Mini Starter wiring question - How to simplify/eliminate the fender mount solenenoid

[vdubn]

Since I am in the middle of replacing wire harnesses, my engine/trans are out, and I'm pulling, replacing, and relooming some harnesses, I figure now is the best time to change over to wiring that eliminates the fender mounted starter solenoid, and simplifies the starter circuit to run the mini starter that has the solenoid built into it.

I have looked at a number of threads on similar subjects, but most find a way to make the mini starter work with the existing wiring and fender mounted solenoid.

Does anyone have a wiring diagram or easy DIY on how to clean things up?

[Haystack]

The fuseable links all need to be wired to the positive of the battery. So does the thick wire for the starter. The small trigger wire can be moved from the trigger post of the starter solenoid on the fender, directly to the mini starter trigger wire. Obviously all grounds need to go either to the engine or negetive cable, thats pretty much it.

Id have the time of my life re-wiring a whole car and gutting a harness. I have had my mini starter on 3 different cars now, i leave the fender solenoid just so i don't have to re route everything under the hood and so that i can still use wiring diagrams. My efi cougar/birds essentially use the same engine wiring as a mustang, but have a completely different chassi and interior setup. If you are gutting the car or eliminating a bunch of stuff, you can make it look really clean pretty easy.

[erratic50]

Why would you want to route always hot leads past exhaust, etc? Candidly after the GM's I've dealt with over the years that do exactly this, I see it as a fire hazard. Heck - frequently the GM guys go the other way to make theirs more like a Ford because they don't like working around that long always hit lead.

Why not hide the stock fender selonoid then jumper the crank lead to power lead on the mini? The cable from the fender to the mini is only hot when cranking this way.

Just my thoughts. Best regards.

[ZephyrEFI]

Ford used to sell a kit for doing this. The instructions that came with it tell you to use 12 gauge wire from the "start" post on the fender solenoid. I'm re-doing a bunch of my wiring this winter and my plan for the trigger wire from the dash is to run that to a regular relay and then run 12 gauge from the power circuit on the relay to the trigger post on the mini starter. That way it should still isolate the small gauge trigger wire sufficiently.

Guys will tell you the fender solenoid helps absorb voltage spikes and such, but I don't see why the starter-mounted solenoid the mini starter setup has wouldn't do the same thing. Also, ALL cars '92 and newer function just fine without a fender solenoid.

[vdubn]

Hmm... good points on both sides... I hadn't thought about the 1992 and later cars eliminating the fender mount solenoid.

Haystack... your simplification of the harness is exactly what I would like to do, since I am at a place where I have all of the harnesses out. I would love to eliminate the EGR, the fender evap solenoids, and a few other things. If you were doing it, would you just un-loom those pieces back to the plug for those particular harnesses, or go all the way back to the PCM plug? For example, the EGR harness... I could just trace the plug back and if it doesn't have shared wiring with other circuits, un-pin the wires from the EFI harness. If there are shared wires, then it would be an issue of just removing as much as I can, then leaving the rest to support whichever other circuit is still in use.

Also, other than EGR and the evap solenoids, are there other items you would consider removing?

[vdubn]

The fuseable links all need to be wired to the positive of the battery. So does the thick wire for the starter.

Any chance you have a pic of the fuseable links? All of my harnesses are currently out of the car, so I can trace them down.

[Haystack]

I can make a quick video tomorrow.

The cougar birds have quite a few more fuseable links, tons of power options standard.

[cb84capri]

The point of running a fender mounted solenoid with the mini starter is so you can run a larger wire to the starter mounted solenoid trigger. You run the factory trigger wire directly to the starter it could have difficulty starting when hot, because the resistance increases in that 18 gauge wire so much when it's so close to the engine it won't have enough juice to energize the starter mounted solenoid. With a fender mount solenoid you can hit it with full battery voltage from a much larger wire. A lot of GM guys set their cars up with Ford fender mounted starter solenoids for this reason.

Cale

[erratic50]

Cale - totally agree.

Battery ---- fender sel ----- |starter
car start -----+................ +- starter start

You only run one big heavy wire to the starter. It is only receiving power when the key is in crank position. This lets you simply wire "start" on the mini starter to the large wire.

as a bonus, if the fender selinoid stops working, you remove one nut and turn the key on then short the cable straight to the 12v to make it crank. Once is starts make sure it's no longer receiving power by putting it back. That friends is how to get to the starting line even when your car is broken...

GM guys have to lean over the fender and short the start to the battery cable with a pliars or screwdriver.

[cb84capri]

I may not have explained this very clearly. Big cable directly from battery or 12v constant side of fender mounted solenoid to big post on mini starter, 12 gauge wire from switched side of fender solenoid to trigger post on starter solenoid. I tried energizing both posts at the same time from the same power supply, the starter drive hangs out for awhile after power is killed because the starter generates power and energizes the starter mounted solenoid.

Cale

[erratic50]

Surprised the starter doesn't have a diod on its terminal already, but you can use a heavy diod such as the one found inside a 70's-90's GM alternator to avoid that.

[Haystack]

Long story short, the mini starter has a solenoid built in. It is identical in operation to the stock fender well, just a bit smaller. Wiring straight to the starter Trigger with a 16 or 18 guage wire is how these cars were stock.

However,...

The starter solenoid is basically two electro magnets. One makes contact for the actual starter, the other just keeps it in place. For about 50ms it pulls anywhere from 25-60amps depending on how exact your measuring equipment and refresh rate is. After that, it pulls around 10 amps. To protect the ignition switch from this quick load spike on initiation, oems now add relays.

Basically, there is nothing wrong with just splicing it to the factory wire, thats how ford did it to begin with. But to technically do it "right" (right being defined as how modern cars with a butt load of electronic goodies) you could add a relay, upsize the wire, or wiring in your own trigger button off a fused curcuit, to protect the ignition switch.

My own honest opinion, its up to you. Id just splice the wire personally. Oems usually don't spend money if they don't have to though, so I'd say it would technically be better to add a relay.

[wraithracing]

Here is the Ford wiring diagram that comes with the mini starter when doing the conversion.



All the aero cars with the mini starter still use the fender mounted solenoid. The wiring is not direct to the starter, just FYI.

[Ourobos]

^ Just to add to this..

With the mini starter and fender mounted solenoid, as was factory in 92+, EVERY SINGLE WIRE goes to the same large post on the solenoid, EXCEPT the trigger wire, which goes on the opposite post.. Fuse links, power windows, etc all go on the same post with the large 2 gauge starter wire and the battery wire.