Fuel Sending unit Spectra FG107A

I spent quite a few hours researching a new fuel sending unit for my 73.  My stock sender is a 2 line FG107A (fuel/vapor) and they do make a 3 line FG107B (fuel/vapor/return).

While researching the FG107A I noticed that almost everyone lists the unit as being a 5/16" output line.  I found this to be incorrect after waiting 2 days for a return email from the Spectra company technical line.  But the email confirmed that the FG107A is IN FACT a 3/8" fuel with a 5/16" return line.  

Even responses from several ebay vendors all stated that it only has a 5/16" output line.  The company Tamaraz IS CORRECT in their auction stating 3/8" and 5/16" lines.  

Some vendors state that the unit is stainless steel but I found that hard to believe.  My unit came today and it is not stainless but zinc plated like factory.  I wasnt expecting stainless, so no big deal.  

All in all, it looks like a good unit.  I still have to put an ohm meter on it to verify the float resistor and trial fit it in the tank to make sure that it fits properly.  It does come with a new "O" ring and retaining ring.  

So if anyone is looking for a new sender, I can attest that the FG107A (2 line) unit has the correct tube sizes.  

I ended up getting it at carparts.com for $55 to my door with the coupon thats floating around the net.  Rockauto would have come to $59.  

Just posting up in case someone needs a sender.

Happy Holidays everyone !!!!!

I noticed this conflicting info a couple yrs ago when I was looking to replace the one in my Laguna. In fact, the one I pulled from the car is this same one (FG107A)...and, for reasons I can't explain, is still hanging on a hook in my garage. It looked brand new when I pulled it...but, the fuel gauge kept bouncing around when I had less than a 1/2 tank. Found a NOS one at the time and installed it. Problem solved.

Ok, quick update.  I had some time to check out this spectra fuel sender.  I removed it from its box and immediately noticed that the float arm is bent away from the resistor housing.  Meaning that it would not be able to hit the full and low "stops" built into the housing.  The arm was a good 1/2" away from the housing.  I thought about bending it back but I know there is a thin wire resistor that the arm rides on inside the housing.  So I decided not to bend it.  

Then upon reading the issue Mcarlo77 had I decided to double check the units ohm readings.  Well, right around a 1/4 tank level, the multimeter took a long time to settle down to a steady resistance.  All other positions had steady readings.  So I have to confirm that my unit would most likely have the same issues Mcarlo77 posted.  And I'd like to thank Mcarlo77 for posting his observations.

So a quick call to carparts.com and they sent me a return fedex label and rma number.  They are refunding my full purchase price including shipping.  So great customer service on their part.  I'd have no problem ordering from them again.

Did some more research and ended up ordering a Dorman 692-131 sender from Autoplicity.com.  With discount it came out to $72.40.  Amazon was selling it for $70.40 with shipping also from Autoplicity but I wanted to use some paypal cash I had so I ordered direct.  

Will post my findings when I get the Dorman.  I've always had good luck with their products.  Hopefully it will continue.

Interested to see what your findings are with the Dorman. I installed a new Spectra unit and it doesn't seem to work either. My gauge was not reading correctly, installed a different fuel gauge same thing. Thought it was the wiring so I installed an aftermarket gauge and same thing, I couldn't get an accurate reading on the gauge. I bought a different Spectra sending unit but haven't installed it yet mostly due to time but also only wanting to drop the tank only once to fix the issue and I don't have much confidence the other Spectra unit will be any good.

What is the part number is for the NOS sending unit?

I've seen a few NOS units on e-bay go for around $100, not to bad, but when you want one you won't find any listed.

I had my sender "rebuilt" a few years back, basically a new sock and it was cleaned up. They said they "calibrated" the sender even though it worked fine when removed. Now it comes off of full rather quick and hangs out around a quarter tank alot longer then it should. It works good enough and I wasn't going to drop the tank again. They should have left the sender part alone, kinda pissed me off, They charged somewhere around $80. Had I known that I would have tried to find a NOS.

I will post my findings when I get the Dorman.

My stock original sender works fine but I'd like to put a new one in after I blast and epoxy the tank.

I replaced the sender in my Chevy pickup with a factory unit, and it didn't come all the way to the full mark. The wire arm for the float is likely bent a bit off etc, but no big problem...

Ok, received my Dorman 692-131 fuel sending unit in the mail. REAL nice unit. Its actually stamped "stainless" on the resistor housing. I put a magnet to the entire unit and it is in fact NON-magnetic stainless, which is good.

Quality looks to be excellent. I removed my original sender from the tank to do a comparison. I have to say, side by side, they are almost identical. Only difference I see is where the vent tube enters the bottom of the top plate. My original sender just has a flat metal cover over the entrance I guess to act like a baffle. On the Dorman unit, the vent tube comes through the top plate about an inch and it has a white plastic thing on it I guess to act as a baffle. No big deal but I think the Dorman might have the better idea.
Another thing I noticed was that the Dorman unit is about 3/4" shorter in overall height.
Tube sizes are correct at 3/8" and 5/16".
Otherwise this is a real nice piece.
I put my Fluke 78 meter on the Dorman. I got good steady readings in all positions. Some slight fluctuation around the 1/2 tank level but it settled right out. It maxed out at 94 ohms and the Dorman site says 95, so its right there. I then did a comparison to my original sender for the hell of it. Got all good steady readings but again with some fluctuations around the 1/2 mark like the Dorman. So I'm not concerned with it. This Dorman unit seems to be operating as it should, quality is definitely good even down to where the flat metal strap attaches from the resistor housing to the top plate stud for the sender wire. And its all stainless which I like.

