Walbro- no improvement

[Detroit Dan]

Finally got around to installing the Walbro frb-5 I bought months ago. Pretty disappointed to see no improvement in fuel pressure. Wondering what I could have done wrong. I cut the plug off the lift pump, spliced onto the Walbro, red wire to brown, black to black because that made the most sense. It makes a little noise and when you touch it you can feel a little pulse, kinda uneven though I thought. My fuel pressure is now at 3 lbs and needles bouncy, under acceleration it drops to zero, just as it has been doing. I thought the Walbro was supposed to be a 10lb pump.

So, only thing I can think of is that A) the power I spliced into for the original LP is somehow a weak signal (OPS?) or B) I should have gone red to black, brown to black??
What about finding a 12v key on power source out of the fuse box to run it, any thoughts on that? I cut the ground off the new pump and spliced it into the LP harness, at someones suggestion, but I'm sure I can make a new ground if need be.

Leaving tomorrow on a camping trip, really wanted to see the fuel pressure improve. Seems as though I read somewhere that low fuel pressure is real bad for the IP. 200 mile trip uphill both ways with zero fuel pressure can't be healthy.

I'm pretty sure it's not the filter, that's been changed out twice in the last 1000 miles or so. Ran it around for a while thinking maybe I had air in the lines or something, but no improvement.

 

[Veg_Out]

How about that little prescreen filter in the bottom of the fuel manager?

 

[Matt Bachand]

If youre hitting ZERO fuel pressure with both LP's you have an issue elsewhere. Either clogged sock, clogged filter, or clogged lines somewhere............

Its not your wiring. Walbro takes like 1.5amps to run (barely anything) and similar to the stock LP. IF its working at all, its wired ok.

 

[Detroit Dan]

last time I changed the filter it improved, but I was still able to hit zero easy. I cant afford to change the filter every 500 miles. too late to do anything about it now.

 

[Turbine Doc]

Sounds like you wired it correctly was this a new FRB-5 or used, have you checked the sock in the tank, also try with the fuel fill cap loose, 3 @ idle is low, mine is 5-6 on avg bouncing to 10-12 if it goes to zero I'm hard pulling at 1st of a WOT demand when filters are starting to get dirty but it recovers quickly normally @ any speed on highway I'm 5+

 

[Detroit Dan]

Filters like new, sock looked fine when I changed the tank last winter. Pumps new, not used. Pulled the filter and tried poking around down in the bottom of the ffm, I think thats the problem cause it gained me a pound, and it takes a little longer for it to drop to zero. Cold starts I have a lot, like 9 lbs. Wonder if theres crud thats dropping back down overnight.

 

[guybb3]

If youre hitting ZERO fuel pressure with both LP's you have an issue elsewhere. Either clogged sock, clogged filter, or clogged lines somewhere............

Its not your wiring. Walbro takes like 1.5amps to run (barely anything) and similar to the stock LP. IF its working at all, its wired ok.

Agreed!! The most the Walbro should pull is 1.83 amps (measured it personally).

 

[Matt Bachand]

Filters like new, sock looked fine when I changed the tank last winter. Pumps new, not used. Pulled the filter and tried poking around down in the bottom of the ffm, I think thats the problem cause it gained me a pound, and it takes a little longer for it to drop to zero. Cold starts I have a lot, like 9 lbs. Wonder if theres crud thats dropping back down overnight.

You should remove the Walbro inlet and blow some compressed air back into the tank (REMOVE FUEL CAP FIRST).

Then see what your pressure does. If you have a sock issue that should free up alot of PSI... Who knows for how long.

 

[Rodd]

Filters like new, sock looked fine when I changed the tank last winter. Pumps new, not used. Pulled the filter and tried poking around down in the bottom of the ffm, I think thats the problem cause it gained me a pound, and it takes a little longer for it to drop to zero. Cold starts I have a lot, like 9 lbs. Wonder if theres crud thats dropping back down overnight.

It only takes one tank of bad fuel to plug the sock. My plugged up in less than a year. Now I have no sock and a racor prefilter.

 

[guybb3]

You should remove the Walbro inlet and blow some compressed air back into the tank (REMOVE FUEL CAP FIRST).

Then see what your pressure does. If you have a sock issue that should free up alot of PSI... Who knows for how long.

From experience, sometimes weeks, sometimes days, sometimes months. Then finally,hours.

