Flchallenger
Well-Known Member
Putting a 6.4 in a 71 challenger. Got a crate motor from dodge a stock wiring harness and ecm. There is no dedicated tach wire. So how do you connect a tach. I have a new auto meter tach.
Tachometer help. Where do I connect on 6.4 stock crate harness?
- Thread starter Flchallenger
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Katfish
Well-Known Member
I couldn't find anything, ended up getting a cheapie ODB2 tach to plug in.
Please post what you find, I had zero luck.
https://board.moparts.org/ubbthread...true/re-tach-for-gen3-motors.html#Post3249161
Please post what you find, I had zero luck.
https://board.moparts.org/ubbthread...true/re-tach-for-gen3-motors.html#Post3249161
Last edited:
Challenger RTA
Well-Known Member
Don't know if this is a help. 2012 diagram. 19 bottom right. You might need a tach adaptor. Different signal?
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Flchallenger
Well-Known Member
There is 8 ignition coils are there not? The diagram I think will help tremendously. Thanks
Flchallenger
Well-Known Member
I went and did more research. I have a auto meter tach and they have some adapters. But it looks like wire 19 in the schematic maybe I connection point. I am checking with there tech support tomorrow.
pschlosser
Well-Known Member
pin 19 looks ominously like the legacy tachometer line. I would try that one, first.
Katfish
Well-Known Member
Yep, they want you to tap into all 8 of the coil packs to an adapter, too much trouble IMO
Wasn't going to cut into a brand new wiring harness 8 times, crazy.
Flchallenger
Well-Known Member
I don't want to tap into 8 coil packs either. There has got to be a better way.
Flchallenger
Well-Known Member
I think I am going to try to GMR pickups on opposing cylinders . I can change settings on my tach to a 4 cylinder. MSD suggested that this might work.
scar426
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So for 2 of my swaps, I used an MSD GMR tach adapter, clamps over 1 coil wire, ran to tach (Speedhut tachs) and switch power, ground, easy peasy works great. On my current Cuda 6.4 swap tried same thing, but with Autometer gauge (tried 2 different) doesn't work. My guess is the gauge. (1 autometer gauge didn't have a dip switch setting for single pulse as required by MSD and the other did, but still wouldn't work properly) At some point I'll bite the bullet and swap to a Speedhut tach. No splicing required with the MSD GMR pickup adapter.
Katfish
Well-Known Member
Interesting, wasn't familiar with Speed Hut.
Looking at website, they have ODB2 versions, so if buying a new tach, why bother with an adapter.
I need to measure the size of the factory tach, they just might have a size to fit.
At the moment I have an ODB2 tach zip tied to steering column, works great, but would be nicer inside the factory spot.
I would however lose the other functions, voltage, temp, clock, error codes etc.
It would be perfect if round, but has weird shape.
And only $40, not $300-$400.
https://postimg.cc/YjL2mvFB]
[/url]
Looking at website, they have ODB2 versions, so if buying a new tach, why bother with an adapter.
I need to measure the size of the factory tach, they just might have a size to fit.
At the moment I have an ODB2 tach zip tied to steering column, works great, but would be nicer inside the factory spot.
I would however lose the other functions, voltage, temp, clock, error codes etc.
It would be perfect if round, but has weird shape.
And only $40, not $300-$400.
https://postimg.cc/YjL2mvFB]
[/url]
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Flchallenger
Well-Known Member
Well looking at a auto meter tach it shows hooking to the coil or msd electronic ignition box. Some wondering if one GMR will work.
sixpactogo
Well-Known Member
When I installed a 6.1 in my 68 Charger back in 2015, I'm pretty sure you just need to tap into one coil pack. I chose # 8 because it was closest. You could contact Chris at Hotwire Auto. He would know for sure.
Katfish
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scar426
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my dash was already changed out to an Autometer set up, in the rightside 3 3/8 hole. The single msd gmr works fine with the speedhut gauge, just not the autometer that was in the car. So,
I bought a different autometer gauge that is supposed to work with the MSD GMR single pulse setting but does not. (I think initially it did for a few days but no longer does)
I bought a different autometer gauge that is supposed to work with the MSD GMR single pulse setting but does not. (I think initially it did for a few days but no longer does)
Flchallenger
Well-Known Member
I had a non rally dash in my car. I took everthing out. Had a 1/8 piece of alumnium cut to match the front. I had holes cut out for the guages. I glued it on with liquid nails. Then cut out the plastic on the back. Mounted the gauges in it. The original dash matched all the screw holes so went right back in. We are still working on a source hope to have this figured out Monday
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