Biting the bullet: Converting to electric fuel pump

[Booyah45828]

You're right, flow and pressure aren't the same. But they are directly related. Pressure is the resistance to flow. So if you're supply pressure is at the correct psi when the engine is fully loaded, then the fuel flow from the pump is adequate.

I guess I assumed your 4.5-5 psi figure was measured when you were having your power issue.

Figure out what your fuel pressure is when it has the low power and then go from there. Once you have that, you can then make a plan.

Did all the people who had the facet pumps and low pressure have power issues too? I don't remember.

 

[Cubey]

You're right, flow and pressure aren't the same. But they are directly related. Pressure is the resistance to flow. So if you're supply pressure is at the correct psi when the engine is fully loaded, then the fuel flow from the pump is adequate.

I guess I assumed your 4.5-5 psi figure was measured when you were having your power issue.

Figure out what your fuel pressure is when it has the low power and then go from there. Once you have that, you can then make a plan.

Did all the people who had the facet pumps and low pressure have power issues too? I don't remember.

I'd say I have poor flow at 4.5psi since accelerating hard from a stop never got the pressure below 4.5psi. 4.5psi with Holley red is roughly 50-55gph, which is way too low for 3000-3500rpm.

It should be getting about 65gph/5-6psi at 3000 rpm and 75gph/5-6psi at 3500rpm. Instead, it's getting 50-55psi at best.

So the pressure is ok, but not the flow.

No tach to reference, but I probably hit 3000-3500 easily with the turbo and 4.10 rear end when accelerating hard with the mech pump.

 

[Cubey]

I'm so irritated with this and would hate to buy another $200 electric pump and still have problems, that I'm about to give up and go back to mechanical, as much as I would hate to admit defeat.

Gonna try to see if something in the system is causing it first though.

At least I'm just city driving right now, and I can take time to diagnose things once the rain quits. I don't have to get on the interstate any if I don't want to.. and how it's acting right now, I sure don't.

It's like riding a 250cc scooter, where you are at WOT to get to 70mph.. and that's there is and there ain't no more.

 

[Shadetreemechanic]

Either I am not reading correctly or you have some more troubleshooting to do. IF you have 4.5 psi at the filterhead under load at WOT then you do not have a fuel delivery problem. I get your specs of the holly pump, but the transfer pump in the injection pump is what is putting the fuel to the injectors, so if there is 4.5 psi pushing into the injection pump under load then there is plenty of fuel volume. A GPH flow rate issue should still show up as low pressure at the filter head because the transfer pump in the injection pump would be gobbling up the fuel faster than the e pump can deliver it.
If I misread and you dont have PSI readings under load, that is what you need in order to diagnose this.

 

[Cubey]

Either I am not reading correctly or you have some more troubleshooting to do. IF you have 4.5 psi at the filterhead under load at WOT then you do not have a fuel delivery problem. I get your specs of the holly pump, but the transfer pump in the injection pump is what is putting the fuel to the injectors, so if there is 4.5 psi pushing into the injection pump under load then there is plenty of fuel volume. A GPH flow rate issue should still show up as low pressure at the filter head because the transfer pump in the injection pump would be gobbling up the fuel faster than the e pump can deliver it.
If I misread and you dont have PSI readings under load, that is what you need in order to diagnose this.

4.5 is under load, driving up to 45mph. Check this video here. Don't bother watching after 3m30s, the phone mount falls and i didn't edit out the last minute of nothing to be seen

https://photos.app.goo.gl/JNZrYscV3VuUrdaD8

I wonder if I figured it out though. Maybe that ball valve between the tank and pump is the problem. I have a couple more left over (it was a pack of 4) and upon closer inspection, the inner ball's passageway is a smaller diameter than the outer 3/8" brass barb, so maybe it's a supply problem going to the pump, not from the pump. Tomorrow, I will remove the valve first before I do anything else and I'll see if that helps any.

 

[Cubey]

I do notice something in the video when cruising at 45, the pressure appears to be slowly recovering, as if it dropped because it couldn't keep up and the pump it taking a long time to recover.

That makes me think of a YouTube video i saw about a certain Facet duralift pump dropping it's fuel level so much on an idi vs another model duralift. The pump was pumping, but it couldn't recover fast enough.

