Cannot find 7.3L Fuel leak - Diesel Forum - TheDieselStop.com
1999-2007 General Questions General questions related to 1999-2007 Super Duty trucks. If it doesn't fit the other categories, post it here. Gas engine discussion that pertains to all models is allowed. Specific gas engine questions should use the Gas Engines forum.

 
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post #1 of 7 (permalink) Old 10-25-2017, 06:43 AM Thread Starter
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Question Cannot find 7.3L Fuel leak

I have a (series) of major leaks in my 2002 Ford Diesel pickup. This is my history and I still cannot find the leak. Any help would be appreciated.

1. Leak at back on engine, no fuel in valley.-Replaced back seal on fuel line into head (also had a bad worn area on line and it was replaced). No leak upon startup.

2. During road test new leak which ran into the engine valley-Replaced seals on drain valve. No leak upon startup.

3. During road test new leak which was spraying up onto the hood insulation.-Removed fuel bowl and replaced all the o-rings on the bowl and attached lines, replaced the fuel bowl drain valve (and the fuel pressure regulator nipple broke off and was replaced). No leak upon startup.

4. During road test, "new"(?) leak spraying down and back into engine valley. Looks like it is coming out of a bolt on the high pressure pump just below the fuel heater/water in fuel electrical plug. Since this bolt only contains motor oil and no fuel, removed the fuel bowl, placed plugs in the lines to the passenger side of the filter housing and the larger lower fuel line on the driver side. Put water in the fuel bowl and pressurized the fuel pressure regulator line starting at 10 psig increasing to 70 psig. No leaks. Replaced fuel bowl and reattached fuel lines (new sealer on fittings). No leak upon startup.

5. During road test now spraying fuel back at hood. The fuel is under pressure and with the exception of the two very fine spray lines as in #4, is more of a fog.

Cannot feel any spray with fingers and everything in the valley is soaked instantly. I tried wrapping the area with wet paper towels and let it dry to see if I could find the leak. Turned the key on until I heard the pressure pump "click" on then turned the key off. The bottom of the dried paper town thoroughly soaked.

Is 70 psig to low a pressure to keep air from entering the fuel pressure regulator? I attempted to find what the pressure should be on the internet and the sites indicated from a low of 50 psig to a high of 70 psig.

Any help; anyone??
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post #2 of 7 (permalink) Old 10-25-2017, 12:13 PM
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Chase that paper towel test a little further. I think that is how you will find it. Might want to clean the valley with hot soapy water and let dry than on turn key on for a few seconds, build up from that. Hang in there you will find it.

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1999 F350 AUTO 4x4 CC LB DRW 4.10
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post #3 of 7 (permalink) Old 10-25-2017, 02:40 PM
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Thread moved. Please post within the "News, Comments, Site Help and Suggestions" if you have any technical issues regarding your account on the site.

Thank you for your understanding and best of luck with your inquiry.


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post #4 of 7 (permalink) Old 10-25-2017, 06:13 PM Thread Starter
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Administrator. Thanks for your help, but this is called a Power Stroke by Ford, but I do believe it is the 7.3 Liter In-Direct Injection Navistar engine. I am a little confused why your header says it is not a Power Stroke. I just want to make sure this post is in the correct forum.

Thanks Denny. The problem is that the leak is so strong that it covers the area instantly. I did cut a small piece of cardboard to deflect the spray and mist. It is coming from just under the Fuel Heater/Water-In-Fuel electrical connection. When I put the cardboard under the connection all the fuel is coming from under the cardboard so it is not the Fuel Heater/Water-In-Fuel housing.

One further item I found. When my wife turns on the key, the fuel APPEARS to spray from the high pressure pump below the electrical connection. After about 30 seconds it stops; this may be why it seemed to stop after I "fixed" the problem, but leaked when I test drove the truck.

Please correct me if I am wrong, but I believe there is not any fuel in the high pressure pump, just motor oil. Are there any other fuel connections in this area?
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post #5 of 7 (permalink) Old 10-25-2017, 09:14 PM Thread Starter
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Problem solved. I was blindsided by my perspective that the leak was around the fuel filter bowl. I researched further and found a clear piping diagram for the engine. There were only four fuel lines and one drain line in the engine bay. I traced the fuel supply to the driver head and it ran across the engine valley about half way between the filter housing and the fuel pump. When I had my wife turn the key on and I stared at the fuel line, I saw a pin hole leak that was shooting up and hitting the filter housing.

Problem solved. I knew if I asked for help I would find it.

Thanks for this forum.
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post #6 of 7 (permalink) Old 10-25-2017, 10:25 PM
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I figured you would find it!!! The good news is you have replaced all the small stuff that tends to leak with time. I picked up a new to me 99 F350 last year and as I started working on injector O-rings went ahead and replaced most all the soft stuff in the valley. I cheat and make Khansen come over and help so it is easy for me.
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post #7 of 7 (permalink) Old 10-26-2017, 08:16 AM
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Quote:
Administrator. Thanks for your help, but this is called a Power Stroke by Ford, but I do believe it is the 7.3 Liter In-Direct Injection Navistar engine. I am a little confused why your header says it is not a Power Stroke. I just want to make sure this post is in the correct forum.
Yes, you are posting in the wrong Forum. A 2002 Ford Navistar is a DI engine,
it is NOT a IDI
. The Admin is correct, Your thread should have been started in the '99 & up 7.3L Power Stroke Engine and Drivetrain - Diesel Forum - TheDieselStop.com.

In an 7.3 IDI engine, the fuel is injected into a precup, in a 7.3L DI engine (Powerstroke), the fuel is injected Directly into the cylinders.

92 F350 Lariat, 2WD, Dualie, CC, LB, E4OD Trans, Banks Sidewinder turbo, GV O/U, Pyro, Boost, Oil temp, Trans temp. Chassis 129K, Engine 7.3L 75K. Bench seat.

"99.5 F350 7.3 PSD 4R100 CC LB 4X4 DRW 4:10 Centurion Conv.
ScanGaugeII SPDiesel Performance Module 40-60-80 HP -- A Pillar - Boost - Pyrometer - Trans.Temp. - Engine Oil Temp.GN Hitch 20K -- Reese 16K 5er Hitch - Draw Tite Brake Control - Aux. Trans. oil cooler - 100 Gal. Transfer Flow fuel tank, W/Trax II computer. DIY black bed liner. Red Knight

IDI firing order 12734568--------1&4-2&5-7&6-3&8 Cyl's @ TDC. 1&4 TDC when timing mark is @ 0. Each 1/4 turn, next 2.

Last edited by Trucker87; 10-26-2017 at 08:32 AM.
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