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Walbro / Racor install

Matt, IIRC you have a hand held test gauge. Take the line loose before the T-valve and test your pressure there or take the line loose from the IP and test the pressure.
 
That brochure doesn't really say much. It looks like there are different outputs availible but doesn't say what the pressure it's giving is, Static or Flow. Flow is more important than Static. Not sure what the 6.5 calls for flow Psi. Static psi is where the pump will shutoff as the frb if I'm reading correctly is a flow on demand pump not continous. It sounds to me like you have a low rated Static PSI pump since there seems to be different ones availble unless that pump is adjustable which it didn't seem like it. I would call Walbro tommorow. They will be the ones to answer.
 
packratt said:
Matt, IIRC you have a hand held test gauge. Take the line loose before the T-valve and test your pressure there or take the line loose from the IP and test the pressure.
Click to expand...

I checked it directly out the back of the Walbro itself.

Doing a ton of searches on walbro's but the same old same articles keep coming up. Funny thing is they sell a regulator thats adjustable from 1-5psi... 5 psi seems like a magic number. They have a ton of versions so it gets confusing. I did send Walbro an E-Mail.
 
Fast response by Walbro.. Here's what I got.

Matt,

It would be very unusual to have a defective pump, but it is possible. The output pressure of the pump is determined by a spring inside the pump (there is no adjustment), and the actual specification is 8.0 to 11.0 psi for deadhead pressure, and that would be tested with ~ 24 inches of fuel lift. If you test the pump with more lift, it will reduce the pump outlet pressure (1.0 psi ~ 32 inches for diesel fuel or 36 inches for gasoline). If there is significant gauge error, that could contribute also.



Can you describe the set-up you used to test the pump?



Regards,

KI
 
Last edited by a moderator:
have this pump installed on my truck.

It is mounted on the frame rail, just about in the middle of the fuel tank.

I have about 3' of fuel line and a racor 490r30 primary filter 30 micron in front of it. Racor says clean element draw is .95psi.

Racor is mounted slightly above the walbro. Then line goes to walbro and up to engine.

I removed the racor and put the walbro's feed into a jar of diesel about 8 inches under the walbro. Tested pressure at engine compartment and it deadheads at 5. While driving idles at 3-5 fluctuating PSI, stedies around 4 with load. Extreme load drops to 3, no lower.

I also (with racor hooked up again) removed the line out of walbro, and hooked pressure gauge directly to walbro and deadheads 4-5, eventually 5ish if given 30 seconds or so.

I was expecting more psi closer to 8-10 deadheaded. with 5+ with load. I have enough flow, but curious why pump was stamped 10psi, and even right out of the back of the walbro I was getting 1/2 of that.

I did a flow test also with the racor installed, and it filled up a 2 liter bottle in about 20-30 seconds, this is right out of the walbro. At the top of my engine is a water drain, and that drain only filled up under 1/4'th of 2 liter bottle in a minute. Thinking the restrictions and relatively low pressure = lower fuel flow. Even cleaned injection pump feed hoses and re-wired a few ways makeing sure i was properly grounded. (to frame and to factory wire harness (2wire))

Thanks for the fast replies.



IS my reply.
 
Turbine Doc said:
You sucking air possibly ???? thereby reducing output of the lift pump
Click to expand...

Tried it with a 8" 3/8ths tube into a container of diesel. Also racor bowl solid as can be, no sign of wetnesss anywhere, racor primed extremely smooth. No signs of air in system drives great.

Walbro also deadheads fast, sucking air would lead to me believe it may not stop pumping?
 
sumthin ain't rite, I'm into a 10 mic Racor pre-lift, & still have the sock in the tank, my Walbro is mounted vertically maybe that is a difference even though it's supposed to work way yours is oriented,
 
This is good reading, thanks Matt!
munch.gif


Sorry you are having such bad luck with the Walbro! :mad2:
 
Turbine Doc said:
sumthin ain't rite, I'm into a 10 mic Racor pre-lift, & still have the sock in the tank, my Walbro is mounted vertically maybe that is a difference even though it's supposed to work way yours is oriented,
Click to expand...

Try rotating the pump Matt.....What do you have to lose?........And then you can rule that out.

Not to bash, but maybe the fittings from Leroy are faulty (manufacturer defect) and causing a slight restriction?

Stranger things have happened.

JMO
 
Matt,

I looks like you may have a weak pump (OK, defective pump). The most likely root cause would be the pressure spring in the pump. If you want to return it, you can do that through the retailer through which you purchased the pump. If you would rather tinker with it, I can send you several springs which you could try to see if they correct the deadhead pressure.



Regards,


Needless to say I asked him to send me the springs :)

About to learn a lot more detail about this Walbro unit:thumbsup:
 
Matt,

If you do take that sucker apart please take lots of pictures of all the cool guts inside! :thumbsup: I am curious what all is inside! ):h

Thanks,
 
DieselCash said:
Matt,

If you do take that sucker apart please take lots of pictures of all the cool guts inside! :thumbsup: I am curious what all is inside! ):h

Thanks,
Click to expand...

Oh it will come apart, pix will fly. He said he'll send me 2 different springs with instructions too he said.
 
I wonder if the range of pre-IP fuel pressures we're seeing is due to individual variability of the fuel pressure regulator (in the return fitting) on our IP's?
 
Shouldn't be an issue, I just changed an IP, on my truck the new one has made no difference to my pressures, from the different pumps configurations that I tried before settleing on the Walbro, it was all about the pump itself, and if delivery was really low, it has been due to sock restriction, or pump itself,
 
I get about the same as Matt with my FRB-5, about 4-5psi at IP. At IP not the drain. But pre filter manager/post FRB-5 I have 8-10psi. I put in new filter and no better. I use a 12 micron pre-LP filter too.

I never hear my FRB-5 either. I mounted it on the cross member, horizontally. I also used AN fittings everywhere to make disconnects much easier and everything tidy. It pumps real smooth and quiet out the drain, pulses when just shooting out the filter manager hole. It only works to maintain a pressure then stops and goes again, so after shut down I never hear it anymore, like I did hear the stock one. All i hear is a tick every few seconds from it, until oil pressure drops all together.

I have done FTB mod, even to the IP fittings.

The truck runs great, better than before and I never lose fuel pressure stays above 3psi at IP, so I am happy. I have a mechanical gauge right after Walbro and it tosses between 5 and 10 psi constantly.

I even removed the fuel heater coil thing to try to add more flow through the filter manager. Only minor improvement. Same pressure using stock tank or Aux tank in bed.

Its all working great, so not complaining. With stock Carter pump I was losing pressure all together, line would go to vacuum.

I should also say this was the same on the one I bought from Lube Specialists and the one I bought from PMDCABLE.com. Both performed the same. I cracked the body on the one from lube specialists though when I went to replace the fitting to AN style and it bottomed out and I turned a little more. Be careful its not real tough metal. The crack only caused a small fuel drip and I used it for a few days, and yes Leroys service was wicked fast, had it in 2 days from the call with regular priority mail.
 
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