Fuel pressure problem

HUENEMEGN

Active Member
I do have my old Walbro fuel pump I can swap out . It’s a little on the older side but was working when removed .
Is this something I can do outside the tank? When I drop my tank and switch the DW pump for my Walbro , can I make a tank out of a gallon jug or something with fuel in it or will I have to reinstall everything back . Looking like I will be dropping my tank 3 times . I think it’s kinda full too . Smh
 

Anthony P

sharing knowledge with those who care to listen
sure you can fab a make-shift tank for testing but having a full tank now sucks - about 6.5 lb/gal. need some fuel approved cans. borrow some from folks in the area?

with no pressure in fuel rail, remove fuel rail cap, remove schrader valve with tool or needle nose pliers. attach fuel rated hose and clamp to fuel rail, running hose to cans. use fuel pump prime connector black behind alternator and jumper wire alligator clips to run pump to empty tank into the cans.

However,

only issue is lack of priming (pressurizing fuel system) prior to startup. once the engine is running, you noted all is OK. you're in CA, so maybe keep driving the car to use up the tank, tackle the fuel pump later
 

HUENEMEGN

Active Member
sure you can fab a make-shift tank for testing but having a full tank now sucks - about 6.5 lb/gal. need some fuel approved cans. borrow some from folks in the area?

with no pressure in fuel rail, remove fuel rail cap, remove schrader valve with tool or needle nose pliers. attach fuel rated hose and clamp to fuel rail, running hose to cans. use fuel pump prime connector black behind alternator and jumper wire alligator clips to run pump to empty tank into the cans.

However,

only issue is lack of priming (pressurizing fuel system) prior to startup. once the engine is running, you noted all is OK. you're in CA, so maybe keep driving the car to use up the tank, tackle the fuel pump later
That will be my best option .To drive out the fuel tank to almost empty. Then remove .
 

Anthony P

sharing knowledge with those who care to listen
been about a month...inquiring minds would like to know...have you driven around enough to use up most of the tank so you can drop it to remove the fuel pump and send it to DW for installation of a check valve?
 

HUENEMEGN

Active Member
been about a month...inquiring minds would like to know...have you driven around enough to use up most of the tank so you can drop it to remove the fuel pump and send it to DW for installation of a check valve?
I did send out the pump last week . Just got a messaged from DW saying they will be sending my pump back this week . So I’m just waiting and so I can get this car back on the road .
I’m cleaning out my tank at the moment . Saw some rusty pieces in the baffle .
 

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HUENEMEGN

Active Member
Okay fellas . So after sending out the fuel pump to Deatschwerks to have them install the check valve. Got it back very fast once they got it from me. I got everything hooked up and it’s BACK ! Has fuel pressure with key ON , motor off! Holds the fuel pressure After running the engine like it should . I’m good to go!
Shout out to Vinh at Deatshwerks!! Great customer service and super helpful . Thanks bud
 

Sweet6

Well-Known Member
Dumb question, is it a big deal if there is not a check valve in that DW pump? Does it adversely effect anything when it is running?
 

Anthony P

sharing knowledge with those who care to listen
Dumb question, is it a big deal if there is not a check valve in that DW pump? Does it adversely effect anything when it is running?
no such thing as a dumb question...the only a dumb question is a question not asked

regarding a check valve or not in the fuel pump...

really depends on what type of car, how it is used, and how it is serviced.

many of us operate ours cars as street cars - cruisin around to car shows, get togethers, using a highway on ramp for a little WOT fun and just taking the car out for a ride on a great day. whether using the factory ecm with whatever chip, xfi, or GNecu most will be using the factory service manual diagnostics for troubleshooting. for that reason, a check valve makes sense to follow along with how the car was built to operate and the service manual was written. having a check valve in fuel pump for a street car will make it easier to diagnose any fuel system issue - a problem with the fuel pressure regulator, an injector problem, cracked rubber hose between pump and hanger, etc.

modifying the car for the track is another story. maybe it's a street car that sees track time. those that have swapped fuel lines for larger sizes, running two in-tank pumps or a second pump activated by boost pressure via a hobbs switch are not necessarily reviewing the service manual diagnostics.

maybe it's a 1800bhp stripped down & built up monster. track only car's electrical system will be totally redone having a whole series of rocker switches to power ignition, fans, fuel pump, water pump, pre-lube oiler, sump, etc. check valve here - who cares? rocker switch powered fuel pump and cockpit gauge shows pressure before pushing button to start engine. Wide band O2 and the six thermocouples providing temps in each header primary plus the info from the data logger says everything is A-OK

for those of use who use the key in the ignition switch to start the car, we typically rotate the ignition switch to ON, pause while we hear the fuel pump prime, then start the engine.

once the engine is running, the presence of a check valve does not matter. you can verify fuel pressure base line static and corresponding drop when vac line re-attached to frp and can verify WOT fuel pressure.

on a street car though, it is helpful to have a check valve in the fuel pump to help identify any fuel system issues once you shut off the engine.
 

Sweet6

Well-Known Member
Thanks for the reply. I thought as you said that once the car is running it doesn't matter.
 

Sweet6

Well-Known Member
I thought back in the day guys would bypass the check valve to get more out of the pump. Back when the 255 liter pump was the only intank stock hangar pump.
 

Jerryl

Tall Chinese Guy
I thought back in the day guys would bypass the check valve to get more out of the pump. Back when the 255 liter pump was the only intank stock hangar pump.
Wondering if the DW400 with a check valve becomes a DW350. Would be interesting to see what DW says.
 
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