Electronic fuel pump 7.3 IDI

ClifFord

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I've seen alot of people bypass there lift pump with electric, but I'm asking if I could put the electric 10psi pump inline with the lift pump. And if so should I put it before or after the lift pump? This is a 7.3L IDI T, K model.

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Clb

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Stop and read some of the e pump threads.
You need a check valve to keep from backfeeding the manual pump
 

Booyah45828

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Has anybody used one of these check valves before the a mechanical lift pump and saw their timing change?

Reason I ask, is that I installed a 3/8" npt back flow prevention valve (https://www.mcmaster.com/7768k69) before my lift pump so that my generator wouldn't suck the fuel filters dry. Anyways, when you run the engine now, it sounds like a big block gasser. So I'm thinking the timing is retarded because of a change in fuel pressure. I haven't checked the timing yet, or the fuel pressure, but I'm just wondering if anybody has seen something similar happen.
 

ClifFord

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Ok so order would be ,from tank, tank switch, check valve, electric pump, mechanical lift pump, filter, hpop/ip.
Right?

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mblaney

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Why wouldn't you remove the mechanical pump and put a cheap block off plate on it? Other than that, your order is correct.
 

raydav

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Ok so order would be ,from tank, tank switch, check valve, electric pump, mechanical lift pump, filter, hpop/ip.
Right?

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I always put the filter before the pump. Get rid of the mechanical. Pulsating pumps have a check valve built in. Rotating pumps don't need a check valve either. I currently have six vehicles set up that way.

I run a two micron filter before the pump, and if it is fuel injected I put a thirty micron after the pump to catch broken pump parts.
 

VanDiesel

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The electric pump should be AFTER the mechanical if you use both. Otherwise, should the mechanical pump diaphragm rupture, the electric pump will start filling your engine crankcase with fuel.

We ran IDI engines like this for years. We eventually just used electric pumps and blocked off the mechanical pump opening with a fabricated plate - but a big block Chevy mechanical fuel pump blockoff plate from a speed shop works perfectly.

Personally, I carry a spare electric pump, just in case. And spare fuel filters.

The huge advantage to an electric pump is that you do not have to waste battery amperage and overheat the starter purging air from the fuel lines after a filer change or running out of fuel. Cranking 440 cubic engines at high compression just to get fuel flow from a mechanical pump is a complete waste of time, energy and wear, when there is an easy alternative.

On a V belt driven IDI, another advantage is that you get more belt adjustment range on the vacuum pump, allowing the use of belts with slightly longer dimensions.

Always have the filter the last item on the line before the injection pump. You do not ever want debris from a worn or failing lift pump to enter the injection pump.

Ok so order would be ,from tank, tank switch, check valve, electric pump, mechanical lift pump, filter, hpop/ip.
Right?

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raydav

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Always have the filter the last item on the line before the injection pump. You do not ever want debris from a worn or failing lift pump to enter the injection pump.

As I said I sometimes run a second filter to catch broken pump parts. In the case of the pump I have on the IDI that is not an issue; no plastic.

But why would you want to put whatever crap you pick up into the pump? I have twice - once gas and once diesel - gotten sludge so bad it seriously impacted performance. But I had filters in front of the pumps and was able to limp home. Had that junk gone into the pump I would have been on a flat bed. And even ordinary dirt will degrade the pump.
 

VanDiesel

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There should be a filter on the pickup in the tank, a water separator, your mechanical then electric lift pump (if you use both), the inline heater in tube or housing, then the large spin-on filter just before the injection pump.

As I said I sometimes run a second filter to catch broken pump parts. In the case of the pump I have on the IDI that is not an issue; no plastic.

But why would you want to put whatever crap you pick up into the pump? I have twice - once gas and once diesel - gotten sludge so bad it seriously impacted performance. But I had filters in front of the pumps and was able to limp home. Had that junk gone into the pump I would have been on a flat bed. And even ordinary dirt will degrade the pump.
 
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raydav

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The day after my last post I remembered, most everyone here still has the original filter that IH put there. I got rid of mine on both the IDI and PSD so long ago I kinda forget it was ever there.

IH put that filter on the engine for their benefit not ours. As soon as the engine is assembled the fuel system is protected. It is protected during test before shipment and during whatever Ford does with it.

That does not mean the engine is the best place for the primary - in Fords case the only filter. It is desirable to filter junk as early as possible. But not too early.

When I got my 84 E350 it would not go over twenty five miles per hour. It had an in-tank pump that was disintegrating. So now I have no degradable or serviceable parts in the tank. On the bottom of the tube that carries the level sender is a piece of hose that extends to the bottom of the tank. No pumps and no shower heads. Junk now gets picked up into a filter where I can see it. I can deal with a plugged filter on the side if the road. Things inside a tank are a different game.
 

VanDiesel

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I cut an access hatch above the sender hole in the tank in the floor of our 1985 E250, that is removable with sheet metal screws. It's not necessary to drop the tank or empty it to gain access to the pickup and filter. A 1984 diesel van does not have a stock in tank pump and the hole is small. I did later install a bigger tank from a Bronco with the larger sender hole.

The day after my last post I remembered, most everyone here still has the original filter that IH put there. I got rid of mine on both the IDI and PSD so long ago I kinda forget it was ever there.

IH put that filter on the engine for their benefit not ours. As soon as the engine is assembled the fuel system is protected. It is protected during test before shipment and during whatever Ford does with it.

That does not mean the engine is the best place for the primary - in Fords case the only filter. It is desirable to filter junk as early as possible. But not too early.

When I got my 84 E350 it would not go over twenty five miles per hour. It had an in-tank pump that was disintegrating. So now I have no degradable or serviceable parts in the tank. On the bottom of the tube that carries the level sender is a piece of hose that extends to the bottom of the tank. No pumps and no shower heads. Junk now gets picked up into a filter where I can see it. I can deal with a plugged filter on the side if the road. Things inside a tank are a different game.
 

VanDiesel

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The large spin on filter also acts as a fuel reservoir, and as a heater for the fuel. On top of the engine, this is efficient, more so on the vans. If you run vegetable oil from the back tank, this location heats the oil to a viscosity level adequate to run the engine.

IH put that filter on the engine for their benefit not ours. As soon as the engine is assembled the fuel system is protected. It is protected during test before shipment and during whatever Ford does with it.

That does not mean the engine is the best place for the primary - in Fords case the only filter. It is desirable to filter junk as early as possible. But not too early.
 

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