Bingo! And way back when... I had no idea about nichrome wire and how solder wouldn't stick to it. Thus why I am having this problem again. I've learned a lot since then.
Least Shoddy Fuel Sending Unit?
- Thread starter MCPObr44
- Start date
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GET A PIECE OF 1/8 CORK GASKET MATERIAL AND MAKE YOUR OWN IT WILL FIX IT.
GET RID OF THE CHEESEY RUBBER GASKET
72Dart6pack
Harder Better Faster Stronger.
Naw. I'll do it my way. That's why we have choices in life. Not one way is always correct. 
If anyone identifies a source for the nichrome or someone who is rewinding boards, that would be great.
The heart of the problem of the replacements is the board and the float arm length.
See Fuel Sending Units and A-Body Fuel Tank Map
@Cuda Al shows his repair in detail -
Fuel Sender Rebuild
as does this How to article (except he gives up on fixing a board with busted wire - as I did at one time)
OEM Fuel Sender Repair 1967 Dart
Thanks. Good info.
Part numbers I looked up in the FSMs were:
1967 p/n 2257 493
1973 p/n 3621 615
Several changes in fuel formulation in th 70s. One of them may have resulted in greater reaction with brass.
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famous bob
mopar misfit
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This is what mine is doing now
famous bob
mopar misfit
You might think so , but he doesn`t stand behind his products . Ask him about the rocker arms he used to sell w/ the procomp heads !!
I wouldn`t buy anything from the duschbag !!
I’ve also heard that Bill Rolik has the best unit out there. It’s $140, but it’s supposed to actually work as intended.
Thread revival POW!
Hey guys, an update. So as it was recommended to me, I ended up purchasing the aftermarket sending unit from AM-Autoparts from ebay.
Fuel Gas Tank Sending Unit w/ 5/16" Line for Dodge Dart Plymouth Duster | eBay
And after running around and fueling the car, I can say that the sending unit is accurate through the whole range of the fuel gauge from full to empty. I never adjusted it either when I got it in the mail, I installed it as it came.
Now, that said... I would like to make an important note. My instrument cluster has had the voltage regulator replaced with a solid state one of my own construction. I'm sure everyone's seen the whole 7805 voltage regulator mod for the instrument cluster. Mopar Voltage Regulator Upgrade
Well, I looked at that mod and wondered why they were using a 5 volt regulator instead of a 6 volt regulator... seeing as it's 6 volt gauges. So I substituted a 7806 in place of the 7805 (last number indicating the voltage).
I wonder if that has anything to do with it? Could that be the solution to these aftermarket sending units? Mine is dead nuts, while tons of others are way off. Did those people do the mod, but with the 7805? Hmm, I say!
On a side note, the original sending unit failed because the float sank.
Hey guys, an update. So as it was recommended to me, I ended up purchasing the aftermarket sending unit from AM-Autoparts from ebay.
Fuel Gas Tank Sending Unit w/ 5/16" Line for Dodge Dart Plymouth Duster | eBay
And after running around and fueling the car, I can say that the sending unit is accurate through the whole range of the fuel gauge from full to empty. I never adjusted it either when I got it in the mail, I installed it as it came.
Now, that said... I would like to make an important note. My instrument cluster has had the voltage regulator replaced with a solid state one of my own construction. I'm sure everyone's seen the whole 7805 voltage regulator mod for the instrument cluster. Mopar Voltage Regulator Upgrade
Well, I looked at that mod and wondered why they were using a 5 volt regulator instead of a 6 volt regulator... seeing as it's 6 volt gauges. So I substituted a 7806 in place of the 7805 (last number indicating the voltage).
I wonder if that has anything to do with it? Could that be the solution to these aftermarket sending units? Mine is dead nuts, while tons of others are way off. Did those people do the mod, but with the 7805? Hmm, I say!
On a side note, the original sending unit failed because the float sank.
What are your plans for your old sender? Is it OEM?
How did you determine that the ranges were correct?
The voltage of the IVR might effect the full range of the guage but not the accuracy thru the ranges.
How did you determine that the ranges were correct?
The voltage of the IVR might effect the full range of the guage but not the accuracy thru the ranges.
I determined the ranges were correct by knowing the capacity of the tank, and driving it until it reached different parts of the gauge (full, 3/4, 1/2, 1/4) and filling it to full again from that point. It always jived with how much I put it to how much it was supposed to read on the gauge, at least within reason for a mopar fuel gauge. My only complaint might be that full is just a bare hair over the full tick mark, by just a tiny bit.
