97formulakid

Ok, I just got my Mallory 685 in the mail today and was going to wire it up. Well, it didn't come with instructions (used) and I downloaded some and read them.

I might as well have been reading Japanese. I have NO CLUE how to wire this thing up. Well, let me restate that. I know how to wire up the ground and power wire, and it came with a MSD coil harness but I don't know what wires go to what. Also, I am using the window switch for my nitrous kit and am also using the timing retarder. PLEASE SOMEONE HELP ME!!!!!

97formulakid

OK after looking at everything and doing some searching I know how to hook up most of it but how do I hook my nitrous kit to it?

Z28dotcom

I am about to hook up the 685 on mine using the timing retard and window switch. Is there any way you could send me instructions how you wired yours?

97formulakid

i still havent wired it up yet. once i do ill let you know

01Z

Since I just did my system with the Mallory Hyfire, I think I can help. Have company here right now so I'll check back in and if no one has posted your solution I'll do what I can to help. By this post I will be able to find the thread again easily....

anaik

Mallory's site has instructions for their products.

http://www.malloryperformance.com/In...aspx?BrandID=6

01Z

anaik is right and that is the best way to understand the wiring. However, I have a few suggestions regarding the RPM window (violet) wire and the the yellow High Speed Retard signal wire that requires a +12 volt input to activate.

But first, here is some help regarding hooking into the coil wiring:
Use the MSD 8876 harness for 93-95 dual connection coils and the 8877 for the 96-97 single connection coil. Here's the wire exchange from the Mallory to the MSD harness:

Connecting MSD harness to Mallory Harness MSD to Mallory:

(MSD)Red to (MALLORY)Red
(MSD)Black to (MALLORY)Black
(MSD)White to (MALLORY)Green
(MSD)Orange to (MALLORY)Yellow

Because the Mallory is a 10 amp ground circuit it is not a good idea to directly ground through the violet wire for the RPM window. Rather use that wire to complete a circuit for a relay and ground through the switch side of it.

Also, feed +12 volts through the yellow wire to activate the spark retard. I have this happen when the RPM window relay kicks in. That way I have full spark advance until the nitrous system gets a ground and becomes active. Then it's -5.5 retard. It gets a little complex using the relays as I have 4 of them for the entire system but it is the most reliable way to augment the functions of the Hyfire. I'm very impressed with this ignition btw.

Here is a helpful link to view as well:
http://web.camaross.com/forums/showt...lory+connector

Z28dotcom

so according to the mallory wiring diagrams....

the 12+ from the battery, does that need to be switched or directly to a power source?


thanks for the help guys

01Z

The small red +12 volt power supply should come directly from the battery or starter, it of course is always on. There is a post on the fender well in my car that I tapped into for that. The Mallory does not come alive until the ignition is switched on because the trigger voltage comes from the coil. So the answer to your question is no and yes.

Z28dotcom

thanks....

I am sure there will be more questions soon....

Also I am mounting it in my Glove box.... you think that heat will be an issue? what about the distance of the wires will votage drop be a problem?

01Z

Mine is in my glove box as well. I don't notice any heat in there but I don't drive the car very often either. As long as you use the proper gauge wire you should have no problem with resistance and power loss.

You can use the loopback connector supplied with the Mallory when you don't need the CD ignition. I only need mine when using nitrous. It has been said that the spark enhancer ignitions make short work of the opti-spark distributor. I don't know how accurate that statement is but since the HEI on our fbodys is plenty good enough, using the loopback will not only unload the opti-spark but also give the Mallory a rest as well. IOW, I won't have the Hyfire in the loop when I take the car on a trip.

Here are some pictures for your viewing pleasure:
Mallory in the glove box

Glove box out of the dash

Tucked away

speed_demon24

BTW, is 14 gauge wire thick enough for all the wiring? Thats what I used on everything. The wires that come off the MSD pigtails seem to be 14 gauge, but some of them on the mallory box look like they might be 12 gauge.

01Z

You bring up a good point. The heaviest of the wires is the yellow as you can tell. I'm sure you are good with the large red and black that goes to the coil. I would think you're okay with the yellow too. It would have been good if Mallory would have given the wire gauge size and/or current load in the manual. Take a look at the copper in the wire ends if you can. You can pretty much tell the difference in wire size diameter by eyeball. Even if you are fractionally smaller there should be enough margin to be safe. Don't sweat the 6 feet or so of length; the biggest neck down is crimping the wire together. Another advantage to having the unit in the glove box is it won't be hard to feel the individual wires for heat.

Here's a good link to help make your decision on adequate wire size: http://www.powerstream.com/Wire_Size.htm ... I don't have one but I'm sure there are tools to check wire gauge.

MichiganSkip

I am currently drawing schematics up for the Mallory 685 box and the MSD 6 AL/(with Window switch) for all you wiring newbies. If any of you would like to see schematics for any other items PM me and I'd be happy to draw them up. These are color coded so there will be no question as to what goes where. These schematics show how to wire Nitrous systems up too, firing relays so that smaller amperage toggle switches can be used. I have an older schematic floating around the net now that I did a few years ago, but since then I've updated and re-drawn the diagrams to try to incorporate the different boxes available.

Z28dotcom

thanks for all the help guys it has really helped me.....

Just and update, I have the Mallory box mounted and hooked up and running. I havent connected the nitrous, timing retard, or window switch yet cause I changed my mind on the mirco switch I want to use..


I am really concerend about heat now... last night I took the car out for a short spin and the mallory box was really hot.... you couldnt hold your hand on it very long.... I was even concerned about it getting so hot it would melt the plastic in my glove box???

I did by the box used so perhaps I go ripped on the deal who knows but it all looked new and came in the original box..

For the time being, I just bypassed the box at the coil for now...

also the car seemed like it will need to be retuned after this, is this normal? the idle was a bit low and rough.... Just for reference the car has already been dyno tuned for all the extising mods...