Does any one have a diagram other than what came with the box???..because that one doesen't have anything about wiring up to an opti stye Ignition.

thanks in advance!!

 

Search in jegs or summit for a connector to our style ignition. I don't have the part number with me right now but I might be able to find it. It's plug and play, no splicing needed.

 

My wiring instructions:
Wiring Diagram

Relay 1 (arming relay) Run a ground through the fuel pressure safety switch
to the ground side of the (85) arming relay. Positive side (86) goes through
your arming switch - I took positive from the defroster activation button.
30 goes to ground, 87 goes to 30 and 86 on relay 2.

Relay 2 (WOT relay). Take the output from 87 on relay 1 to 86 and 30 on
relay 2. Your WOT switch should be + (should use ATPSS if possible) and take
that to 85. 30 goes to 12V + batt and 87 goes to 85 on relay 3.

Relay 3 (Windows switch relay). Take output from Relay 2 on 87 to 85 on
relay 3. 86 goes to grounded output from Mallory purple (window switch). 30
goes to 12V Batt +. 87 goes to nitrous solenoid + AND yellow (timing retard
input) on Mallory box.

You can not hook the ground from the window switch to the atpss for some
reason on relay 2. I couldn't get mine to work so that's why the 3rd relay.

Also by not allowing them to have + or - until arming relay is activated it
stops unnecessary relay clicking while driving from the window/WOT relays.

By having the ground on the main arming relay go through the FPSS it turns
off the entire system if no fuel pressure.


Part Numbers for MSD Harness
94- 95 uses MSD GM Dual Connector Wiring Harness Adapter - PN 8876
96 uses MSD GM 1996-Up Wiring Harness Adapter - PN 8877


Connecting MSD harness to Mallory Harness
MSD to Mallory
Red to Red
White to Green
Orange to Yellow
Black to Black

Hopefully this information will help anyone with the install of a Mallory 685, and aid in the install process of nitrous. Good Luck!

 

I do believe I got this part # 29068 off here for the Mallory harness. Maybe Loadre or someone will confirm this # is correct or not. Don't want someone buying the wrong part.

 

#29043 Just got it in the mail today. The box says it is for a GM HEI, so I called Summit to be sure I have the right part. The tech said that #29043 is the one Mallory list for the lt1. Still waiting for my box!

 

Thanks guy's!! you were all a great help!! I have all the answers I needed!

 

Nice installation instruction

 

Just wanted to update this so that no one orders the wrong harness. (I'm sorry if you already did) Both Summit techs I spoke with were wrong! Dam minimum wage labor! I could not find out which mallory harness was needed for my car so I just went with the MSD harness.

 

I ordered the same harness #29043 then found this on the Mr. Gasket site. http://www.mrgasket.com/AskTechResul...dID=1&ID=69711 Guess I have a part to return to Summit.

 

This is the one I used.....worked perfectly.