Vintage Mustang Forums banner

21 - 40 of 52 Posts

·
Registered
Joined
·
12,133 Posts
Discussion Starter #22
Ok. :D I think we're getting a little off track here. Maybe I should start another thread. I'm very familiar with relays and most things wiring. My car has many fuse boxes and relay boxes. I have boxes of relays at my disposal. hah Maybe my phrasing was poor:

My question is, does anyone know the amp draw of a Mini-starter/Gear reduction starter (Let's say Remy 97101), and has anyone run their ignition switch Crank wire directly to it, as with a new gen. My current wiring is how you guys are recommending, which I did out of laziness and time crunch (but I'm using the fender solenoid instead of a Bosch style relay.. Same wiring).

Summary ii: Newer gens, I believe, have the Crank wire going directly to the starter reduction solenoid. Does anyone have first hand experience running it this way (Can a 67/68 ignition switch handle the current. Do we know the required current, and current capacity?)

Thanks guys. Clean start here. Looking for numbers, particularly of the ignition switch capacity. lol
 

·
Registered
Joined
·
12,133 Posts
Discussion Starter #24
Ok, that was one of my questions, thanks! If I had 2x 68 ignition switches, I suppose I could just turn up the juice on a psu to see when it burns out, but.. I don't.. lol
 

·
Registered
Joined
·
320 Posts
My original reply was with the idea of clean slate wiring from the ignition switch to the starter and I still would just throw a relay in under the dash somewhere.
 

·
Registered
Joined
·
12,133 Posts
Discussion Starter #26
I do have a spare relay in my underhood box if need be, although I was hoping to use it for something fun. :D Currently have High, low, Fan 1, Fan 2, FP).
I suppose tomorrow I'll check the draw on the fender solenoid vs the starter mount solenoid and see what the difference is and we can go from there.
 

·
Registered
Joined
·
12,133 Posts
Discussion Starter #28
Originally it was Fox EFI.. I now have (regrettably!) removed every trace of wire and redid it all from scratch to install this Sniper, except I kept the battery in the trunk, and my original (not the original) starting and charging circuit. Now I'm moving the battery up front again to remove every wire that isn't 100% necessary. My last setup had relays that triggered relays that triggered ECU's that triggered relays. I'm going for a zen-like experience now.
 

·
Registered
Joined
·
320 Posts
Good call, what isn't there can't fail.

But either way a relay would take some strain off the switch although I suspect the original switch can handle it just fine.
 

·
Registered
Joined
·
35,121 Posts
As far as starter solenoid current draw I'd say 30 peak, 10 to hold the "slug" in place. What are you running for an ignition system? Do you need a coil "bypass" wire (solenoid "I" terminal)?
 

·
Registered
Joined
·
3,263 Posts
I would run a relay. My 89 Toyota runs the starter solenoid through the Ignition switch ( and was designed to do so ) , but it's a very common mod to add a relay to improve starting issues and problems with the Ignition switch contacts.
 

·
Registered
Joined
·
12,133 Posts
Discussion Starter #32
I'll hopefully get around to some updates tonight. .....Unless it's over 10 amps. Then I'll get around to buying a new dmm. hah

Woodchuck, no nothing like that. I've always run EFI of various incarnations. Actually I've only ever used the Fox solenoid, which doesn't have an I terminal.
 

·
Registered
Joined
·
1,725 Posts
According to the 95 Mustang Shop Manual the starter relay is number 14N089 if that means anything to anyone. It also says in the starter motor specs that the starter under normal load draws between 130-220Amps.

I can't find any mention of the actual draw of the relay itself so it's probably not too much. It'd need bigger wires if it was going to pull any real amperage so I think you're ok.

Here's how Ford describes the 95 OEM starting wiring for reference in case it helps:
755339
 

·
Registered
Joined
·
2,864 Posts
Johnny, not sure why you'd want to risk having a large, always hot wire on the starter ? The Ford Solenoid is up on the apron to prevent this problem. Chevy guys with starter issues buy Ford apron solenoids and use them instead the solenoid on the starter- look at the MAD 'start em up' kits. I believe you're thinking backwards. LSG
 

·
Registered
Joined
·
20,790 Posts
Any coil is going to produce a kilovolt spike. Even the stock fender mount solenoid. The equipment back then was pretty rudimentary and if anything very durable. Modern cars with all the electronics are susceptible to these kilovolt spikes produced when power is removed. Even though a relay doesn't fire a spark plug it still has the same DNA as a ignition coil. The purpose of the diode is to trap the spike the coil makes. The diode is installed in what's called reverse bias or backwards to how a diode works.

On our Mustangs you probably could just have the ignition switch without a relay operating the solenoid on the PMGR starter. It's really no different then the fender solenoid as far as current draw or anything else. Just run the battery cable to the starter and the wire that normally goes to the "S" terminal on the fender solenoid going to the small terminal on the PMGR starter. That's basically what I did. I'm using the fender solenoid mostly as a terminal block at this point. I have the starter cable going to the same stud on the solenoid that the battery cable goes. On the "S" terminal I have the factory wiring going to it with the PMGR solenoid wiring going to that terminal. Everything works find, no diodes but then again no electronics outside of my Duraspark box and that isn't complaining.
 

·
Registered
Joined
·
1,749 Posts
Curiosity almost killed my voltmeter... 💥

I measured 3.4 amps draw (steady state) with the original fender mount solenoid and 30 amps (!) draw just for the PMGR solenoid (my Mustang is down getting a new engine so this was an easy experiment). You will need a decent sized relay (40A+) to survive powering that PMGR starter solenoid. You will let the smoke out of the ignition switch and wiring if you try going directly to the PMGR solenoid!
 
21 - 40 of 52 Posts
Top