MSPNP2 tach malfunctioning in 1.6
So I have two cars:
1st: Mine, 1.6, stock CAS, GM coils, no ignitor, tach rads 1/2, lots of throttle cuts the tach off. Does this with TPS plugged/unplugged, and with stock wiring and the alternate tach out pin. 2nd: Project Lazaraus, MSM, NB cam/crank sensors, VVT coils, tach reads correctly, but cuts off with lots of throttle, just goes to zero. Let off and it it'll turn back on at the correct location. Any ideas? Both have the yellow/blue and black/white wires crimped together from the ignitor, as per the VVT/NB swap instructions. |
What exactly is driving the tach on both of them?
You may be better off rewiring it to the MSPNP tach output. |
I did this. I cut the splice at the old igniter location, and the tach died. I then ran the yellow/blue wire to the tach out in my front plug, and it reads half, and shuts off with hard throttle.
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Did you tie together the black/white and blue/yellow wires? That could be why you are only reading half of the revs.
https://www.miataturbo.net/attachmen...ine=1327066127 |
Damn reply keeps being deleted.
I followed your instructions when I wired my toyota cops, then converted it to the GM coils. They're the same, except no coil output, instead power, trigger, and two grounds AFAIK. I followed Savington's VVT coil wiring instructions for Laz, in the VVT swap megathread. |
Where does the tach out go on 1.6 mspnp?
Edit: nvm saw its the front plug. |
Any chance you have the tach output settings on half speed?
http://i62.tinypic.com/2v7xvr5.jpg Laz's problem sounds like its a weird gremlin, your half speed problem sounds like a setup (wiring, or tune) problem. |
Did some more digging and ignore my black and white comment, I don't think that is necessary with the GM coils. Fingers crossed its the setting.
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Goes to the ignitor. Then the ignitor sends the signal to the dash. That's why you need to crimp the two together when you install cops.
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And no, when enabling the front tach output in, it's running on pin "IGN", and "normal". half speed makes it run at 1/4 speed.
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Do you have a pull-up resistor on the tach signal, like in the diagnostics box?
MX-5 Miata Forum - View Single Post - [NA] weird tach behavior with megasquirt Although the megasquirt tach out might not need it. |
MX-5 Miata Forum - View Single Post - [NA] weird tach behavior with megasquirt
Sounds like the tachout pulls to ground and the later wiring has a pull-up resistor in the wiring. So with no pull-up you could get erratic tach signal. |
I don't think that's right. I have no pullup, and I did the same blue/yel to black/wht Curly's done. Both of these cars were 1.6's right? Don't you have Laz old motor Aidan?
My setup is on pin TACHOUT though, not IGN. Since the 1.6 doesn't use the ECU to drive the tach in stock trim I had to wire the blue/yellow wire that goes to the ignitor to the MS tachout pin. I am on a DIYPNP though, they can't be that different? Sure sounds like you've already done all this. My tach still drops out occasionally, like it missed reading a single tach pulse. It thinks it's quickly decelerating, but then snaps right back to normal. I wonder if the early miata tachs just suck? |
On a 1.6L, if youre using TACHOUT instead of the ignitor:
you can send it to the B/W wire on 2I. This brings the tach signal to the ignitor wiring. There you must combine b/w and y/b as show above. This brings the TACHOUT signal from the MS to the y/b wire. This is the wire that goes back to the dash tach. There should be nothing else connected to the y/b wire--no coils, no 1K pullup in the diagnostics box. I've seen heard on anyone having issues using tachout from the MS -- your two on these MSPNP2 are the first I've ever heard of. |
Hmmm, the half tach is still weird.
I assume its correct in tuner studio on both setups right? |
I think the output pin should be changed from IGN to TACHOUT.
It fires batch, and it's reading off the spark channels so it reads half right? |
Yes, both tachs in TS work fine no matter what throttle.
let me try changing tach output to TACHOUT and see if anything changes. I'll also recrimp the black/white and yellow/blue wires together, right? |
If you have the blue/yellow wire connected directly to the ecu then the black/white shouldn't matter.
