Gunner Dog

I'm complete with my 2006 5.3 with 46,000 miles into my 68 Camaro. Only engine modification was a Trick Flow cam. I'm extremely happy with the performance and drivability. There are two fuel system issues that I have questions on.
I bought a Tanks, Inc tank and fuel pump (Welbro) kit. First issue is the car takes a two fuel pump cycles (two key turns) to allow the pump to build enough fuel pressure to start the engine. Seems like I'm loosing fuel pressure after the car sits for a while. I asked Tanks, Inc about this and they said the pump does not have a check valve built into it and most of the time you don't need a check valve to hold fuel pressure. Is that true? They suggested installing an in-line check valve near the pump to fix the problem.
The other possible issue is the pump makes excessive noise (high pitch whine) that changes frequencies while driving. Tanks, Inc. suggested the pump pick-up may be pressed against the bottom of the tank, causing the pump to work harder to pull fuel, which would cause excessive noise. I was very **** about measuring and cutting the tubes to fit properly inside the tank so I doubt this is the issue. Also, I don't hear the whinning pump during warm-up, only when the engine is hot. Maybe this is normal and I'm just over thinking the noise? What have you experienced?
Thanks. Doug

gm-ntmr

iTrader: (1)

Check valve is a must if you want it to fire first go.

The pump whining could be multiple things, first that come to mind for me is the pump wired straight or do you have a good relay?

As far as being to close is very possible but it sounds like when the pump gets hot it starts to whine which could be caused by it being to close.

Don't know if that is really the answer your looking for

Gunner Dog

Thanks for the input. The pump is direct wired from the wiring harness...no relay. Again, maybe I am over thinking the whine. Does others have the same sound or do I need to do something about it? There is no issue with fuel delivery. These engines flat get with the program.
I will plan to install a Russel in-line check valve in the near future.

66chevelle_02SS

iTrader: (7)

I would suggest checking your pressure at the rail. I had an issue where the car didnt want to start on the first turn of the key. The hose from the pump to the outlet burst and I was only getting about 15 psi at the injectors. The car still ran and drove with no issues. As far as the whine my pump whines a little and does get louder with less fuel in the tank. It changes pitch a bit due to voltage fluctuation as well. It has done this since day one and i have about 15000 miles on my swap so I am not too concerned about it.

M6 Swap

iTrader: (1)

not trying to hijack the thread here but...gunnerdog what are the specs on your trick flow cam? how much of a power increase did you see?

bczee

iTrader: (12)

How is the rest of the fuel system (tubes, hose, filter and regulator) setup ?

would suggest checking the following:
- Checking how close the bottom of the pump/sock is to the bottom of the tank.. to close ?
- Reguator, what pressure are you getting at the fuel rail ?
- Return, is it block or restricted ? dead heading the pressure and causing the pump excessive pressure on trying to feed.
- on first start up.. what is the pressure at the rail ?. what is it running at idle and also at WOT ? needs to be 58psi regulated.

Gunner Dog

Trick Flow Track Max cam for GM LSX. Part # TFS-30602001. This cam has a mild lope and pulls hard from 2000rpm and up. My engine builder friend told me this cam runs better than the Vette Z06 GM cam he has used in the past. He plans to use this cam from now on.


My entire fuel system is new. I used pushlock hose and connectors with a Vette fuel regulator/filter. I also used a PCV valve (one way valve) mounted above the tank to relieve the gas pressure build-up in the tank...I would not think this is contributing the pump pressure issue at start-up? I'll check the pressure at the rail per your suggestions. As much as I don't want to, I will drop the tank and verify the pump/sock clearance too. Thanks.

S10xGN

iTrader: (11)

My (carb'ed) external Holley black pump makes a racket and changes pitch frequently. It's got less than 3 ft of #10 wire from my battery thru a relay to the pump. No idea why this is... On any FI system, the regulator acts as a check valve on the return side but the pump itself should hold pressure on the inlet side. At least the Aero-340 in tank pump in my GN powered S-truck does...

Pop N Wood

iTrader: (1)

My external mallory pump got a lot more quiet when I switched to a lower pressure drop pre filter. It use to get more noisier as the fuel level got lower.
Any sort of restriction on the inlet will increase the pump noise level.

Hot fuel can flash to a vapor in the pump causing it to cavitate. A different noise, but that does make the pump work harder.

While you have it out I would consider back flushing the pump and looking for debris.

rigid

iTrader: (5)

I've had several cars with walbro pumps and they have all whined a little. All my walbros have had check valves built in and didn't require any additional priming. Is this an external pump or in tank? I had a bosch 044 external and it whined super loud and the pitch changed constantly. It also had no check valve and I would have to prime it multiple times.

ijimmy

i have a walbro 255 in my 64 chevelle along with a corvette regulator , allways fires quickly and is dead quiet

S10xGN

iTrader: (11)

Pop,

I've got a 100 mike inline RobbMc pre-filter with a large 10 mike BG canister post-filter, is that too restrictive?

Pop N Wood

iTrader: (1)

Sorry for the thread hyjack but with the exception of the brand names we are running the same set up with the same size pumps and filters. As long as the pump is mounted level to the bottom of the tank and assuming good line routing that is about as good as it gets. A return style regulator helps. My previous pre-filter was a high buck paper element type. I replaced it with a cheap 100 micron screen type and the noise really went down

Having said all that mine is still pretty noisy. A good part of that is due to the way I have it mounted and the total lack of sound deadener in the car. But I also think 140 gph is way more pump than I need. It would probably be a lot more quiet with something about 100 gph.

But to the OP, pumps don't like to suck as much as push, so any restriction in the intake path will make the pump work harder increasing noise. That could also be affecting your ability to build pressure. I could see where a line leak or loose fitting on the inlet side would do the same.

Gunner Dog

I wanted to post to close the loop on this thread. First I checked the fuel pressure, which was 62 psi. Next I pulled my in-tank pump to check the overall length of the pick-up tube. Decided to trim 1/4" off the the tube to allow some additional room at the pick-up filter. That fixed it and no more whine!

I went ahead and installed a Russell check valve in the fuel supply line as well. I have immediate starting now too.

Thanks for the suggestions.

bczee

iTrader: (12)

Glad we could help ! ... Now if you would only post some dawg pictures of your project ! LOL

BC

Gray86hatch

iTrader: (83)

I have installed 2 tanks kits and neither required a check valve and both start first click of the key. Both have welbro pumps.

Tim

Gray86hatch

iTrader: (83)

I have installed 2 tanks kits and neither required a check valve and both start first click of the key. Both have welbro pumps.

Tim

Old Geezer

iTrader: (3)

"I also used a PCV valve (one way valve) mounted above the tank to relieve the gas pressure build-up in the tank...I would not think this is contributing the pump pressure issue at start-up?"


U can't use a 1 way valve that vents, but shuts off when the tank pressure drops.
Fuel heats up, pushes the air out of the tank..OK
Fuel cools down, and the valve closes.. No deal. The pump inlet is now operating under a vacuum. That will kill it, as it will cause cavitation.

Gunner Dog

My gas cap also vents so the tank should never be in vacuum. My thought was to allow additional venting due to oxygenated fuels that are required in my region of the country. I could just cap off the vent that came with the Tanks Inc. kit but I'd be relying 100% on my cap for venting. Maybe a better suggestion? Possibly a fuel filter in lieu of a PVC valve?