Wiring from I6 to a 350 question

[ATrain707]

Hey guys I just put in a 350 in place of a I6 I have some extra wires coming from a harness they were never hooked up when I bought the truck with the I6 the harness has a purple and yellow and I know those go to the starter, there's also a light green and green wire that are together with a plug at the end and those I know go to the reverse lights(were never hooked up) and there is another yellow wire I took off the coil witch I'm not gonna use and run a new wire for the hei, there are two wires left that were never hooked up, a blue wire with a plug at the end of it and a green wire with nothing at the end of it any ideas? I'll have some pics up in a min or two
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[VetteVet]

That sounds like the temperature sending unit wire, dk green and the oil pressure sending unit wire dk blue.


The temperature sender is usually in the left head between the first two cylinders and the oil pressure sender is usually just behind the distributor.

[ATrain707]

Ok, thanx I forgot about those two. Don't need them I guess cuz I installed custom gauges
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[ATrain707]

One more question, I doing a push button start instead of key, can I tap into the batt wire behind the ign key switch or should I run a wire from the batt? I'm gonna use a toggle switch instead of key to give power to the hei and push button to crank the starter, when the truck is running everything will work? Like heater and radio and stuff even tho I'm not using the key?
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[VetteVet]

The red wire on the back of the key switch comes directly from the battery. So yes you could. If it is your intention to bypass the key switch altogether then there's a couple of things you should know. Besides connecting the ignition wire and the starter and the accessories to battery power, the key switch also sends power to the no.1 terminal on the alternator to excite the alternator fields. If you have a alternator charging light the key switch also grounds the light in the cluster to test it. It does the same thing to the brake light. Obviously you can't run a ground with the hot wires through the toggle switch. Depending on the year of your truck you would have to feed the fuse panel through the accessory wire, and also you would have to have a separate switch to isolate the accessory wire for the times when you didn't want to have the ignition on. Having a separate wire just for the ignition would accomplish this, just remember to turn it off when you don't want the truck to run. I never was a fan of using toggle switches to bypass the key switch and if you're doing it for security then it's not very effective.

[VetteVet]

see this thread for an in depth discussion of the wiring circuit.
http://67-72chevytrucks.com/vboard/s...d.php?t=457986

[ATrain707]

Ok, I'm not the best at wiring so if I leave the key switch n put the key in and turn it to acc then use a push button to start it, would everything thing else be fine? If I did it this way would I hookup the push start one wire from acc wire to the purple wire of the starter? Or connect one wire to the red batt then to the purple wire?
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[ATrain707]

Is there a way to use a toggle and leave the key switch? Use the toggle like you would the key?
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[ATrain707]

My truck is a 68 c10
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[ATrain707]

So if I was gonna hook it up by bypass the key switch and using a toggle and push start would the charging system still work? And the dummy light for the breaks and alt light would just be on? I install all new gauges also
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[VetteVet]

Originally Posted by ATrain707

Ok, I'm not the best at wiring so if I leave the key switch n put the key in and turn it to acc then use a push button to start it, would everything thing else be fine? If I did it this way would I hookup the push start one wire from acc wire to the purple wire of the starter? Or connect one wire to the red batt then to the purple wire?
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This is the way I think it works.
When you turn the key to on, the switch connects the big red wire to the ignition wire (pink), to the accessory wire (brown), and to the brown/white wire to the firewall block behind the fuse panel.
Then when you turn the key to start you get. Red wire power to the pink ignition, brown/white to firewall block, and purple to starter through the neutral safety switch (automatics). This cuts out power to the accessory wire, and it also grounds the green temperature light wire and the tan brake light warning wire to test them.

So to answer your question, no you would not be able to turn the key to the accessory setting and use the start push button because there would be no power to the ignition (pink) wire so the truck wouldn't start.

As to the second part, you could turn the key to on and connect a red wire to the power wire on the key and run it to a push button and then connect a purple wire to the purple wire on the key and run it to the other side of the push button switch to have a push button starter.

The only problem with this is that you would still have the accessory wire hot to the fuse panel and every thing in the truck would be hot that was switched on. You want the accessory wire to be cold during start so that the solenoid and starter gets all the power from the battery.

you see why this gets complicated and is it worth the trouble.

[VetteVet]

Originally Posted by ATrain707

Is there a way to use a toggle and leave the key switch? Use the toggle like you would the key?
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You can use a toggle to connect between the red power wire on one side of the switch and the ignition(pink), accessory(brown), and brown/white wire to the firewall block to the other side.

Then you still need the push button for the starter and you can't test the temp and brake lights.

[VetteVet]

Originally Posted by ATrain707

So if I was gonna hook it up by bypass the key switch and using a toggle and push start would the charging system still work? And the dummy light for the breaks and alt light would just be on? I install all new gauges also
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The charging system would still work as long as the red power wire and the Brown/white wire are connected provided all the other circuits are correct.

The idiot lights are grounded at the key switch to turn them on so they would not be on unless the senders grounded them but you could use another toggle to ground them for testing if you used a DTDP switch. This means a switch that goes one way for one light and the other way for the other light. You have to do this because you can't connect the two wires together or each sender would work both lights.

If you're going to install new gauges then you won't need the temp and oil pressure lights and the alternator charge light any how.
I hope I have helped you somehow. VV