After removing the gauge due to rain, I drove up to 55mph for about a mile, and it seemed to slowly speed up to that point after I had basically picked about 50 (when I let off the throttle a bit) as if the pressure was recovering still for quite some time, changing timing and therefore still increasing throttle slightly.

Since pressure to the IP messes with timing, maybe the slow pressure recovery time is messing with things, making it hard to get up to speed properly with the pedal to the floor.

What pressure the IP wants seems up for debate. Some people say 5, some say 6, some say 7. Regardless, 4.5 is less than all of those.

Perhaps the 14psi Holley blue (or black) with a regulator set to 6psi would be more appropriate, giving it a more constant pressure.

Gonna troubleshoot what I have first of course, but it's almost undrivable on highways over 55mph right now so something has to be done.

 

[Cubey]

Huh... in addition to Holley making the Mr Gasket pumps that look like the Holley red/blue/black, they also make "Sniper" pumps that have almost identical flow rates and pressures as red/blue/black, but cost way less. I wonder why. Inferior quality parts?

The blue equiv:
https://www.holley.com/products/fue...carbureted_electric_fuel_pumps/parts/80000101

The black eqiv:
https://www.holley.com/products/fue...carbureted_electric_fuel_pumps/parts/80000102

The black equiv shows $82 and the regulator for $21 from oreilly, both special order. Walmart has the pump for $90 and they take back everything, even used, so... i might get one from them to try, if I can't get Red flowing right this week.

 

[Booyah45828]

Either I am not reading correctly or you have some more troubleshooting to do. IF you have 4.5 psi at the filterhead under load at WOT then you do not have a fuel delivery problem. I get your specs of the holly pump, but the transfer pump in the injection pump is what is putting the fuel to the injectors, so if there is 4.5 psi pushing into the injection pump under load then there is plenty of fuel volume. A GPH flow rate issue should still show up as low pressure at the filter head because the transfer pump in the injection pump would be gobbling up the fuel faster than the e pump can deliver it.
If I misread and you dont have PSI readings under load, that is what you need in order to diagnose this.

This.

If your pressure to the lift pump is within specs, then your flow is fine. The gph figure doesn't matter, as long as the lift pump delivers enough flow to have 5 psi at the injection pump at all times. I don't know where you got your figures for fuel flow requirements, but if the injection pump requires 50 gph, and you supply more then that, it shows up as pressure in the system /less then that will and it will show up as vacuum.

Your holley red pump looks like it will only supply around 5 psi, because at 6, it nose dives. It would be nice to have an actual flow figure at 5 psi, vs something extrapolated from the graph.

But at the end of the day, the gph doesn't matter to the engine, as long as it has 5 psi to the pump inlet.

The only time the gph figure matters is when your shopping for a bigger pump because your current one doesn't provide enough. You don't know if your current one is or isn't providing enough, so check your pressure when you're having issues. Only that can tell you if you have fuel supply issues. So do that before you toss the mechanical back on, buy a holley black pump, or anything else.

 

[Cubey]

. I don't know where you got your figures for fuel flow requirements,

From here:

https://mid-atlanticema.org/wp-content/uploads/93-94-7.3-IDI-Turbocharged-Diesel-Engine.pdf

It says at the bottom of the page that we need to see at least 1 psi of pressure and one pint of fuel from the lift pump at 675 rpms in 30 seconds. That gives us a formula for a minimum fuel volume we can manipulate. Im going to round to 700 rpms, but basically we should get 2 pint per minute at idle, converting that to gallons per hour we get 15 gph at idle, which means just for a stock IDI to idle properly, youre already using half of the Facet 40222's rated fuel flow. Since the mechanical lift pump is a fixed displacement, we can multiply our idle speed by 5 to see what minimum volume we should be getting at 3500 which would be the rpm which the most fuel would be needed for the IP. 15 gph x 5 = 75 gph.

This means we should at the least have 75 gph to supply a stock IDI, whether turbo or na ford doesnt seem to think it matters.

Link to post: https://www.oilburners.net/threads/carrier-facet-pump-observations.85386/#post-1022046

 

[Selahdoor]

Yeah, I was thinking about that as well.

You have a certain rated flow at a certain rated pressure.

