Walbro / Racor install

[Matt Bachand]

Installed my Walbro FRB-5 and Racor 490R30.

Everything seems to be running fine, however, I only have about 4psi at idle.

They way I wired this was took a pigtail off of another stock LP, and wired the hot lead to the red wire on the walbro, and the black (ground) to the torq nut on the walbro where the black wire is mounted on the walbro.

Is this wired up correctly?

Wondering why I only have 4-5psi.

I feel it do a pulse like series about every second. I cannot even come close to hearing it. I did mount it directly to the framerail with a 3/8ths solid piece of rubber mat in between.

I can see the pulses in the fuel lines, and feel them forward, and all the way back to the racor.

Did I wire the pump wrong to cause it to only output 1/2 of its spec?

Before I did anything I hooked my temp fuel pressure gague up to t-valve and AC Delco pump at idle read 7.

Now it reads 4. Havn't road tested it (still jacked up and raining), but I expected alot more.

I don't see any leaks anywhere.

Any Ideas?

Stamped right on the Walbro says 10psi. Seems odd I'm getting exactly 1/2.

 

[Matt Bachand]

I want to note with the racor's prime pump, i opened up the filter manager bleeder, and primed the fuel from my tank, through my walbro and out the filter mgr. Worked like a champ.

Smithville showed me a nice E-Bay link where they deal with refurbished Racor units. I ended up getting the 490r30 w/primer pump and heater for 60bux. PM me for link if interested.

 

[Turbine Doc]

make sure your gnd is good so you have solid 12v going to pump, was this a new walbro or "used but good one"

 

[Matt Bachand]

make sure your gnd is good so you have solid 12v going to pump, was this a new walbro or "used but good one"

Where does that ground go to? I wired it to the ground? that is the black wire in the factory pigtail.

What PSI at idle is yours putting out Tim? I have to say, she seems really quiet at idle for some reason. Perhaps its because I was undertruck looking for leaks.....

Brand new pump I got from PMDCABLE.COM... Leroy.

 

[Matt Bachand]

Truck off using LP Diagnostic jumper under hood, it builds to 6psi. I can't hear it AT ALL??

Fire up truck, goes to 4. I'll go do a volume test.

 

[Turbine Doc]

Frame rail top side of rail is the ring lug, sort below filler neck, mine runs 10 psi @ idle & pumps louder than a GM lift

 

[Matt Bachand]

One minute of running at t-valve, not even a quarter of a 2 liter bottle. So volume is matching PSI, TOO LOW.

 

[Matt Bachand]

I'm going to have to either re-install my original pump with the racor and verify that good, or bypass the racor and see what pressure is. Whatever's easiest to eliminate one of the systems.

I was really close on fuel hose too, Not sure how many inches I can lose by cutting the barb off.

Any tips on pulling the barbs off? Knuckle bashers.......... It primed so easily I can't imagine its the racor, But I need to be sure.

Any other ideas so I can narrow my symptoms?

Can't imagine I got a piece of crud in the line....

At least I have all weekend to figure it out.

 

[Burning oil]

Is the Filter before or after the pump?

 

[Matt Bachand]

Is the Filter before or after the pump?

Racor is before the walbro.

Racor 490r30 rated at 90GPH, specs say

Clean Element Pressure Drop .95 psi.



BTW Leroy, thanks for the lighting fast postage. Paid Friday, arrived Monday.

Also thanks for rounding up all the fittings and such. Much appreciated, top notch service.

I will try to hook it up to the tank instaed of racor-tank and see what that yields, or maybe just a hose into a thing of diesel and check pressure.

Since I've never used this racor unit before, havn't proven it good yet.......

 

[Matt Bachand]

Nice things about your Fuel pump fittings Leroy... Going back is no problem what so ever.

Great work on those BTW.

 

[packratt]

Frame rail top side of rail is the ring lug, sort below filler neck, mine runs 10 psi @ idle & pumps louder than a GM lift

I get 4-7psi with mine at idle and 75mph. At startup it is louder than the stock pump.

 

[Burning oil]

Sounds like a plan eleminate the Raycor filter (temporarily) and see what that does.
Thanks for the kind words. I try to keep it simple.

