Biggest baddest fuel pump in a stock canister

[SnowFlake]

This is how I wedged a walbro 485 into a stock canister.

All parts needed.


Part numbers and prices.


Stock canister


White connector, stock.. prone to melting vs a pump like the 485 that draws a lot of current.


Start unplugging stuff... Since we're upgrading the connectors pop the fuel level sender pins out with the provided safety pin.


Have fun removing this from the stock pump. Save it, you will need it later.


After everything is unplugged, popping the connector out is EZ.


Baller connector pops right in no fuss.



This is all trash now... including venturi hose, toss it all.


Put the fuel level sender pins into the new in tank wiring harness (part number ITWH-029)
Make sure to slightly bend the little pins on the back that holds it in place.



EZ


New filter sock... you'll need a 15mm drill bit later.



See that prong?


Kill it.


Same with this...



Use your 15mm drill bit to put a carefully placed hole in the bottom of the canister.
Fit filter sock through the hole.





Have fun connecting the corrugated hose to the canister top and pump outlet.


Cap the stock return, break the little tabs on the evap port and drill it out with a 3/16th bit. This will be your new return line. It'll pour fuel in from the top, keeping the pump cool.


Gut the evap **** out of the top.


This is what you should have so far.




Now just plug the wiring harness in to the pump and top.
Replace all the little holding tabs for the connectors.




The new hotwire kit will adapt your stock wiring to the new connector that won't melt.



Now install the hotwire kit and plug it in.
The pump feeds right off the bottom of the tank, so you can make it home on ~1 gallon of gas if you need to.
It also retains fuel in the bucket keeping the pump cool.
The upgraded wiring and harnesses enture proper current to the pump without melting things.

This pump should support 250-300whp more than a walbro 255.
With the pump picking off the bottom of the tank, you can never suck the canister dry.

For guys maxing their 255s... this is a perfect solution.

[99GTChh]

Just figuring it out. So u took the Evap out. and put the return line on the Evap so the returned fuel will fill the canister correct?

Sent from my SPH-D710 using Tapatalk

[Silver2kgtp]

Awesome

Great job

[GMR Badass]

Curious as to why you used the EVAP as the new return line? Stock return line fitting feeds directly into the bottom of the bucket originally. What are the advantages of using the EVAP connection?

[SnowFlake]

It rains fuel in from the top and will never back up. The stock return setup at times may not have enough pressure to fill the canister up. With the pump not feeding out of the bucket it may cause issues. this is just a theory though.
To ensure there's always fuel dumping into the canister to keep the pump cool this was what I went with.

[Turbocharged400sbc]

that connector will melt as well
the only true fix is drilling a hole and using 10 gauge wire with it sealed with RTV

[SnowFlake]

I've been putting mine through the paces and the connector barely even gets warm.
20psi of boost, 75-80psi of fuel pressure, running the pump at 15v... Should be drawing well over 20 amps at those figures.

[Turbocharged400sbc]

higher voltage means less current.
it may barely get warm but I can get a sizable voltage drop across those terminals at 8-12 amps

[Turbocharged400sbc]

then again I also run a direct relay power feed for the injectors and ICM because of the factory voltage drop through dozens of electrical connectors.
the only thing those connectors are good for is for easy service

[SnowFlake]

higher voltage means less current.
it may barely get warm but I can get a sizable voltage drop across those terminals at 8-12 amps

I'd like to know more about what you're saying. According to this chart, current jumps way up when you run more voltage.
I even upgraded to the cs144 alternator to make sure this pump is fed. Voltage at that pump (connector) is around 15 and never flinches.

[Turbocharged400sbc]

I am referring to the voltage drop across the 4 connections you have....
the fact that you can feel it even being warm means that you have a problem with voltage drop which means your pump is running closer to 14 volts. which means your current is also less

[Turbocharged400sbc]

God its such a pain in the ass using a phone for this kind of stuff
my voice to text function hates me

[SnowFlake]

If that's even the case... the pump has been flawless so far so I'll run it until something melts lol
My 255 was kicked at 13-14psi of boost. Couldn't even hold fuel pressure in the 30s...
This pump holds 75 with another ~150hp on top.

I'm happy AF.

[Turbocharged400sbc]

its far from ideal is what im saying

only on the two stage setup i have on the TR do i use the factory wiring...and that pump is at 0psi and makes the venturi system look like a ***** so the walbro/044 can draw from a completely full canister.

dont get me wrong thats about as good as it gets right there what you did, the later systems also draw from the outside. i just hate how bad the voltage drop is across the oem type terminals when we exceed the current that the OEM pump runs at.

if you get the chance to test it, backprobe and watch your inj/ICM supply voltage

we already bypass lots of oem resistance with a FP rewire why stop there?

i run a dedicated ground wire instead of relying on the unibody, maybe i just overdo everything lol

[SnowFlake]

Ahh... I get why you'd want the wiring to be boss. But you're some kind of evil genius building racekars.
This setup will plug right in for anyone else lol
With any luck nothing will melt and it'll still support 650-700whp on e85.
I have to imagine my car on 20psi is close to that.

I didn't want to deal with 2 pumps, sumping the tank, running all custom lines and stuff... So for me and possibly a few others this works pretty well.

[Turbocharged400sbc]

as these cars are getting older um finding alot of the intermittent faults/issues im seeing are directly related to the connections and voltage drop -specifically through the unibody ground path....turns out a few winters of rust attacking your spot welds can create some interesting ground loop issues as systems are grounded to different portions of the unibody.

lookup a TSB about the metripack connector fretting issue.

dealerships are literally unplugging and replugging harness's to fix issues.

if the connections are **** from the factory, at OEM power/voltage/current levels...i sure as hell aint gonna think they are adequate to a modified car.

id rather slam my dick in a car door than trust any of the oem connections for such a vital component as your fuel pump/pumps/JATO rocket.

it'd suck to have an intermittent electrical fault that would only occur under high stress to happen...while under high stress at full boost and you suddenly go lean.

fix it

the two pumps is nothing more than a stock type pump flipped over the side of the can (towards the rear) once its in the tank with its outlet into the bucket keeping the primary pump well supplied with fuel when you need it most..accelerating.

GM wisely got rid of the venturi systems...its a pump parasite with no real gain.

so really just replaced it with a dedicated pump operating at 0psi so it should last forever

[darkhorizon]

Just replaced those ****ty racetronics connectors in the blazer. They burned up bad.

[BillBoost37]

If you feel warm through the plastic of the connector etc, those terminals are heating up enough to cause an issue. Maybe it's not showing itself at the moment, over time you'll start to lose the tinning on the pins etc causing more resistance and heat.

[SnowFlake]

Could be it was just really hot that day.
took a pull yesterday and leaned back to feel the connector and it was stone cold.

[darkhorizon]

Ur so smrt