Sick Pony: 74' Sport Resto Mod for Trail and Street

[scbronco]

So the MSD ignition cam in yesterday and spent the rest of the day figuring out which of the 5 possible ways of wiring the tach signal was correct. Edelbrock provides for 3 manners to wire this signal via the 3 pin weather-pack harness pigtail provided with the kit.

1) for HEI- use one tan wire in pin A of connector to tach signal wire. No Dice
2) For CD Box- use one White wire form Pin B of connector to CD box tach output wire. Edelbrock suggested to use this option connected to the tach signal wire on the HEI (cap) once I changed over to the MSD ignition module. Also No Dice.
3) for Mag/Hall Sensor- use all three wires and connect white B pin to Tach output, and Black C pin to Igntion ground.

turns out it was the 6th possible way which MSD's instructions says is not ideal for a strong tach signal, and Edelbrock's instructions doesn't even consider. Had to connect the B pin White wire to the additional tach output wire provided by the MSD Igntion. it's an extra grey wire in addition to the standard HEI Tach signal post off the cap. it provides square wave tach signal across 20*. this was the only wiring option that worked.

BUT IT WORKED!!! Fired up on the second crank, ran a lil rough and then settled in. I had to fuss with the idle setting to cal the TPS quite a bit, and i'm still not real pleased with the idle, but I don't wanna mess with it much until the system has a chance to learn some more. it's just making a lot of correction right now, and kinda "hunting" for the right rpm. I checked all my vacuum and think I will switch from tight zip ties to worm clamps on all those connections to ensure i'm not leaking...

While cruising and accelerating though, it's already a million times improved over carburetion. super smooth, and perfect throttle response. also I think my vacuum brake booster has benefited as well as she stops about 80 feet quicker from 40 mph than before. (noticed at a stop sign I stop at often)