I need 12v

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Backally

Backally

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i posted last winter looking for ideas to power a Holley sniper. Never got a clear answer, probably didn’t phrase it well. 70 Duster, stock wiring other than Crackbacks headlight relay and alt-batt connection. I have gone through and cleaned/replaced connections so pretty confident they are in good shape. I do have a wiring schematic.
I need 12v while both cranking and in run. It’s less than 3amps. What I did was run wires from ign 1 and 2 at the steering column connection, connect them and run them to the sniper. Although it works I read on another forum I am putting to many volts to the coil, it could overheat, also possibly damage my ignition box.
So how can I wire this to get 12v while both cranking and in run without causing problems elsewhere?
 
you are getting 12V from both wires. One is 12v while cranking, one is 12v in run. That's all you are getting, 12v. My FiTech is wired the same way, with it's constant 12v coming direct from the positive battery terminal.
 
You need to modify the ignition system so that it is a type that WILL run on straight 12, or else add a relay from the IGN2 so that it only jumpers over to the supply side of IGN1 during start

The DIFFERENCE is that originally, IGN1 supplied "straight 12" only in run to the ballast resistor. It goes "cold" in cranking, so your EFI would be dead. But the IGN2 jumpers power to the coil which puts the ballast resistor in between the two (IGN1--IGN2) So you need a way to get that IGN2 over to IGN1

Only "easy" way I know would be a relay.

My solution would to not use a relay. Replace your Mopar box with a GM HEI module, and eliminate the resistor.

I think Greg drew up this really neat diagram from my henscratch LOL

4pin-jpg.jpg


Many guys upgrade the coil but I did not. Used the Mopar dist and factory coil
 
sounds like you jumpered Ign1 and Ign 2 together then ran one wire to the sniper?
 
Per JoeSBP’s response, if I am pulling the 12v from ign 1and 2 before the ballast resistor, will I harm anything? It is working, just don’t want to cause trouble down the road.
 
Backally said:
Per JoeSBP’s response, if I am pulling the 12v from ign 1and 2 before the ballast resistor, will I harm anything? It is working, just don’t want to cause trouble down the road.
Click to expand...

You have effectively bypassed the resistor. There is no way to simply jumper them and maintain the ballast resistor
 
I believe you can do this with a diode, but you need a big one, say, 10A or so, to be safe. Connect between IGN1 and IGN2 with the stripe end at IGN1
 
67Dart273 said:
You have effectively bypassed the resistor. There is no way to simply jumper them and maintain the ballast resistor
Click to expand...

Ok, I get what your saying.

67Dart273 said:
I believe you can do this with a diode, but you need a big one, say, 10A or so, to be safe. Connect between IGN1 and IGN2 with the stripe end at IGN1
Click to expand...

From what I was told, this is no more than 3 amps. This runs the ecu, the big power draw is off a relay. Would I still need that big a diode? Would Napa or someone have those or an electronics store?
 
Ah..........yes. If you put it ONLY in the EFI wire that would limit the current you need. I would measure it. Doesn't that system have a "full time" 12V and then an ignition trigger line? That trigger likely does not draw much. There are some diodes NAPA may have, but finding something they have and you want may be tough. I'd just get on line, even Egag, about a 5-10 amp rectifier at 25V PIV or more is enough.

If that is the case, you would want to hook the diode to coil+ (as if it was ignition switch and the other end ONLY to the EFI power trigger wire

Then leave the wire on the EFI side of the diode connected to IGN1
 
Backally said:
i posted last winter looking for ideas to power a Holley sniper. Never got a clear answer, probably didn’t phrase it well. 70 Duster, stock wiring other than Crackbacks headlight relay and alt-batt connection. I have gone through and cleaned/replaced connections so pretty confident they are in good shape. I do have a wiring schematic.
I need 12v while both cranking and in run. It’s less than 3amps. What I did was run wires from ign 1 and 2 at the steering column connection, connect them and run them to the sniper. Although it works I read on another forum I am putting to many volts to the coil, it could overheat, also possibly damage my ignition box.
So how can I wire this to get 12v while both cranking and in run without causing problems elsewhere?
Click to expand...
Have you talked to Holley about this? I find it hard to believe that they would produce a fuel injection set up that requires special electrical requirements without including the necessary pieces in the kit or information in the instructions.
 
toolmanmike said:
Have you talked to Holley about this? I find it hard to believe that they would produce a fuel injection set up that requires special electrical requirements without including the necessary pieces in the kit or information in the instructions.
Click to expand...

