gauge frustration

-
66Glassback

66Glassback

Active Member
Joined
Sep 23, 2023
Messages
42
Reaction score
42
Location
Rochester, NY
I have a 1966 Barracuda. The voltage limiter in the temp gauge stopped working and burnt out some of my gauges. I purchased a used instrument cluster which the voltage limiter in the temp gauge also didn’t work. However, I took 3 AA batteries taped them together to get 5 volts and tested all the gauges. They all swept properly. I purchased an external limiter and installed on the outside of the cluster. I took the 12 volt feed to the temp gauge and spliced a terminal on the wire so it would plug into the voltage limiter. I then plugged the voltage limiter into the other terminal on the temp gauge. My temp gauge stays on cold. I test the senor wire for voltage and I am getting the proper swing about 0 to 6 volts on and off so I know the limiter is working properly. I ground the sensor wire and the gauge sweeps properly. I am on my 3rd sensor and cannot figure out why it is not working. Any help would be greatly appreciated.
 
Shouldn't the gauge with the ivr have 3 studs? 12v in, 5v out (to the other gauges), and one to the sender. Not sure about the 66's, but the ivr is in the fuel gauge on the early 70's rally gauges. Sorry if I am poking my nose in where it doesn't belong.
 
Iirc you have to properly disable the limiter inside the gauge.

Go to rt-eng.com they have a procedure for the 67 up fuel gauge with the IVR inside.

Should be similar
 
Last edited:
Yes, in 67-69, at least, the IVR was in the fuel gauge, not the temp gauge. Don't have any experience with 66 though.
 
Chinese senders are crap. I have had multiple bad ones. Check with an ohm meter before you install it and after you install it. Should read about 70-80 ohms cold.
 
66Glassback said:
I have a 1966 Barracuda. The voltage limiter in the temp gauge stopped working and burnt out some of my gauges. I purchased a used instrument cluster which the voltage limiter in the temp gauge also didn’t work. However, I took 3 AA batteries taped them together to get 5 volts and tested all the gauges. They all swept properly. I purchased an external limiter and installed on the outside of the cluster. I took the 12 volt feed to the temp gauge and spliced a terminal on the wire so it would plug into the voltage limiter. I then plugged the voltage limiter into the other terminal on the temp gauge. My temp gauge stays on cold. I test the senor wire for voltage and I am getting the proper swing about 0 to 6 volts on and off so I know the limiter is working properly. I ground the sensor wire and the gauge sweeps properly. I am on my 3rd sensor and cannot figure out why it is not working. Any help would be greatly appreciated.
Click to expand...
You are confused. The only limiter is in the FUEL gauge which has 3 terminals. This internal limiter is used on the early A's and on the later ones with a Ralleye cluster.

1 terminal is 12V from the ignition switch, TO the limiter, the limiter outputs 5V nominal (pulsating) to the fuel gauge internally, and also feeds the 5V to another of the 3 terminals. The last terminal is of course for the fuel sender

The terminal with the limiter 5V output connects to a PC board trace which feeds the limiter output to the temp gauge and oil gauge, if equipped.

Here is an article on conversion. you MUST somehow isolate the old limiter to avoid problems.

RTE Gauge Faq - rte

www.rt-eng.com www.rt-eng.com

If you have a good ohmeter, you can "set" a rheostat to the proper gauge test resistances and find out if they work correctly and accurately, or order some resistors of the proper values

www.forabodiesonly.com

checking gauge function

How do you check gauge function.. I have a '68 Charger I'm taking the dash out to redo the faces, and need to see if the gauges work. Right now none of them register anything.
www.forabodiesonly.com www.forabodiesonly.com
 
According to the 1966 service manual, the voltage limiter (a.k.a. IVR) is in the fuel gauge.

Barracuda cluster:

66B.jpg



Valiant cluster:

66V.jpg



In both cases, the wire that should be feeding 12V+ to your IVR is a black 18ga wire. The wire coming out of the IVR to feed 5V+ to the oil gauge is 18ga brown (Barracuda only). I'm guessing there's a trace to feed the temp gauge?

