Biting the bullet: Converting to electric fuel pump

Most do, that can be a source of air intrusion after you shut the truck off.

What the heck, Ford?!

I spotted a tiny 4" piece of return hose bridging 2 steel lines, where one already has a longer rubber hose right close by. Did they really need another flex line again so soon?

The longer hose got replaced last year because it was leaky. The shorter hose is really old, but has probably been touched at some point since it has a squeeze clamp on one end and a worm gear clamp on the other.

It feels pretty mushy so it definitely needs to be replaced, and it will be when I work on the other portions.

Return line check valve will be here tomorrow, and I will see about undoing the return line from the filter head too.

I dunno where these specs below are from, but if that's true, it's no wonder it's acting up timing wise. 3x normal at idle, but 5-6x normal at highway speeds.

Too bad there is no cheap/easy way I could lower the pressure. There is a $37 Mr Gasket fuel pressure regulator for 1-6psi but I dunno if I want to mess with that when a timing adjustment will probably solve it.

Fuel Pressure (Filter Inlet) 14 kPa (2 psi) @ idle
Fuel Pressure (Filter Outlet) 7 kPa (1 psi) @ 3000 rpm
Fuel Pump Suction 20 kPa (6 in. H2O) @ 3000 rpm
Fuel Return Line Pressure 14 kPa (2 psi) @ 3000 rpm

I found that at:
https://www.ford-trucks.com/forums/...diesel-engine-performance-specifications.html

Return line check valve? You're putting that in your transfer line from the other tank right, and not actually in the return line to the tank?

What pressure are you talking about?

Those pressures for filter inlet and outlet are the minimums when troubleshooting issues. Injection pumps are calibrated at 5 psi inlet pressure, so supply somewhere around that to the pump and you're golden.

You should set/check the timing regardless. It's been known to change with age and wear.

I still think you have return issues. There shouldn't be any pressure there, if there is pressure, there is a restriction. Did you ever check what the return pressure was with the engine revved up? You've stated there is nothing you can do about it, but that's not the case. Any pressure there can eventually cause the return caps and o-rings to leak. So IMO, avoiding fixing this problem will only lead to more down the road.

Booyah45828 said:

Return line check valve? You're putting that in your transfer line from the other tank right, and not actually in the return line to the tank?

What pressure are you talking about?

Those pressures for filter inlet and outlet are the minimums when troubleshooting issues. Injection pumps are calibrated at 5 psi inlet pressure, so supply somewhere around that to the pump and you're golden.

You should set/check the timing regardless. It's been known to change with age and wear.

I still think you have return issues. There shouldn't be any pressure there, if there is pressure, there is a restriction. Did you ever check what the return pressure was with the engine revved up? You've stated there is nothing you can do about it, but that's not the case. Any pressure there can eventually cause the return caps and o-rings to leak. So IMO, avoiding fixing this problem will only lead to more down the road.

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I was talking about IP fuel supply pressure in that last post.

I'm using the return line for both, but not at the same time. Although, I did try both when driving up to around 25-30mph on a side street with no traffic and the engine tone didn't change.

The rear tank supply is fed into front tank's return line by a pump via a tee near the front tank. The pump is on a switch located next to the headlight switch so it's not running constantly.

Cubey said:

I was talking about IP fuel supply pressure in that last post.

I'm using the return line for both, but not at the same time. Although, I did try both when driving up to around 25-30mph on a side street with no traffic and the engine tone didn't change.

The rear tank supply is fed into front tank's return line by a pump via a tee near the front tank. The pump is on a switch located next to the headlight switch so it's not running constantly.

Click to expand...

I assumed that, which is why I said the 1 and 2 psi specs were minimums.

I thought so, and that shouldn't be an issue as long as running both doesn't create pressure in the return system.

I assume your check valve will be placed between the transfer pump and the tee in the return system?

Booyah45828 said:

I assume your check valve will be placed between the transfer pump and the tee in the return system?

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Correct.

I will also change the tee so the engine return doesn't have to make a 90 degree turn, which might help reduce the pressure.

Here is how I set it up at first. Look between the two pumps for the tee, below the rear tank return line with the bolt in it.

Cubey said:

Fuel Pressure (Filter Inlet) 14 kPa (2 psi) @ idle
Fuel Pressure (Filter Outlet) 7 kPa (1 psi) @ 3000 rpm
Fuel Pump Suction 20 kPa (6 in. H2O) @ 3000 rpm
Fuel Return Line Pressure 14 kPa (2 psi) @ 3000 rpm

I found that at:
https://www.ford-trucks.com/forums/...diesel-engine-performance-specifications.html

Click to expand...

