Tach died today

quote:

because I have voltage to the plug.

Mike,

Grounding is a common weak link in our electrical systems. Open or poor ground can result in some weird behavior.

When you get voltage at the plug, where are you getting the ground for your meter? Should be in the plug. In any case, search out, disconnect and clean the headlight ground wires.

Tach also needs a ground, and most of the gauges daisy-chain the ground from one to the other.

You have this schematic from PanteraPlace?

Larry

Thanks for posting that diagram.

My car has the stock fuse panel behind the kick panek, and then also has what I think is a custom panel on the opposite side of the front "firewall" that uses modern fuses and has modern relays.

I've been reading and I think this is done to relieve the ignition switch of all the high amp, high draw stuff that normally would be controlled directly by the ignition switch.

I was able to fix half of my issues by just cleaning the fuses and fuse panel behind the kick panel. I'm hoping maybe the tach issue is just another corroded or blown fuse (although if the fuse is blown, I may have a "fuse blowing" problem that I'll have to troubleshoot.

Once, I killed a tach by accidentally hooking the polarity of the wires wrong, but in this case I've touched nothing accept poking around with my DMM and fuse inspecting.

I hope it's something simple.

Incase it is not something simple...I found a posting with a link to this
http://www.dinoplex.org/tachoconversion/

quote:

and then also has what I think is a custom panel on the opposite side of the front "firewall" that uses modern fuses and has modern relays.

Knowing Roger and the time frame of the car, I am pretty sure the front trunk panel is one of the kits sold by Rick Mosley, which you have correctly noted as being designed to remove high amperage from the ignition switch.

Larry

The tach is sensitive to a really good ground or more correctly lack of one. The ground wire can come loose from the tach case.

That wire is also grounded to the stud that is attached (welded)to the inside of the front bulkhead under the dash. About directly above the clutch pedal.

That one is really tough to get at unless you pull out the dash OR remove the speedometer. If you have a single pod dash, I would stay away from attempting that. A dual pod is POSSIBLE for human hands to get back there, but a single pod, well...it just ain't!

Everyone of these ground studs that I see has very heavy and obvious surface corrosion on it from "flash rust" which is what happens to steel based metals that are exposed to just the oxygen and the moisture normally in the atmosphere.

As a result, that ground just normally will "go away".

The blue wire in the harness, the one that looks like a strange circus color bright blue, is the sensor or if you will, trigger wire from the ignition. It just runs to the white plastic tach harness plug behind the gauge BUT the tach connection is just on a spade connector with the origianl Italian style "quick connect" jumper female plug.

They often wiggle themselves loose. I have even seen them break off of their mounting to the tach case.

There is also a wire in that mini-harness (pink?) that is the 12v power from the ignition switch.

Be advised that when these Pantera ignition switches "go", they sometimes are selective internally as to if they are going to supply current to every wire that is connected to them?

So besides the possibility that the tach itself actually died on you, which is probably the remotest possibility, you have to eliminate the other connections I just mentioned as the culprits.

Now there is also something else that you didn't mention, that could be a player in this as well. An MSD ignition.

If you should be so unfortunate to have one installed in the car, then it undoubtedly has an MSD tach adapter piggybacked along with it, and maybe an exorcist can help you with that?

They are subject to all kinds of connection issues. Whether it be from their own add on harnesses or loose or maybe better stated as "not tight enough" connections to this unilateral decision that they seem to make that lets screw with this guy now.

I've seen racers change them out three and four times a season. The brain just goes away. Where to? I don't know. Maybe to ACCELL?

That actually is quite simple to remedy though. You rip the entire MSD entourage out and install a Pantera Electronics Ignition.

Enlightenment sometimes comes hard? It surely does for me.

Thanks for the reply Doug,

I'm decent at wiring and troubleshooting, but this car will test me abilities I think.

I'll check those things you mentioned, as you (and I) suspect, I doubt the tach itself just died out of the blue, it's a wiring or bad ground issue I'm sure.

I've already spent hours cleaning up the original fuse array, popped every fuse, cleaned, greased with dialectric grease, cleaned the whole fuse panel, and put it all back. I actually fixed the "no blinkers" problem, and the "no taillights" problem, the passenger headlight still has me baffled.

