LS3 engine and fuel system questions
 

Hi everyone. Got a couple small questions I am hoping you can help me with. It relates to the fuel system for my LS3.

So first up, with the factory fuel rails on these engines, I am guessing it is set up for a dead head system. Tho I do see an outlet on the end of one of the rails, but think that is for a pressure gauge? Not sure, but wonder if it could be used as fuel out?

If not and I need to replace the fuel rails, can anyone recommend a good place to purchase them?

Moving on to the rest of the system, I want to set it up using 3/8 bundy tube, but am finding it hard to know where to go for the little fittings that you slip on to the tube before you flare the ends. Again, can anyone help?

For the fuel pump, I have bought a Holley EFI in-line pump that has -8 AN O-ring inlet/outlets. I need some fittings that will go from that to 3/8 EFI fuel hose, then some more fittings to go from the 3/8 hose to the 3/8 bundy tube. For the latter, was hoping for a push on type fitting that would push into the hose then screw on to the tube.

Google has not helped me solve all this, so am hoping you guys can.

And one last question. Fuel tank venting. I think you have to go to a charcoal canister, then to the intake manifold. Is this correct? What is a good charcoal canister to use? Are we just finding one from a wrecked car and putting that in?

Many thanks in advance everyone.

Are you using a GM ECU??
 

Jethrow Been working for GM for over 25 years Here what I have found and run a FI system on my car,
Dead head system is good and bad. Good Only use one line for supply the pressure regulator in the gas tank and part of the fuel pump module Need regulator in system to not blow out lines or damage injectors. Pump pressure can go to 100 psi, way to much. Bad side. The gas in US is getting crappie. You need a fuel filter with better that a 20 micro filter to just keep the big crap out of the injectors. The problem is over time the small partials get through this filter and end up on the dead end pipe and start to lean out the end injectors. Problem is ECU doesnot know this is happening and just keeps adjusting the fuel to stop lean out. When motor gets bad enough the SES light will come on with lean codes. At this time O2 sensor or black and done, spark plugs are fouling, gas in the oil smell, the list is endless and have seen it all. We have a 2010 Camero with LS7 got bad gas and the whole system was replaced and paided for by customer, he's sueing the gas station for bad fuel. Good luck in this state. $5,200.00 bill for everything.
I would tell you to use a 2 line system from front to back with a pressure regulator on the fine line of the return. #8-#10 supply line and #4-#6 return line. If you add on down the road a turbo or supercharger you have the supply system to handle a 1,200 HP motor in place.
Evap system you will need to have both the purge valve and vent valve working in the system. The system will need to hold vacuum of a couple of pounds or fail evap test and you get a P0442 or other codes for evap system. Vent soleniod will be in the back of the car. Need a fresh air hose to it with filter to keep out debrie from road,dirt, or water. All these hoses should be plastic. Methonal or Alcohol will break down the tubing if rubber and cause all kinds of problem with the fuel system. SS hoses with tephlon inner hose is needed.
For connectors, both Jegs and Summit have everything you need for this with lines and connectors. I like screw on connectors over clips with "orings" Need a yellow tephlon tape that will not be effected by fuel to seal connections. Same for "o" ring on injectors need to use green or blue seals and gaskets.
Charcoal canister needs to match the motor and evap system. Would look for a S, or T truck to help you for this problem. Large enough to handle system but not that big to not fit under car. This will be you other problem of where to mount it and clear everything. You have your work cut out for you. Some of your friends down under may be able to point you in the correct direction on this. You will need to run wiring to this, pressure sensor in fuel tank also.
Easiest thing is to convert to pipe thread and then to NPT couplers for fuel lines. Hope this helps Rick L.

I was just about to start another thread with similar content, so I thought I'd add to this one...

My question is a little simpler, do you need to run a return line for LS1? (ls3 is probably the same).

We were having a debate the other day and a couple of guys have said they don't run them, but if it was good enough for the factory stuff why wouldn't I.

