Herminator

I got a high flow 225 lph intake fuel pump making some noise. Sounds like its trying to pump but making a lound pumping noise. I noticed I was running lean on the A/F guage on WOT so I shut it down and went home slowly. I swaped the high flow with my factory fuel pump and the noise went away. My question is.....

Did a small debree get into the high flow fuel pump and get stuck inside it?
Did the Walbro fuel pump take a **** on me?
Whats a good reliable fuel pump?

My setup is.....
Greddy turbo no blue box.
VAFC
AEM FPR
Vortech FMU
(fucked up) Walbro Fuel pump
310 injectors

And yes I know I need a standalone. Just saving up so please spare me.

littlebluecrx

what is your fuel pressure doing?is it staying constant, walbro's can go bad especially if you run the tank dry, the bearings will seize.Does the fuel sock look like it has debris, in it? If you dont have a sock on it it probally did suck some stuff up. Jason

Herminator

Static pressure is at 40 psi. When I hit the throttle it goes up to 60 psi. At WOT it goes 100 psi. I'll probably run lower boost until I get my standalone and bigger injectors.

BHSCGSR

Does it hold at 100PSI? - Or does it start dropping off?

Herminator

I have an engine fuel meter. I saw it stay at 100 psi WOT at the dyno but I really have no idea what its doing now cause I have no X ray vision . I really need to invest into a fuel pressure meter inside my car.

Update on the fuel pump being bad. Apperantly when I installed my stock pump its still making the noise. Sounds like its trying to pump the fuel but something is blocking its path. Now I got new questions......

Could my Damm FMU be causing this?
Injectors cloged?
Something is lodged in the fuel lines?

skilzz

Here is a very important question for you...are you still running stock injectors? what happens sometimes is with too much fuel pressure behind stock injectors the injector coil is not strong enough to pull the plunger up resulting in the injector staying shut when the pressure gets that high. It is not your FMU if your fuel goes up per pound of boost and by the way those 255lph are usually pretty loud, a lot louder than stock walbro usually makes a good product so it shouldn't be going bad especially if you hear it buzzing. One more thing if you installed the pump with any kind of obstruction in the pick up then that could affect it operation, make sure there is enough clearance between the pick up screen and the bottome of the tank. Thats all i got for ya hope it helps

therealnapster

I had the same symptoms, and same pump as you, it got really loud and when looking at my fuel press guage (electric guage, inside car) my fuel press (using fmu) was'nt going all the way to 100plus as is should have been. I bought a new pump (same one) and everything went away and car ran much better. The filter bag on the pump was extreamly dirty, this most likely caused my pump to wear out prematurely.
.ad.

Herminator

I got 310 injectors. I'm planning on getting 600 in the future. As for the fuel pump, I swaped the walbro out with my stock pump and same results. So I dont think its the feul pump. I'm thinking either injectors or FMU. Sounds like its resonating.

Yes the humming noise was there when I first installed it, everything was fine and dandy then I hear this resonating sound. Sounds like tis trying to pump but something is obstructing its flow.

I'm gonna try and find someone with an extra FMU and swap it out.

CKim

This may be off topic, but if you're running the Walbro GSS-317, it will not be able to sustain fuel pressures over ~85-90psi for extended periods of time.

The GSS-342 is a better bet with those kinds of fuel pressures.

Herminator

Yessir thats what I got the GSS-342 high flow pump.

Its odd because when I boost at 5 psi my A/F reading reads rich @ WOT. When I boost 8 psi my A/F reading reads lean @ WOT.

littlebluecrx

how is your fuel filter? is there a kink some where in the fuel system?, also check to make sure that your fuel pump is getting at least 10 volts if you run a seperate relay bypassing the stock main relay your fuel pump will get battery voltage will deffinently increase flow at higher fuel pressure and demand,Jason

Xerxes

I was thinking you shoudl double check and make sure you have no vacuum leaks! there might be a vacuum leak between the manifold and the FMU, which would account for weird activity at idle and lean running under high boost.

You're probably rich at 6psi just because you have relatively high base fuel pressure & are running big injectors.. and then the FMU does nothing, so you get lean at higher levels

-Xerxes

Herminator

Well today I riped apart my Vortech FMU and everything looks ok except some lose screws. I tightened everything up as close t 2 foot pounds as posible and now the sounds gone but it still lean at high boost and rich low boost.

I'll check the vacum lines again. Seems like I'm losing boost presure at high boost. Mybe I got a boost leak somewhere.

Xerxes

with the car idling, spray some wd40 around any possible vacuum leak places.. if there's a leak, the wd40 will get sucked in and combust, and you'll hear the engine rev..

-Xerxes