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Yeah, the crimping of wires is to keep from having to run a new wire behind the dash so it still needs to be done. The ECU gets a signal from the ignitor in stock form, that's the one between the ECU and ignitor on 2I. The dash reads right off the ignitor though, so that's why we can splice them together and rewire 2I to the tachout pin. Just saves a wire behind the dash, basically.
edit: the wires are super critical, but there's no need to stick any pullups between the tach and the pulse generator of the MS. |
IGN should be what you're using for one of the spark outputs--selecting that should be causing a conflict error.
you should be using TACHOUT. unless DIY does something funky, but looking at their 94-95 basemap for the MSPNP2, they use TACHOUT. |
You already broke out the blue/yellow to the ecu though?
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Arg, you guys are talking too much before I get to try anything!!
I twisted the black/white and yellow/blue wires back together, and set tach out to TACHOUT pin, everything is working now. Thank you. I'm hoping this same change will fix laz. Thanks! |
If you want to make it cleaner, you can send the tachout to the black/white and not run the blue/yellow.
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God dammit aiden, listen to us.
The yellow/blue wire is already in the harness. It's wrapped and pretty from Mazda from the tach all the way to the ignitor, and now goes along the black/white wire to the ecu. It's not getting any prettier than that. |
Haha I thought you added a wire from the blue/yellow all the way to the ecu. I broke out the booze a little early today.
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Originally Posted by curly
(Post 1212416)
Arg, you guys are talking too much before I get to try anything!!
I twisted the black/white and yellow/blue wires back together, and set tach out to TACHOUT pin, everything is working now. Thank you. I'm hoping this same change will fix laz. Thanks! :party: |
Tach :party:!
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2 Attachment(s)
Shit, didn't load the second page on mobile. Ignore the necro bump.
* Since I already bumped this thread, and it was a great help. Let me aid for anyone in the future wanting to solve this issue, this thread really helped bridge the gap for me. DIYPNP. Run pins 4I to TACHOUT inside megasquirt (90-93 cars). Open TunerStudio, go to Tacho output-> ON, select output pin-> TACHOUT, Select speed-> normal. If you open your Ignitor and solder the joints like I did, there will be no reason to crimp wires. Everything will be ready to go. This is what your soldered ignitor should look like, probably a better solder job because I am using some shitty equipment. Attachment 233791 A horrible diagram of how it is all connected and run. I'll also link a youtube video on me installing them but I do not setup my megasquirt in the video. Attachment 233792 |
Originally Posted by 90civichhb
(Post 1401603)
Shit, didn't load the second page on mobile. Ignore the necro bump.
* Since I already bumped this thread, and it was a great help. Let me aid for anyone in the future wanting to solve this issue, this thread really helped bridge the gap for me. DIYPNP. Run pins 4I to TACHOUT inside megasquirt (90-93 cars). Open TunerStudio, go to Tacho output-> ON, select output pin-> TACHOUT, Select speed-> normal. If you open your Ignitor and solder the joints like I did, there will be no reason to crimp wires. Everything will be ready to go. This is what your soldered ignitor should look like, probably a better solder job because I am using some shitty equipment. https://i.imgur.com/LkQGwgJ.jpg A horrible diagram of how it is all connected and run. I'll also link a youtube video on me installing them but I do not setup my megasquirt in the video. https://i.imgur.com/F78koeR.jpg https://www.youtube.com/watch?v=JLmOWPc80KU 90civichhb, I followed your first video and installed the Toyota COPs. They worked fine, except they started to fail after four or five laps at the track. They worked completely fine on the street. I think they were overheating at the track. I connected the white and black wire with the blue and yellow wire and connected that to the TACHOUT pin on my MS diypnp. And the tack worked fine with the Toyota coils. Next I converted over to the ls coils just like you did. And just like you, I lost my tach. I followed your recommendations to get the tack back, but it didn't work. Did you simply solder the two center pins in the igniter? It worked with the Toyota COPs, but not with the LS coils? |
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