The headlights were modified using (I think) old Camaro low beam or back-up lights. Small, rectangle, and the headlight housings adjusted so they only opened up a couple inches, which looks way cooler. This however left the car with only low beams (no big deal, I don't plan on night driving very much anyways" but I DO need BOTH of those lights to work, one won't cut it.
I get voltage to the plug, checked and the light is good, I think it might be a bad ground issue. I'll figure it out soon enough.

Thanks for the tips.

I inquired and apparently the tach is a little temperamental.

I expect it'll probably work, and not work, until I get to going through everything myself.

Start looking for another tach.

These things have two things that go wrong with them internally.

1) the needle is on a "jewel movement". It wears out then the thing is junk 2) there is a printed card in the tach. It cannot be replaced. If it fails, the tach is for display purposes only.

Your's is showing the symtoms. Look for a spare tach now is what I would do?

Mike, if you open up the tach case by VERY carefully prying up the plated-brass bezel, there is little inside beyond a matchbox-sized printed circuit board and the needle mechanism. On the board are 1% glass fuses which sometimes inexplicably crack, opening the circuit. It's a rather simple tach that most shops or even a good home-technician can repair. Palo Alto Speedometer does this sort of thing by mail.

The relay system in your car was designed and built by Roger who worked for PG&E for 30 years. I have the same rig from him in our car. The functions are similar but not identical to Rick Moseley's system. Ask Roger for details.

Not so fast Doug, it may not be junk yet. Perhaps a decade ago, I acquired a non-working Pantera tach. I believe it was SO Bill who sent me instructions to repair it. It involved removing a component (transistor-like)on the circuit board. Unfortunately, that info with pics was stored a hard drive that crashed perhaps four years ago. Although, I believe that in good form, I had forwarded the info on to others (Mr Woods - Were you among them?) The piece removed did not seem to compromise the unit and I still use that tach to this day. SO Bill - Can you help? He may only follow the other Forum.

The tach schematic is on pantera place webpage under electrical diagrams.

Well, Snow White definitely has a Gremlin. I'm going to name him jorge.

Last night, Jorge decided to screw with the tachometer, which still is not working.

I took a couple drives today, only to notice now all the original gauges (amps, fuel, oil pressure) have also been shut off by Jorge.

Now, I know Snow White was already kind of a wild girl, living with all those dwarfs, and I went into this relationship knowing this about her, and fully accept and love her, but GREMLINS?? No Way!! Did you see tha movie? crazy little things, feed'em after midnight and they take over the town, NO WAY.

I'm officially on the hunt for Jorge the Gremlin!

Upon starting the car to come home a few mintues ago, the gauges all sprang to life for 10 seconds, and then died again.

According to the kick panel fuse list, the gauges and maybe the tach are controlled by fuse #12. SO, I just popped #12 out, noticed the tabs had very little tensions holding the fuse in place (fuse spun VERY easily) so I bent the tabs, replaced the fuse which fit much more tightly now.

I just turned the ignition to "on" and the gauges all turned on, but i didn't start or drive the car, I'm done for today. So HOPEFULLY this was just a loose fuse issue, and then I'm back to fixing the last two things, (tach and passenger side headlight), and I've got my eyes peeled and my 1911 ready for Jorge the Gremlin though, he's got to go!

The dwarfs are gone now, it's just me and Snow White, getting to know each other, starting this beautiful new relationship. I'm taking it slow, I'm a gentleman, it'll be 2 weeks before I get her on a lift and I get my first "upskirt views", soon we'll go "all the way" but I'm gonna wait til she's ready, not push anything. She'll give it up when she's ready. lol

quote:

Originally posted by JTpantera:
Not so fast Doug, it may not be junk yet. Perhaps a decade ago, I acquired a non-working Pantera tach. I believe it was SO Bill who sent me instructions to repair it. It involved removing a component (transistor-like)on the circuit board. Unfortunately, that info with pics was stored a hard drive that crashed perhaps four years ago. Although, I believe that in good form, I had forwarded the info on to others (Mr Woods - Were you among them?) The piece removed did not seem to compromise the unit and I still use that tach to this day. SO Bill - Can you help? He may only follow the other Forum.

The guy I had work on both of my tachs told me that if the board goes out it is not repairable. Same with the jewel movement.

Since I am not the "Doctor" here, I only go by what "he" tells me.

I asked Roger and he said the tach was temperamental, and he mentioned the placement of the MSD ignition in the car and suggested I start there, which is what I plan to do.

The whole electrical system I think is plagued with ground issues. I'll be going through and checking every wire on the car eventually.

