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Old 04-12-2017, 10:22 AM   #1
63C20
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Ok folks explain me this one!

I get my new motor in. I hook up my new ignition switch. The very last thing i do is plug my HEI into the fuse panel, then crank. nothing. what the?? eventually i found my HEI wire is 12v, til i plug it into the HEI then it drop to 6v. no there is not a resistor at all. Bad module?
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Old 04-12-2017, 11:18 AM   #2
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Re: Ok folks explain me this one!

-
I am going to move this to the electrical forum.

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Old 04-12-2017, 01:00 PM   #3
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Re: Ok folks explain me this one!

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Originally Posted by 63C20 View Post
I get my new motor in. I hook up my new ignition switch. The very last thing i do is plug my HEI into the fuse panel, then crank. nothing. what the?? eventually i found my HEI wire is 12v, til i plug it into the HEI then it drop to 6v. no there is not a resistor at all. Bad module?

Well assuming that you have bypassed the resistor wire, from the ignition switch through the firewall connector, to the original points distributor, and run a new wire directly from the fuse panel to the BAtt connection on the HEI distributor. You should not see anything less than 11 volts at the HEI distributor Batt wire connection.

If You connected to the IGN UNfused terminal on the fuse panel you would have the correct connection to the distributor for the conversion from points to HEI.

Below is the two connections used for the conversion. The first one is the original wiring using the resistance wire and the second shows both the original and the conversion wiring. NOTE that the conversion wiring shows the HEI wire coming directly from the ignition switch through the firewall to the distributor. This can be done but the resistance wire from the firewall to the HEI distributor must be removed and replaced with a regular awg wire usually 12 gauge. Running the wire from the fuse panel does the same thing you just have an extra wire in the circuit. AWG just means standard automotive grade wire.

Measuring from the end of the HEI wire to ground with the key on yields 12 volts. You say that when you plug it into the distributor, your reading drops to 6 volts. Where are you taking that reading?


Original points wire.

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HEI conversion coming from the key switch.

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The left side is the original points side showing the resistance wire and the 12 volts bypass wire from the starter which are both no longer needed.
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Old 04-12-2017, 01:01 PM   #4
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Re: Ok folks explain me this one!

What else is on the 12V lead you have connected to your HEI?

ME I would run a direct 12v line from the battery to a relay then to the HEI. Have a switched lead activate the relay.
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Old 04-12-2017, 01:05 PM   #5
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Re: Ok folks explain me this one!

i have run one from the fuse box and battery, same thing happens. it drops to 6v at the connector all the way to the opposite end
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Old 04-12-2017, 06:32 PM   #6
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Re: Ok folks explain me this one!

Is you engine grounded to the cab & frame?

Might be a ground issue?
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Old 04-12-2017, 07:08 PM   #7
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Re: Ok folks explain me this one!

fixed, was a resistor wire hiding on me :P
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Old 04-18-2017, 09:32 PM   #8
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Re: Ok folks explain me this one!

Quote:
Originally Posted by Palf70Step View Post
What else is on the 12V lead you have connected to your HEI?

ME I would run a direct 12v line from the battery to a relay then to the HEI. Have a switched lead activate the relay.
I am going through the process of doing this conversion, and I like this idea, could you sketch out the connections?

What kind or number of relay?

Thanks
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Old 04-19-2017, 10:51 AM   #9
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Re: Ok folks explain me this one!

no need, if you use the IGN leads on your fuase box they already have relays on them, they are behind the cluster
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Old 04-20-2017, 05:05 PM   #10
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Re: Ok folks explain me this one!

The way I did mine, was remove the original resistor wire from the engine side of the bulkhead connector on the firewall, and replace it with a 12 gauge pink wire connected
to the BATT terminal on the HEI. The wire from the ignition switch to the bulkhead connector on the dash side of he firewall is already a 12 gauge pink wire. This will allow you to run the wire in the stock location and look like a factory installation. You will need a Packard 56 connector, can't remember if it's male or female, for 12 gauge wire. I got mine from the local NAPA store.
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Old 04-20-2017, 05:11 PM   #11
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Re: Ok folks explain me this one!

again the IGN is already on a relay
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Old 04-21-2017, 07:08 AM   #12
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Re: Ok folks explain me this one!

There are no relays in a stock fuse box, just taps that are powered through the ignition switch when it is in the run position. I also like to run an hei off a relay. Power from the battery to the relay, power from the relay to the hei bat terminal, new wire from the key switch or from the firewall to the relay and a ground from the relay to the firewall. This bypasses all the old wiring and ensures good voltage to the hei.
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Old 04-21-2017, 08:27 AM   #13
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Re: Ok folks explain me this one!

Quote:
Originally Posted by PGSigns View Post
There are no relays in a stock fuse box, just taps that are powered through the ignition switch when it is in the run position. I also like to run an hei off a relay. Power from the battery to the relay, power from the relay to the hei bat terminal, new wire from the key switch or from the firewall to the relay and a ground from the relay to the firewall. This bypasses all the old wiring and ensures good voltage to the hei.
Jimmy
I haven't tried it yet but I believe the old resistance wire is more than enough to operate the relay. The relays only require a few milliamps to close.

I like stovebolts method best, because the key receives battery voltage and delivers it directly to the HEI BAT terminal. The relay is another possibility for ignition failure.
The best use for relays on our trucks IMO is the headlight relay mod. It takes the burden off the headlight switch of carrying the total headlight voltage and eliminates the voltage drop for the headlights which will give noticeably brighter lights.
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