No need to run a return line. Just use the std GM in tank pump and regulator unit. 3/8 flare nuts are available from any hydraulic supplier.

Standard LS1 does not run a return line.
fuel pump is in teh tank with built in regulator.
I used a factory setup in my car with single fuel line.

Charcoal canister, I personally used a mid 90's Ford Telstar one (small and compact).

how much u want to spend

we just got some annodized ls2 fuel rails from rocket for an l98 into an r34 skyline

fuel lines then go in one one side and out the other
outlet then goes to fuel presure reg then to return to tank
used dash 8 i think braided lines
get expensive but easier to make than bundy tube

charcoal canister can depend on yr engineer
i think there is a calculation so it needs to be a certain size compared to motor
they also sometimes say needs to be simialr size to what motor came with
i usually grab ones of a early corolla as they r tiny but u need to find the 2 hose type
not the 3 hose type

if u run genuine hlden pump assembly u can easily buy the quick kit adapters and the
electrical connector

now theres a very big warning
sometimes u hear stories of cars catching on fire due to fuel eating hoses
u need to use good proper fuel lines when there is no bundy
u will notice nealry all cars run full plastic lines
alot of fuels these days break down certain types of fuel hoses
so do yr research and if u do buy fuel hose ask them about how good it is on
e10 fuel
e85 fuel
98
etc etc
unfortunately spending 800 to 1000 bucks on a fuel system is easily done these days

Jethrow, my thoughts for a street car fuel system.
Ford BA fuel module is easier to fit than the holden unit.

http://www.clubcobra.com/forums/../p...sedan_1612.jpg

Then use a corvette filter/regulator mounted close to the tank. This gives you a filter and a regulator in the one inexpensive unit.

http://www.clubcobra.com/forums/../p..._regulator.JPG


The fittings shown do not come standard with the filter/Reg unless you buy a kit from some-one like Speedway motors in the states.The filter/reg has an inlet, a return to the tank, and the outlet to the engine.

Carbon canister as selected. Bundy between the filter/Reg and the engine compartment. Suitable hose between tank and filter/reg and between engine compartment and engine.

Jethrow,

As others have noted you can go either way.

I am running -8 braided lines from a Commodore tank with Walbro fuel pump. Billet fuel rails from ASE.

FUEL SYSTEMS - FUEL RAILS LS1 LS2 LS3 L76 L98 - ASETurbo

My return goes via an Aeromotive regulator and then back to the tank.

Hope this helps,


Ben

I run a return system on a L76 - one minor prob is if I switch off engine, and have to restart I have to switch past acc for a few seconds at least or the fuel pump wont run when turned to "on" and build up pressure. With the return-less system I am guessing the drop in pressure is minimal when you first switch off, and want to restart it should go - just speculating and its not a biggy either way (more a issue when troubleshooting or testing where you might be switching off and restarting). The corvette filter reg as per Les's suggestion is the way to go IMHO. Phil used it on the orphan and it is very neat.

Also Jump onto the summit web site - you should be able to search for the fittings you need by size and type. Even if you buy local you can get part numbers.

I'm using a VL Commodore charcoal canister, and yes, straight from the wreckers.

Andrew, there is a way around this. Run a one way check valve on the outlet of the fuel pump. This stops the fuel draining back through the pump and into the tank. The regulator on the other side of the fuel rails and the check valve will keep pressure in the lines for a while but it will slowly bleed away. However you should still have a head of fuel left in the lines. That will give you pressure at the injectors as soon as the pump starts pumping the next time you turn the key.

Cheers

I used a VZ canister and my reasoning for this was that it was designed for the LS engine you can buy it new from Holden (not as expensive as you would think), it sits on a bracket which is easy to mount anywhere. Due to the fact you will have to pass emissions I believe it's a good idea to have a new canister because it won't be saturated with fuel vapor. Albeit a little bulky...

The VZ canister is also what the current CR build manual suggests. It is what I will be using.