Anyone familiar with 69'-73' Fury/72'-73' Dodge Polara/Monaco instrument clusters???

[moonrunner1972]

:icon_rolleyes: I am in desperate need of some advice from anyone with extensive knowledge on the instrument clusters found in 72'-73' Dodge Polaras & Monaco's. These models use instrument clusters very similar to those found in 69'-73' Furies. ANY advice is welcome. :sSig_thankyou:

 

[polara71]

the 69 through 71 Furies and the 71 Polara/Monacos share the same instrument cluster. The 72 and 73 Furies, Polaras and Monacos share the same, all are similar. What advice are you seeking?

 

[moonrunner1972]

wiring help

:sSig_thankyou:Thanks for the response. I am trying to eliminate reasons why my fuel gauge does not read. I have recently swapped the OEM voltage limiter with a Redline gauge kind that eliminates the condenser that screws on to the braket by the speedometer cable plug. The cars temperature gauge works as well as the low fuel lamp and door warning buzzer yet the gauge does not register. I disconnected the lead from the sending unit to measure the voltage and discovered a 0.00v reading. I used the factory service manual as a guide for wiring as well as following the printed words on the back of the instrument cluster that tell you what color goes where. I cannot imagine what I had done wrong but I am looking for any help you can provide me.

 

[moonrunner1972]

Gauge works

:eusa_clap:I believe I have discovered the problem. I ran a jumper wire from ground to the sending unit plug and was able to see the gauge needle move from empty to full. This proves that the gauge itself works and if I am correct that my aftermarket sending unit is crap. I have been refered to Vans Auto on the web that sells a replacement unit for $95. Thanks for the help I greatly appreciate it.:sSig_thankyou:

 

[Fury440]

You did remember to install the ground strap across the rubber hose between the hard line and the tank sender? Without that ground, the fuel gauge won't work properly.

 

[moonrunner1972]

Indeed

:tiptoe:I did make sure that the strap was located below the fuel line on the sending unit and above it on the line mounted to the body. As an added measure of protection I plan on replacing it along with the sending unit. Thanks for the input.:upside down:

 

[polara71]

You did remember to install the ground strap across the rubber hose between the hard line and the tank sender? Without that ground, the fuel gauge won't work properly.

That was going to be my next suggestion but it seems like he has it figured out. Thats good:congratualtions:

 

[moonrunner1972]

Still no luck

:rant::icon_rolleyes: Well it appears that I am in no better shape than when I started the project of attempting to fix my fuel gauge. I installed another aftermarket fuel sending unit and the gauge in the instrument cluster still reads innacurate. I pumped 15 gallons into my 23 gallon fuel tank only for the gauge to barely register 1/8 of a tank. Thusfar I have replaced the sending unit and the voltage limiter in attempts to fix this problem. The next step is to have someone rebuild my instrument cluster or to hope & pray I find an OEM replacement gauge on eBay. Either way I guess this will cost me at least another $300+ to fix this problem. Has anyone else out there run into this problem. :violent4:

 

[69SSNewport]

You need to pull the sender and do an ohm test. Connect an ohm meter between the sender output and the body of the sender (ground). With the float in the "empty" position you should have around 70 ohms resistance. With the float in the full position you should be in the neighborhood of 7-10 ohms. If you get readings like this then you can rule out a sender problem.

BTW, I have a complete cluster pulled from a '71 Polara available.

 

[moonrunner1972]

My feeble attempts at problem solving

:tiptoe:Sadly I did just that on both the old and new sending units and came up with readings very close to those readings you mentioned +/- 1 ohm. I also performed a test that involved a jumper wire from the female socket that plugs into the stud on top of the sending unit and ran the other lead to ground. The gauge needle moved to the FULL position when I performed this test. Recently I replaced the factory voltage limiter with a solid state upgrade made by Redline gaugeworks. The temperature and ammeter gauges work much more accurately now but the same problem still persists with the fuel gauge. Since I first purchased the car in March of 98' the gauge has NEVER functioned properly. Any ideas as to what I may be overlooking?

 

[69SSNewport]

Perhaps there's excessive resistance somewhere - like a corroded connector. There's a body harness connector near the DS kick panel that includes the sender wire.

You could try running a temporary wire from the sender directly to the gauge to see if there's an issue with the wiring. It's the dark blue wire side of the gauge. Be sure not to connect it to the 5v side.

 

[moonrunner1972]

Update

:iroc:Well folks I just finished speaking with a technical representative from Redline Gaugeworks regarding my fuel gauge woes. The conversation was very informative. I learned that the replacement (aftermarket) fuel sending units are often made poorly and will decieve you when you perform the test outlined in the factory service manual. Supposedly the float arm will not move all the way to the top where it would register FULL on the gauge. I can say that this has frustrated me and kept me up at night wondering what I missed during the diagnosis. This can frustrate even the most calm and patient auto restorer that is tired of pushing 2 tons of Detroit iron off the road when their car runs out of gas. ottytrain3:

If however you determine that the gauge in the instrument cluster is the problem Redline gauges offers a rebuld service that offers reasonable prices. Theur customer service is second to none since I have already bothered them at least a 1/2 a dozen times. Each time they offered me free advice and guidance on how to help narrow down my problem.

 

[69SSNewport]

Didn't you say the gauge has behaved this ways since before replacing the sender?

 

[moonrunner1972]

continuity through change overs

Correct, this has ALWAYS been a problem with this car. Originally the car came with the stock 120 MPH speedo/instrument cluster and only registered 3/4 when full. When I replaced the original with a certified 140 MPH version the problem remained.

 

[69SSNewport]

Then, the problem isn't necessarily the aftermarket sender. I'd try a substitute wire and see what happens.

 

[moonrunner1972]

Just to be sure....

:icon_rolleyes: Just so I conpletely understand, I can run a jumper wire from the stud on top of the sending unit directly to the stud on the back of the fuel gauge where the dark blue wire connects? If this works then can I assume that there is some form of resistance from the sending unit to the gauge?

 

[moonrunner1972]

sending unit gasket leak

:angryfire::angry:Well if it weren't bad enough that the gauge still does not work properly the sending unit spilled gas all over my garage floor. I must have done something wrong when I replaced the sending unit while the tank was mounted. I changed the rubber gasket and used the recommended replacement wrench as opposed to the popular hammer & screwdriver alternative. I am guessing that if the thing doesn't sit EXACTLY right it will leak when the tank is filled. Is there a recommended sealant to avoid future :bs:when I attempt this again? My dreams of driving the car to FL (790+ miles) looks like they are going to ottytrain3:away.

 

[Rusty Muffler]

Why don't you test it as above with the sender OUT and gently move the float to different positions like halfway and see if the gauge reads half and so forth. Just remember to give the gauge time to move. That will prove it's working completely,.

By the way, I've read the ammeter should not have anything to do with the fuel and temp gauges. It's independent of them and works differently.

 

[moonrunner1972]

test, test & retest

Rusty Muffler,

I had my wife help me try this experiment with the sending unit I pulled from the tank. When I moved the float arm to the top it would only read 1/2. This weekend I plan on taking out the new one to conduct the same experiment. I will keep you posted with the results

 

[The Moffittman]

This will be a dumb question... the float in the sending unit isn't full of gas, is it? if the gauge reads something... anything, even when full... I'd check the float

matt