Walbro Fuel Pumps

[smurfmods]

Can I replace the stock fuel pump with a 255lph walbro without upgrading MAF and 550 injectors?

I have the fuel pump and the injectors (if they are the real 550s - ebay buy) but I don't have the MAF yet.

Can I put at least the fuel pump in until I get the MAF? Will the engine just send the extra fuel back to the tank? Will I run even richer than I already do?

I believe I need to replace the fuel pump asap to fix my hard starts. After it's been sitting for a couple of hours it has trouble starting. BUT after its running for at least 5 min it will start up and shut down no problems. I read somewhre that it could be a bad fuel pump check valve. I think it keeps positive pressure in the fuel system so it's easier to start. That's on the pump right? If that doesn't fix it, maybe the cold start injector is bad... Who knows.

Here is the link to the problem I'm having.

 

[MDCmotorsports]

You can run the walbro with stock every thing IIRC. You might need an AFPR but thats it.

 

[smurfmods]

Do you think that will fix my hard start problem? Also, is the fuel pump check valve on the fuel pump or the fuel rail?

I'm still somewhat new to this car. Had it donated to me after the hurricane. Spent 2 month rebuilding and upgrading. (New Orleans native) T

 

[MDCmotorsports]

It might help it. You need to check and replace the fuel filter and check to make sure the cold start injector is working.

 

[smurfmods]

The fuel filter I think I can handle (it's not in the tank is it?).... but the cold start I have no idea how to check it.

 

[bluemax]

Fuel filter's above the differential.
Good Luck in replacing it. Get a flare nut wrench. I forget what size.
From my experience in changing mine, get a Toyota filter. Don't get a Purelator one. It leaks.

 

[MDCmotorsports]

The flare wrench you'll need is a 14mm. Also.... LOTS OF PENETRAITING SPRAY.

Only replace it with WIX or napa.

 

[smurfmods]

Great advice guys!

It's in the paint shop now getting a facelift. Blue to black metallic. I'll post pictures when she's done.

Good idea to replace the filter and the pump?

 

[MDCmotorsports]

Yes do both at the same time!

 

[mcpcola]

I can replace my filter in 5 minutes its not hard and the pump i have a walbro 255 and it works fine took like 30 minutes to put in

 

[smurfmods]

Hey one last question (maybe last one...)

How do you troubleshoot the cold start injector to know it bad or good?

 

[MDCmotorsports]

You'll have to look at the manual, but basically you'll test the circuit to make sure it has power, and you'll test the sensor to make sure it measures the right resistance.

 

[jester1341]

iirc didn't someone have trouble with there stock fpr 'exploding' with a walbro??

i know plenty of pepl replace the pump then the frp later, but i wouldn't chance it, i'm doing the afpr then pump.

my .02

john

 

[MDCmotorsports]

BTW heres every thing you need to know about the Walbro!

Thanks John Lunsford!

http://www.jblmk3.com/id82.htm

 

[lagged]

iirc didn't someone have trouble with there stock fpr 'exploding' with a walbro??

i know plenty of pepl replace the pump then the frp later, but i wouldn't chance it, i'm doing the afpr then pump.

my .02

john

ive heard of this, never seen it first hand.

 

[jester1341]

me either just hearsay


but better to be safe
john

 

[shaeff]

with the walbro fuel pump, you MUST drill out the J-tube, lest you run ridiculously rich. your stock fuel pressure regulator will be fine, but the J-tube WILL NOT bleed the pressure off fast enough to the return line. just follow the return line from the fuel pressure regulator down to the metal pipe that's bolted to the side of the block. that's the J-tube.

to drill it out, take off the rubber hose that connects to the back of it, (going to the back of the car and fuel tank), and simply drill it out to the size of the rest of the inner diameter, or bypass it completely with some new rubber hose from your local autoparts store. (it doesnt have to hold crazy amounts of pressure, as the return line is NOT pressurized.)

-shaeff

 

[gixxer750]

I run my stock FPR with a walbro and 550's.... its been that way for 7000 miles without a hint of a problem. Also, you won't run rich with the walbro.....unless you do nothing with the J tube.

 

[smurfmods]

with the walbro fuel pump, you MUST drill out the J-tube, lest you run ridiculously rich. your stock fuel pressure regulator will be fine, but the J-tube WILL NOT bleed the pressure off fast enough to the return line. just follow the return line from the fuel pressure regulator down to the metal pipe that's bolted to the side of the block. that's the J-tube.

to drill it out, take off the rubber hose that connects to the back of it, (going to the back of the car and fuel tank), and simply drill it out to the size of the rest of the inner diameter, or bypass it completely with some new rubber hose from your local autoparts store. (it doesnt have to hold crazy amounts of pressure, as the return line is NOT pressurized.)

-shaeff

Great advice! Thanks gixxer750 & shaeff.. I remember when I rebuilt the engine that the j tube is in a tough spot to get to on the block. I may not be able to get a drill in there. If I just remove the j tube completely your saying I can run straight hose? Is it better to replace the whole hose or get a connector to attach the two pieces already there?

Can I just leave the j tube in place with maybe some rubber caps on the end to protect the ends? If I remove it, Do I need to have a block off plate? (lunsford sells em) I don't know what's under the j tube plate... bare block maybe?

 

[Afunk]

just a hole to the block