Finally looking at those gauge issues on the Barracuda

[1969383S]

Decided to pull out my instrument cluster last week and research issues with the oil pressure and temp gauges. I had started this thread IVR pulse at 4 volts gauges read low About 2 years ago.

After getting the cluster set up for bench testing here is what I found. At 23 ohms to ground on the sender terminal of the gas gauge it will pull to half (good)! Move the test lead to the temp sender and it just pulls up to the first line. Same for the oil pressure. IVR voltage reads the same on each (I -5VDC) terminal for all three as measured with an analog meter. Roughly seen as about 4.5 volt swings. Seems the only good gauge is the gas gauge. I even pulled the gauges and tested to confirm no voltage drop on the board.

Opened up the oil gauge and the NiChrome wrap is black toast. The bi-metal strip is still pretty straight. Same for the temp gauge. At this point I thinking what the options are, replace with original used pieces, have them rebuilt or swap them all and go with the electronic IVR. Opened up the gas gauge and it looked much better, insulation was not black but showed some signs of heat. Guess the car was always run more empty than full, oil pressure at cruise is 85psi and the car always ran 200-230 back in the day with an inadequate cooling system. That would seem to make sense that the oil and temp gauges led a hard life (saw more voltage). I had mechanical gauges back then as well and did not pay much attention to the original ones as they were always close to being pegged and accuracy was not trusted. Mulling over and knowing the gas gauge and IVR will eventually fail I decided to replace them all with the available upgrade kit. Pricy it is but at least YearOne (one of the retailers) is about 20 miles away and I can save shipping costs! Only wanted to do this once!!

Those of you that have done the upgrade can I assume the noise Capacitor installed by the factory on the ignition feed terminal to the gas gauge can be omitted?

 

[1969383S]

Installed the new gauges and Solid state IVR in the cluster this evening. The amp gauge is a bit tricky due to a tight fit. I drilled the holes to 19/64 as the directions called for and still was not happy. Ended up cutting a couple small sleeves of hard plastic tube to insulate the holes the gauge passes trough. Even then the gauge needed a little tweaking cause a small nub on the bottom of the needle was contacting the center stub of the cluster housing. Checked it all for shorts to housing and was clear. Ran a bench test at 23 ohms to ground on each and all 3 swept to mid point and "quickly". I think the $400 was well spent, replacing the oil and temp gauge would likely cost anywhere from $50-200 and would still have the mechanical IVR that would surely fail at some point. And yes the instructions say to remove and toss the noise capacitor (filter).

 

[1969383S]

Pics of install for anyone interested.

 

[Darthomas]

If you value noise free weak signals on the radio, the capacitor should be retained.
Yes, your mechanical 5 volt regulator ran a bit too high on duty cycle, could been fixed with opening the rectangular little package and slightly bending the contact arm.
Even with a new solid state voltage regulator, the cap is a good idea for proper engineering.
I switched out to solid state inst reg in 1985 Had to make my own noise suppression and make the gauges more stable.

 

[RedFish]

That solid state regulator wont generate a noise, so no noise suppression is req'd. It has nothing to do with instrument stability.
Otherwise biting my tongue. I hope they work good for you for many years to come.

 

[1969383S]

When I do listen to music it usually with the iPhone and blue tooth BOSE box not the AM radio, so not to worried about that.

I think the original IVR in the fuel gauge is still working fine, The nichrome on it looks nice and white and the voltage looks good. I will not open it in case someone is looking for a working original later on.

This is what happens when the originals are subjected to high thermal load for long periods of time ie. 80+ PSI oil pressure. Original oil and temp gauges look like this.

 

[1969383S]

That solid state regulator wont generate a noise, so no noise suppression is req'd. It has nothing to do with instrument stability.
Otherwise biting my tongue. I hope they work good for you for many years to come.

Don't bite your tongue, that hurts!! We are all civilized here, speak your mind.

If you are thinking about that ignition feed, it has been removed from the barrel and will be plugged onto this extension to feed the IVR.

 

[4spdragtop]

Looks great Gerald! I cringe at the thoughts of doing this with the 69.
Link to the upgrade?

 

[1969383S]

Chargerspecialties.com

Will see how long they last. Tried to make sure I could always go back to originals by not hacking the board or harness. Plug and play.

 

[Darthomas]

The orig regulator is always on-off, on-off, and each time the contacts open, a tick can be heard in weak AM AND FM signals.
The capacitor keeps that pulse from being radiated throughout the vehicle wiring.
It also is the most efficient, only drawing power 5/13s of the time, letting the thermal hot wire gauges act as if there were a HUGE capacitor to damp their action.
A solid state regulator normally gives you your solid regulated voltage and turns the extra voltage into heat, and this does use a little more power than the original design.
I did this in something like 1983 to get rid of noise on the FM.

 

[1969383S]

Steve,

Install Docs if you are interested. A bit vague but if you know these cars and the wiring it's pretty self explanatory.

They should have include some insulating bushings like I made, with the kit however.

 

[1969383S]

Back together and all checks out. Wondered about the red dot on the ammeter post that is on the side the black hooks to on the stock gauge. Hooked them backwards from stock on a Hunch and sure enough they reversed them with the new gauge. Glad I checked that before the cluster was all back in. There was no note in the destructions to warn you they are backwards!

 

[RedFish]

For the amp gauge wiring, Only red was marked RED on your OEM (scribed into the circuit board ). They did mark that new gauge for you. You might notice the 5 volt post of your fuel gauge has moved also. The original post is gone now so you couldn't hook that one up wrong. Cheers

 

[1969383S]

For the amp gauge wiring, Only red was marked RED on your OEM (scribed into the circuit board ). They did mark that new gauge for you. You might notice the 5 volt post of your fuel gauge has moved also. The original post is gone now so you couldn't hook that one up wrong. Cheers

Guess that's what I was saying. They reversed the connections on the ammeter. Just would have been nice to see it proclaimed in the instructions. I saw the red dot and made the assumption! Won this time!