Hotwire harness-how to get around the 12v at start

[Red383]

For those of you who used a Hotwire Auto harness on their new Hemi's, how did you get around the Pink wire "12 Volt Run and start". Chris at Hotwire told me it's easiest to use a start button, but I really would like to use the keyed ignition.

Can I wire a relay in to have 12v to the pink wire at key on and start position?

Thanks

 

[67Dart273]

I am not familiar with this. It did come up with someone else. The implication is that the original Mopar switches, is that what you are using? has a "gap" when going from start to run. Frankly. I'd try it anyway.

What does this pink wire do? What happens if you tie the old bypass contact in your switch (IGN2) to the run (IGN1) like everybody does for alternative ignition?

How about the start contact? Run a diode from the start contact to IGN1 or add a second relay to do that job

How did the original installation take care of this? Is this part of the setup in the original ign switch?

 

[Uhcoog1]

Yes, you can do it with a relay. It will make your pink hot on both.

This is a layout as provided by american autowire. DON'T DO THIS, must change. THIS VERSION WILL BACKFEED and keep the starter running. For pin 30, use a 12v battery hot all the time wire and it will work perfect.

 

[Red383]

Yes there is a "Gap" when going from start to run. I did try it and mine works sometimes and other times it doesn't.
The pink wire on the Hotwire harness is "12 Volt Run and start. (ignition key on position)" I don't have the wiring diagram in front of me, but I believe I tried tying ign1 and ign2 together.

This is on a 73 dart, by the way.

I am not familiar with this. It did come up with someone else. The implication is that the original Mopar switches, is that what you are using? has a "gap" when going from start to run. Frankly. I'd try it anyway.

What does this pink wire do? What happens if you tie the old bypass contact in your switch (IGN2) to the run (IGN1) like everybody does for alternative ignition?

How about the start contact? Run a diode from the start contact to IGN1 or add a second relay to do that job

How did the original installation take care of this? Is this part of the setup in the original ign switch?

 

[cudadan]

im about to go through this too,, chris said to use a push button for it,, didnt really want to

 

[abodyjoe]

these guys get what $900 for a harness and can't figure out how to get it to start and run without a pushbutton? thats just nuts. i would want it to start just like any other old mope with the key.

 

[67Dart273]

Yes there is a "Gap" when going from start to run. I did try it and mine works sometimes and other times it doesn't.

There has to be an easy way to build a simple relay timer circuit, probably just as simple as a one or two transistors, couple of resistors and a timing capacitor to hold the relay "in" for a second or two so that you can bridge the gap from start to run.

I would guess that this is originally an issue that was set up in the original ignition switch on the hemi car.

Something like this. Push button would be your ignition switch start contacts, probably fed through a series diode. The contacts would be fed 12V and switched contact would go in parallel with your "run" line.

This thing looks like it might work

http://www.grainger.com/product/5WML9?cm_sp=HIO-_-HIDP-_-BTM_BTB_P&cm_vc=IDPBBZ11

 

[Map63Vette]

Interesting, I think I just tied the stock wires together as well. Makes for a pretty good head scratcher the first time around when your computer keeps losing power during cranking. I suppose if you turn the key very slowly it might still see a gap in the power, but I've never had a problem with it by just hooking the wires together.

 

[cudadan]

What wires did u put together

 

[67Dart273]

What wires did u put together

The issue is this...........

On systems such as MSD (or in this case EFI) which no longer use a coil ballast, the "run" known as "IGN1" goes dead in start. This was "used to be" traditionally powered during cranking with the "bypass" (IGN2) circuit. HOWEVER there is / can be a slight disconnect or gap as the key is moved from start to run. Evidently this becomes a problem with some EFI systems

 

[cudadan]

Im still a few wks away before i get to fire it. I dont mind using a button if i have to. I found a real nice button from delcity..

 

[Red383]

I believe I tried wiring Ing. 1 & 2 wires together, but I can't remember for sure. I have pulled the harness and intake to reroute some stuff, so I will try it again in a couple weeks when it's back together.

Thanks

 

[72BBSwinger]

My button
http://www.ebay.com/itm/141013417977?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2648

 

[Uhcoog1]

Yes, you can do it with a relay. It will make your pink hot on both.

This is a layout as provided by american autowire. DON'T DO THIS, must change. THIS VERSION WILL BACKFEED and keep the starter running. For pin 30, use a 12v battery hot all the time wire and it will work perfect.

Yes there is a "Gap" when going from start to run. I did try it and mine works sometimes and other times it doesn't.
The pink wire on the Hotwire harness is "12 Volt Run and start. (ignition key on position)" I don't have the wiring diagram in front of me, but I believe I tried tying ign1 and ign2 together.

This is on a 73 dart, by the way.

Test light did not show a gap on mine when wired as above. Megasquirt starts and runs fine, no issues.

Don't make it more complicated than it is.

 

[67Dart273]

You are not being very clear here In one post you say the diagram is wrong, don't do this, then you say "it works fine there is no gap."

HERE is what you have evidently done?

Bosch relay

Battery + to 30

IGN1 to 87

So these are the N.O. comtacts

Ground 85

86 to the START wire

So you are activating the coil with the start signal, and switching battery to the IGN1 line during start. Fine.

How is this different than using the original bypass contacts and jumpering to IGN1? Are you claiming that ALL Mopar switches don't have a gap between start and IGN1 and they DO have a gap between IGN1 and IGN2?

