Ok I am adding a Holley EFI on to my 1984 Z28. The car was originally carbureted. I was looking at my fuel system and I have a 3/8" supply line to my mechanical fuel pump and a 5/16" return line to the tank. Holley recommends that a return line drops down inside the tank to avoid agitation in the fuel when it is returned from the EFI system. I have found several pictures of fuel sending units they show the return and vent line to the top of the unit and that is it. I have also saw a few pictures where the fuel return line dropped down inside the tank with a tube.
Does anyone know exactly how the 84 Camaro fuel sending unit looks like? I am trying to avoid dropping the exhaust and rear end to drop the gas tank. I am running Holley inline fuel pump.
Just trying to verify the configuration on the fuel sending unit. unfortunately I can not find one for sale to see what they actually look like.
Thanks

 

I'm pretty sure the return line for fuel injection has to be bigger than 5/16"...

 

I just verified with Holley on the installation video that minimum requirements are 3/8" supply and 5/16" return.

 

Oh well that's good...

 

yes hopefully I can find out about the return line into the tank.

 

I once rigged up EFI on my '82 using the carb tank and sender-ran it a couple years with no problems at all before i eventually swapped in an EFI tank that also has the plastic tray around the pickup to prevent fuel from sloshing away from the pickup sock when fuel is low.I mounted my electric pump for the EFI on the engine in the area of the mechanical pump-supposed to be a no-no,but it worked fine in all conditions...

 

https://www.thirdgen.org/forums/tech...-modified.html

 

I was wondering if I could put my pump and filters up in the engine compartment. when I un-hooked the mech. fuel pump the fuel keeps running out of the supply line. I had to put the rubber hose back on the line and put a bolt in it. I am guessing they would rather have you push the fuel rather than sucking it?

 

Electric pumps are better pushers.
Mechanical pumps are better suckers.
The supply lines to either pump should be below the tank.

 

the fuel tank will usually continue to push fuel through the supply line at the fender well when it is opened. relieving pressure on the tank by cracking open the fuel cap will usually stop it.

if it continues to siphon, clear the fuel out of the line with an air hose.

the return line does dump into the top of the tank. I've run a fi tech through these steel lines (connected with flex to the fitech) with no trouble for thousands of miles. I used a walbro 255 in-tank connected to the stock pickup on an 87, which came from the factory with an in-tank helper pump.

I would recommend the in-tank pump option using as much of the steel lines as you can.

 

so you just let the return line drop the fuel into the top of the tank? I think that is the plan and try it. If it doesn't work then drop the tank.
I bought the in line fuel pump kit from Holley. I am using the steel lines front to back and didn't need the 40' of earls 3/8" hose I got. I should have researched it more and got way less. Just bought what they suggested.

 

40 feet of rubber line will be a restriction.

 

this is what Holley sells you they told me I needed 40' the other kit comes with 20'. I wish I would have went a different way on the fuel pump.

 

Where is the return line in the engine bay? Was it over by the charcoal canister?

 

It's right next to the feed line...

 

Thanks. I’ve had a regular carb so long I couldn’t remember. Researching Edelbrock fuel sump and Holley sniper on my L69 car.

 

Took a look and found vent from charcoal canister on drivers side and return directly below

Return

Charcoal vent