North American Turbocoupe Organization



factory tach not working with edis
speedofamongoose Offline
Junior Member
#1
i just bought my car and the tach wasn't working. i found the tach wire coming out of the edis module but my tach is still not working. we pulled out the cluster and checked all wiring to and from the coil plug from where it gets its signal normally. we hooked up a tach directly to the edis module and it worked but still no luck in getting the factory tack to work. has anyone ran into this? the car also has a megasquirt on it and it has four wires coming out of the box which is supposed to be for a wideband and something else. i would appreciate some help with the tach and what the four wires coming out of the megasquirt are for. thanks aubrey
Aubrey Bailey, Jr.
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flylear45 Offline
Member
#2
What tach worked off the edis?

I have gotten factory Ford tachs to work with EDIS 2 ways. One was to use the 3 diode method, and the last one I had to build a 12v pulse generator out of a relay. Both methods are documented in the Megamanual under EDIS.

Those 4 wires could be anything. You need to ask the person who built it, and hope they documented it. If not, you could post up pictures(Closeups!) of the front and back of the board, and with a copy of your .msq I may be able to decipher it.
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Pete D Offline
Administrator
#3
Does this by ny chance have an MSD box on it? If so it may?? require a tach adapter.
Pete Dunham


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speedofamongoose Offline
Junior Member
#4
The tach I used was an equis or something like that. It was something cheap from O’Reilly’s just to test with. I’ll have my brother-in-law look at the schematic in the megamanual about getting the signal from the coil packs. Is the 12v pulse generator you built do the same as an msd tach adapter? I was just puzzled and thought I had a bad tach in my instrument cluster. I really appreciate the help.
As for the megasquirt, it was made by bamafuel and from what I gather he isn’t very popular due to some bad business. The only thing I got from the previous owner was a disc and it had a basic tune to get it running – no paperwork. Is the ms1 a good computer or should I be thinking of going with a bigstuff3? I want to drive my car and enjoy it and not be worrying or tuning constantly. I plan on contacting murrilo motorsports in texas about tuning it for me. I want everything to be right and I get overwhelmed when I start trying to understand the ms1. I’ll still take some pics and post them to see if you or anyone can help with the wires coming out and what they are for. Thanks for everyone’s help.
Aubrey
Aubrey Bailey, Jr.
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speedofamongoose Offline
Junior Member
#5
The tach I used was an equis or something like that. It was something cheap from O’Reilly’s just to test with. I’ll have my brother-in-law look at the schematic in the megamanual about getting the signal from the coil packs. Is the 12v pulse generator you built do the same as an msd tach adapter? I was just puzzled and thought I had a bad tach in my instrument cluster. I really appreciate the help.
As for the megasquirt, it was made by bamafuel and from what I gather he isn’t very popular due to some bad business. The only thing I got from the previous owner was a disc and it had a basic tune to get it running – no paperwork. Is the ms1 a good computer or should I be thinking of going with a bigstuff3? I want to drive my car and enjoy it and not be worrying or tuning constantly. I plan on contacting murrilo motorsports in texas about tuning it for me. I want everything to be right and I get overwhelmed when I start trying to understand the ms1. I’ll still take some pics and post them to see if you or anyone can help with the wires coming out and what they are for. Thanks for everyone’s help.
Aubrey
Aubrey Bailey, Jr.
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flylear45 Offline
Member
#6
I'm not familiar with the msd product, so I can'[t help you there. There are plenty of guys on TF with Bamafuel, so asking what the wires are over there should get you squared away.

Whether or not a tach works with the EDIS output depends on the tach and the EDIS module. Some tachs require a large voltage hit to trigger, others can use the square wave pulse from the module.
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