12v hot in run/crank
12v hot in run/crank like the title says i need to find a circuit that is hot in run and crank. every circuit ive tested is either always hot or hot in run only. i had both wires hooked up to a switch on the dash to get the car running but now its time to clean all the wiring up so i need help with this. car is 72 nova with an ls1 swap ebay harness and a painless chassis harness. the red and pink wire that provide power to the ecm require the red to be always hot for pcm memory i guess and the pink needs to be hot in run and crank to provide power to the injection system. any help is greatly appreciated.
72's didn't have HEI's. Question, Why would you need the pink wire hot on both run and CRANK ? I've only wired my ECM / Pink hot while Ign is on Run..
Most of the older 60's and 70's Chevy's.. used a second wire to the points that came from the starter solenoid, This was to give full 12 volts to the point/coil.. as the coil/points were connected to a resistor block to reduce the 12 volts to a lower voltage. (some had it, some didn't use it)
As stated, a fused Relay circuit should be used to power the Injectors, coils, etc. You can use the wire that goes to the Coil/points or if it has a resistor block, use that wire to activate the Relays.
You should also find a Ign/Run Hot off of the 72' Fuse box. Also suggest running a fused relay system from it.
BC
Most of the older 60's and 70's Chevy's.. used a second wire to the points that came from the starter solenoid, This was to give full 12 volts to the point/coil.. as the coil/points were connected to a resistor block to reduce the 12 volts to a lower voltage. (some had it, some didn't use it)
As stated, a fused Relay circuit should be used to power the Injectors, coils, etc. You can use the wire that goes to the Coil/points or if it has a resistor block, use that wire to activate the Relays.
You should also find a Ign/Run Hot off of the 72' Fuse box. Also suggest running a fused relay system from it.
BC
I'm assuming your EBAY harness is looking for a key ON/CRANK source? To power the EBAY harness's fuse block?
On the factory Nova chassis harness there would have been an 'IGN' port in the fuse block which would provide power in Key 'ON' and 'CRANK'. The 'ACC' ports lose power when you are cranking. The painless harness should have the same. As stated above, HEI was not available until around 1976, so your factory ignition wire (white braided) would not be 12 volts as it is a resistor wire. I would look for the purple or pink wire at the base of the column (test for 12 volts in key on and crank) if you cant find something in the painless chassis harness.
Jon
PSI
On the factory Nova chassis harness there would have been an 'IGN' port in the fuse block which would provide power in Key 'ON' and 'CRANK'. The 'ACC' ports lose power when you are cranking. The painless harness should have the same. As stated above, HEI was not available until around 1976, so your factory ignition wire (white braided) would not be 12 volts as it is a resistor wire. I would look for the purple or pink wire at the base of the column (test for 12 volts in key on and crank) if you cant find something in the painless chassis harness.
Jon
PSI
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I did as PSI suggested, 1974 was the transitional year for HEI some cars had them and some didnt if you had HEI that ignition wire is the one you want to use, if you had points it was the cloth covered resistor wire, my car had the cloth one I traced it back to the fuse box and removed the terminal at the fuse box and removed the cloth wire and soldered in a 12 gauge wire at that terminal and that is my 12V ignition wire that is hot in the run/crank position.
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Verdad Gallardo I also did what lizeec did.. I re-did my OEM Fuse box and ran a new 12+ Hot circuit wire to the Fuse box from the Battery due to the increase Amp's that I expected to be pulling.
I also added a Painless 7 circuit fuse box and ran a few new wires to feed the PCM and other circuits out of it.
I had no trouble with voltage dropping after the Ign switch was moved from Crank to Run.
BC
I also added a Painless 7 circuit fuse box and ran a few new wires to feed the PCM and other circuits out of it.
I had no trouble with voltage dropping after the Ign switch was moved from Crank to Run.
BC
87, 86, and 30 are obvious, but were does 85 come from? im guessing a wire from the ign switch on the column, but the pink one is constant and the car wont shut off with it wired to that one.
If you have a pink wire that is constant 12v, then you may have other problems. Pink wires should always be switched 12v and orange wires should be constant 12v.
Maybe try asking someone that has done a 72 Nova before. I looked at the wiring and I think you are right that there is no wire on the switch that is live in crank/run. It appears your coil was power from the starter solenoid.