Quad Gauges not Working ..... STILL!! ... NOW WORKING!!

[chaps70rt]

a) 12V at the IVR  (Multi-Meter)
b)  5V out of the IVR
c)  all gauges tested for function with three AA batteries
d)  Check that the threaded posts on the back of the gauges are not touching the chassis of the cluster (grounding)
    Each gauge should have a non-metal gasket between the nut and chassis of gauges.  I even added some heat shrink to
    each post.  Confirmed.
 e)  Check the 4-post jumper from the IVR to each gauge for internal shorts. No Issue ..... 4.9V at the post.

HOW DO I TEST THE READINGS COMING OFF THE DASH HARNESS THAT CONNECTS DIRECTLY TO EACH GAUGE????

Failing that ..... I am out of options.    Will need to check all the other entries on this forum for other ideas.

AFTER 17 years of rebuilding this car, it is the last mechanical/electrical issue that won't resolve.   

Can't drive without OIL, TEMP, FUEL!!!!

[Bullitt-]

  Here is someone that was having a similar issue, resolution in his next post https://forum.e-bodies.org/index.php?msg=101908

  You never mentioned having the cluster body grounded.

  A simple check for the harness would be a test light or multimeter  connected to power on one side & to each of the wires from the sending units should show a completed circuit, glowing light or meter reading. If you get nothing ground the wires at the source, to eliminate the sending units, & see if you get anything. 

[chaps70rt]

Just to confirm .... I added a few ground wires from the back of the chassis and bundled them together with a spade connector and attached it to a bolt on the metal dash frame.

This afternoon I also swapped out the dash with an unmolested original 1970 rallye dash.  Same result.. three gauges don't work still, so that eliminates an issue with the gauges or mounting of the gauges.   Here is a picture of the back of my gauge cluster (with voltage gauge that works great) and noise suppressor removed. IVR is from RT Engineering (solid state).

Any other ideas of what I can check??

Gary

[chaps70rt]

Here is someone that was having a similar issue, resolution in his next post https://forum.e-bodies.org/index.php?msg=101908

  You never mentioned having the cluster body grounded.

  A simple check for the harness would be a test light or multimeter  connected to power on one side & to each of the wires from the sending units should show a completed circuit, glowing light or meter reading. If you get nothing ground the wires at the source, to eliminate the sending units, & see if you get anything. 

Here is someone that was having a similar issue, resolution in his next post https://forum.e-bodies.org/index.php?msg=101908

  You never mentioned having the cluster body grounded.

  A simple check for the harness would be a test light or multimeter  connected to power on one side & to each of the wires from the sending units should show a completed circuit, glowing light or meter reading. If you get nothing ground the wires at the source, to eliminate the sending units, & see if you get anything. 

Thx Bullitt .... I will try this test and report back.  Will try to do it this afternoon.....  Gary!!

[Bullitt-]

@chaps70rt Has your ammeter been converted to a volt meter?
  If not in my mind grounding it would be a dead short!

[chaps70rt]

Yes .... I eliminated the ammeter in favour of a Voltmeter (SunPro).  Red and black wires were soldered together and double wrapped with rubber shrink wrap.
New voltmeter works great.

[chaps70rt]

Just checked for continuity from the blue wire at the tank/sending unit all the way to the 90 degree connector that plugs into the gauge.   I have clean contact and continuity.

NOTE:  I pushed the probe into the connector which provided continuity, but never thought that there was a weak connection inside the crimp connector.

[dodj]

I'm thinking your dash frame is not grounded... run a jumper just to make sure it is.

[MoparCarGuy]

I usually hesitate to offer electrical troubleshooting assistance as these threads can become a serious chore for technical writing. That being said, you sound like you have a decent skillset with checking your wiring/connections so I will give it a shot.
Below is your picture rotated for visual troubleshooting of the wiring and a wiring diagram of the Rallye Instrument Cluster. The RTE IVR you installed looks correct for wiring with 5V power output grouped and going to each gauge (TEMP, FUEL, OIL). What we are not seeing is the connections you are making to provide the 12VDC to the IVR input or the sending unit GND wires you are connecting for each gauge. It sounds like you supplied the 12VDC to the IVR since your Voltmeter worked and you measured the 5VDC IVR output and got approximately 5VDC. So far, so good.
The only GND in the picture is the VOLT gauge ground to the cluster body which goes out to the dash frame/body GND. *That GND needs to be checked.

Let's start with this much and see if a good cluster to body GND solves your issue. If not, begin with the FUEL gauge since you have worked that part a bit already.

FUEL GAUGE: You have already checked the BLUE wire from the gauge all the way to the fuel tank sending unit and it had continuity. It should have between 10 and 73Ω depending on fuel level.

With no 12VDC power and using your multimeter on Volts DC, check the FUEL (BLUE) wire at the unplugged 90° FUEL gauge connector to the dash frame. You should also see between 10 and 73Ω. This will check to make sure the dash frame to body GND is good.
Essentially, you are using the multimeter's power to check a complete circuit from the dash frame out the BLUE wire to the fuel sending unit's GND. If the tank/sending unit GND is not there, your gauge has no GND reference to complete the circuit.

Let us know what results you get to determine where to go next.

[chaps70rt]

Okay guys ..... here is my latest update.

Bullitt .... thanks for talking over the phone.   That really helped to eliminate the obvious and zero in on the issue.

Turns out I had two issues.   

a) During testing of the IVR, I inadvertently shorted the 12V with the 5V tab.  Ordered a new IVR from RT Specialties .... all good now.

b) Fuel Gauge - Crimp connector at the sending unit behind the tank ...... wires into a join and crimped.   Removed and soldered.   Gauge came to life!!

c) All gauges now working, except the Oil Pressure.    Off to resolve this today.   Bought another new Sensor from Napa.

GETTING CLOSER!!!

THANKS AGAIN FOR ALL THE ADVISE .... everyone had some interesting things to check or confirm.   Learned a ton about auto wiring.

[chaps70rt]

Yesterday's Discovery ....

Oil pressure not working.  I had installed a new Napa oil pressure sensor years ago, never worked. 
My Mopar friend Mike Terzis brought over a used working sensor and the gauge came to life!!   Thanks Mike!!!

Now all of the quad (FOTA) gauges finally work.  Well actually it is a FOTV gauge now.   What a great feeling to have it all working again!!

Thanks to all those that helped along the way to debug my gauge issues and other electronic issues!!!   You guys are the best. 

Gary