[DeTomaso] Fuel level sender removal

Tue Feb 12 15:49:18 EST 2019

Mike,

You'll cause no harm if you connect the Yellow and the White/Black wires to the sender wrong.  
Both of the sender's terminals work by pulling the voltage towards ground, one does so with a switch and the other with a variable resistor.

I'm assuming you've already installed the sender in the tank and hence you can't move the sender's float arm.
If you have an Ohm-meter, it's likely that even with the gas tank empty, the gauge terminal will measure as a higher Ohm reading than the tank-empty lamp terminal.  Both of these measurement should be made between the respective terminal and the sender's ground terminal.

Doug Braun
Blue 73L #5505

-----Original Message-----
From: DeTomaso [mailto:detomaso-bounces at server.detomasolist.com] On Behalf Of Mike Drew via DeTomaso
Sent: Monday, February 11, 2019 7:39 PM
To: Julian Kift <julian_kift at hotmail.com>
Cc: De Tomaso List <detomaso at server.detomasolist.com>
Subject: Re: [DeTomaso] Fuel level sender removal

Julian,

Right, got that.  That’s not the issue. 

The issue is, which contact ON THE SENDER is for the needle and which for the light?  Both are connected to wires that disappear inside the sender. I would like to be able to simply tell visually which is which without having to install and hook them up. 

Worst case, I have a 50/50 chance of success.  Actually probably more like 75/25 because one would hope the new sender follows the same scheme as the old one. 

This whole thing is being driven not by a bad sender (my existing one is perfect), but instead by a bad gas tank. 

Somebody gave me a free perfect-looking tank 25 years ago. When my old tank started leaking (from the top it turns out) I reconditioned the free replacement inside and out, after carefully inspecting it of course, and then installed it (a non-trivial undertaking since it required engine removal).

Come to find out that free gas tanks are free for a reason!  The fuel pickup pipe inside the tank apparently has a pinhole about 2/3 of the way up. It works perfectly when the tank is full. At about 2/3 full fuel pressure drops to less than 1 psi and when the level is less than that, it doesn’t feed fuel at all. 

The later cars had the fuel pickup built into the sender. So by installing a later sender into my early tank, I can move the fuel hose over to the sender and fix my problem without having to pull and change the tank again.

And, I will have a perfect Pre-L sender available for sale afterwards too. 

Mike

Sent from my iPad

> On Feb 11, 2019, at 19:29, Julian Kift <julian_kift at hotmail.com> wrote:
> 
> Of course you could just go to Pantera Place and look at those wiring diagrams Bill spent so much time developing!
> 
> Yellow low fuel warning light and white/black fuel gauge.
> 
> Julian
> 
> On Feb 11, 2019, at 19:22, Julian Kift <julian_kift at hotmail.com> wrote:
> 
>> Mike,
>> 
>> Once you get the unit out it should be pretty evident which wire feeds what and wether that is oriented the same on the new sender. In theory it shouldn’t matter as the wires are just connected to either side of a variable resistor one side to the wound resistor coil the other the resistor wipe arm (float).
>> 
>> Julian
>> 
>> On Feb 11, 2019, at 18:40, Mike Drew via DeTomaso <detomaso at server.detomasolist.com> wrote:
>> 
>>> Hmm,
>>> 
>>> Server seems to have stripped my photo away....
>>> 
>>> 
>>> <image1.jpeg>
>>> 
>>> 
>>> Mike
>>> 
>>> 
>>> Sent from my iPad
>>> 
>>> > On Feb 11, 2019, at 18:34, Mike Drew via DeTomaso <detomaso at server.detomasolist.com> wrote:
>>> > 
>>> >     Thanks Curt.
>>> > 
>>> >   Turns out I had a photo of my sender, and my recollection was
>>> >   completely wrong. Mine is two-wire with a ground tab.
>>> > 
>>> >   image1.jpeg
>>> > 
>>> >   I have to just hope that the new sender respects the old sender wiring
>>> >   orientation.
>>> > 
>>> >   Still waiting to hear from somebody who has successfully pulled the
>>> >   sender without removing the window?  It may not be possible.
>>> > 
>>> >   Mike
>>> >   Sent from my iPad
>>> >   On Feb 11, 2019, at 17:29, Curt Hall <[1]cuvee at sbcglobal.net> wrote:
>>> > 
>>> >   Mike...
>>> >   Here is a photo of my 73. I had problems last year with gauge reading
>>> >   on E? Pull the sender and found the Float was full of fuel, replaced
>>> >   the float and all is good. 50/50 chance of wires bring wrong, I have my
>>> >   windows out so I was able to hook up and test things before installing.
>>> >   Good Luck Curt
>>> >   <20190211_172047.jpg>
>>> >   [2]Sent from Yahoo Mail on Android
>>> > 
>>> >   On Mon, Feb 11, 2019 at 3:00 PM, Mike Drew via DeTomaso
>>> >   <[3]detomaso at server.detomasolist.com> wrote:
>>> > 
>>> >   All,
>>> >   It seems to me it's possible to remove the fuel level sender without
>>> >   removing the side window glass. In fact I'm fairly certain I've done
>>> >   it, years ago, but can't remember for certain. Can anybody confirm
>>> >   please?
>>> >   Also does anybody know which wire goes where on a two-wire sending
>>> >   unit? My old one has three wires but new one has no provision for
>>> >   ground, so I will have to fabricate one. I have a 50/50 chance of
>>> >   getting the other wires correct but would like to improve my odds. I
>>> >   have no reason to believe the new sender will respect the wiring
>>> >   orientation of the old one?
>>> >   Mike
>>> >   Sent from my iPad
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>>> > 
>>> > References
>>> > 
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>>> >   2. https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature
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