Outer Limits 4x4 Board

Just come back from a mild drive out at toolangi, did a couple of steep hills and the first one i was just crawling and it kept dieing on me half way up. I managed to roll back slowly to a washout and was just priming the pumps a few times till i figured the surge tank was full enough for me to blast the last bit. Now it has a low pressure holley pump filling the surge tank but its not keeping it full it seems is there any reason why i couldnt use a normal high pressure pump between it an the tank?

Not realy a reason you cant
But will probably need to add a rising rate fuel regulator

a regulator at the engine or between tanks? I dont need more fuel at the engine i just need fuel there all the time.

I would still use it between the surge tank and engine to controll fuel pressure ,
But depends on what type of high pressure pump you use and how much extra pressure itll have

it looks like an bosch 044 comin out the tank, holley blue pumpin in. can hardly tell its running. maybe its just fuct

HUSSLN wrote:it looks like an bosch 044 comin out the tank, holley blue pumpin in. can hardly tell its running. maybe its just fuct

Yep, the low pressure pump might be rooted, test it. You don't really want a high pressure pump feeding the surge. All you need is low pressure/high volume. Low pressure pumps are designed to suck which is why you want it feeding the surge. High pressure pumps don't suck too well and will die quickly if they run dry.

Just take the hose off an see if its pumpin consistantly? Out of curiosity is there a more compact low pressure/highvolume pump cos the holley hangs below the chassis im guessing it cant be mounted horizontal? Or some nuffy has just set it up that way

HUSSLN wrote:is there a more compact low pressure/highvolume pump cos the holley hangs below the chassis im guessing it cant be mounted horizontal? Or some nuffy has just set it up that way

Of course.

http://cgi.ebay.com.au/ELECTRONIC-FUEL- ... 0093913500

No idea on whether the holley can be mounted horizontal, I really can't see why not but there should be specs out there somewhere.

I would ditch it, I have yet to hear a good word about a Holley pump and yours is the second thread like this in a few weeks.

chimpboy wrote:

HUSSLN wrote:is there a more compact low pressure/highvolume pump cos the holley hangs below the chassis im guessing it cant be mounted horizontal? Or some nuffy has just set it up that way

Of course.

http://cgi.ebay.com.au/ELECTRONIC-FUEL- ... 0093913500

No idea on whether the holley can be mounted horizontal, I really can't see why not but there should be specs out there somewhere.

I would ditch it, I have yet to hear a good word about a Holley pump and yours is the second thread like this in a few weeks.

Yeah they are good and that's not a bad deal. Make sure you get the "optional rubber shock mounts" for it too either from that supplier or Repco, etc. Although reliable, they are noisy pumps at best but those dampeners help alot.

Is this a recent issue? Or has it just reared its head?

Are you running your fuel return line from motor to the surge tank? Or from motor to the fuel tank?

L/P pump could be stuffed.

My motor bike runs the same setup to the pic ray has posted. When the needles close it build preasure and shuts the fuel pump off. Cutting edge tech from 1990.

Is the fuel return usually skinny? if so it runs the factory line back to the tank. The factory intank pump seems to be feeding the surge as well as the holley. The pumps gonna be low which ever one i buy cos the tanks low which sucks. And it has only just reared its head cos on christmas eve i spent longer on steep inclines and rougher hills and didnt have trouble.

Running a high pressure pump to the surge tank is only useful if the surge tank can handle the pressure and if the volume of the high pressure pump is considerably greater that that of the current pump.
As mentioned, your return needs to go to the surge tank, not the main tank, other wise you're asking you're lift pump to move as much fuel as your main pump.
You then need a return from the surge tank to the main tank to avoid over pressurising the surge tank.
Your lift pump only needs to be able to pump about 2-3 litres per minute. Check it with an empty 1.25 soft drink bottle and time how long to fill it. Anything under 30 seconds is sufficient.
I would hazzard a guess that the issue will be in the plumbing rather than components.

Dan

Ok well ill have to take the surge tank out then and get some fittings plumbed in.

Is the fuel return usually skinny? if so it runs the factory line back to the tank. The factory intank pump seems to be feeding the surge as well as the holley. The pumps gonna be low which ever one i buy cos the tanks low which sucks. And it has only just reared its head cos on christmas eve i spent longer on steep inclines and rougher hills and didnt have trouble.

