Tach Signal Wiring Explained (With or Without an MSD Box), Foxbody Mustang, Racecar
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- čas přidán 10. 08. 2018
- If you've got questions about tach signal wiring, this is for you! Walk through of how it works and what you need to do for wiring. This is on my 86 Foxbody. Enjoy!
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Due to factors beyond the control of ClevorBMF, I cannot guarantee against improper use or unauthorized modifications of this information. ClevorBMF assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Use this information at your own risk. ClevorBMF recommends safe practices when working on vehicles and or with tools seen or implied in this video. Due to factors beyond the control of ClevorBMF, no information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. Any injury, damage, or loss that may result from improper use of these tools, equipment, or from the information contained in this video is the sole responsibility of the user and not ClevorBMF. - Auta a dopravní prostředky
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Well done, very helpful
Thanks 🙏
Thank you, you helped me tremendously sir
Awesome, good to hear!
ty very helpful
Brilliant video.
Thanks
Clevor BMF I just had a question. I don’t have an ecu but I assume the premise is the same. I need to wire before the msd which looks like it’s coming from the ignition.
That’s correct!!!
Thank you sir.
You bet! Glad it was helpful
Great video but it raised more questions than answers, like 1) can you explain or do a video on what you used and had to do for the aftermarket gauge cluster? Ive heard some have issues. 2) i have the cheap mechanical gauges and no longer get the readings going to the ecu ( i believe the only gauge that matters is the temp) so if i switched it out to a electrical after market gauge what wire would go to the factory sensor wire?
The only sensors that go to your ecu are the two or more wire sensors. If it has just one wire, it’s for a gauge. There are two coolant sensors from the factory. A two wire that goes to the ecu and a single wire for the gauge. If you change to electric gauges, they will come with sending units that you install and wire to the gauge only.
Hey I have a factory tach on my 1995 mustang it's starting to kick in and out some times works properly. Which wire from the car is hooked up to the msd. It's not on the tack output spot on the 6a1
I’d have to look at a wiring diagram to get the exact color, but you’ll usually connect the wires that are on the factory coils to the Emma’s box trigger wires which are orange and black I think… and then the white and red wires from the msd box goes to the coil. You’ll have to Google the model of msd box you have and get a wiring diagram to know for sure what’s positive and negative.
I have a sn95 mustang i removed the 3.8l v6 and put 5.0 HO engine im not using my ecu and im carburated now i have a msd fire box and im trying to tap into my rpm tach can i do it or should i buy after market tach please help me out thanks
Your tach goes off the negative signal from the coil. Run that to the tach input wire on your dash gauge and it should work
I was curious if you know where to wire the 4 wires that need 12v to activate on the MSD 6al2p ignition box? I bought the wiring harness to plug into my coil. I am super stuck on this part
Is 6al2p the part number of the ignition box?
I looked up the manual on summit racing… pretty standard wiring but also depends on how you’re using it…. Thicker red and black are constant power… thinner red is 12 volt when key is on…. Orange and black go to coil with orange being positive… white wire go to factory coil - trigger wire…. Blue is 12 volts when wanting to activate the 2 step….
the wiring going to the dash is just fine to trigger your tach, where the inaccuracies come from is the stock tach which is very inaccurate. Case in point my factory 89 tach is almost 350rpm faster then my autometer tach
Very well said!
Does a tach absolutely have to be hooked up or can it be left disconnected if you don’t have a tachometer in your vehicle?
It’s not going to hurt anything if it’s not hooked up
Hi! Good video my question is, my 85 fox has a HEI distributor so coil and else are built in it. Someone stupid had cut out the taxh cable coming from the distributor to the harness, I just cannot figure or find out where the eite must go to make the tach to work again, I read that it supposed to go to a green yellow striped wire but idk if such wire is connected to another adapter and if so, how does it look like? For my car got the msd box rid off. Thsnks in advance!
It’s really hard to say where to tie it in without seeing the harness or what was done to it by others
green and yellow should be correct, check on the 8 pin connector by the brake booster
I have a '73 Mercury Montego GT, my tach is wired inline between the ignition switch and the positive side of the coil, not the negative. Is there a similar way to wire the MSD with the factory tach, or will I need a tach adapter?
Man that’s a good question…. I’m not sure you can without a tach adapter… I’ll have to look over the wiring diagram…
@@BMF_Garage Thanks man! I'm not totally illiterate to wiring, but most of the time I have to stare at it in confusion long enough before I figure anything out 😂
So my aftermarket tach works fine but dash is dead. Why would this be? I have msd box, msd distributor, and msd coil. 331 carb set up. Is it because car was a 4 cylinder? Can I run wire from aftermarket tach to stock tach wire?
