Tach is reading twice what it should.

[chargd72]

You could have a grounding issue.  If this is paint buildup through restoration of parts/body.  The cluster is grounded to the frame by the attaching screws. Back a few in and out many times.  The frame is grounded to the body by the bolts on the side behind the kick panels, steering column mount area, and bolts underneath the windshield.  Back a bolt out on one side by the kick panels and ensure it has a good clean ground.

Simple checks and may not be the issue. 

I have power to the sidelights now.  Grounding was the issue.  They are nice and bright.  One more issue down.

Sorry to sidetrack you but where was the grounding issue for you side markers?  I'm having a similar issue.

Ok, first thing make sure of there are bulbs in the sockets, urgh!  They were new and for some stupid reason, I thought the bulbs came with the new sidelights.  Ok, I can make a stupid mistake.  But, once the sidelights were attached, there is a screw on type of nut that holds the light on in it's hole that wasn't getting ground through the new paint.  The fender had been completely dip stripped of paint, so it wasn't rust.  But, the new primer/paint on it was keeping the circuit from grounding which is why it still wouldn't work even after adding the new light bulbs.  Once that was scratched through, the circuit was complete and bingo, lights.  I was thinking earlier that maybe the fender wasn't grounded to the rest of the car becasue of the paint buildup,  but, that wasn't the case after all.  My newly painted engine block was proving that ground is important as the bolt on the negative cable to the battery was over painted and not getting contact.  No engine start.  Solved with the paint scrapped off.

[fy469rtse]

There's a replacement voltage reducer that's digital to replace the old analog type,
I used the board from charger speciality's that has the voltage reduction incorporated in board , like you had issues even with this not working , earth bad , took a fair few goes at the earth
Main one , center top is the culprit

[warpspeed]

Going into dash cluster today to check ground.  Maybe that is the problem all the way around.  We'll see.  Wish me luck.

[john108]

Take this with a grain of salt, but I seem to remember, a while back, an issue with tach reading high.
I believe it was related to an electronic module.  It may have been MSD-6AL and that it has multiple sparks.  There was some reference to the tach being sent to someone to be re-calibrated for the multiple spark module.

[A383Wing]

he has Mopar Electronic ignition, not MSD

[warpspeed]

Ok, A383, I have pulled the dash, yuck, what a pia.  But, I can not find anything wrong at the moment.  Will check the voltage on the VR output first thing.  But, here is the next important question.  You say to check for ground on the tachy.  I have checked the ground on the outside case. There isn't much else on the world wide wide, that I have found, to show how this thing is suppose to work.  There is ground on the back case, no problem. And the imput line was fine too.  Where does the ground come into effect on this if it isn't the outside case?  Otherwise I am stumped.

[warpspeed]

Well, I know one thing for sure,  the Radio Shack VR is bad.  It isn't regulating voltage.  I will replace it tomorrow and try to re-insert the dash tomorrow.  That is the basically the last thing I need to do before getting the car on the road.  The parking lights work now (why do engineers connect aluminum and steel together and expect no corrosion to occur and insulate voltage from ground?).  If the VR works then the temperature/oil pressure/gas gauge should work properly, RIGHT?

[A383Wing]

ground for tach is case mounted to dash, then dash mounted to frame....I still say you have a resistor issue inside the tach.....

again, find another tach or digital timing light and see if it reads the same or different from your in dash tach

and yes, if you get the instrument VR working correctly, all 3 of those gauges should work if the internals are in good shape...again, cluster needs to be grounded before turning key on...otherwise you let the magic smoke out of the gauges

[warpspeed]

Then the only thing I can do is take the tach apart.  I will fix the VR tomorrow.  The dash is definitely grounded.  Thanks, I will keep you posted.

[warpspeed]

It has been a while since I checked in.  Been very busy lately and haven't gotten around to finishing up the re-installation of the dash.  The VR was bad.  Shorted to 12+ volts.  Put the dash back in yesterday and started up the car.  The dash gauges seem to be all working.  The oil pressure went to 25 # and didn't go any further.  Didn't give the engine time to warm up, but the temperature gauge didn't peg out.  And I know there is no gas in the tank to register.  So, I think that is working.

BUT, the tach is still too high.  Not going to worry about it now.  It runs and there isn't anything I can do.  Worry about it later after I get the car on the road.  But, I did take the tach apart and reinstalled it too.  Didn't see anything wrong with it though.