I highly recommend getting the Real Time Engineering solid-state IVR as linked by @Dana67Dart. The home-grown 7805-based versions are much less expensive, but there are drawbacks which are listed on RTE's website. I've lived that nightmare. I built my first 7805-based IVR in 1997 for a '72 Satellite. It cost about $3; I used the OE IVR case as a heatsink. It worked for about a month, then had to swap clusters. I'd never use another. I have RTE IVRs for every one of my cars that use one.
 
Sorry, I did mean the fuel gauge. I was so focused on the temp gauge not working that I misspoke. I have disabled the limiter in the gauge. I took the feed and sent it to the new external limiter so the gauge no longer gets the 12 volt feed. Do I need to open the gauge and cut the wire to the limiter? I then took the 5 volts from the external limiter and sent it to the 3rd terminal on the fuel gauge, the 5 volt terminal. I also replaced both circuit boards. My fuel and oil pressure gauges work just fine but the temp doesn’t move from cold. I’m getting the fluctuating voltage at the sensor and when I ground that wire the temp gauge sweeps. From what I understand from that is, the gauge and the limiter are good. I am on the 3rd sensor. I thought that maybe I ordered one for a dummy light, so the next one I ordered, I made sure it was for a gauge. I temporarily put a temp gauge under my dash for now but I want to keep the original look.
 
66Glassback said:
Sorry, I did mean the fuel gauge. I was so focused on the temp gauge not working that I misspoke.
Click to expand...
I wondered if that was the case.

It seems you're passing all the tests for the IVR and the gauge/wiring. Have you got an old intake manifold lying around that still has the sender in it? If so, try the old part. If not, call one of your local Mopar pals and see if they do, and you can borrow it. It really doesn't matter what it's from; the sender was the same from 1963-'89. The factory senders are pretty reliable. Call me a cheap bastard, but I'll usually clean and reuse what was in the car if the gauge worked before the swap. In my Valiant, I changed the sender with a new one (Standard Motor Products #TS17) because the gauge didn't work. It turned out the gauge had failed due to a bad IVR. I found an NOS gauge and it works with the new sender. I'd bet the old one was just fine, though.

One other thing to consider: Did you paint the intake manifold? Paint is a wonderful insulator, and the intake is only grounded through its mounting bolts. Did you cover the sender threads in Teflon tape? You may not be getting a solid ground through the intake manifold. Just for fun, run a jumper wire from battery (-) to the sender body and re-test.
 
I will try running a jumper wire and see what happens. I don't have anything on the threads. However, the machine shop that rebuilt my engine did paint everything.
 
66Glassback said:
Sorry, I did mean the fuel gauge. I was so focused on the temp gauge not working that I misspoke. I have disabled the limiter in the gauge. I took the feed and sent it to the new external limiter so the gauge no longer gets the 12 volt feed. Do I need to open the gauge and cut the wire to the limiter? I then took the 5 volts from the external limiter and sent it to the 3rd terminal on the fuel gauge, the 5 volt terminal. I also replaced both circuit boards. My fuel and oil pressure gauges work just fine but the temp doesn’t move from cold. I’m getting the fluctuating voltage at the sensor and when I ground that wire the temp gauge sweeps. From what I understand from that is, the gauge and the limiter are good. I am on the 3rd sensor. I thought that maybe I ordered one for a dummy light, so the next one I ordered, I made sure it was for a gauge. I temporarily put a temp gauge under my dash for now but I want to keep the original look.
Click to expand...
According to Redfish, who the Great Big Red Print ran off of here, you need to be very careful in there with the limiter, as you can damage the gauge, or cause a short condition which will electrically damage the gauge. As I recall, he recommended carefully bending the limiter contact and doping it with goop or RTV
 
I just ran a jumper wire from the ground on the battery to the base of the sender. Still nothing. I think I am going to pull the cluster back out and look into bending the limiter contact in the gauge. Other than that, I think I am going to go with some new white face gauges.

Gauge Kit.jpg
 
You must log in or register to reply here.
-

Back
Top