It depends on what wire they are using for the tach. It's hard to give advice on something like that when I have no idea what they did to the wiring....
Aye bro! I need some help understanding this. Getting my tach to work has been a nightmare. I'm using my stock tach, with a Hyfire 685 box. So behind the dash, I see a wire that's light green with a white stripe, do I cut that wire and splice it to another wire behind the dash?
Additional question to clarify: I connect the light green/white stripe wire behind my cluster, to the ecu trigger wire out in the engine bay? What color is the ecu trigger wire? I believe my ecu trigger wire is
red/grey stripe out by the box
You shouldn’t have to change anything to get your stock tach to work... the way it’s connected from the factory is the way it should still be connected. Adding the hyfire box just connects to the factory wire to get a signal to activate spark... I think you may be making it more complex than it should be...
Does this apply to the holley dash
I’m not sure about that 🤔
I'm actually wanting to run the tach adapter. I'm running an sds ECU, it's getting it's own rpm reading and I don't want to mess with that. So. That being said, how do I hook up the tach adapter? Some are showing red wire to the tack 12v, some are showing the purple wire to the tack trigger wire. I have no idea how to look for l, where to look for, what color, any of that for the the tach.
So, you’re wanting to hook up an aftermarket tach to the foxbody and you’re running the msd box with an sds ecu? I’m not familiar with the sds ecu... but it’ll depend on what kind of tach you are connecting.
I’d look for what the tach manufacturer specifies for an input first. Whether a negative or positive pulse and how many pulses per revolution it needs.
@@BMF_Garage I'd like to hook up to the stock tach in the dash. Hence buying the tach adapter. I can't for the life of me figure out what wires go where. And how to hook up to the tach in the dash.
The factory tach connects to the negative signal from the factory ignition system. Does your ecu utilize a negative trigger or positive trigger for firing the coil? If it’s positive you won’t be able to use it. If it’s negative, you should just be able to connect the factory tach to the negative trigger from your ecu.
Ok so I was able to wire the stock tach to the msd box. Works but now my tach has doubled. Why?
The tach output from the msd isn’t meant for a stock tach. Different pulses
What do I do if I’ve completely removed my ECU and want to run an aftermarket tach AND the factory tach?
Should I reconnect the ECU just for this function?
That depends on what distributor you’re running… ??
@@BMF_Garage yes that info would’ve been helpful. Sorry. Ignition is an MSD 6AL (6425) with a Blaster 2 coil. I believe my distributor is a magnetic one. The only connection is a green and purple coiled wire.
There’s usually a tach output wire that connects to a tach. You’d likely want to run an msd box between the dizzy and the coil. Dizzy would connect to mad box input and coil would connect to the msd coil output
@@BMF_Garage yea I wired what I think was the factory tach wires (two green and yellow wires crimped together that were on the negative post of the TFI blaster when I had it) and the Autometer output wire to that grey wire coming off the MSD. No dice.
@@BMF_Garage I sent you a video I made on instagram. I’m not sure you use that for communication or not. Hope I’m not intruding.
Hello sir..just ask a little cuestión i bought a external tachometer.and my car has a ignition pack..im woried to do the wire connection of the tach..should i connect the green wire of tach that i have to the connection of the tachometer of my car at the back of the dashboard?thanks Godbless
Tach always gets connected to the factory tach wire. Don’t connect to any wiring on the output of an aftermarket spark box or anything like that and you’ll be fine
@@BMF_Garage awsome ..thanks for the big help sir..hopefully i can find easyly the connection of my aftermarket tach of my car..and there is no problem if they going to function both of them..hopefully no warning sign pops up on my dashboard after i tap my external tach to the aftermarket tach..thanks sir
It’ll work with both of them fine
@@BMF_Garage thanks sir ..your the best...
🤘🏻🤘🏻🤘🏻
So is your car a 1986 EFI 5.0 then? What if I have a 83 carburated car?
Mine is an 86 efi.... but has a wiring harness from a 92 lx... so mine is kind of a mutant
@@BMF_Garage I would probably have to run the tach adapter in my carbbed fox then right? Why are they $80??? Lol
I’d have to look at the wiring diagram for your specific model, but for most people that’s easier
When using a 6AL2 that has a tach output wire. Where would you connect that wire to?
The tach output wire is supposed to be connected to an aftermarket tachometer.
I’m not using the tach output from mine. I’ve got the tach connected to the ground output signal from the ecu (same wire that triggers the coil)
That’s a nice looking cluster. Would you consider building one for sale?
Absolutely
What would it cost me?
Are you wanting just the bezel the gauges sit in, or gauges as well?