IF this works, you don't even need a relay. All you need is just one diode. .

 

[66plyValiant]

I am not familiar with this. It did come up with someone else. The implication is that the original Mopar switches, is that what you are using? has a "gap" when going from start to run. Frankly. I'd try it anyway.

What does this pink wire do? What happens if you tie the old bypass contact in your switch (IGN2) to the run (IGN1) like everybody does for alternative ignition?

How about the start contact? Run a diode from the start contact to IGN1 or add a second relay to do that job

How did the original installation take care of this? Is this part of the setup in the original ign switch?

ignition switches have a gap, but the starter relay takes care of that, most of the 70's mopars (all of the late 70's) have a dedicated power when cranking that is separate then the starter solenoid power when cranking

this wire is generally brown; much like the solenoid wire for starter, but in a different location on the relay

 

[67Dart273]

ignition switches have a gap, but the starter relay takes care of that, most of the 70's mopars (all of the late 70's) have a dedicated power when cranking that is separate then the starter solenoid power when cranking

this wire is generally brown; much like the solenoid wire for starter, but in a different location on the relay

Sorry this is not correct, or maybe explained poorly. All vintage Mopar switches have four separate distinct switch contacts, starting whenever they went to the engine bay mounted starter relay in 60?

accessory

ignition run (IGN1)

ignition bypass (IGN2)

start

The start relay does not take care of any gap. The start contacts in the switch fire the relay, the relay fires the starter

The problem here is there is a gap between IGN1 and IGN2

and the question with this relay circuit is, "is there" a gap (in the switch) between IGN1 and START because there certainly is in the 67 switch I have.

 

[Uhcoog1]

IF this works, you don't even need a relay. All you need is just one diode. .

Good call. Didn't think of this. Easiest way.

 

[67Dart273]

I just remembered.........I've got a 73 column "out there." When / if it warms up in a few days, I'll do some looking at ignition switches. I think I remember seeing one more junker late model switch "in the pile"

 

[cudadan]

I believe I tried wiring Ing. 1 & 2 wires together, but I can't remember for sure. I have pulled the harness and intake to reroute some stuff, so I will try it again in a couple weeks when it's back together.

Thanks

cool keep us posted

 

[loganscuda]

I put a start button in place of the cigarette lighter. nice and hidden. The problem is resistance, there is a voltage drop through the ignition switch at least on my 67. If you do a relay it is a momentary contact normally open.

 

[blown71duster]

For those of you who used a Hotwire Auto harness on their new Hemi's, how did you get around the Pink wire "12 Volt Run and start". Chris at Hotwire told me it's easiest to use a start button, but I really would like to use the keyed ignition.

Can I wire a relay in to have 12v to the pink wire at key on and start position?

Thanks

The factory pcm grounds the ASD relay to energize the coils ,O2 heater, and fuel injectors etc. and I think the logic is that it keeps it on for 1.8 seconds , then will shut off relay unless it gets an ignition signal.

I wonder if that pink wire energizes the circuit that the ASD normally does, I would think if it is , then keeping that circuit at 12v in both crank/run with the posted suggestions would work great. I wouldn't think the slight time lapse from crank to run would interrupt enough to cause a problem.
Maybe run these ideas through Chris at hotwire.

The only downfall to that would be whatever is on that circuit would be energized with the key left on, where the ASD would normally shut off after it times out.

 

[RealWing]

I put a start button in place of the cigarette lighter. nice and hidden. The problem is resistance, there is a voltage drop through the ignition switch at least on my 67. If you do a relay it is a momentary contact normally open.

I found high resistance on my '69 Cuda switch, however after operating it several times, the resistance improved significantly and is now ~0.1 Ohms. Looks like there was high resistance due to dirty contacts.
Although I'm installing a FAST system, I face the same problem with the start circuit.
I've simply disconnected the brown wire from the IGN2 terminal on the switch and at position T on the bulkhead connector.
I then will run a new wire from the ACC circuit (12V when Ign switch is on) with a new fuse, to a start PB (hidden in the console ash tray) and then back to Position "T" at the bulkhead connector (which then goes to the starter relay)
I like the idea of hiding the start PB in the cigarette lighter. Hadn't thought of that place!!!

 

[Boony405hp]

I'm just getting to this stage now. So how does it work exactly, you still have your ignition barrel, but do you need to turn the key to a certain position and then push the start button. Or being 12V hot permanently can it be fired up without a key anytime? I'm trying to picture how the two work together, ie. if you just wanted to turn your accessories on you'd need to have the barrel for this to happen.

 

[ralphie361]

I'm just getting to this stage now. So how does it work exactly, you still have your ignition barrel, but do you need to turn the key to a certain position and then push the start button. Or being 12V hot permanently can it be fired up without a key anytime? I'm trying to picture how the two work together, ie. if you just wanted to turn your accessories on you'd need to have the barrel for this to happen.

If you feed the control side of your button from ign1 it will only engage the starter when the key is on. If you go 12v battery it will crank at any time, only start when the key is on. Either way the starter will not crank when engine is running because the PCM sees rpm and protects against double start.

Just saw this topic on another thread, and I would try jumping ign1 and ign2 first, it's easy and if it doesn't work you can add the button. Mine has started every time this way in 1200+ miles... So far, I'm sure I just jinxed myself...