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hei
#1
runninpony 
I have a 1972 Mach 1 with a 351 Cleveland motor. I installed a 2 wire hei distributor. Took out the stock distributor and the coil. I wired a dedicated 12 volt wire to the bat. side of the unit and the tach led to the other side. It will not start or even backfire. Is there something else I need to disconnect? Even though the unit is new could it be bad? I really need some help here.   Thanks in advance.
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#2
I am a little confused on how you wired this. You should have used your existing trigger wire to a relay and then the 12v from the relay to the distributor.

73 Grandé H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

- Jason


[Image: 082-hot-rod-power-tour-2017-1970-1970s.jpg]
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#3
Throw away the Chebby stuff and install a duraspark dizzy and box. I just hate the looks of a hei on a ford. But is does sound like you have it wired incorrectly.

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

https://youtu.be/SoW1fhaFPzY  Burn Out Video. 

[Image: 044.jpg]
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#4
The hei instructions were clear to run a 12 volt wire that is hot when you turn the key on to the battery side of the dist. and tach wire to the other side of the dist. It says nothing about a relay or a trigger wire.
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#5
Do you have an original Ford tachometer?



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#6
OK. Let me see if I can be more clear with some Ford Specific Instructions.

Your original coil wire has a resistor in it dropping the voltage down from 12 volts to avoid pitting the original points. The HEI needs the full 12 volts.

Here are two ways to wire this. I am running an HEI style distributor.

Option 1 is to bypass the resistor in the pink wire under the dash and use that to supply voltage to the HEI (not my suggestion as I don't like to cut up factory wiring).

Option 2 install a relay, use the original coil wire as the trigger for the relay, supply 12v to the relay and the output to the distributor. (this is how I wired mine and works flawlessly)

Where did you get the 12v source from that you used? You need to have voltage when the key is on but also when it is cranking.

73 Grandé H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

- Jason


[Image: 082-hot-rod-power-tour-2017-1970-1970s.jpg]
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#7
(09-30-2019, 12:49 PM)Don C Wrote: Do you have an original Ford tachometer?
Yes
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#8
Sounds like you have 12V at key on but not at start.

Factory Ford tach will not work connected GM tach port.

Bob

Tachs, Voltmeters, Headlight kits, Wiper delays and more at
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Rocketman's Classic Cougar (and Mustang) Innovations, LLC
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#9
I will check the voltage. What can I do about the tach/ Thanks
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#10
Tach output is a pink resistor wire (well, red/green on 7123's). It goes to the connector on the back of the fuse box, where it joins with the headlight harness to a red/green wire that goes to the positive side of the coil. The Ford tach MUST be used in-line between the ignition and the coil, but you can replace the resistor wire with a standard wire (not easy to do, especially in the car itself---best to remove the underdash harness and work on it on a bench).

Let me check your shorts!
http://midlifeharness.com

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