Why do you have an intank pump feeding a holley? You should only need the intank pump feeding the surge tank and have the return coming from the top of the surge tank. What motor are you running? Your factory intank pump could have enough flow to feed it all by itself without any need for external stuff apart from filter and regulator.

Kitika wrote:

Is the fuel return usually skinny? if so it runs the factory line back to the tank. The factory intank pump seems to be feeding the surge as well as the holley. The pumps gonna be low which ever one i buy cos the tanks low which sucks. And it has only just reared its head cos on christmas eve i spent longer on steep inclines and rougher hills and didnt have trouble.

Why do you have an intank pump feeding a holley? You should only need the intank pump feeding the surge tank and have the return coming from the top of the surge tank. What motor are you running? Your factory intank pump could have enough flow to feed it all by itself without any need for external stuff apart from filter and regulator.

x lots

If you have a factory in tank pump then I'm thinking this is an EFI setup already (high flow in tank pump with tank baffles/swirl pot section) in which case you wouldn't need a low pressure pump or surge tank or the secondary high pressure pump. More info needed. What car, what motor, what tank and in tank pump?

Alright sorry should of pointed out a few things from the start. Its a lux with a holden v6. I didnt build this thing im just re building it. The line from the intake pump goes to the surge tank as does the one from the holley, how it works together i have no idea. The return line is as factory goes back to the tank. Im all ears on how it should be setup properly.

One option, although probably not the "best", would be to direct the return line to the surge tank, then have overflow from the surge back to the main tank.

This will always keep your surge tank full (or as full as possible) but the downside is (theoretically) hot fuel returning from the engine will elevate the fuel temp in the surge tank. Theoretically, this is bad, but I've never seen any real-world reports to indicate it's a real problem.

This is the setup I ussually use for EFI conversions.



Sorry if its hard to read.

Gutless wrote:This is the setup I ussually use for EFI conversions.



Sorry if its hard to read.

That's what I've got with two differences, one is I have a filter in the line from the tank to the low pressure pump, the other is that I only have one hose doing the job of your "fuel return" and "breather return" hoses. I am wondering if this matters.

I tend to go Holly near the tank feeding the surge tank,
A small pump from the surge tank to the engine with a regulator.
If your allso running a intank pump I wonder if that is not working properly/not at all and is restricting the fuel flow

edit: Had another look and post below explains

Ok upon closer inspection and since learning a few thing (thanks guys) it looks to be like this. The holley is feeding the surge, what i thought was the intank pump line is actually the return/breather for the surge to the tank, there is a return line from the engine going to the surge tank and correct me if im wrong also looks like ones going to the tank as well. So buy the looks of it its plumbed right, but maybe the shape of the surge tank has its flaws?
ok this pic shows the return/breather line from surge to tank


This pic shows in the left corner the feed line from the holley and the right corner is the return line from the engine.


This is the holley mounted ready to get ripped off


and finally this is the H/P pump and where it draws form the surge.


sorry about the iphone pics i dont have a digi camera but you get the general idea.

Weres the surge tank located

In the 3rd pic with the holley you can see the tank which is in the factory position and you can see where the surge tank is also

I Think

1) Its located in the wrong place
2) Its the wrong Shape

Relocate it to the engine bay level or above the engine
Your Horizontal one is prolly causing the surging as it looks alittle long
Change it to a verticle one

Also make a plate to protect the holly

Trace the lines carefully and draw a diagram of what hoses go where.

And what height they are at on the surge tank.

IMHO the shape of the surge tank shouldn't matter that much as it is probably 100% full all the time (when the pumps etc are working correctly).

Ditch the Holley, for fifty bucks you might as well eliminate it as a possible problem.

chimpboy wrote:Trace the lines carefully and draw a diagram of what hoses go where.

And what height they are at on the surge tank.

IMHO the shape of the surge tank shouldn't matter that much as it is probably 100% full all the time (when the pumps etc are working correctly).

Ditch the Holley, for fifty bucks you might as well eliminate it as a possible problem.

chimpboy wrote:Trace the lines carefully and draw a diagram of what hoses go where.

And what height they are at on the surge tank.

IMHO the shape of the surge tank shouldn't matter that much as it is probably 100% full all the time (when the pumps etc are working correctly).

Ditch the Holley, for fifty bucks you might as well eliminate it as a possible problem.

Im thinking the shape of the surge tank because hes getting surging from the surge tank which suggests it dosent have or isnt being supplied with the right amount of fuel.
I beleive he said there was heaps of fuel coming from the lines or maybe he was going to check that