PS. make sure the body of the pump is grounded to the frame. You can run a separate wire from the pump mounting bolts to the frame and leave the pigtail like you have it.
Got any pictures?

 

[Matt Bachand]

Sounds like a plan eleminate the Raycor filter (temporarily) and see what that does.
Thanks for the kind words. I try to keep it simple.

PS. make sure the body of the pump is grounded to the frame. You can run a separate wire from the pump mounting bolts to the frame and leave the pigtail like you have it.
Got any pictures?

I'll get pix tomorrow, was all raining today... The bolts go thru the walbro and then through a rubber piece (dampener) and nut and bolt thru the frame with stainless hardware, so that should be ground?

I'll find out more tomorrow.

 

[Matt Bachand]

Well I took it for the hardest 'beat' I've laid upon her since Early PMD failures before These forums were found, and I was trying to blow it up .

ON the steepest highway grades I know, 11psi boost, 65-75mph slowing down and throttling back in to acceleration, I could never get it to drop under 3 psi. Most of the time it stays a touch above 4.

What do you guys think? It was dead quiet this morning, jumpered LP diagnostic connector and I heard it make a quiet click or 2. Can't hear it at all. Like i said, i have a 3/8ths piece of solid rubber 'pad' in between walbro and frame, mounted with SS 1/4 nuts and Bolts.

I'll get some pictures, although Its hard to show the complete picture.

 

[Matt Bachand]

Racor is mounted basically on the 4x4 lengths that my utility body sits on. I padded it out to clear the frame with a few pieces of pressure treated decking I had, liquid nailed, and screweed, then I lagged the walbro through everything with 3" galvanized lags.

Walrbo is about 1' to the rear of original LP. Easy spot to fit, and drill. Can even drill from the outside of the frame. I rough drilled one hole from the outside (easy access) then put the bolt and walbro up, and marked the 2nd hole, then drilled it and installed.

Last 2 pix shows leroy's fittings so I don't have to disturb the factory lines.

I had to create a U with 1/2 fittings to loop back to the Racor from the tank lines.

Notice all the BS I have to deal with on the frame rail due to dual factory tanks. Other trucks frame rails seem empty in comparison.

 

[Turbine Doc]

You should have a very hearty purr out of that Walbro

 

[Matt Bachand]

Direct wired Walbro, verified self ground to frame is direct and good, Same psi of 4.

Put hose from walbro inlet into container of fuel, about 5 psi truck not running. (Same)

Still have no humm or audible noises out of Walbro, other than a faint clicking you can barely hear with truck OFF.

I think I have a bummed Walbro.


Fuel coming out of FLT MGR Drain with LP jump is a slow trickle...

It does seem to kick itself up a notch when demand is placed on it.

It seems to me like the internal regulator in the walbro is set too low to around 4-5 instead of 10.

Any more ideas?

 

[Matt Bachand]

Mutava, if you are reading this thread, what was the problem you had with your Walbro that caused you to un-install it?

 

[matuva]

Matt,

my Walbro is a "used but good" one. It was used for veg oil, and it was a bit "pasty" inside.
I cleaned it as much as I can and intalled it.
It was purring stronger than the stock lift pump, though, I had about 1-2 PSI only at the gauge reading.
But strangely, I had a lot of fuel coming out at the drain valve.

I put back the stock one, and read only about 1 PSI at the gauge, with still a good flow at the drain valve.

So, I ended keeping the stock one and put the Walbro back on the shelf (was late in the day), as I suspected both pumps were fully functional, fuel gauge being weird...

During the days coming, accuracy of fuel gauge slowly went up. I do believe may be a piece of gum junk inside the Walbro did obstruct the fuel sender, and cleaned itself then.

So, I'm pretty sure the Walbro is a good choice. I wast just short of time to put it back.

I have change my set of gauge, and now with my 93 K3500 lift pump, I'm having 12 PSI at glow cycle, 6~8 PSI at idle or cruising, and 4~5 PSI at WOT.

I will probably put back this Walbro, but as It told you previously, pretty busy at the moment, and a bit lazy too, tired of laying under the truck to work ):h