fuel pump install

[ercp98]

i just did this for my car and I also replaced a rusty and leaking fuel pump housing. i installed a (gss-342) walbro 255lph pump.
great thanks to tredmkv for getting the pump to me ASAP. it was not a bolt on affair. i followed the suggested install from Auto performance Engineering. the instructions were straight forward enough to follow.
i do have a few questions.
1. will there be any gains in rewiring this pump or will
this be sufficient for 18 psi of boost?
2. does any one know where to source the nuts for the fuel pump cover plate?
i reused the old ones for now. the old nuts are rusted to half their size.

thanks in advance and pics for reference.

 

[Terry Posten]

The biggest gains to rewiring the pump will be a more consistent fuel pressure at all engine loads and a reduced possibility of leaning out at high revs (when it is the most dangerous).

 

[ercp98]

^ so it will still be worth while to rewire this even for just peace of mind. thanks.
any ideas about the pump cover plate nuts?

 

[grocery_getter]

Those are just 6 x 1.0 nuts, might want to add flat washers with the regular nut to spread the load.

 

[SmoothCustomer]

Quoting ercp98:
^ so it will still be worth while to rewire this even for just peace of mind. thanks.
any ideas about the pump cover plate nuts?



I would rewire it, you can do it yourself really from radio shack parts or you can buy a kit, either way it should be

 

[Muskrat]

Here's RRE's website with pump flow rates. Rewired you'll be seeing about 14v at the pump.

RRE Fuel Pump Flow Tests

 

At 18psi you aren't going to see any difference. As long as the volume the pump is supplying is more than the injectors need the pressure is going to remain steady. Jeff Lucius's graph shows you when you need to rewire:
click
Take your injector size X .24 to figure out the maximum flow in liters/hour at 100% duty. Then, add 18psi to whatever base fuel pressure you are running (37psi is stock). As long as the liters/hour of the 12 volt (non-rewired) 342 pump is above the amount your injectors can flow, you are safe. If you start getting close to the graph line its time for a rewire to give you a safety margin.
If you are running a stock FPR you do NOT want to rewire, or it will make the FPR overrun even worse.

 

[gtluke]

after 8 years of an upgraded fuel pump all of your connectors will go bad and leave you stranded one at a time.
ask me how I know /ubbthreads/images/graemlins/smile.gif
I've fixed each one on the side of the road.
I'm on my 2nd MPI relay & harness, had to repair the fuel pump connector and now my trunk connector is dead. I got the stuff to rewire it this week so I'm finally going to do it. Now I know I'm going to have fuel pressure problems because it's going to flow more, and I have a stock regulator.

 

[ercp98]

^ so you think the rewire will minimize the break downs by keeping the wiring "freshened up"?

 

[gtluke]

no,
the rewire prevents you from pulling twice the juice through the stock wiring that it was designed for.

 

[broxma]

for the op. Where did you get the new in tank sending unit? I have two walbros sitting on my workbench and a sending unit so rusted out I broke 2 of the studs off getting it out.

/brox

 

[ercp98]

gtluke, thanks. with this almost 20 yr old car, that make sense to me.

broxma, best chance would be to post in the wtb section or just wait. they pop up in the
for sale section once in a while. i broke one of the studs holding the plate cover too. but i believe i caused that because i rushed removing that nut knowing full well that it was rusted in. i should have taken a before and after pics.