Gas tank and sending unit help..

[Tuff 1986]

I'm wanting to order a new Gas tank and sending unit for my 1986 Chevy C10, V6 4.3L.. I only have 1 tank on the drivers side.. I've looked on the Haynes repair manual with no results on if I have a 16 or 20 gallon tank or a 2 or 3 hose plug sending unit.. I think my truck has a 3 hose plug sending unit and a 16 gallon gas tank.. Can anyone confirm this I don't want to order the wrong stuff..

[pontgta]

Originally Posted by Tuff 1986

I'm wanting to order a new Gas tank and sending unit for my 1986 Chevy C10, V6 4.3L.. I only have 1 tank on the drivers side.. I've looked on the Haynes repair manual with no results on if I have a 16 or 20 gallon tank or a 2 or 3 hose plug sending unit.. I think my truck has a 3 hose plug sending unit and a 16 gallon gas tank.. Can anyone confirm this I don't want to order the wrong stuff..

Short bed = 16 gallon
Longbed = 16 or 20 your choice

I would think you have hoses you can probably take a quick look underneath and see. 1 supply,return, and vent..

Looks like a step side... Short bed so i would put my money on 16g

[Tuff 1986]

I took a look underneath and there appears to be 3 hard lines going to the tank.. So I'm pretty sure it's a 3 line sending unit.. Thanks for yr help

[jhngardner367]

If it has TBI,it should only have 2 lines,and an in-tank fuel pump.
If it has a carb,and an engine-mounted pump,it should have 3 lines: 3/8" supply,5/16 return, and 1/4" vent line .
Usually,the stepsides,and SWB trucks had a 16gallon tank.

[Tuff 1986]

Originally Posted by jhngardner367

If it has TBI,it should only have 2 lines,and an in-tank fuel pump.
If it has a carb,and an engine-mounted pump,it should have 3 lines: 3/8" supply,5/16 return, and 1/4" vent line .
Usually,the stepsides,and SWB trucks had a 16gallon tank.

Thank you sir..

[hatzie]

Originally Posted by jhngardner367

If it has TBI,it should only have 2 lines,and an in-tank fuel pump.
If it has a carb,and an engine-mounted pump,it should have 3 lines: 3/8" supply,5/16 return, and 1/4" vent line .
Usually,the stepsides,and SWB trucks had a 16gallon tank.

TBI started in 1987. There were no 86 model year trucks with TBI. ALL TBI senders have 3 lines... Feed, Vent, and Return... with an in-the-tank fuel pump.

1973-1986 gasoline I6, V6, & V8 were ALL carburetor engines. The stock 1986 V6 should have an R4M4MED or R4M4ME Rochester Electronic Quadrajet with a mechanical fuel pump, a return line, and a 3 line sender.

All senders have vents but there were some trucks in the 70s that had 2 line senders with vent, feed, and no return line. GM added the return line to mitigate vapor lock. By 1986 they all had return lines.

[motornut]

both my 78s have two line pumps,both 79s have 3 lines,might be the year it changed...