R33 loss of power (fuel pump)

[Mitch r33]

R33 loss of power (fuel pump)

Hi guys,

having problems with my r33, fueling issue I believe. I've had a walbro 255 fuel pump installed for over 1000kms and haven't had problems besides it taking a bit of throttle and a few extra turns of starter motor to start. But that's ok.

The problem im facing now is loss of power with the foot down. No loss in boost still running 10psi fine. Also a very loud noise when it primes at key turn, not a squeal sound quite like a quiet boat horn. I've tried having a full tank but still doing it. I'm wondering if fuel pump came off the rail? I did have a flat battery today, but I've driven it for over an hour and still doing it. The loud prime and loss of power wasn't there before I had a flat battery. I also caused a little spark near horn when installed new horn. But I doubt that could of caused anything but thought I'd throw it in

 

thanks in advance

mitch

Edited September 20, 2017 by Mitch r33

[Birds]

Could be stuffed or blocked.

You can check fuel pressure by disconnecting fuel line after filter and priming it into a bucket (ignition, no start)

Check the fuel filter isn't clogged, too.

But yeah failing that stuff, might be time to pull it out and have a look.

Did you wire it with the stock wiring? Think I remember with the walbros you need to get rid of the variable voltage wiring that the stock pumps use.

[Mitch r33]

 

1 minute ago, Birds said:

Could be stuffed or blocked.

You can check fuel pressure by disconnecting fuel line after filter and priming it into a bucket (ignition, no start)

Check the fuel filter isn't clogged, too.

But yeah failing that stuff, might be time to pull it out and have a look.

Did you wire it with the stock wiring? Think I remember with the walbros you need to get rid of the variable voltage wiring that the stock pumps use.

Fuel filter is new, I'll have to take the pump out and have a look I guess. It does make like a blocked noise. Is just weird how it did it after flat battery. how can you test it by going into a bucket, I have no clue how much flow is supposed to be right. I used stock wiring. But no problems before tune or after tune so wouldn't think it'd be that?

thanks for your help

[Birds]

Trace the fuel line from filter to the start of the rail and pull the hose off...then hold the hose into an empty bottle while someone turns the key to ignition...fuel pump will try to prime the rail but it'll effectively just keep squirting into the bottle. It should be a fairly strong stream.

That might at least save you the hassle of fking around with that damn pump cradle bracket...

[Mitch r33]

I'll pull it out from after fuel filter, hopefully that'll work? 

[Mitch r33]

I have grounded the fuel pump to the chassis giving it 12v constantly. Fuel pump still makes a bad noise when starting and am still having the detoninating problem. I replaced the battery and that fixed it or like 10 minutes but not its doing it more

[Birds]

Remove hose and check that fuel flow. It kind of sounds like the pump may be fked.

[Mitch r33]

8 minutes ago, Birds said:

Remove hose and check that fuel flow. It kind of sounds like the pump may be fked.

Checked for flow. Was fine. But hardly drives now. Removed walbro fuel pump, turns out the fuel pump filter inside tank has fallen off. Guessing the fuel pump has filled up with dirt now and is rooted. Will get a new one and try and see how that goes

[Birds]

Believe it or not, I was going to suggest the pump had sucked up some sediment...but after googling your pump, saw that it had a sock filter like the standard pump and ruled it out. Well done on finding that though...it's almost certainly the cause of your issues. What may look like good fuel flow from the hose may not be enough under heavy throttle / higher RPM. Testing the flow this way doesn't have the resistance of the fuel rail / regulator to build up pressure and really push the pump. But it can sometimes show if a pump is not working at all.

Might be a good idea to drain the fuel tank / give it a flush out to stop it happening again. Also replace your fuel filter as it'll no doubt have copped some of the crap the pump sucked up. Alternatively, I can't recommend the 040 enough as a replacement pump if you can be bothered doing the hose clamp stuff to make it fit the cradle. They are a tractor pump so hardy against sediment and have a metal mesh on the end to stop heavier stuff getting in anyway.