MSD Installion and Tach woes

[red-beard]

Nothing is ever as easy as it is made out to be.

1st, let me just say, before anyone asks, yes, I installed the Tach adpater.

ON the 914/6 Factory unit, the installation is different than the 911. The wires leading to the C/D unit are different colors. And of course the system doesn't match a regular 914/4 either. The colors of the wires are: Black with a Red stripe, Black with 2 red stripes and Black. The Black with red stripe comes from the ignition. I think the one with two stripes is intended for the tach. The black wire definitely goes to the points.

After getting everything straight, I try starting the car before getting into the tach adapter. Car starts, cool! Seems to run pretty good, but I'll give a run down of the differences later. Tach? What Tach. Dead. Nothing. Nada.

Ok, install the tach adapter (Wire it in, but not mounted). Start the car. Tach seems to be working. Hit the Gas, engine speeds up, tach goes to 0. Uhhh. What going on? Too make a long story short, above about 1000 RPM (My Sears $29 tach/dwell works fine with the msd, whether hooked up the the MSD tach output, or connected directly to the coil!) the Tach dies. I thought it might be because it wasn't mounted. Nope, made no difference.

If I hook my internal tach directly to the coil, 914 style, the tach shows the MSD spark speed (3x up to about 1500, 2x up to about 3000, then 1x above 3000). This how I'm presently setup, as I'm more concerned about the upper end than the lower end, except for tuning, and I can use the Sears guy for that right now.

What gives?

Bob, what did your mechanic do to make the tach work in your 914/6 with the MAD unit?

Differences: Well, I'm still getting a single pop when I change gears under heavy accelleration. But the main difference is in situations at very low RPMs where the car used to stall, not anymore. Under heavy accelleration, the car is very smooth. Of course, I really tuned the carbs yesterday, so that may be part of the good operation. But the stalling issue is a definite improvement. I'm sure the popping is either from the under jetted condition or one of the accellerator pump sprays is still not right (One was dribbling, due to a defective seal).

The Humbling continues.

Maybe I should rename "Vee-one" to "Humble"...

[Brad Roberts]

Did you cut the wires on the side of the MSD under the little cover ??

The ones that tell the MSD whether or not its a 4-6-8 ??

The tach adapter has been useless for me.

I send the tachs off and have them gone through by Palo Alto Speedo (cause thats where I am) They convert the tach to the signal that the MSD is looking for square wave or some such.. I just pay them.

We run the MSD's on our cars.

B

[red-beard]

This is the 6200, and it doesn't have the rev limiter (I run a rev limiting rotor). So no wires on the side.

What does Palo Alta Charge for a tach upgrade? It seems my Sears dwell/tach can sort out the signals, even from the raw multiple spark coil input signal.

I guess I'll give them a call tomorrow. I'll send them a couple of speedos too, so they read right with my mish mash of tires and wheels.

James

[Brad Roberts]

Interesting.

The ONLY reason I run the MSD's is for the soft touch rev control feature.

They dont do anything above 3k RPM so the only benefit to me is the rev control.

I dont recall what they charge.. easy phone call. Call them and tell them what you have and what you need. I would recall if it was outrageously priced.

Hollywood Speedo is closer to you.

B

[red-beard]

True. I'll check them out too.

James

[J P Stein]

I use the MSD 6AL and high vibration coil. With the plugs gapped at .045 and Magnecore wires (To keep the spark going where I want it), it has made a world of difference below 3000 rmps.(where I was having problems)

As for hook up, I just followed the directions (gasp!) for use with a Pertronics unit. No tach adaptor.

The onliest thing that pi$$ed me off was that the chip for the rev
limit I wanted didn't come with the unit. To get what I wanted, it was 35 bucks .....which gave me the 7300 chip and four other chips that I didn't want. I gots rev limit chips comming out of my ears.....Anybody that has the need, lemmeno.

[6 Shooter]

Hello Red-Beard,
In case you needed the number for North Hollywood Speedo, here it is: (818) 761-5136; 761-4857fax
e-mail: info@nhspeedometer.com
www.nhspeedometer.com
HTH