Walbro 255 Fuel pump very loud!

[gvincent]

I'm about to install a Walbro 255 in my 280Z with an LT1, Yeah I know wrong forum but I too have had a lot of fuel pump issues.

Here is my history:

Bought a Mallory 110FI pump, had the stock fuel rails modified with -6AN fittings, ran new 6-an braided hose for send and return lines. welded up a mount in the stock fuel pump location, the Mallory has it's in and out on the bottom sides so both are very low.

I even mounted the Mallory with rubber isolation bolts and nuts so there is no metal to metal touching to transmit vibration. (well the braided fuel lines but they are not solid)

 

I ran a 1/2" hose from the tank to a huge long 100 micron filter with -8an fittings in and out then another very short piece of 1/2 hose to the pump inlet with -8an fittings.

I have a -8an to -6an 90 degree fitting mated to the braided -6an hose to the front drivers side fuel rail.

 

I mounted a brand new Aeromotive FRP 10" from the passenger fuel rail mounted on the firewall and attached to the -6an braided hose back to the 280Z tank. Just before returning to the tank I have a "T" fitting that connects to a smaller third fitting on the very bottom of the fuel pump and back to the tank.

I didn't have this T fitting before and would notice the pump would run hot and slow down and did not like being below a half tank.

The T fitting did improve but sometimes the pump would sound like it was cutting out sometimes and I would loose power, I have not been able to run WOT without starvation yet.

 

I sent the pump back to Mallory for a rebuild ($50) re-installed it and it runs the same, still noisy, still has moments where it sounds like it wants to stop but got me through all last season but still no WOT.

 

So enter a Paxton pump which is the same as an Aeromotive A1000, very loud and could not maintain a constant pressure, the fuel pressure gauge at the FPR would jump all over the place, sent it back and re-installed the Mallory.

Took the Z out for it's first run last saturday and after an hour the pump sounded like it would quit on me, it would seem like it stopped for a 1/4 second about every minute or two.

Limped it home. I will remove the Mallory for a 3rd time and get it rebuilt again for free and put the Walbro I just bought in.

I will let you know the results.

Oh the Aermotive FPR does not hold pressure, never has, I called and they said that as long as it passes the pressure test and has no fuel coming out the vacum fitting all is well?

I am begining to wish maybe I should of done the Z28/Firebird tank swap, but a frien of mine can't get it to work with the Datsun fuel gauge...another story

Thanks,

Greg

[Dans toy]

For the 110FI they suggest 1/2" feed and return. You might talk to Mallory about the 6an lines ( possibly to restrictive). Just a guess.

[Pyro]

Every loud pump I ever had was caused by a restriction on the input side of the pump.

 

Either the filter or intake tube.

 

A walbro 225 needs a 1/2" feed line with a 100 micron filter of decent size.

 

As a test, try it without the filter and with a 1/2" feed line directly into the tank (down the filler hose).

[kj280z]

Yep -

 

I solved the problem with my Walbro 255

 

It was multiple minor issues all combining to make it loud...

 

1. I had a 90 degree elbow on the suction side of the pump - eliminated it and replaced with a straight through fitting. I also drilled it out as well.

2. The filter from Summit Racing between the tank and the suction side had to go - it was 100 micron but every time I tried to add it into the system after trouble shooting it would add noise - still trying to find a good solution for this

3. Added a filter near the FPR in the engine compartment

4. Lowered the pump in relation to the tank

5. Put a larger hose (1/2") on the suction side of the pump