Observations about Walbro/Racor/In-Cab Fuel Pressure

[Turbine Doc]

Matt where is your vac monitor located in the system, inlet of your lift pump or IP inlet after filter I have one as you know on outlet of each of my filts, really all you need to know something is wrong with fuel delivery is have one at the outlet of the filter mgr, that is the one that comes on 1st with mine, which stands to reason as it is a lower micron rating than my racor and would sense flow restriction earliest as it has the finer media.

If the racor or the tank sock get cruddy filter mgr trips my switch/alarm LED as IP is struggling to get fuel, I also see it on my in cab gauge on hard acceleration when my IP inlet pressure gauge starts spending a lot of time @ near 1 psi.

 

[Matt Bachand]

My vac indicator is located Directly before the Walbro. I Put a T.

I originally put it in the filter as suggested by the Racor (but since IT didn't trip I thought it was in wrong spot, so I tried the other port, and then put it right before the Lift pump.

I replaced my FFM the day before, so that told me it was my Racor that was cruddy, so I installed the indicator so I could see how far down it clicked, and no trippy.

HEre is the unit. http://www.go2marine.com/product.do?no=160213F&WT.mc_id=gb1

 

[bison]

1/4 m x 1/4 fm good for up to 5000 psi snubbers are only $12 cnd at winters,got mine via bumper to bumper.
needle bounce is all but gone.

Looks like the walbro is'nt any better than stock IMO

 

[buddy]

Im pretty sure the stock LP wouldnt be able to output 10-12psi to the FFM after a 12micron prefilter like I have. My Walbro still puts out 12psi after a year. When you make it deadhead at the restriction of the FFM it doesnt know how much pressure is after or flow it needs before you need it.

You might try running power to it straight from battery, see if its lacking current capability. Like the OPS and LP relay could both have bad contacts.

 

[Matt Bachand]

I'm going to swap out my Racor filter. I Know its all buggered up now. I'm just really curious as to how low PSI I need to get to before it triggers my indicator.

I still have 2 psi, on the highway I was able to floor it yesterday and that was it, using 100% of available fuel.

Walbro is better than Stock/HO's, it does about 2x the GPH's regardless of the PSI your reading. Plus its pulling through restrictive pre-filters, doesn't rust, serviceable/cleanable, and costs about the same.

It is still a reciprocating pump though, these aren't nearly as strong as rotary vain jobbies.

I started out around 7-9 psi, and it gradually dropped. I have no way to tell which filter is clogged though when PSI drops.

Going from a 30 micron to a 10 with filter change. I already have a toggle switch and power leads going to the rear for my xfer tank LP, so I may just toss the lesser walbro as a pusher IFO racor to see what happens with fuel pressure/water drain flow.

Pure curiosity at this point.

I guess I could plumb in a cheapy mechanical fuel pressure gauge directly after the walbro so I can go underneath and read what pressure is there. If FFM is clogged up, that reading should be close to deadheaded One would think.

 

[Matt Bachand]

Im pretty sure the stock LP wouldnt be able to output 10-12psi to the FFM after a 12micron prefilter like I have. My Walbro still puts out 12psi after a year. When you make it deadhead at the restriction of the FFM it doesnt know how much pressure is after or flow it needs before you need it.
.

The pump walbro built me is a constant flow unit that consistenly puts out max PSI, needed or not. I like that much better than watching the needle bounce around with the Pulses. I have no idea what inside could be different to make it constant vs the pulse style. Something to do with the electromagnet. I also replumbed everything a few months ago. Not being scared of cutting factory lines I was able to really clean it up, especially with the FFM back all fresh hose.

 

[Acesneights1]

......No fuel pressure problems for me...In fact I can adjust mine to whatever PSI I want.....
Matt, you were likin that Raptor wern't you...come on.... When the LP goes in my Dually I think I'm gonna spend the Money for the Raptor Kit for the 6.5TD. Thing I like about it is it eliminates the whole OPS problem with the included harness. In fact after seeing how much ill effect air in the fuel has, I am seriously reconsidering the Airdog 100. My fuellines look like doggy doo so I may revamp everything.

 

[Matt Bachand]

Raptor is a real pump for sure....

 

[Acesneights1]

And it sounds really cool too....

 

[orrum]

Hello there folks about that fuel pressure gauge sender being protected by a snubber, the snubber wont save ur sensor from going bad, there is a very fine wire in the sensor and the fluctuation will wear it out. A snubber will reduce the needle bounce but wont eliminate it. Use a needle valve, it will solve the problem. Fastenol carries all kinds of them. First put a isolator hose before the needle valve and sensor, a 18 inch grease hose works well, then put the needle valve on the hose end and then put the sensor on the needle valve. To adjust the needle valve turn it down till when u start the truck the needle very slowly goes up to the pressure ur pump is actually producing. At the engine start the needle does a quick litlle climb to a few pounds and then crawls the rest of the way up to idle pressure, thats an proper setting and will save ur sensor. Wow I impressed myself with that one. This thread has a bunch of good info that I have been looking for in my thread "Fuel pressure at idle and WOT".