Funny thing was. When I went back to try some more readings on my original sender, I got nothing. I tried another meter and still nothing. So I think my original might have bit the dust after 43+ years. LOL. I wasnt going to put it back in anyway after I blast the tank.

So I have to say, the Dorman 692-131 that I received looks to be a nice unit and operate properly. WAY BETTER than the Spectra I received.

Happy Holidays Guys !!!

Thanks for your efforts, Joe. Should be some assurance to those who are looking to replace their sending unit with a reliable brand.

No problem at all. I like giving experience. / findings.on stuff.like this. Hope it helps someone out.

Good analysis Joe ! Since the sender float is moving around a bit most of the time, the center/half tank area wont likely show up as anything anyway, with the damping of the gauge unit etc...

Bill

Cool. Thanks Bill. I was just rummaging through my parts and came upon another 73 tank with sender still in it. I was going to drag it out and test it as well but I dont think its worth the effort since the dorman is reading good.

BTW I also found 3 items NOS in original gm boxes. Door pin switch date 2/73 and left and right stainless wiper arms. I remember buying them back in the early 90s and never put them on. They'll be going on this time. LOL

Thanks Joe. Added to the list of spring time purchases.

Anytime. Glad to help out .

I have a 73 SS which I thought had a bad sender so I bought the Spectra and the guage is still pegged. I cleaned up the ground wire when I had the tank out. Also the horn will honk when the wheel is touched. Car has been sitting for along time and just getting around to working on it. Can a horn wire cause instrument cluster issues? Thanks.

Dorman has been around since 1916 I believe. Likely one of the only companies with it['s original name & not gobbled up by some holding company.

I dont Know about the horn issues, but I was not happy with the spectra part.

If you remove the horn button ( the center trim on the wheel) ( two screws from the bottom side) , you will see a jumper wire with a female spade clip on the end of it, which clips to the bottom of the horn button.

Be careful removing the spade clip so you don't pull on the wire for the brush in the plastic socket.

The other end of the wire goes into the wheel hub, into a plastic socket, and it removable like an old style bulb, the bayonet type..about 1/8 of a turn CC & it comes out. Inside of the (white) plastic socket is a brush with a spring on it, that runs on the slip ring assembly. Remove that too.

The plastic socket where that wire plugs in is part of the slip-ring assembly, which is held in place by the spring that holds the plate under the steering wheel. If that slip ring and brush holder is broke, they are available at Oreilly auto parts, p/n I believe is 38232, for a bit over six bucks. OPGI gets $28.99 for them !!

So, to remove the top plate above the turn signal switch, you need the compressor for that job. Not very expensive, and maybe available to rent from a parts store. The compressor pushes the plate above the turn switch down enough to remove the little snap ring on the steering shaft, so the plate the the slip-ring/turn cancelling assembly is removable....

Not a bad job really. I've had mine apart at least 3 times in the past couple months !!

I wonder is the coupe fuel tank sending unit the same as el camino's?
My gauge doesn't give correct readings too. So can I order this Dorman too?
My tank has sending unit mounted on top.

It's weird that Rockauto doesn't show a fuel sending unit for El Camino. But, there's no reason to believe that it would be any different than on the coupes.

The El Camino tank unit may be a different part number ? I know the GM Elco tank sender was scarce for a long time. I bought the last one they had when the El Camino Store was out on the West Coast, before Ecklers bought them out. Last I saw listed some place was an after market two-pipe sender. Mine is a 3-pipe sender. Maybe Dorman has some now (??)

Mcarlo77 wrote:It's weird that Rockauto doesn't show a fuel sending unit for El Camino.  But, there's no reason to believe that it would be any different than on the coupes.

Yes, that is strange. That's why I am asking. Fuel tanks seems to be not the same shape and dimensions according to photos and rockauto numbers, so the height of sender unit can be different too

Here is your GM part numbers for fuel sending units. Looks like El Camino would be #6429288 for 350-2 & 4 bbl w/o C.A.C. (Controlled Air Conditioning).

http://www.gmpartswiki.com/getpage?pageid=86235

You can bag this NOS one off e-Bay for a mere $175 (plus $22 shipping)!

http://www.ebay.com/itm/FUEL-TANK-SENDING-UNIT-1971-1972-1973-1974-1975-1976-OLDSMOBILE-CHEVROLET-BUICK-/282083069062?hash=item41ad760c86:g:tWEAAOSw0e9U0O~R&vxp=mtr

I just checked Ecklers El Camino store, and they have the 2 and 3 line senders..The 3/8" line,
the 3-line sender is part no 55-199133-1, and is $79.99. Some senders are for the small (?) engines & have 5/16 lines

Thank you for the info! I have 2 line sender and it looks like the same as ebay item with sock mounted purpendicular to line. But 200$...lol

Yes Elcamino store has senders but as for the picture they list for 2 line sender it's different sock mount position and looks like it has shorter line inside the tank...
http://www.elcaminostore.com/el-camino-fuel-tank-sending-unit-two-line-1973-1977.html

And how does AC in car influence on number of sender lines?
Now with 383sbc I have only 1 line used for fuel, and second line is used nowhere, to vent tank.