No tach ms2pnp - 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 11-29-2015, 12:00 AM   #1
Junior Member
Thread Starter
 
Join Date: Sep 2015
Location: Knoxville TN
Posts: 46
Total Cats: -3
Default No tach ms2pnp

I have a 1991 with a 1994 turbo motor. I can't get a tach signal. I tried the resistor trick in the dignostic port and still nothing. What am I doing wrong lol
MeOtter is offline   Reply With Quote
Old 11-29-2015, 06:08 PM   #2
Senior Member
iTrader: (3)
 
Join Date: Sep 2011
Location: Plano TX
Posts: 595
Total Cats: 2
Default

No tach in tunerstudio or dash?
90 Turbo is offline   Reply With Quote
Old 11-29-2015, 07:38 PM   #3
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,457
Default

Which coils are you using. 94? Or 91? Do they have 3 wires or 4?
aidandj is offline   Reply With Quote
Old 11-30-2015, 01:11 AM   #4
Junior Member
Thread Starter
 
Join Date: Sep 2015
Location: Knoxville TN
Posts: 46
Total Cats: -3
Default

I'm useing all 91 electornics so 3 wire and on the dash.
MeOtter is offline   Reply With Quote
Old 11-30-2015, 01:22 AM   #5
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,457
Default

What did you jump in the diag box.
aidandj is offline   Reply With Quote
Old 11-30-2015, 10:02 AM   #6
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,848
Total Cats: 1,788
Default

you did the resistor wrong, or you fubared your ignitor.
Braineack is online now   Reply With Quote
Old 11-30-2015, 03:13 PM   #7
Junior Member
Thread Starter
 
Join Date: Sep 2015
Location: Knoxville TN
Posts: 46
Total Cats: -3
Default

I did the IG- to B+ with a 1/4w 1K resistor. And I've got a brand new igniter.
MeOtter is offline   Reply With Quote
Old 11-30-2015, 03:15 PM   #8
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,457
Default

aidandj is offline   Reply With Quote
Old 11-30-2015, 03:22 PM   #9
Junior Member
Thread Starter
 
Join Date: Sep 2015
Location: Knoxville TN
Posts: 46
Total Cats: -3
Default

I read though that. Was slightly confused though. I'm not running cops.
MeOtter is offline   Reply With Quote
Old 11-30-2015, 03:25 PM   #10
Junior Member
Thread Starter
 
Join Date: Sep 2015
Location: Knoxville TN
Posts: 46
Total Cats: -3
Default

What should my tachoutput be in mega squirt?
MeOtter is offline   Reply With Quote
Old 11-30-2015, 03:28 PM   #11
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,457
Default

Off.

Wait, if you are still running 1.6 coils and everything the tach should never have broken.

Dead fuse is my guess.
aidandj is offline   Reply With Quote
Old 11-30-2015, 03:32 PM   #12
Junior Member
Thread Starter
 
Join Date: Sep 2015
Location: Knoxville TN
Posts: 46
Total Cats: -3
Default

Oh ok I'll start checking fuses.
MeOtter is offline   Reply With Quote
Old 11-30-2015, 03:35 PM   #13
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,457
Default

Do you have 12v at B+?
aidandj is offline   Reply With Quote
Old 11-30-2015, 03:51 PM   #14
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,848
Total Cats: 1,788
Default

i wrote a huge reply and lost it explaining why the resistor works and why the tach goes dead when you pull out stock ecu, even though the 90-94.5's tach is driven through coils.

i dont feel like writing it again right now. :(
Braineack is online now   Reply With Quote
Old 11-30-2015, 03:54 PM   #15
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,457
Default

Now I want to know...even on 90-93 with the ignitor?
aidandj is offline   Reply With Quote
Old 11-30-2015, 03:57 PM   #16
Junior Member
Thread Starter
 
Join Date: Sep 2015
Location: Knoxville TN
Posts: 46
Total Cats: -3
Default

Dang that sucks Brain. Can u sum it up. It's just weird driving the car with no tach lol it's not a fuse.
MeOtter is offline   Reply With Quote
Old 11-30-2015, 04:12 PM   #17
Junior Member
Thread Starter
 
Join Date: Sep 2015
Location: Knoxville TN
Posts: 46
Total Cats: -3
Default

Why does the tach go dead with the megasquirt?
MeOtter is offline   Reply With Quote
Old 11-30-2015, 04:17 PM   #18
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,848
Total Cats: 1,788
Default

because the stock ecu provided the pullup to power the tach signal.

the coils go to ground with each spark event.

the signal must have voltage to start with.

when coils ground, the tach sees constant voltage, then none -- the rate it sees those events is how it knows the engine speed.


1K from B+ (12v) to the tach signal (IG-) puts power back on the wire. otherwise there's no activity on the wire, cause youre going from no voltage to ground -- no signal.
Braineack is online now   Reply With Quote
Old 11-30-2015, 04:20 PM   #19
Junior Member
Thread Starter
 
Join Date: Sep 2015
Location: Knoxville TN
Posts: 46
Total Cats: -3
Default

Very nice. Thank you brain. I now understand it better. My megasquirt is set to tachoutput should it be off with the resister in place?
MeOtter is offline   Reply With Quote
Old 11-30-2015, 05:11 PM   #20
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,457
Default

I don't think the mspnp's even have tach output hooked up. Or at least the jumper shouldnt be set. Adding the resistor is emulating the stock ecu. If adding the resistor isn't working you have bigger problems.
aidandj is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
2 quick questions about my turbo path miataa DIY Turbo Discussion 8 01-06-2016 10:05 AM
My 1991 Mazda Mx5 1.6T Sean Young Meet and Greet 14 11-27-2015 02:29 AM
Megasquirt PNP and turbo manifold Nick WTB 0 11-25-2015 02:29 AM
Will this turbo work? miataa DIY Turbo Discussion 3 11-24-2015 11:45 PM
N00b from Denver, planning a low-budget turbo build discontinuuity Meet and Greet 1 11-23-2015 07:27 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 09:19 AM.