HEI Problem

[C20-67_N_MO]

Okay I bought a '72 c/10 and found out something interesting with it.

It has a HEI dizzy but wasn't wired correctly.

The only way to turn it off (key doesn't do it) is to reach down and unplug a wire from the fuse block.

How can I correctly wire this so when the key is off the engine dies?

Thanks!

[LONGHAIR]

Changing the place where that wire is connected will do it. It needs to be a "switched" source....something that goes on/off with the key.

[C20-67_N_MO]

Okay that sounds simple enough.

So just look for a "switch" connection then.

Cool, Thanks!

[Sammy]

There is a switched plug on the fuse box you can use. Go to FAQ and look at the pic of the fuse box, your fuse box maybe hard to read to find the correct spot.

[C20-67_N_MO]

Originally Posted by Sammy

There is a switched plug on the fuse box you can use. Go to FAQ and look at the pic of the fuse box, your fuse box maybe hard to read to find the correct spot.

Yeah the problem is it looks like SEVERAL hot wires are feed into this one plug on the fuse block. Someone really did a hack job on the electrical system of this poor truck.

[Blue72slab]

You can also run it off the back of your ignition switch. I would recommend #12 primary wire to insure a good solid 12-14V to the distributor.

[C20-67_N_MO]

Okay now I got another odd problem.

If I hook up the wire going to the dizzy to a switched source on my fuse block the engine will not start unless I release the key (which stops turning it over) and then it will start. (Sometimes).

But if I hook it up to power all the time it starts right up.

Is that switch connection maybe not a full 12volts?

Help!

[LONGHAIR]

You really need to find the right place in the fuse block. The place you have now is only "hot" in the "run" position. It need to be "hot" while cranking too.
Some things go "off" while the engine is cranking (like the radio) to save it all for the cranking/starting process. Obviously, the distributor cannot be one of those.

[Wrenchbender Ret]

The best way is like Slab says. Tie in to the pink wire on the back of the ign. switch with 12 gauge wire. I peel off a little insulation & solder the wire to it. This way you have no voltage drop & the wire can't come loose & shut you down.

[RussGapp]

The reason That your truck won't start unless you release the key, is that the wire to the original coil on a 67 was a resistor wire, which prevented the the points from getting a full 12 volts and dying an untimely death. When the engine is cranked over the coil is fed about 9 volts. when you release the key to run, you get 12 volts and the engine will start, sometimes. You need to replace that wire from the firewall plug to the HEI with a #10 or #12 wire. This will allow 12 volts to the HEI when cranking.

[C20-67_N_MO]

Okay, will try to tackle this job on the weekend.

Thanks guys.

[fixit-p]

The port (ign unfused) on the fuse block comes from the pink ignition wire and if it's not getting power in the start position then your ignition switch is bad or the PO modified it.

[C20-67_N_MO]

Thanks fixit-p.

Yeah the PO did a LOT of damage to the entire wiring system of this poor truck. Everything from direct wiring of the headlights to other fire hazards.

Your picture should help a lot.

Appreciate it.

Scott.

[RustyDan]

Hey FIXITp...A little more rust and the pic with the camper could be my rig the day I got it from Pop. Still trying to download from my cam. Nice truck/camper. got more pics? info?

[fixit-p]

Originally Posted by RustyDan

Hey FIXITp...A little more rust and the pic with the camper could be my rig the day I got it from Pop. Still trying to download from my cam. Nice truck/camper. got more pics? info?

Thanks, no pics but I ditched the camper and it did an awesome job of preseving the bed floor and interior.

Tested connection at IGN and it is dead. On either side of the fuse is dead as well. Very strange deal. Like I said the PO did a LOT of hack job to this electrial system.

Hate to do it but might just have to take it to a shop next week.

It may just be a bad ignition switch, if you can disconect the plug on the back of the iggy switch you could use a jumper wire to connect the red and pink wires if power is restored to the ign port then you know the ignition switch is bad if it didn't restore power look for a break or suspect connections on the pink wire.

[RustyDan]

Yea...My camper did a fine job saving the lumber in my truck as well.
Pop said he only had it off the truck 2 times in 33 years. LOL

[C20-67_N_MO]

Tested connection at IGN and it is dead. On either side of the fuse is dead as well. Very strange deal. Like I said the PO did a LOT of hack job to this electrial system.

Hate to do it but might just have to take it to a shop next week.

[jamie72]

instead of taking it to the shop i would just used that $$ and buy a new wire harness...

[C20-67_N_MO]

Originally Posted by jamie72

instead of taking it to the shop i would just used that $$ and buy a new wire harness...

Oh I have one!

And it's not going in this '72, but rather saving it for when I use the parts from this truck on my '67.

I know of a guy that won't charge me too much or we trade services so it will not cost me too much any way.