99,MSII,stock sensors - 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 10-30-2006, 11:47 PM   #1
Junior Member
Thread Starter
 
Join Date: Aug 2006
Location: Ridgecrest, Ca
Posts: 308
Total Cats: 0
Default 99,MSII,stock sensors

I'm still on the breadborad but tonight's testing looked pretty good.

I've been working on a pair of circuits. One accepts the cam and crank signals and returns the 2nd and 4th crank pulses after the cam pulse(s). These are 180deg apart so MSII accepts them as tach pulses. The second circuit accepts the ignition and cam pulses and splits them between two outputs. The second circuit will be obsolete shortly with 4cyl wasted spark coming for MSII but I didn't discover this until recently.

I left it out of the diagram but each chip should have a 10uF capacitor from Vcc to gnd to cut down on noise. I also isolated the cam and crank signals with transistors.

Frank
Attached Images
File Type: bmp MS_Miata.bmp (30.6 KB, 86 views)
File Type: bmp MiataLayoutInD.bmp (23.2 KB, 71 views)
arga is offline   Reply With Quote
Old 10-31-2006, 11:30 AM   #2
Junior Member
 
Join Date: Oct 2005
Location: New Hampshire
Posts: 248
Total Cats: 0
Default

Have you run the car with this setup yet?
kingofl337 is offline   Reply With Quote
Old 10-31-2006, 12:23 PM   #3
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 406
Default

can this be used to satisfy something like, say, an AEM for a honda?
y8s is offline   Reply With Quote
Old 10-31-2006, 05:26 PM   #4
Junior Member
Thread Starter
 
Join Date: Aug 2006
Location: Ridgecrest, Ca
Posts: 308
Total Cats: 0
Default

Quote:
Originally Posted by kingofl337 View Post
Have you run the car with this setup yet?
No, unless in the garage with jumper wires counts? Even then I haven't been controlling spark, just reading the outputs with an O-scope. I also only ran it up to 4k rpm. The signals continued to look good, though, and MSII did indicated the correct RPM. I'll take it out on the road this weekend under fuel control but it may be 2 to 3 more weeks until I swap the coils and try fuel and spark. I still need to solder the circuit, mount it in an enclosure and find a place to put it so it won't slide behind the brake pedal. The harness work is all done, though.

I posted this now because I saw another post a few days ago where someone was looking for a similar design. I thought I'd share what I'd done so far. To be safe, I'll add the following:

EXPERIMENTAL CIRCUIT. BENCH TESTED ONLY. USE AT YOUR OWN RISK.

Frank
arga is offline   Reply With Quote
Old 10-31-2006, 05:50 PM   #5
Junior Member
Thread Starter
 
Join Date: Aug 2006
Location: Ridgecrest, Ca
Posts: 308
Total Cats: 0
Default

Quote:
Originally Posted by y8s View Post
can this be used to satisfy something like, say, an AEM for a honda?
I'm sorry, I'm not familiar with the specifics of either. The next few days are shot for me but I'll try to look into it this weekend. My niece’s BF is a Honda fanatic. His Integra is from the early/mid 90's, though. Did the sensors change much between then and now?

A D flip-flop with a square wave into the clock and !Q (not Q) wired into it's input will cut the frequency in half. Every time the clock pulse goes from 0 to 5v, the output, Q, will toggle from low to high or high to low. If you AND that output with the original signal, only every second pulse will make it through. Because the D flip-flop only changes state at the specific time the clock goes from low to high the output doesn't "hunt". One potential problem with my design is if both the reset (cam pulse) and clock (crank pulse) events happened at the same time. That only happens on the Miata when the timing belt breaks, though, so I should be OK.

Frank
arga is offline   Reply With Quote
Old 11-01-2006, 11:47 AM   #6
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 406
Default

I'm not familiar with the honda either... but that's the AEM unit that people like to use on miatas. It just doesn't work well with the stock 4-pulse unevenly spaced M2 crank trigger.
y8s is offline   Reply With Quote
Old 11-25-2006, 10:51 PM   #7
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Haven't gone through the circuit in detail, but I built a similar sort of circuit that takes the 99/00 cam and crank signals and turns it into an AEM friendly signal.
JasonC SBB is offline   Reply With Quote
Old 11-26-2006, 02:33 AM   #8
Junior Member
Thread Starter
 
Join Date: Aug 2006
Location: Ridgecrest, Ca
Posts: 308
Total Cats: 0
Default

I'm running fuel only with it now. I have problems but the RPM signal has been reliable. I've had it up to 6k rpms and I haven't seen any spikes in the MS logs.

I have a set of GM coils from a mid 90's Saturn (free) and two VB921's. I'm still missing a .333ohm resister to make an igniter circuit. I'd like to get spark working by year end but I've got serious problems on deceleration and cold starting to fix first. I also have to get my WB installed.

The AEM solution is interesting. Up until this thread I didn't realize it was an option. Now that I know a little more about fueling, it makes since and I'm surprised it's not more popular.
arga 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 57 07-19-2017 05:11 PM
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Going back to stock. Need some 1.6 parts. Trent WTB 2 10-01-2015 01:15 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 08:40 AM.