Knowing about this for years, reading a few threads, and not wanting to pull a bunch of tanks looking for a good sending unit, (even if I got a good one it is still 20+ years old, so I opted for a new aftermarket one)
I decided to try this method and take a bunch of pics.

the threads I read,
https://www.fiero.nl/forum/A...130314-2-114616.html
https://www.fiero.nl/forum/A...090219-2-078597.html

The stock sending unit is dead, it has break in the wire





So I ended up with this one SN38A, I was going after the model shown in one of the thread, I got his one not sure the exact differances.


This is how it came.


A quick test.




Now to take things apart.




The stock arm apart.



Now being the sending unit I got, just bolting up it put the float at the backside of the tank, won't work so I had to flip it around.
So I got the bracket that came with it and bent it up to be able to flip it around, I also bent it so the pivot is at the exact same place as stock.











I decide to use the stock arm, grind it down a bit to fit in the set screw hole, looked good, but with out the extra length to hit the stop, at the top most postion it would off the slide and not read, so I had to bend the new arm to match the stock arm.
The stock arm.







I bent the arm like the stock one.







Installed.



I did have to cut/solder the sending unit wire to the stock wire, (I replaced all the wires and plugs as they were falling apart.)
Some more pics of it on.















Now it doesn't qiute want to fit in the tank.





But putting the pump in not hooked up and putting the pulsator after I got it to fit in.
You can see here the pulsator is not on yet., this is just to get the pump in, I put the pump in the bracket and the sock on, then lowered the unit into the tank haveing to tip the pump sideways to get it in.





As you can see it does fit, but I had to put on the pulsator after the unit is in, not hard at all, as you can pull most of the unit out up to the sending unit and slip on the pulsator. (or hose if you are going that route)



As always use brass to tap the ring in so no sparks can ever happen.



Now to test with it in.



To test it at the full mark, I just turned the tank upside down.



Perfect.


Enjoy


<---- Don't forget to rate.


Edit to add: This only cost $40

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[This message has been edited by sardonyx247 (edited 02-27-2015).]

NO "Hose CLAMPS" on the hose ??

quote Originally posted by Lou6t4gto: NO "Hose CLAMPS" on the hose ??

You don't use hose clamps on a pulsator, IE there is no hose to clamp.

Didn't see that you re-used the pulsator, removed it in mine. if it works, that's great !

What did you use to bend the arm so perfect?

Steve

I always find your How To's informative.
My 88 has a different style fuel sending unit than the OEM one your replacing. Its good to know I can retrofit to something newer.

https://www.detroitspeed.co...01-sending-unit.html

Nice write up and a + rating for you!

quote Originally posted by 86soon3.4: What did you use to bend the arm so perfect? Steve

A vise and a hammer.

Update Edit: I just tested the float operation in a sink of water, and it worked great. Now ready to install in the tank.

Hi sardonyx247,
Today I am working on the mods, like you did, on the Classic Instruments SN38A Tank Sender that I bought from Summit.
Everything is going well, but what concerns me is how much finger pressure I need to move the small 2" rod they ship the part with where the float rod eventually goes.
I am hoping the pressure on the float will be able to rotate it once it is in the tank. Did you notice that on your part?
Thanks,
Luke

[This message has been edited by hdryder (edited 04-26-2015).]

Ingenious adaptation of a new sender. BTW, a pulsator is only needed with a gerotor (vane type) fuel pump. If you have a modern turbine pump there are no pulses to suppress so you can just put in a short piece of submersible J30R10 fuel injection hose. We use Bosch pumps as they are the turbine type.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Once again, great info from "sardonyx247". A big Thank You for your efforts!

sardonyx247,
I mounted my new Classic Instruments Sender just like you have done. I bench tested the ohm reading before I put the f/p module back into the tank, and it read 0 to 90 from Empty to Full.
After installing the f/p module back in the tank, I re-installed the tank back in the car.
But the fuel gauge reading stayed on empty, even after putting about 5 gallons in the tank. There is a new change. With the old sender unit, the gauge was pegged above the Full mark.
After I ran the car for several days to empty the tank, I dropped the tank again out of the car. I was expecting to see a broken wire, or float and rod that may of come loose, etc, but everything was all together. I then bench tested the sender out of the tank again, and still was getting the 0 to 90 ohm reading from Empty to Full.
Then I plugged the f/p module with sender, while still out of the tank, into the chassis wire harness to read the fuel gauge in the car. The fuel gauge moved from Empty to Full along with the corresponding float locations.
So now I am trying to figure out why it is not working when the f/p module is in the tank, and the tank is in the car.
Any ideas of what to look for?
Thank you for anyone's help on this issue.

Maybe it is hanging up in the tank, if you still have the tank out try turning it upside down with the sender in the tank and see what it reads.

I am still trying to troubleshoot my new sender unit, and will most likely have to drop the tank again to do so. But before I do that, can anyone tell me if the sender unit and the fuel pump are grounded together, or do they have separate ground wires?

Thanks for the help.

Yes the pump and sending unit use the same ground.