Electric fuel pump

[SLE-883]

I have just installed a carby convereted 304 engine in my SLE.

It has an Edelbrock AirGap manifold, Pacemaker headers and 650 DP. As part of the set up I've installed a Cater fuel pump. It's the 4600 model which is rated at 8-9psi.

I had installed the pump originally too high compared to the tank and was getting a 2psi reading in the engine bay. I've now relocated the pump on the rail near the back door and although when I first start the car I am seeing a 6-7psi reading, after driving the car I pop the bonnet and the guage is reading 3-4psi. I don't have a regulator to achieve this.

This seems low however the car it running fine and the fuel bowls are filling up. I went on the highway to see how it went at speed and at 100km/h didn't notice any pinging.

From your experience is 3-4psi ok? Should I upgrade the pump to the Carter 4601model which is rated to 15psi and the use a regulator?

Thanks in advace for your help

 

[gtrboyy]

Ideally you'd want regulator + gauge just so that can mess with it to see if turning pressure up when hot compared to cold makes a difference then see if fine afterwards on cold starts etc.

Couple of things on mine were heatsoak issues & fuel tank pickup restricted fuel flow on my 355 up high as it doesn't sit low enough in tank & too small.

It did have constant 5-6psi with holley black 150 in boot.

Try regulator first then fuel pump...seen a few car cars that had their f/pumps attached to fuel tank strap or bracket above it like vk efi/vl & early vn cars.

 

[waikato willy]

mine did the same at the first street meet at the drags a few weeks ago, dropping to around 4psi at the carb, the fuel pump and regulator were about 15-20 years old , under a big third gear skid to warm the slicks I would run out of fuel and car would die, driving around normally it was fine
I swapped fuel pump (holley blue)out for a Aeroflow Blue pump and I changed the regulator from a dead head to a Aeroflow pass through with a return line, I mounted the pump where a VL fuel pump normally goes but at the right orientation
Fixed the issue straight away, ill get a pic of it tonight where I mounted it
fuel pump and regulator were really cheap compared to a holley replacement

 

[waikato willy]

i know the pumps are not really designed to suck, but this works a treat, i will probably replace the fuel line with a piece of aluminium pipe eventually

 

[shane_3800]

i know the pumps are not really designed to suck, but this works a treat, i will probably replace the fuel line with a piece of aluminium pipe eventually

If the pump is primed but below tank level it's not sucking.

 

[SLE-883]

Ok, so I think the issue is the guage I'm using.

When I turn the ignition on and prime the pump the guage reads 6.5psi it also stays at 6.5psi while idling. As the car warms up it drops to about 4psi.
I went for a long drive on the weekend and was hot when I go home I checked the guage before turning the car off and the guage was now close to 0psi.
The car never pings or nose dives even on the highway going 100kms.

I read up about others that have had the same issue and it came back that cheaper guages may fail as the liquid in the guage heats up and gives a false reading. I'm running a $35 aeroflow guage but am looking at getting a ARO15632 - Aeromotive guage that states addresses the issue

 

[SLE-883]

So the update is the Carter pump crapped out after just a few months of use. It must of been faulty from the beginning because I've since installed a Holley Blue and the guage is showing 12psi without a regulator right off the bat. It installed the reg and turned it down to about 8psi and installed a second guage at the reg. Now both the original guage at the carby and the new guage at the reg show the same PSI consistantly.

 

[SLE-883]

BTW - The Holley blue is so loud though. sounds like a hammer drill.

 

[gtrboyy]

Holley Black is much quieter could barely hear mine over the exhaust at idle...was in boot rubber insulators.

Probably why they made the black version as blues were annoying as hell.

8psi sounds high for n/a carb...think the 2 holley regulators one is fixed at 4.5psi & other adjustable iirc

Good shop out west for carby gear is Hume Performance

 

[vc commodore]

A carb needle and seat like 7 psi..... 8 psi might be fine for a bit, but may cause the needle and seat to fail....Don't hold me to the failure but.

Perhaps turn it down to 7 psi just to be safe