I'm going to clean/clarify this data here.

Fuel Pressure (Filter Inlet) - Minimum 14 kPa (2 psi) @ idle
Fuel Pressure (Filter Outlet) - Minimum 7 kPa (1 psi) @ 3000 rpm
Fuel Pump Suction - Maximum 20 kPa (6 IN.HG) @ 3000 rpm
Fuel Return Line Pressure - Maximum 14 kPa (2 psi) @ 3000 rpm

That's what they should read.

FordF250HDXLT in the FTE thread messed up the conversion for fuel pump suction. I corrected it to read in.hg, which is what most pressure/vacuum gauges read.

20 kpa is about 6 in.hg, not 6 in.h2o. 20 kpa is about 80 in.h2o. 6 in.h20 is like a quarter of a psi, which is a small number.

I didn't check the return line pressure between changing the tee and disconnecting the filter head, but after doing both it's about 1.5psi at idle now (near the front tank at the tee). I think changing the tee connections so that engine return goes straight through it probably dropped it by 0.5psi more than the filter head connection did.

The check valve came and I installed it too.

I dug up this video of somebody testing the fuel pressure of a mechanical pump, both at idle and at speed. Their idle pressure is about 4.8-5 psi and their driving pressure is about 3psi.


Mine is about 7 at idle, about 6 when cruising at 60-70, and about 5 even when floored at 70mph, but getting no more speed out of it. So I'm at least 3psi higher than normal.

Maybe I'll go pick up the $38 Mr Gasket fuel pressure regulator and carry it with me, just in case it ends up needing it to be reduced. Heck, it might even fix it so that it doesn't need timing. But, then again maybe it'll help my MPG a bit. I can return it, if I don't need it. Would be nice to have it on hand, so I can stick it on in a pinch.

I'm reeeeeally hoping the timing service fixes it on the first go, so I don't end up having to repeatedly pay, ie: before and after the addition of the regulator.

Oh, and the other day when I had it iding during the transmission fluid refill, I noticed a tiny bit of grey smoke at idle. I had to really stare to see it now and then, so it wasn't a lot. The tailpipe is behind the rear wheels on 176" WB, so..... that's why I can't really see when driving in my side mirror. It could be blowing grey smoke at highway speed, but be danged if I can see it in the mirror against the grey highway 14 feet back from the passenger side mirror.

So, Cubey, what is the final analysis of your electric pump conversion?

lonnoid said:

So, Cubey, what is the final analysis of your electric pump conversion?

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Can't say. The pandemic broke out right after I got it done, so I haven't gone anywhere. I did buy dial turn Mr Gasket fuel pressure regulator so I can adjust it as needed, but I haven't installed it yet since it hasn't been a high priority. I will install it by the Racor water separator, so it's not a big job, just messy.

I need to fix the power steering return line before I can even run the engine right now. I bought a new complete return line (because the old one got damaged when I installed a new pressure line. I just can't win.) but it wouldn't thread in to the gear box right for some reason due to stuff in the way and angles. I hope it didn't cross thread, but I don't think it did. I got frustrated and cut ff the line with the inverted flare and nut, putting the hose on the bare steel line with no barb. Sure, it threads into the gear box easily easily now but the hose leaks pretty good still since it doesn't seal very well. .At least, I hope that's where it's leaking, not the threads. So... I have no return line hooked up and can't run it at all.

I just bought one of these yesterday (from ebay for less) to hopefully fix that and make it easy to install. It should be here in about a week.
https://www.summitracing.com/parts/...2I7hsK58o4FEq7Dbdefku3ysXQVK1aOhoCupUQAvD_BwE

I'm driving my F250 IDI right now, but only 3-5 times a month since I'm staying in and away from people (even more than I normally do) and I have access to it here.

Oh and I hope I bought the right fitting... it not, this might be it.
https://www.summitracing.com/parts/edd-822660

EDIT: Yeah, that is. Darn it. Guess I'll order that too.

O'Reilly lists the return as 5/8-18 on the gear box:
https://www.oreillyauto.com/detail/...ord/e-350-econoline?q=steering+gear+box&pos=0

For what it's worth, some used inverted flare and some have an o-ring seat. Just a heads up in case it leaks with the new fitting. I "think" yours should be inverted flare like you ordered.

chillman88 said:

For what it's worth, some used inverted flare and some have an o-ring seat. Just a heads up in case it leaks with the new fitting. I "think" yours should be inverted flare like you ordered.

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The pressure hose uses an o-ring at the pump side and inverted flare at the gear box.

The return line is a bare hose that goes on a hose barb on the pump, and uses inverted flare at the gear box.