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Hi everyone. It's been awhile since I've posted. I'm going to change the fuel pressure regulator in my 1988 E350 and want to know. If anyone else has done this and if they have any installation advice. I have the doghouse off and the air cleaner housing but can barely see the regulator. Does anyone know what type of screws attach it?
 

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Welcome to the FFO!

It has been awhile since I changed one. I believe the fasteners were torx.
The only caution is to relieve fuel pressure before removing. Otherwise it isn't that difficult.

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Thanks. What's the best way to relieve the pressure? I found a YouTube video where someone changed one in a F150. He said it was a 4mm Allen wrench.
 

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There is a schrader valve in the fuel rail. Engine off depress the schrader valve. Have a rag over it at the same time so fuel does not spray at you.

Could be an allen screw. It has been some time for me

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I have discovered that doing almost any repair to an engine on an Econoline requires someone way more agile than me. Quarters are tight in the engine bay. After wrestling the doghouse off I discovered the Fuel Pressure Regulator is still just out of reach. Does anyone know a contortionist I can hire to accomplish this task? Now I know why my mechanic scowls when I bring the old beast in for repairs.
 

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What engine?
Do you have a shop manual?

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Why do you want to replace it?

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What engine?
Do you have a shop manual?

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I have a 460 fuel injected engine and I only have a Haynes manual which is not very descriptive. The reason I want to replace the fuel pressure relay is because I've had problems with the fuel tank system. I have never been able to transfer fuel from the main tank. It seems to run for awhile then sputters and dies. I've replaced the original fuel transfer valve with an electric one because folks on the forum were saying the manual valve was known to be problematic and the electric valve solved their problem. Since that didn't solve the problem I started researching again. Others were saying a new fuel pressure relay solved their problems. I've always been a shade tree mechanic but have worked on my own vehicles for 52 of my 68 years.
 

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The Haynes manual is very much less than.
For $30 you can have a factory set on CD
https://www.ebay.com/itm/FORD-1988-...403739?hash=item3633aff5db:g:3mIAAOSwkvFaU6TK

There is a fuel pressure regulator and a fuel pump relay. There is no fuel pressure relay.

The fuel pressure regulator regulates the fuel pressure in the fuel rail on the engine to the fuel injectors. If the engine runs on either tank the fuel pressure regulator is good because there is enough pressure to operate the injectors. Stop pursuing replacing the fuel pressure regulator

Assuming you have dual tanks -
The fuel pump relay directs power to the fuel pumps. There are 3 in a dual tank. One in each tank (low pressure) And one high pressure pump mounted on the frame rail. IF the engine runs at all the fuel pump relay is good. It either works or does not not.

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If the system is stock, (and even if it is not) the likely problem you have is a in tank fuel pump is not working at all or not pumping enough pressure. You switch to the bad tank and the engine operates for a very short time and then stalls out. It is because the in tank pump is not producing enough pressure. This is a common problem if the fuel level in either tank goes very low to empty. The fuel is used to cool the pump. However if you operate the pump to empty on any tank the pump no longer has fuel to keep it cool and the pump can only handle a few low fuel events. (BTW later fuel pumps were changed so that is not as much of a problem for fuel injected systems in the 1990s and later)

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In the stock system, the fuel tank switching is accomplished by fuel pressure. The switch on the instrument panel operates which pump and fuel sender to work. With a given tank that pump pressurizes the system to a valve on the fuel rail near the fuel filter. The pressure pushes the valve (think of it as a Y valve) to operate and fuel to the high pressure pump.

When the operator in the vehicle selects the other tank, the power to the first tank is stopped and power is sent to the pump (and sender) in the other tank. That pump pressurizes the line from the tank to that Y valve. The valve moves to the other side BECAUSE OF FUEL PRESSURE and sends fuel to the high pressure fuel pump.

That Y valve has no power to it and is switched when fuel pressure from one tank is greater than the other. Because one tank pump is on and one tank pump is off.

NOW, lets assume one tank pump is not producing pressure. If you are on the other tank, no problem. That other tank is producing pressure and that pressure is going to the Y valve, fuel filter and high pressure pump.

Switch to the bad tank and power is cut to good tank pump. So the fuel pressure drops in that fuel line to the Y valve. The bad tank fuel pump is getting power but the pump can not produce fuel pressure to the Y valve. No (or low) pressure means either the Y valve does not switch. Or if it does switch the pressure is not high enough for the high pressure fuel pump. ….. Engine stalls. Driver is unhappy. And passengers look at the driver and say …… well you know what they say.

Replace the fuel pump in the tank for the side that does not work.

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If you want to test this diagnosis, you can do it by switching to the bad fuel tank. Opening the fuel filler cap. Then have some one turn the ignition key to run. No sound should be heard through the fuel filler neck pipe.

Remove the fuel cap of the other tank. Have your helper switch tanks. You should hear that fuel pump turn on for a very short time. Once the pressure builds up the pump will stop.

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Discussion Starter #13
Thank you for the information. You provided a wealth of knowledge. Two things, I realized I said Fuel Pressure Relay instead of regulator after I posted. Second, I realized I have a Chilton, not Haynes, manual. I just now ordered the CD manual on Amazon. It should provide way more information.
I will try your suggestions and quit pursuing the regulator. Thank you!
 

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Check to see if both pumps are working.
With engine off and key flipped to the on position, which ever one is selected will make a sound for a very short period of time. Once pressure is built up it will shut off. With the engine off it will take almost no time at all to build up pressure.

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