Another VERY TOUCHY subject in these cars is MSD ignitions.
So many, including myself have had ridiculous problems with them ESPECIALLY in relation to the Tach.
Good luck with that and I'll just leave it at that.

Last night I went back through the fuse array, cleaned and greased each fuse again and cleaned the board. Low and behold, I got my gauges back working!

The tach actually decided to make an appearance for a few minutes, but then konked out again. I suspect Jorge is messing around with the ground wire to the tach.

He's done a number on my passenger headlight, stil haven't figured that out, but I don't plan on driving at night too much anyways.

Weather report has some MAJOR storms coming in the next day or 2 (like 6-8 inches of rainina one day) so there may be some action soon.

I spoil my girlfriend so much, I bought her a generator so she's not without power because in her small town, the power ALWAYS goes out in big storms, sometimes for days.

It'll give me a chance to spend time with Snow White though, and see if I can't find that nasty little gremlin, Jorge.

Been researching and trying to decide what oil to run in my precious new ZF gearbox. Something good will be filling that gearbox up, and I have Brad Penn Hot Rod high zinc formula 15-50 motor oil going into the engine.

Good times. My journey continues.

quote:

Originally posted by forestg:
The tach schematic is on pantera place webpage under electrical diagrams.

I am not having luck in finding.
if some one could post a link I would appreciate

also hoping for more info on the "fix" JTpantera mentioned

I was lent a 1972 Pantera shop manual that may contain that information.

Ill see if I can't make a copy

I don't find that internal tach diagram either.

Read this.

http://www.msdignition.com/for...owthread.php?t=19975

This is very typical of the MSD's in Panteras. It centers around the lack of function to the Pantera Tach.

I could go on and on about how many people have had this issue in this car.



SIMPLIFY YOUR LIFE. Put this in and forget about the problems. Your tach will no longer be finicky.

This ignition is desined and built for the Pantera. It is not some universal kit made for Camaros, Mustangs, Hemi Taxicabs and drag racers looking for contingency money from MSD.

It may in fact be the ONLY ignition that fires AND CLEANS fouled spark plugs. I tend to think that it is. The MSD isn't for sure.

It wires easily to the Pantera harness WITH NO TEMPERMENTAL ADAPTERS.

Remember, I told you so. When you get tired of bumping your head in the dark, this will end your problems.

http://pantera-electronics.com/eis.htm

I will try to attach tach diagram. Not sure as I have never attached a photo before.

I know "New York" Doug absolutely despises MSD and from his experiences, has good cause for feeling that way. BUT, lots of us run MSD ignition without any problems. Mine has been flawless for over 5 years now.
You have a wiring issue.

Doug M

quote:

Originally posted by Doug M:
I know "New York" Doug absolutely despises MSD and from his experiences, has good cause for feeling that way. BUT, lots of us run MSD ignition without any problems. Mine has been flawless for over 5 years now.
You have a wiring issue.

Doug M

I do not hate MSD. I am past that. I am very happy for anyone who has gotten it to work successfully in their Pantera. Kudos to you.

They were recently purchsed by Accell.

Thanks for posting the tach diagram. As a follow up to my earlier post, removal of the mystery part SO Bill references repaired my tach's functionality.

I do have a manual, but I'd thought I'd ask here first.

IF, I need to get the tach out for repair/inspection, do I need to remove the dash board, or can I just reach up under there and unscrew something that allows it to come out?

Dashboard removal not required. Takes a bit of contortioning but you can get it out from under the dash.

The dual pod you can get the thumb screws off. The single pod is another story. On the single pod they must have had a special tool to get the last nut on the stud.

On the single pod you have to take the speedometer out so that you can reach the inner thumb screw on the tach.

Then you need a special tool to get the inner thumb screw back on the speedometer.

It's a universal size to grip the nut, then you squeeze a trigger on the tool to rotate the nut.

You CAN NOT get your hand in there.


IF you have the dual pod, there is a steel cage that clamps the speedo in.

DO NOT take that out from behind the dash. Leave it in there.


The single pod will also likely flatten the defroster duct going to the corner. Be careful you do not tear it or knock it off of the nipple.

Or, once you get them out, experiment with tape around the outside of the tach and speedo cans and "press" fit them into the pods. Mine have been installed that way for 20+ years. They don't rattle or move and I can get them in or out in minutes.