Request for tach hookup clarification

[runamoc]

[FL-Frank]

Second capacitor added to the diagram.

Whats the best way to connect the positive leads of the capacitors to the wires which continue on to the regulator and the doubler?

Also, in order to avoid drilling additional holes in the chassis for ground connections, can I use the same existing hole to connect all 4 ground leads?

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“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[runamoc]

[FL-Frank]

Thanks, it’s a 1964 and has only one factory hole on the driver’s side hood spring bracket (or whatever its called). Like I said, I really don’t want to drill more holes...will stacking the 4 ground connections at this location suffice?

_________________
“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[runamoc]

[FL-Frank]

[FL-Frank]

This morning I fabbed a harness to add the inline voltage regulator and the two capacitors, and connected everything as per my previously attached diagram (the one with the two capacitors).

Although I was very hopeful this would resolve the previous issue of the tach reading too high....Now the tach needle doesn’t move at all

With a multimeter and the engine running...

6.21 v at terminal 15 on the back of the ignition switch leading to the VR through the capacitor

0.0 v at the + inbound post on the doubler

0.0 v at the + outbound post on the doubler

0.0 v at the + post on the back of the tach

I know the doubler and the tach were functioning before I wired in the VR and capacitors, so it would appear that this new issue has something to do with the VR and/or capacitors. I’m wondering if the problem is being caused by the way I connected the 3 wires to VR. Since its lead are so close together, crimping isn’t a viable option. So, I used narrow shrink tube to join each of the VR’s three leads to their respective wires, followed by a larger diameter shrink tube encasing the VR and the wire connections. I gave the wires several good tugs, and nothing budged.

Since it looks like I’ll have to dismantle the whole thing and start from scratch, what is the best way to connect the 3 wires to the VR leads? There is only about 1 mm space between the leads, and they’re very rigid. I didn’t want to risk breaking them by attempting to bend them to separate them further.
_________________
“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[FL-Frank]

I just disconnected my VR and capacitor harness, reconnected the tach as I originally had it, and the tach reads again. Too high, but at least its not dead.

Multimeter readings at idle are now....

6.21 v at terminal 15 on back of ign switch

6.21 v into doubler

12.13 v at + terminal on back of tach

Now what?
_________________
“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[FL-Frank]

I also read the voltage this morning with lights off and on. Although the voltage at the ignition switch dropped to 5.5 v with the headlamps turned on, the doubler was still delivering 12.13 v to the tach with lights on.

On Friday afternoon, I called and updated the folks at NHS on the situation, and they volunteered to send me a tested and known to read accurate 6 v tach that I can install without the doubler. The thought is with both tachs connected simultaneously, if the second or “control” tach reads accurately, then we’ll know something is amiss with the 12 v tach in the dash. If the control tach also reads high, then the problem lies elsewhere...possibly the Pertronix ignition. If it gets to that point, I’ll probably have to swap in a set of conventional points to see if that corrects the high reading issue.
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“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[VeloMikey]

[FL-Frank]

The “control” tach from NHS arrived today...they actually sent two, one 6 v to be connected without the doubler, and one 12 v to be connected with the doubler.

I first hooked up the 6 v control tach, and had it in my lap so I could watch it and the original dash mounted tach while I test drove. The control tach worked perfectly....accurate readings throughout the rpm range regardless if lights were switched on or off. The dash mounted tach still read way high and dropped down when lights were turned on.

Next I hooked up the 12 v control tach through the doubler and test drove again. It worked perfectly...accurate readings throughout the rpm range regardless if lights were on or off.

I called NHS with the results, and their conclusion is

There is nothing wrong with my cars wiring

The doubler appears to be working correctly

The original tach they sent me is faulty

So, I’ll send the original one back to them along with the 12 v control tach so they can swap the movement from the control tach to the original tach.

I really hope this is the final resolution to the problem, even though I’m getting pretty good at removing and installing tachs
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“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[FL-Frank]

The latest edition of the tach from NHS arrived today. 5 minutes to install it and connect the wires....and...finally...it works correctly!

This project certainly tested my patience, but it was worth it in the end!

_________________
“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[c21darrel]

Congrats, that was quite a battle. Now not only can your hear it vroom vroom, you can watch it vroom vroom.
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GhiaBuild
http://www.thesamba.com/vw/forum/viewtopic.php?t=481184
1967 DC build
https://www.thesamba.com/vw/forum/viewtopic.php?t=693583&highlight=67+dc
Stop dead photo links! Post your photos to The Samba Gallery!

[runamoc]

_________________
Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires

[FL-Frank]

Update....

A couple of weeks ago, the tach mysteriously stopped working. After checking all connections, I reported the problem to NHS and they asked me to send it back to them for diagnosis. The following week they contacted me to say the board was toast, and that they were sending me a replacement tach.

The replacement arrived and When I installed it, same issues as I originally had with inaccurate readings. NHS worked with me on the phone to try to adjust the tach to read correctly, however, we could only get it fairly close and the needle fluttered quite a bit.

Meanwhile, I saw a link to Pertronix Tech Support Bulletin on another post that recommends using an inline resistor rather than the inline diode.

http://support.pertronix.com/kb/faq.php?id=34

I replaced the diode with the resistor today, and voila! The tach now reads accurately at idle and up and down the rpm range. The needle no longer flutters, and the sweep is silky smooth.
_________________
“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[Sofia74]

This post has been very helpful but I have a NHS specific question. I haven't heard back from them yet so I thought I'd throw it out here.

My tach has three tabs - labeled green, black and red. And I know I need power, coil and ground.

Am I right in thinking:

green - coil
black - power
red - ground

I see online that it looks like different companies use different color coding.

Wondering if anyone has any experience with NHS color coding. Still bugging them as well...

[VeloMikey]

Red is positive or hot
Black is ground
Green is negative side of the coil
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'58 Ghia 2387cc with a Berg / Folts 5 Speed

Ghia Build Thread https://www.thesamba.com/vw/forum/viewtopic.php?t=768748

[Sofia74]

Thanks. Sure wish I understood why red is power sometimes and black is power sometimes and maybe they could have used brown for ground...?

But thanks. Exactly what I needed.

[VeloMikey]