Quick fuel pump question

[radiod]

Just curious about installing a higher capacity fuel pump (such as the walbro) in to the stock system. Would I need to change anything with the J-tube or get a different fuel pressure regulator or is that stuff all fine until you go to a 550cc injector setup? The car's going to be up on the hoist in the near future and was thinking about doing the fuel pump while it was up to support other stuff in the future and give me one less potential cause of problem when I DO actually install 550cc's and electronics.

 

[Mjcsupra]

i have a 90 and my tank has a access panel in the hatch so dont drop the tank if you dont have to. im running a upgraded walbro with stock injectors and a adjustible fuel pressure reg, it runs great.

 

[radiod]

Mine's an 89, but I'll take a look anyways for that access panel. Didn't realize that any of our cars had that access panel. Will the walbro blow through the stock regulator?

 

[toyotanos]

Yeah, stock mk3's do not have an access panel that allows complete removal of the sender, only the wires are accessable from the stock access port ...that was likely a mod done by a previous owner. For a mk3's fuel pump to be changed you have to disconnect the fuel lines and drop the tank to get the sender off of the tank. The lines are what get in the way since they go to the edge of the tank.

For a walbro to work, you need to drill out the J-tube, its a backup regulator that can cause problems for you! I'm not sure if the stock FPR would be able to bypass enough of a 255's flo to keep the pressure under control- I'd go safe and get a good AFPR.

 

[Jay C]

I know on driftmotion's site they say that the Walbro could be used as a stock replacement. It may be worth a call or PM to them to find out more info. I personally threw one in my car when I dropped the tank to flush it and replace the Fuel filter (i know people have said these shouldn't need to be replaced) but I did since the car is 22 years old and I'm not sure what the previous owner's have done. I will be running it on the stock injectors untill i upgrade. I am however, trepidatious about using it with the stock FPR so I may get an aeromotive.

 

[3p141592654]

You cannot use the Walbro or MKIV pump without removing the J-tube restriction. The stock regulator is fine, but it is (obviously) not adjustable.

 

[JStoked]

O so the 255 doesn't do any good with out drilling out the j-tube? I know they will run with one in because i have one in mine and didn't drill out the j-tube and it ran OK till my rings crapped out. Granted i do have 550s, Lexus maf, and neo.

 

[toyotanos]

The J-tube restricts fuel flow as a backup fuel pressure regulator. When you put a walbro in, it won't flow enough fuel without driving the pressure up too far.

 

[radiod]

You cannot use the Walbro or MKIV pump without removing the J-tube restriction. The stock regulator is fine, but it is (obviously) not adjustable.

That's exactly what I was looking for, thanks . I've got the fuel pump readily available, just not the other pieces, so I will just wait until I can do it all at once.

 

[3p141592654]

The J-tube restriction results in overpressure since the regulator low pressure side gets too high and causes it to lose control. If you don't see a problem chances are you are either running the pump with the stock dual pressure relay/resistor in place which will throttle the pump enough to prevent over-pressure at low load, or you have other wiring issues leading to low voltage at the pump.

 

[JStoked]

Yeah, stock mk3's do not have an access panel that allows complete removal of the sender, only the wires are accessable from the stock access port ...that was likely a mod done by a previous owner. For a mk3's fuel pump to be changed you have to disconnect the fuel lines and drop the tank to get the sender off of the tank. The lines are what get in the way since they go to the edge of the tank.

For a walbro to work, you need to drill out the J-tube, its a backup regulator that can cause problems for you! I'm not sure if the stock FPR would be able to bypass enough of a 255's flo to keep the pressure under control- I'd go safe and get a good AFPR.

Ok how exactly do you drill out the j-tube?

 

[D.J.T.]

Ok how exactly do you drill out the j-tube?

^ My thoughts......

 

[Compton74]

pull the jtube off, when you take the lines off of it youll see the pipe on the jtube has a small small small hole in it, grab a drill and drill it out. Leave a little bit of meat left as you have to re mount a line the the drilled out j tube. But the afpr kit driftmotion sells comes with the block off for the jtube. So instead of doing all that just get that kit.

 

[JStoked]

pull the jtube off, when you take the lines off of it youll see the pipe on the jtube has a small small small hole in it, grab a drill and drill it out. Leave a little bit of meat left as you have to re mount a line the the drilled out j tube. But the afpr kit driftmotion sells comes with the block off for the jtube. So instead of doing all that just get that kit.

AHH!! ok thanks man.

 

[JStoked]

Ok just checking myself. But i want to drill out the part that faces towards the fuel rail to match the top part of were the relief valve goes on the j-tube. Right? And yes an afrp will be ordered soon from dm.

 

[Compton74]

Well heres your options

A. Order the AFPR kit from driftmotion install, and completely bypass the jtube
B. Drill out the jtube and yes its the line going up to the rail, you can tell because its like a small pinhole surrounded by extra tubeing, find a bit will drill out the hole larger but wont drill out the end of the tube

 

[OfnaRcR4]

Like this

 

[Compton74]

thanks for the backup ofna was trying to find the thread last night but didnt have any luck

 

[TurboStreetCar]

IIRC I found the stock regulator (J-Tube Bypassed) Is a large restriction when used with a walbro at full 12V.

When i installed my Aeromotive Regulator (After installing walbro and running with stock regulator) I had to add a bunch of fuel. I believe i have the Aeromotive unit set to 40psi with no vacuum.