RCC Innovation conversion

Help Support 7173Mustangs.com:

1hotboss

Well-known member
Joined
Jun 12, 2015
Messages
55
Reaction score
1
Location
Canada
My Car
1970 Boss 302
Had Bob do my OEM tach...but I am a little confused on the re-install wiring. I am a newbee to all this. So I have made a jumper wire and have that in place...I understand that I will have to lengthen the green wire and attach it to the negative side of the coil.

Now here is were I am confused....1) where do I ground with the black wire

and 2) how do I splice in the red wire to the 12V on ignition switch.

Help please thanks

 
Joined
Jun 21, 2011
Messages
408
Reaction score
70
Location
Mills County, TX
My Car
69 Cougar XR7 460/C6
The easiest thing to do is connect the red tach wire into the jumper you put in the original tach connector.

The screw that holds the IVR (the little silver box) onto the back of the cluster is a great ground - the IVR grounds through that screw.

 

1hotboss

Well-known member
Joined
Jun 12, 2015
Messages
55
Reaction score
1
Location
Canada
My Car
1970 Boss 302
Ok how do you get the green wire to the negative side of the coil? Best way?

 
Joined
Jun 21, 2011
Messages
408
Reaction score
70
Location
Mills County, TX
My Car
69 Cougar XR7 460/C6
Get a small piece of brass tube with a large enough diameter to pass the signal wire through the center. The tube only needs to be a few inches long.

Sharpen one end. I just spin it against a grinding wheel.

Stick a small pick or Phillips screw driver through the center of the tube.

Now poke the pick / screw driver through the rubber grommet that carries the engine harness through the fire wall from inside the engine compartment. Be careful not to hit any other wires, and stay close enough to the center to make sure you go through the hole in the sheet metal. It will take a bit of force as the rubber is probably pretty hard after 45 years.

Once you get it through, remove the pick, leaving the tube in place.

Run the signal wire ( use 20 gauge or larger) through the tube. Run a bunch through as it will make it easier to find on the inside (The hardest part is finding the blessed wire under the dash.)

Then once you have found it, connect it to the Green tach wire.

Under the hood, pull the tube out of the rubber grommet, and slide it down and off the wire.

Connect the wire to your tach signal source.

 

computercarguy

...can't get there from here...
Joined
May 8, 2014
Messages
607
Reaction score
45
Location
Northern NY
Get a small piece of brass tube with a large enough diameter to pass the signal wire through the...
Nice! Hope I can remember that the next time I have to pass a wire through. :thankyouyellow:

 

midlife

Shorts checker
Joined
Jan 24, 2012
Messages
4,082
Reaction score
502
Location
Tucson, AZ
My Car
No Mustangs at the moment.
Ouch. I have a way of fishing wires through the wire cluster within the grommet without going through the rubber. It's kinda tough to do, but I've done it several times on my bench...I wouldn't want to attempt it in the car itself.

When folks ask me to modify the wiring for an aftermarket tach, I rig the wire through the center of the wires, route the wire along the headlight harness to where the engine gauge feed connector is, and terminate the wire with a female bullet plug. I then supply a matching male bullet and wire of sufficient length for the owner to reach the coil.

 

1hotboss

Well-known member
Joined
Jun 12, 2015
Messages
55
Reaction score
1
Location
Canada
My Car
1970 Boss 302
Ok...I got the conversion all setup with the new tach...but no improvement at all...the tach continues to be bouncy what is going on? any suggestions...

 

midlife

Shorts checker
Joined
Jan 24, 2012
Messages
4,082
Reaction score
502
Location
Tucson, AZ
My Car
No Mustangs at the moment.
OK...tell us what you have for an ignition system and any other modifications that may impact the engine running.

 

1hotboss

Well-known member
Joined
Jun 12, 2015
Messages
55
Reaction score
1
Location
Canada
My Car
1970 Boss 302
petronix instead of points and stock coil....nothing else

 

midlife

Shorts checker
Joined
Jan 24, 2012
Messages
4,082
Reaction score
502
Location
Tucson, AZ
My Car
No Mustangs at the moment.
Petronix I or II?

Does your engine run smoothly at idle or does it have an occasional miss? What's the condition of your engine gauge feed harness? It may be that the signal to the coil is erratic. Do you have a good ground from the back of the engine (passenger side head) to the firewall?

 
Last edited by a moderator:
Top