As for the old sender, it is afaik original to the car, or at least the original style. I plan on replacing the sunk float and stashing it for if the after market one fails or if I get another A body.
I just install a new Spectra unit in my 69 Dart. Seems to work good so far.
Bought one from Van's in Wisconsin on Ebay.
I knew the float level for the gauge was goin to be off, so I took the time to rebend the float arm so it would read the proper level on the gauge in the dash. Then permanently installed it.
Worked Fine
QuickDart360
Well-Known Member
I had an original fuel sender with brass float. Over time float cracked and sunk in fuel. Back then oredered one from my local dealer. (Still available then.) It came eith a plastic float! At 1st I was like why did chrysler sell me taiwanese junk! However, float has been working great ever since!
The 7805 regulators that I used to build the demon IVR would start cold at about 4.9V but as it warmed up output would climb as high as 5.4V .
Oh? In the electronics world, that would be considered out of tolerance and would be pitched in the garbage. You might consider replacing it.
My 7806 regulators would start at exactly 6 volts and would heat up and be at 6 volts. I bench tested it under load for about a week before installing in my car. Then I made a spare just in case.
The 7805 family is a little sensitive to output capacitance. It could be that or a setup issue. I have used them for years on military electronics and they are usually solid as a rock. I had trouble with mine on my cuda too. Maybe some sort of mopar witching thing.....
You guys know more about this than I. Two observations that may be relevant.
1. When I tested the gages with a contant voltage source of 3.1 to 3.2 Volts, the pointers all swung 7/8 full scale.
2. Same gages connected hooked up on the circuit board with 22 Ohm resistors substituting for sending units, went to 1/2 scale. The analog multi-meter showed the IVR output pulses to swing from zero to 4+ Volts at most when read on the 15 Volt scale. I have a beat up analog meter that might have a 0-10 scale. If so, I'll retest.
My takeaway is that a 5 V constant may not have the same effect on the resistance wire and gage movement as the pulsing IVR.
And just to add a little to that.... before I trashed the original voltage regulator, I hooked it up to an oscilloscope. It didn't just pulse on and off, but had a jagged mountain sine wave shape to it, without regular spaced peaks.
Makes sense because it sure didn't swing the needle like a metronome. LOL
With a capture scope we could probably get a better estimate of the average over Voltage time for the IVR. Wouldn't be surprising if it was less than 5 V.
We were able to do some basic channel math on the screen captures were doing in 1998 with 4 channel dgital connected to a micro-computer.
With a capture scope we could probably get a better estimate of the average over Voltage time for the IVR. Wouldn't be surprising if it was less than 5 V.
We were able to do some basic channel math on the screen captures were doing in 1998 with 4 channel dgital connected to a micro-computer.
You can’t always measure an ac voltage with a multimeter. Multimeters on the dc setting have an integration (settling) time that is required to get an accurate reading. The voltage must be stable for that time and also long enough for your eye to read it.
Multimeters on the ac range are designed for 60 cycle house voltage. Any other frequency will not give you a correct reading.
I have never looked at one with a scope, but since it is damped with some capacitance, I wouldn’t expect a square wave. A bunch of wire wrapped around a piece of metal is an inductor, so you also have that in the mix.
I am assuming that since the 5-6 volts seems to work for most people, if you integrated (averaged) the voltage over a period of time you would come up with that value. As said above, if you had one of those fancy scopes like we do at work with math functions, you could come up with some real data. However, my brain hurts too much to do unnecessary math anymore, so I just relied on other people’s work.....
OK to be more exact... Starts ranged from 4.88 to 5.02. after 10 minutes 5.02 to 5.42. All with no load on output, just run to test before packaging. The prototypes ran in my 67 and our 73 for 18 months before the 1st retail unit went to market. I shipped over 360 units during 8 years. I know of only 3 field failures. The resistance of anything and everything changes with temperature. I'm not the electrics wiz though, my brother is.
Ok, that makes sense, the 7805 also acts poorly with no load. Obviously worked fine when installed
That is exactly what I was looking for!
@dart67 your mailbox is full, would you PM me I would like to get some data on the specifics of the OEM gauge based on your thread (the dumbass I am I threw out 2 old nasty ones when I did the daughters Duster....)......
Fuel Sending Units and A-Body Fuel Tank Map
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