Fuel sending unit for 1987 GMC Sierra

[Captain J]

My truck is a 1987 GMC Sierra R3500, 7.4L TBi, with dual fuel tanks.
Question what is the correct fuel sending unit number for it? Is it one sending unit or 2 sending unit Safety?
Someone told me it’s FG05M, FG05N???? But I’m not sure if this is correct, but if it’s, which one is for the passenger and which for the driver?
Does any of the sending unit fits any tank, OR each tank has a different fuel sending unit? Because I got confused
Thanks

[AustinBelair]

I was just about to post this. My half ton 87 has dual tanks and it lists pump assemblies for Aux tank and regular. I googled and it seems nobody know which tank is Aux and which is regular.

[Captain J]

Originally Posted by AustinBelair

I was just about to post this. My half ton 87 has dual tanks and it lists pump assemblies for Aux tank and regular. I googled and it seems nobody know which tank is Aux and which is regular.

Most of the trucks I owned have dual tanks, some may consider the main one is the passenger side. I saw some videos of truck restoration, with only one fuel tank on the passenger side. I hope this helps

[4x4k30]

the right side is the main passenger side on 73-91 gm fullsize trucks drivers side it optional . the fuel tanks for a 87 up first efi models use fuel tanks that are baffled so the fuel can be picked up. they do call for that both tanks to be swaped for the efi setup the sending units are different part numbers for right and left tank.

[sweetk30]

Originally Posted by 4x4k30

the right side is the main passenger side on 73-91 gm fullsize trucks drivers side it optional . the fuel tanks for a 87 up first efi models use fuel tanks that are baffled so the fuel can be picked up. they do call for that both tanks to be swaped for the efi setup the sending units are different part numbers for right and left tank.

ifthis is true how does my truck run with factory left/driver side only ? ?

[RyanNewberry]

I’m not sure how much difference it makes to begin with. I daily a 87 Silverado and I just replaced my drivers side tank and sending unit. Since I didn’t know better I ordered the sending unit for main tank, not auxiliary. I installed it in the new drivers side tank and it worked just fine. I bypassed the selector valve and got rid of the passenger side tank all together. Been running good ever since.

[4x4k30]

Originally Posted by sweetk30

ifthis is true how does my truck run with factory left/driver side only ? ?

what year is your truck ?

[sweetk30]

Originally Posted by 4x4k30

what year is your truck ?

80's they swapped to driver side if just one .

mine is 80's .

[4x4k30]

Originally Posted by sweetk30

80's they swapped to driver side if just one .

mine is 80's .

ok I was talking about dual tank trucks only. I have seen trucks with just one tank on the drivers side they were in the 80s.

[Captain J]

I’m still waiting for someone to reply to the full sending unit numbers and which side they fit?

[haycatcher]

just looked at spectra's online catalog and fg05m is driver side#
fg05n is passenger side for your app

[Captain J]

Originally Posted by haycatcher

just looked at spectra's online catalog and fg05m is driver side#
fg05n is passenger side for your app

First thanks for your effort on this,
The reason I’m asking, because I got confused & frustrated, some eBay sellers, they say any unit can fit any side, one well know parts store gave no answer, the other store kept telling me about if the truck left hand steering wheel or/and right hand steering wheel,

Can you pls link the spectra catalog here, thanks

[haycatcher]

spectra's site

http://www.spectrapremium.com/products/fuel_tank.html

[Captain J]

Originally Posted by haycatcher

spectra's site

http://www.spectrapremium.com/products/fuel_tank.html

Thanks

[Captain J]

To share with you my findings on the 1987 GMC Sierra with 7.4L & TBI, fuel sending units.
The FG05M (driver side) and FG05N (passenger side) are correct sending units but they don’t come with fuel pumps.

To have a complete sending units ,
SP05M15H (driver side) from Spectra
SP05N1H (passenger side)

[Wwes]

I mentioned this in another thread, but the only difference on the Spectra units is the left side has longer output nipples than the right. This is because the right side has short lines from the fuel selector valve. That said, it's easy enough to use either one for either side by varying the length of the rubber connection hoses.

[Captain J]

Originally Posted by Wwes

I mentioned this in another thread, but the only difference on the Spectra units is the left side has longer output nipples than the right. This is because the right side has short lines from the fuel selector valve. That said, it's easy enough to use either one for either side by varying the length of the rubber connection hoses.

Your absolutely right, even the regular FG05N sending unit it has longer output steel hoses. My truck have the same sending units on both sides, but they’re completely rusted out (not sure why), so I’m putting back the same sending units that truck came with when new.