 

[Acesneights1]

Now I'm definatley putting a Raptor on my Dually.

 

[Acesneights1]

Curious though, where are you tapped for your guage and when are you getting zero FP. At WOT ? I didn't notice FTB in your sig. Could that be your problem running abigger turbo and a tune ? That was what inspired FTB to begin with.

 

[great white]

Now I'm definatley putting a Raptor on my Dually.

Mine is waiting patiently in the garage......

Half kinda wish I gone a few bucks more and bought an airdog II though.

 

[guybb3]

I forgot to mention, Dan, that the Walbro puts out double the volume of the stock lift pump. So, unless the Walbro is bad, you have a problem elsewhere.

 

[Detroit Dan]

Curious though, where are you tapped for your guage and when are you getting zero FP. At WOT ? I didn't notice FTB in your sig. Could that be your problem running abigger turbo and a tune ? That was what inspired FTB to begin with.

tapped about 8 inches or so after ffm, and yes I have FTB. I guess I'm going to have to pull the FFM back out and see about this screen. After poking around in it before leaving I got a little better, pulled 5-6 lbs most of the way, only hit zero on the WOT long pulls. But on the way home I had barely three at idle and zero at anything over 3 lbs of boost. Still feels ok, making tons of power. I can blow back into the tank, but I doubt thats the problem. I just replaced the fuel tank last winter, the tank is nice and clean, the sock looked nice and new after 12 years, so it would seem odd it got crapped up after only one year.

 

[Matt Bachand]

Give it a shot with the air, only takes a few minutes, and will rule it out. Be sure to remove fuel cap.

You must figure this out before winter IMO. Who knows what will happen once the fuel thickens up from coldness.

 

[guybb3]

Give it a shot with the air, only takes a few minutes, and will rule it out. Be sure to remove fuel cap.

You must figure this out before winter IMO. Who knows what will happen once the fuel thickens up from coldness.

I agree with Matt. Dan, only a bit of shit fuel can plug up those socks. At the end mine would only run the truck for a few miles.

 

[chrisk1500]

Are you sure the gauge is accurate?....

 

[buddy]

Check the ground on the LP, make sure its good, and like everyone said, check for clogs in the line or the filter manager. If your filter manager has a corkscrew looking thing running up the cental shaft around the fuel heater, just take it out. If you didnt before, blow the lines from the FFM to the LP, could have crud in there as well. The IP was designed to have 8psi supply fuel pressure, so yes they are much happier with good fuel pressure.

You will find that the Walbro is 10psi, but it deadheads at the FFM, and what comes out the other side is like 30% less with a good clean setup.

 

[Detroit Dan]

pulled the ffm, I hate that job, worst part is trying to get the stupid drain hose reattached. Only screens I saw are kind of around the center post, it looks like the fuel flows in the bottom, comes up around the outside of that tube then thru the screens, into the inside of the filter then I dont know where it goes. Anyway, couldnt see the screens beause of the angle and couldnt find a little mirror, so all I could do was soak it down from both sides with brake cleaner then blow it both ways with air. Did that a few times. Blew a little air into the other lines, which was probably useless since they were still hooked up at the other end. Then I pulled the line off the walbro and blew into the tank a few little squirts.

Testdrive: First thing I notice is the fuel pressure gauge is reading about 4-4.5. Motor sounds quieter, like when I did the injectors. Pulled out onto the main road and was really rollin' some coal! More black smoke, and a little longer before it dissipated at higher rpms. Not complaining, I like blowing smoke under WOT. I'm not hurting the environment as much as BP.
Under sustained WOT (I like saying that: sustained WOT) the fuel pressure drops more slowly to zero than before, but it seemed to still get down there. No more bouncing needle like it did before. Not sure how accurate my gauge is, it seems like it must have air trapped in it, since I drained the lines and cant bleed the gauge.
Lastly, I can't say for sure, but seat-of-the-pants the truck feels way better. I have never in ten years felt the truck feel so racy. I was dying to have somebody mess with me at a light! If the planets align and I have the time, I'm going to try to get it on the track Wednesday night. It's weird, it feels faster than what I'm used to, while at the same time the low revving is misleading, makes you think you arent accelerating fast. I drive my company car WOT numerous times everyday, and that thing is running twice the rpms, so it feels like it's screaming but I know it's not a fast car.
Anyways, I'm pretty happy right now.