It probably works on a chev or Ford, from what I understand the ign 1/ign2 is a mopar thing. Anything with a 12v during both crank and run is what they are looking for.

67Dart273 said:
Ah..........yes. If you put it ONLY in the EFI wire that would limit the current you need. I would measure it. Doesn't that system have a "full time" 12V and then an ignition trigger line? That trigger likely does not draw much. There are some diodes NAPA may have, but finding something they have and you want may be tough. I'd just get on line, even Egag, about a 5-10 amp rectifier at 25V PIV or more is enough.

If that is the case, you would want to hook the diode to coil+ (as if it was ignition switch and the other end ONLY to the EFI power trigger wire

Then leave the wire on the EFI side of the diode connected to IGN1
Click to expand...

Yes, what I jumpered is the trigger wire. That runs to the ecu, which controls the relay supplying 12 straight from the batt. Found a 6a at a starter/alt rebuild shop. Will put that in the “jumper” wire, so that should stop current from bypassing the ballast resistor, which is what I understand you feel I need to do. That sound correct?
 
This is a common problem on these systems Mike. Neither my Commander 950 nor the HP upgrade addressed this, and neither does the EFItech system. The entire problem is this:

Mopar "run" line goes dead in "crank" Mopar is the only manufacturer to use the bypass system in the ignition switch. "Everybody else" had a contact on the starter solenoid.
 
I messed up slightly. The diode will have to feed all ignition loads during start. So you need to determine what the IGN/ EFI load is and size the diode appropriately.

Only way to isolate the EFI would be to use two diodes, "steering" they are sometimes called.
 
And just a learning thing here, when in run, is ign 1 or 2 hot?
Thx for all the help!
 
what ignition system are you running?
 
67Dart273 said:
I messed up slightly. The diode will have to feed all ignition loads during start. So you need to determine what the IGN/ EFI load is and size the diode appropriately.

Only way to isolate the EFI would be to use two diodes, "steering" they are sometimes called.
Click to expand...

I did not disconnect the either of the ignition 1 or 2 wires from the connector, so that should feed everything as normal. If I just put that diode on the jumper (the pink wires in the pic is the jumper) so that current cannot cross over to ign 2 during normal running operations

A6EFC085-1FF3-4E7A-9799-EF35F0354E32.jpeg
 
Backally said:
And just a learning thing here, when in run, is ign 1 or 2 hot?
Thx for all the help!
Click to expand...

1 is hot only in run, 2 is hot only in start. However IGN2 is NOT the same as the "start" contact going to the starter relay. They are separate contacts, to prevent feedback.

Again, you want the diode stripe (cathode) on the IGN1 end
 
Ok, this may be a stupid question. You can see by the pic how this is wired. Any benefit to wiring in a diode in each of the pink wires right off the connector, isolating any current from going between ign 1&2? It could only follow the pink trigger wire?
 
so are you going to EFI, but leaving the stock points or electronic ignition on place? Or is the sniper driving the spark?
 
Msd distributor at this time. I may have it control the timing down the road but want to do one step at a time
 
You are making so much extra stress. Brother it is simple as can be. What is actually controlling the spark? MSD box?
 
I have FiTech, but I can't imagine the Sniper being any more complicated. You just need a two wire MSD alternator(or MSD clone). All the timing etc is just simply punching in the numbers you want. Then you run her down the road. You don't like it, bump a number up or down while you are rolling, until you are happy. I would personally go that route before I spliced in diodes etc. Also the voltage drop is to protect the OE ignition, if you are running aftermarket, you can have it all full 12v
 
Right now I got a Rev-N-Nator. Works good for me. Really not stressing. Not real strong on electrical, learned I may have something that could cause problems later and want to straighten it out
 
JoeSBP said:
I have FiTech, but I can't imagine the Sniper being any more complicated. You just need a two wire MSD alternator(or MSD clone). All the timing etc is just simply punching in the numbers you want. Then you run her down the road. You don't like it, bump a number up or down while you are rolling, until you are happy. I would personally go that route before I spliced in diodes etc. Also the voltage drop is to protect the OE ignition, if you are running aftermarket, you can have it all full 12v
Click to expand...

Sorry the issue is that HE IS RUNNING A MOPAR BREAKERLESS ignition WHICH MUST USE a ballast resistor.

Also you might want to correct your post. ???MSD alternator??? Whut?
 
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