walbro fuel pump question

[maxkid123]

has anyone ever had problems with the walbro 255hp fuel pump before?? i just recently installed mine and went to get dyno tuned and had a problem with fuel pressure dropping around 4500 rpms im wondering if its the fuel pump but idk

[Instigator1225]

hmm ive neve rheard of that one.

and ive used 255's alot with my friends cars... and two of my own cars.

the only thing i am not fond of is people using two of them.


but ive never heard of that kind of problem.

[maxkid123]

im also running a begi fmu on my car...im wondering if that thing is shot and is screwing up the fuel pressure up top idk

[bdmaxima]

a i know a few guys with it no problems. maybe there's sumthin wrong with urs. replace it and see if it fixes itself

[maxkid123]

bd ur talking about the begi? or the walbro?

[bdmaxima]

the walbro.

[maxkid123]

ohh...well i have another pump laying around ima try but idk i dont think thats it...i think it might be this stupid fmu

[matt@turbotek]

while i have seen walboros go bad , i have never seen a new one do this. does the preassure drop around 4600 and then come back up or does it stay low? if it rises again i say that is something fmu related.

[Instigator1225]

^^ agreed... the 255 would be shaky all over.. not jsut at certain rpm if it was bad.

[SovXietday]

^^ agreed... the 255 would be shaky all over.. not jsut at certain rpm if it was bad.

Eh, doubtful, if the pump is bad it will struggle to keep up under higher demands. Not so much during low speeds unless the pump is REALLY shot.

But then again, if you're using an FMU, the last thing you need to worry about is your fuel pump lol.

[Silverfc88]

I would check your pressure regulator and also make sure your alternator is giving your system a full charge at higher RPM's. Are you using the stock wireing to the fuel pump?

[Big Mike]

Watch out where you buy your pump there are fake pumps out there. Read the link below!

http://www.exelife.com/blog/automotive/walbro-fuel-pump-forgeries-who-knew.html

[Kevin]

Fuel pump rewire and aftermarket fuel pressure regulator.

[Spoolin_VQ30DE]

might be your FMU try cartech or the vortech one

[OMGz Turbo]

fmu= vortech yo.

[maxkid123]

okay when i was on the dyno as soon as he floored it everything was fine fuel pressure was rising like it should with boost pressure then as soon as he got to like 4600 rpms or soo the fuel pressure just like stuck there and it started leaning out like CRAZYYY!!!

[Silverfc88]

Whats your whole setup? What are you using to tune with? ECU? What injectors? Where are you getting your vac source for the regulator?



Before you said the fuel pressure was dropping and now it just stays there at a certain RPM? What fuel pressures are you seeing?

[maxkid123]

im running stock injectors im tuning with safc stock ecu my vac source is comming from manifold...im trying to remember what exactly was happening...caause when hed floor it the pressure would only get to like 60 63 pounds then it wouldnt go any higher...almost like as soon as it got to there it hit a block or there was a massive leak...like it wouldnt go ANY higher it was weird i still cant figure it out to this day...so im thinkin either the fuel pump wont put out more pressure then that ( which i doubt) or the fmu is effed up

[ImportDPS]

im running stock injectors im tuning with safc stock ecu my vac source is comming from manifold...im trying to remember what exactly was happening...caause when hed floor it the pressure would only get to like 60 63 pounds then it wouldnt go any higher...almost like as soon as it got to there it hit a block or there was a massive leak...like it wouldnt go ANY higher it was weird i still cant figure it out to this day...so im thinkin either the fuel pump wont put out more pressure then that ( which i doubt) or the fmu is effed up


So your using a FMU and the SAFC??? You really dont even need the FMU. There is no reason to have to raise fuel pressure with boost if you can compensate for the fuel on the high, low map on the SAFC.

I think even the 255hp would have problems supporting 60+ PSI of fuel pressure, not to mention having the SAFC adding fuel for your car.

In short, ditch that FMU to start. Then go from there. Walbro's go bad here and there, but your demanding alot out the pump for 60+psi.

[mike92stealthtt]

My 255lph went bad in half a year and I only run 44 psi base fuel pressure and I only boost to 15 psi. They are cheap but I hope the new one I just put in lasts a little longer.

[maxkid123]

import dps...idk if i can ditch the fmu and run without it being so i have stock injectors on my car and im running 9 pounds of boost ive read plenty of threads saying that even tho i have the safc i wont be able to add the fuel that is needed up top i need either bigger injectors or a fmu to add that needed fuel

[cburwell]

My personal preference would be to ditch the FMU because it sounds like your injectors cannot flow enough fuel to support the power you are making. Get bigger injectors and tune them with the SAFC.

[maxkid123]

cbur thats on my list im getting 550s but i need to save first im kinda broke...i wish this bs fmu would just work lol

[SovXietday]

Why can't people just have patience and do things right the first time?

[maxkid123]

um cause the fmu should be working...i didnt know id have to deal with a faulty one.

[SovXietday]

um cause the fmu should be working...i didnt know id have to deal with a faulty one.

Even if it was working correctly and not losing fuel pressure... how do you know it's working? Do you have a wideband on the car to make sure you've got correct AFRs?

And no, an FMU was NEVER the correct way to do it. 550s aren't that much money, you should have just waited until you had everything you really needed and you wouldn't have any issues.

But whatever, I don't know what I'm talking about.

[maxkid123]

dude the fmu came with the kit i bought... and yes i have a wideband..