryan_G is online now   Reply With Quote
Old 10-05-2012, 03:00 AM   #2
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,441
Total Cats: 198
Default

1) Yes.
2) Engine
3) Use any 12V switched power source from the engine bay for one of the two wires of the solenoid; the other wire goes to the green wire on the MS harness.
4) The ECU wiring.
5) That's not what the "output" wires do. These are on/off outputs, ie they can switch a relay on or off, thats it. I'm not aware of any ECU that does what you want. You will need to tap into the MAP sensor inside the MS to share the vacuum/boost signal.
Reverant is offline   Reply With Quote
Old 10-05-2012, 09:43 AM   #3
Elite Member
Thread Starter
iTrader: (8)
 
Ryan_G's Avatar
 
Join Date: Jan 2012
Location: Tampa, Florida
Posts: 2,579
Total Cats: 155
Default

Thank you very much for the response. I assume by "yes" you mean I can run both items from the same switched power source. Are the grounding wires I need to use from the ECU wiring also black or some other color?
Ryan_G is online now   Reply With Quote
Old 10-05-2012, 09:48 AM   #4
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,441
Total Cats: 198
Default

You can use the black wires on the top connector of the ECU, pins 20-24.
Reverant is offline   Reply With Quote
Old 10-05-2012, 11:52 AM   #5
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,683
Total Cats: 1,561
Default

And you can put a tee in the vacuum line going to the MS and run that to a mechanical boost gauge or plumb your sending unit for an electrical gauge into it.
sixshooter is offline   Reply With Quote
Old 10-05-2012, 12:18 PM   #6
Elite Member
Thread Starter
iTrader: (8)
 
Ryan_G's Avatar
 
Join Date: Jan 2012
Location: Tampa, Florida
Posts: 2,579
Total Cats: 155
Default

Quote:
Originally Posted by sixshooter View Post
And you can put a tee in the vacuum line going to the MS and run that to a mechanical boost gauge or plumb your sending unit for an electrical gauge into it.
I am not gonna switch to a mechanical boost gauge for two reasons. The first is I already have the electronic gauge. The second reason is because it is both a wideband and boost gauge and will take up less space that way.

I am not sure I understand the second part you posted. Are you referring to what Rev said about connecting the wire from the gauge to the sensor inside the MS or are you talking about something else.
Ryan_G is online now   Reply With Quote
Old 10-05-2012, 02:21 PM   #7
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,683
Total Cats: 1,561
Default

I was saying just re-use the sender from your gauge for your gauge.
sixshooter is offline   Reply With Quote
Old 10-05-2012, 02:40 PM   #8
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

Quote:
Originally Posted by Ryan_G View Post
I am not gonna switch to a mechanical boost gauge for two reasons. The first is I already have the electronic gauge.
That electronic gauge is going to be calibrated to expect a signal from the sensor which it came with, which is quite probably different from the calibration used by the sensor inside the MS. Thus, you are going to need to do what Sixshooter said: use the sensor that came with the boost gauge to drive the boost gauge.


Also, as an aside:

When you tap into an analog signal line and branch it out to another device, you increase the likelihood of introducing noise into the line.

For lines carrying non-critical signals which are not sensitive to minute changes in amplitude (such as the IAT and CLT lines), this is not a big deal.

For lines carrying critical signals which ARE sensitive to minute changes in amplitude (such as MAP and O2), this is an Extremely Bad Idea™.

In other words, even if the calibration did match, tapping into the MAP sensor inside your MS and bringing it out to a boost gauge located some distance away and at a different ground potential brings with it the possibility of introducing noise into the MAP line which will negatively impact the performance of the MS itself.
Joe Perez is offline   Reply With Quote
Old 10-05-2012, 02:44 PM   #9
Elite Member
Thread Starter
iTrader: (8)
 
Ryan_G's Avatar
 
Join Date: Jan 2012
Location: Tampa, Florida
Posts: 2,579
Total Cats: 155
Default

It did not come with its own sensor because I did not order one. I assumed I could tap into the one for the MS. So do I need to order one? I'm not fond of opening up the MS.
Ryan_G is online now   Reply With Quote
Old 10-05-2012, 02:54 PM   #10
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

Quote:
Originally Posted by Ryan_G View Post
So do I need to order one?
Yes.

What gauge are you using?
Joe Perez is offline   Reply With Quote
Old 10-05-2012, 03:57 PM   #11
Elite Member
Thread Starter
iTrader: (8)
 
Ryan_G's Avatar
 
Join Date: Jan 2012
Location: Tampa, Florida
Posts: 2,579
Total Cats: 155
Default

Vei systems dual monitor wideband/boost gauge.

Site: veisystems.com
i would give you a real link bit I am on my phone.
Ryan_G is online now   Reply With Quote
Old 10-05-2012, 04:41 PM   #12
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

Huh. They don't seem to give any specs whatsoever on the sensor calibration for the boost/vac side. They just tell you to buy the SEN-P70B sensor, which for $39 is precisely what I'd do.
Joe Perez is offline   Reply With Quote
Old 10-05-2012, 04:52 PM   #13
Elite Member
Thread Starter
iTrader: (8)
 
Ryan_G's Avatar
 
Join Date: Jan 2012
Location: Tampa, Florida
Posts: 2,579
Total Cats: 155
Default

Ok, that is what I will do. Thank you for the information.
Ryan_G is online now   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
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
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
Any pnp megasquirt for 2001 Big_gumby WTB 0 09-30-2015 04:34 PM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM


Thread Tools

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 08:48 PM.