Walbro 450 Lph E85 Fuel Pump Issue/ Power Supply

[camoo]

Gday all.

Yesterday I installed the walbro 450 LPH fuel pump into my R34 GTT.

I HAVE NOT REWIRED DIRECTLY FROM BATTERY... yet.

This is the only thing i have changed in preparation for e85, and now under load is missing and breaking down.

The car was running fine with my Bosch making around 300 RWKW.

Have any people had experience with this pump?

Does it require 13-14v to function normally at that KW due to the design of the pump?

Im going to test the LPH output now and see what i come up with, but any advice or experience would be helpful.

Standard lines, rail and reg too.

Cheers, Cam

[Simon-S14]

Yes they need a full 13.8v to flow at their rated capacity

[Ben C34]

I melted the plug with mine. Definitely needs sometging better than stock for wiring.

http://www.skylinesaustralia.com/forums/topic/423664-melted-connector-plug-due-to-larger-in-tank-pump-pics/

[camoo]

Thanks man, I know to get their rated capacity it will require a direct feed, but would the lack of power supply reduce its out put to the point where the car misses?

I thought it would be able to keep up at this stage?

[Dose Pipe Sutututu]

Thanks man, I know to get their rated capacity it will require a direct feed, but would the lack of power supply reduce its out put to the point where the car misses?

I thought it would be able to keep up at this stage?

That doesn't sound right at all, it will still flow even a lower voltage..

Jab a multimeter on your fuel pump power and see if it rises as you flex the throttle.. even a stationary jab will raise the voltage.

I have a feeling the factory wiring isn't keeping up with the current load and in turn the pump isn't getting what it needs.

[camoo]

That doesn't sound right at all, it will still flow even a lower voltage..

at idle and dabbing the throttle its around 4.3v

Jab a multimeter on your fuel pump power and see if it rises as you flex the throttle.. even a stationary jab will raise the voltage.

I have a feeling the factory wiring isn't keeping up with the current load and in turn the pump isn't getting what it needs.

Edited January 6, 2014 by camoo

[camoo]

at idle and dabbing the throttle its around 4.3v

[Dose Pipe Sutututu]

That doesn't sound right, try ground off the -ve line and see if the voltage increase

[camoo]

I direct fed it from the battery and now seeing 14.2v at the pump. Still missed under load when car was cold, then comes good one warm. got me confused. ..

[Simon-S14]

maybe its not really related to the pump.

start by checking plugs and coils

[camoo]

plugs and coils are all good. And everything was perfect before the new pump install.

[Dose Pipe Sutututu]

Check them again, maybe plugs are shot now from all the fuelling shenanigans

[hypergear]

I have the same fuel pump. It needs an extra earth to work properly.

Connect it to the factory + / - wiring inside the fuel tank

Out side thank, Tee an earth wire into the factory earth wiring that is connected to the fuel pump. It will then work fine.

[SiR_RB]

If his connected it directly to battery via a relay (assuming with thicker then Standard cables)

It would be earthed directly to the chassis, wouldn't that be enough?

[Dose Pipe Sutututu]

As Sir_RB said, earth it directly, teeing the original ground feed is pointless and makes the wiring messy

[camoo]

Ok update is now rewired with 8g wiring. Still doing it. Old pump back in.

Still doing it.

as johnnilicte suggested, im leaning towards plugs may have crapped out due to fueling. But that's a tomorrow job to check.

[Dose Pipe Sutututu]

do you have access to a hand held wideband O2?

usually much easier to assess what the car is doing than trial and error

[camoo]

I should be able to get hold of one later today. ill do some quick checks and if nothing obvious prevents itself I'm able to chuck it on a dyno on Thursday

[Dose Pipe Sutututu]

I'm going to be re-wiring my pump (same one) with a drop resistor & beefed up relays.. I'll write up a guide once I'm done!

Will retain the factory drop resistor, but on throttle the pump will get full power without melting shit LOL

[Ben C34]

I'm going to be re-wiring my pump (same one) with a drop resistor & beefed up relays.. I'll write up a guide once I'm done!

Will retain the factory drop resistor, but on throttle the pump will get full power without melting shit LOL

If we don't hear back I will assume that you have exploded yourself