i have a carbed 84 camaro and i switched to a later model 2.8 block. therefore i need to install an electric fuel pump.

What is the return line?

The electric fuel pump has no place for a return line

Can i just block it off?

What was its purpose exactly?


Any help would be nice thanx qytum

 

The return line goes from the fuel injector rail to the fuel TANK (not the pump). It returns excess fuel not used by the injectors to the tank. The pump sends out 60 PSI, and the injectors only run at 35-40 psi, maybe a bit more at WOT, but they don't run at 60 psi all the time. The fuel pressure regulator only allows a certain pressure to the injectors. The rest of the fuel goes back to the tank. 'Fact, this is a way to check the fuel pump. If you crimp the return hose shut, and put the key from "off" to "on", the pump primes, and pressure at the rail should go to 60. If it doesn't, the pump's dead!

So you've got two methods. Are you going to use an in-tank pump? If so, you've gotta get the pump hanger (and might as well get the whole friggin' tank) from an 85-92 fuel injected f-body, could be v8 or v6. The pump hanger drops in from the top of the tank, and has 4 hoses going into it; fuel feed (from pump), fuel return, charcoal vapor canister, and tank pressure vent. I'm not sure of an 82-84 fuel tank's pickup... if the pump hanger (which also holds the fuel gauge float) from 85-92 will fit into the 82-84 tank. The hole in the top might be smaller.

Second route would be to use an external fuel pump. In this case, somewhere on your tank, you'd have to create a provision for a fuel return line. This is dangerous, might want to have a shop do it for ya, because sparks + fumes = death!!! I've seen adapters that allow a return line to be spliced into the tank's filler neck. Lemme see if I can dig one up...

Dammit, can't find it... searched thru http://www.yahoo.com , guess I'm not putting the right things in. Came with a section of filler neck, and two silicone-type hoses. I did find this page, though, that mentions it: http://home.att.net/~airdoc/t1fi.html But again, be careful working on that gas tank... you don't want it to blow up in your face!! I think getting an 85-92 tank would be the easiest and safest solution. Plus, you might be able to rob the donor car of it's fuel lines (return AND feed), too! Then you wouldn't have to figure out how to run them along the car; they'd already be bent to fit the car.

 

remember, this is a carbed 2.8 NO fuel injection. The return line and main feed line hook into the fuel pump. A third line then goes out to the carb.

I think i found a solution. I went up to advance and bought a filter with has 3 ports on it. 1 in and 2 out , the 2nd out on the side of the filter does not let fluid out unless the 1st out is blocked.

I will give it a try.

Thanx TomP for replying

 

Oh, you went to a newer block, but kept the carb?? Sorry 'bout that, I thought you meant that you swapped the intake, too. But I'd think the same thing holds; electric pumps have fuel pressure regulators, too. Excess fuel is returned to the tank. Only difference is, the pressure regulators for carbs are low pressure (5-12 psi) compared to fuel injection (35-60 psi). Here's an example of one: http://store.summitracing.com/partdetail.asp?part=7737

 

don't know if this will help but...

If you switch to a newer block and reuse your original timing chain cover, you'll be able to reuse your original fuel pump and carb (although for 13 bucks you can get a new pump).

Hope that helps

 

MD, the pump hangs off the timing chain cover? Didn't know that! Is the pump driven by a cam lobe or the timing belt?

 

There is a rod that goes into the cover and (I think) there is an off centered ring on the cam that pushes the pump in and out. Only reason I'm not sure is because it's been two years since that part was removed (I did the balancer sleeve and seal with the cover still attatched)

 

So the timing chain cover has an extra hole in it? Cool. Back when I had that '84 carb'd Firebird as a parts car, I never thought to look at the motor; I was too busy trying to get my car back on the road! One problem tho, if he got an '85-up block, I don't think the MPFI cams kept the fuel pump lobe, he might have to swap cams, too...?

 

I thought about that but then i realized the cams are different. The newer block had a more agressive cam then the old one so i decided to keep it.

I'll be trying the filter this weekend, Those pressure regulators cost a ton just for a return line.

I'll let you all know how it turns out