2nd Gen Non-Engine/Transmission fuel gauge stopped working!

[butch59]

My 2002 dodge diesel pickup fuel gauge goes from full to empty. does anyone else have this problem? I have replaced one float valve kit in it. And checked the connections at the dash. Nothing seems to solve the problem. Three other dodge trucks in the neighborhood are doing the same thing problem not solved on any of them. Been to two shops and the dealer dosen't know whats wrong with it. Help!Oo. Replaced the float rheostat checked the resistance range all is ok. Checked the wiring all the way to the dash and found nothing wrong. Guage goes from empty to full and sometimes works for a small amount of time. Code showing is a P1693=DTC Detected in ECM or PCM? 12v is going to the unit but not much going out if any. Does't seem to be making the full circle for the electrical system to work. Is this the PCM not seding any signal to the buss?

 

[rweis]

By the float valve kit do you mean the rheostat and arm and float system?



There is 12v applies to the float rheostat and based on float position the resistance reports back a different voltage to the PCM. The PCM then converts this to a value and sends that on the bus to the gauge.



I would look to see if you have 12v going to the rheostat. Then measure the voltage coming out of the rheostat and ours is a max of 7. 0 volts. you can also check the resistance range of 20 - 220 +- 6 at each end. After that it would be the PCM toconvert thevoltage to a bus signal.



There is a modification to the rheostat that holds the float arm against the rheostat so you will get good readings consistantly.



Beyond that there is a thread about the float deterioation and how a Stewart Warner float mechanism would work, but you have to put a 2700 ohm resistor in parallel to adjust the SW resistance values (35 - 240) to the DC resistance values (20 - 220).



Just some ideas



Bob Weis

 

[Missouri Mule]

The fuel sending unit is known to go out. You mite want try a search in the 2nd generation (no engine or transmission). A long time ago the TDR magizine had an article how to fix it so it would not fail again (for a while any way) and I believe it was posted in a thread.

 

[cArNiVaLwOrKeR]

I have that problem too, I just make sure I Re-fuel b4 I hit 500Miles.

 

[rweis]

In this thread:



https://www.turbodieselregister.com/forums/showthread.php?t=179541



we are very very close to fixing the tank rheostat / float problem permanently. Hang on for about 2 more weeks till we get some tanks dropped and the modifications installed.



My part is to experiment with taking off the DC OEM rheostat and replace it with a Stewart Warner rheostat and also replace the tank float that disentagrates and replace that with a Stewart Warner brass float. When you do this you have to put in a 2700 ohm parallel resistor to send the correct values to the DC PCM. I think it will work, we'll see.



Bob Weis

 

[J.BURCHFIELD]

I have a 98 12v I bought new. The fuel gage is obviously built by the lowest bidder. Completely undependable. When I fill up I set the Trip Odometer and when I get to 400 I look for fuel. I fear that if I go to all the trouble of replacing the float in the tank where I understand the problem is I may or may not have a dependable readings on the gage after that. So I have taken the easy way out. For me it is no trouble, I am checking fuel mileage anyway.

 

[Missouri Mule]

I have had two sending units go out on my truck, one was replaced under warranty the other one is still in there (I use the trip odometer and fill up after I hit 500 miles).



This is link a to repair the sending unit.



http://dodgeram.org/tech/repair/fuel_sender/Huey_C-sender.htm



This is from 12 vavle forum search.

 

[RON'S RAM]

I did this repair over 100,000 miles ago, still working good.