Turbo and Walbro 485 Fuel Pump

[Eazy-V]

I have the FBM base turbo kit with GTX2867R, Flex Fuel Kit and Walbro 485 kit, but at around 16psi with E55 the fuel pump seems not be able to supply enough fuel. The fuel pump should be able to meet the fuel demand, so my tuner said it might need a wiring kit because the FRS fuel pump wiring might not be able to provide enough amps. Does this sound right?

[Hags86]

I'm no expert but there is a 20A fuse for the fuel pump and a Walbro pulls 14A at max flow so I'd be looking elsewhere than wiring.

The fuel pump controller takes a pulse width modulation output from the ECU and turns that into a voltage between 0-12V for the pump. Maybe see what the PWM duty cycle is and up it on the tune.

Maybe what he means by a wiring kit is to bypass the fuel pump controller and just run it 100% duty cycle on straight 12 volts.

[Eazy-V]

Ok, I'll re-confirm with my tuner, he meant the wiring on the FBM Walbro 485 pump itself, thinking the wires are not thick enough.

If someone that has the Walbro 485 can chime in on this, that would be great. I don't want to buy a Deatswerk wire kit when it won't make a difference.

[Hags86]

Did you find out about this? I'm about to install a second fuel controller to run a Walbro in a surge tank and would like to confirm my understanding.

[Eazy-V]

Originally Posted by Hags86

Did you find out about this? I'm about to install a second fuel controller to run a Walbro in a surge tank and would like to confirm my understanding.

No, not yet, was waiting to see if anyone replied on here.

[Sportsguy83]

Originally Posted by Eazy-V

I have the FBM base turbo kit with GTX2867R, Flex Fuel Kit and Walbro 485 kit, but at around 16psi with E55 the fuel pump seems not be able to supply enough fuel. The fuel pump should be able to meet the fuel demand, so my tuner said it might need a wiring kit because the FRS fuel pump wiring might not be able to provide enough amps. Does this sound right?

The Walbro 485 pump is more than enough at those power levels with stock wiring.

I ran 20 psi with E89 (yes E89) and never had any starvation issues. I would start looking at installation and see if there is something within the pump in teh tank not properly installed (e.g. the rubber rings on the neck) and maybe fuel pressure is escaping there.

[Eazy-V]

Originally Posted by Sportsguy83

The Walbro 485 pump is more than enough at those power levels with stock wiring.

I ran 20 psi with E89 (yes E89) and never had any starvation issues. I would start looking at installation and see if there is something within the pump in teh tank not properly installed (e.g. the rubber rings on the neck) and maybe fuel pressure is escaping there.

Thanks for the info!

Btw what power levels was that at and what injectors were you using?

[Sportsguy83]

Originally Posted by Eazy-V

Thanks for the info!



Btw what power levels was that at and what injectors were you using?

550 whp 480 wtq

1000CC injectors


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[extreme-86]

The 485 does have high current demands and on regular (non PWM) setups a hard re-wire relay kit is required. I'm not sure if/how this platform's wiring configuration and PWM setup influences that.

If the actual voltage supplied to the pump is too low via the PWM controller then the fuel flow will drop off dramatically - try and check what voltage the pump is receiving as a base starting point and whether it increases with rpm/load.

[GsxrMe]

I have no problems with my FBM 485, I've been running E75 all year around. Check the o-rings and install on the pump. Something was completed wrong. Make sure you install that huge metal spacer they gave you, You have to work in on slowly. The manual for the pump doesn't give you enough info. Leaving that big metal spacer out might squeeze your pump pre-filter to much on the tank and starve fuel. I slowing squeeze that huge metal spacer on with a wrench and slowly worked around it until it was fully install. I don't think i'll ever be able to remove it.

[Eazy-V]

Originally Posted by GsxrMe

I have no problems with my FBM 485, I've been running E75 all year around. Check the o-rings and install on the pump. Something was completed wrong. Make sure you install that huge metal spacer they gave you, You have to work in on slowly. The manual for the pump doesn't give you enough info. Leaving that big metal spacer out might squeeze your pump pre-filter to much on the tank and starve fuel. I slowing squeeze that huge metal spacer on with a wrench and slowly worked around it until it was fully install. I don't think i'll ever be able to remove it.

Ok, hopefully I have time next week to finally take a look at this.

[BRX]

I had a Walbro 485 and I had all sorts of problems with installation. The easiest thing to mess up is the gasket below the metal spacer as it gets pinched easily. This causes the fuel pump to bog when you run the tank at about half.

I re-installed the gasket properly but still was not able to drive the car at below 1/3 of the tank. Last chance I gave it was using zip ties to hold the bucket like the OEM clips did. This gave the best results as it didn't bog until 1/4 of the tank.

I finally gave up and went with a DW300c pump. It uses 3 o rings and no spacers. Ran all the way to empty and I was still able to floor it with stable AFRs. If it works fine when the tank is full then I would recheck your installation of the gasket and tighten the bucket like I did. If that fixes your issue, then I wouldn't recommend driving the car under boost at low fuel level. Walbros don't like that even in my previous build (Toyota Tundra) I couldn't drive aggressively once the fuel level got below 1/3.

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[BrightSlide]

Hey i am having similar issue as OP
After about 5.5k rpm (making around 8-12psi there and peaking 16-17psi WOT redline)
the car leans out abruptly and tuner thinks it is due to fuel lack of fuel pressure
I tested fuel pressure before bc another tuner suspected it previously to be the cause of a rough idle but it checked out fine at idle and with stationary throttle input

If it was a fuel pressure pump instal error wouldn’t it b all the time?

Also could i run a dw300c instead if I find out it is the fuel pump? (1300cc injectors, Sbd500x gt3076r pushing 16-22lbs depending on map, built motor 10.0:1)
Thanks in advance

[BRX]

Originally Posted by elliotfrs

Hey i am having similar issue as OP
After about 5.5k rpm (making around 8-12psi there and peaking 16-17psi WOT redline)
the car leans out abruptly and tuner thinks it is due to fuel lack of fuel pressure
I tested fuel pressure before bc another tuner suspected it previously to be the cause of a rough idle but it checked out fine at idle and with stationary throttle input

If it was a fuel pressure pump instal error wouldn’t it b all the time?

Also could i run a dw300c instead if I find out it is the fuel pump? (1300cc injectors, Sbd500x gt3076r pushing 16-22lbs depending on map, built motor 10.0:1)
Thanks in advance

I used to run 20 psi on my 10.5:1 FA20 with a DW 300c pump and 1050x injectors and it had room for more. I was never able to get the Walbro working properly as it kept running out of fuel at about 1/3 of the tank but when it had fuel in it, it would run fine. I don't think it's a fuel pump issue.


I had 850 injectors before and no matter what my tuner wasn't able to dial them in. Went with the new ID1050x injectors and we dialed them in in a handful of revisions.