Say 50gph at 5pounds of pressure. (Using these numbers to be nice round numbers.)

If your flow fell off to say 30gph... it would show in your pressure reading as well. So if it were only supplying 30gph, you should see a lower pressure as well. Say 3pounds. (It wouldn't be exactly that, but I am not here to argue graphs and technicalities or to pick at nits. Just to make what should be a rather simple point.)

If it didn't supply at least 50gph at 5 pounds of pressure, could it legally be rated at that?

Long point short... If you are not seeing a lowering of pressure at those times you are concerned with, you aren't experiencing less flow, either. The problem is something else.

 

[Booyah45828]

From here:
Link to post: https://www.oilburners.net/threads/carrier-facet-pump-observations.85386/#post-1022046

Yeah, I remember reading that now. Wes came up with that 75 gph number based off of ford's pressure and supply requirements at idle. Now, I'm bot saying it's a bad figure to go off of if you're buying a new electric pump. And he mentioned that it's better to buy a higher flowing pump, and then regulate it down, vs running something marginal. But I question whether it needs 75 gph at 3500 rpm. The old adage has always said that 1 gph is good for 10 hp, but that doesn't take into account the fuel bypassed by the pump to keep it cool. And I also found on here one time the stock mechanical pump is only good for 30 gph, which is less then half of the supposed 75 gph requirement. So who/what is wrong?

I guess if we want exact fuel supply figures/requirements, someone like wes should rig up a flow meter on the pump test bench and see what the fuel flow is required to maintain 5 psi during full load throughout the entire rpm range. Then we would have a concrete figure.

But at the end of the day, if you don't know what your fuel pressure is when you're having the issue, then condemning the holley red is no more then a guess. I guess my problem is that countless people have ran the holley red and none have had issues. So unless you show that it's down on pressure, like people have done on the facets, I don't think I can condemn it. And you don't seem like the type of person that can keep throwing money at this hoping the problem is fixed.

 

[Cubey]

Had to tend to my mom's leaking trans ccooler hose today. After chopping off 1/2" or so of the ends of the hoses, and putting in a brass 3/8" hose barb mender in place of the silly "repair part" the trans shop put on years ago, plus new clamps, her leak is fixed. Cost $6. (I mention this since it came up earlier in the thread)

So now that's done, she's happy to let me use the driveway again to work on troubleshooting my fuel pump problem.

Gonna get a bite to eat, then put the test gauge back on, then remove the ball valve and the Racor W/S and then go drive it and see if it's any better.

Might close off the value supplying the tank transfer pump too, in case that's somehow causing a return line problem.

I'll report back later...

 

[Selahdoor]

Don't do a bunch of stuff and then test. Just put the gauge back on, and finish the test from before.

Take it through the range you are concerned about, and watch the gauge.

Then you have more accurate data, before you start making changes.

 

[Cubey]

Don't do a bunch of stuff and then test. Just put the gauge back on, and finish the test from before.

Take it through the range you are concerned about, and watch the gauge.

Then you have more accurate data, before you start making changes.

Yeah, I decided to try one at a time. I put the gauge on and removed the questionable ball valve. As you can see, it's smaller inside. It was installed before the pump, causing a supply restriction.

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And the results: My fuel pressure is higher. Idling at about 7 to 7.3psi. When driving, it almost ever dips below 5psi. Feels a little more responsive, so I got on the interstate for a mile. It's still a bit different from mechanical I think, but it's better for sure. I had the pedal to the floor after merging and it appears to be sitting right on 5psi. When I let off a bit it goes to 5.5-6. Totally let off and it jumps to 7ish.

Maybe it just needs timing done to fix the rest.

Here is a better framed video of that drive, showing the gauge and a view of the road. Plus I edited it down.

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Once the exhaust cools down, I will also try removing the Racor just to see what difference it also makes, since I did notice issues with the old dirty 2 micron filter it had with the mechanical pump. It has a new 30 micron, but maybe it's still too restrictive. It's just a hose swap to bypass it, so I'll try that too. If there is no noticeable change, I'll put it back.

 

[Selahdoor]

Looks like it's consistent.

Gets down to just over 5 when you have your foot into it.

And back up to over 7 when you let off.

I'm betting 5 pounds of pressure is delivering sufficient fuel. I'd try the timing.