7.3 fuel system upgrade
#16
#17
I believe that omitting the return line from the filter head is a bad idea, because it allows air bubbles to escape the filter head, thru the small orifice restricted fitting installed there, when small amounts of air are picked up in the tank from slosh, and pumped to the ip they are directed to this return line, (the high point of the system) the fuel line to the ip is down hill from the filter head, thus difficult for the tiny amount of flow to force air bubbles down hill to the ip, approx. 9.14 oz. per min. I have not done the math for the orifice, but the return line flow could be half that, quit easily. if omitted, all air, that find's its way into the fuel system, would have to pass thru the ip. and a hand pump, or e pump will not fix this problem, unless their is a path back to the tank from this high point. when you experience a 10 or 15 second delay in starting, is most likely not air intrusion, most air intrusion, symptom's, are it starts normally and quits about 50 seconds after starting, because the filter is empty, and you don't have a e pump to fill it before cranking. and the mechanical pump can't fill the filter, before the engine run's out of fuel in the vertical section of fuel down to the ip. with no return you have to crank all that air thru the ip, to get her going. my $1.55
#18
Dont hate the messenger, im just passing on what i read from Ford. The reason to remove that return line is due to the fact that it is more often than not, responsible for air intrusion- so sayeth the bulliten
Mine was already gone on my 89 engine in the 79 and ive never had an issue. I removed the one on the 92 when i ditched the stock filter and still no issues, in fact im inclined to say it runs cleaner when you first start it up, but i cant say for certain.
Mine was already gone on my 89 engine in the 79 and ive never had an issue. I removed the one on the 92 when i ditched the stock filter and still no issues, in fact im inclined to say it runs cleaner when you first start it up, but i cant say for certain.
#19
Join Date: Feb 2002
Location: Greater Austin, Texas
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Do you have a number for the TSB? I would like to read it to see what Ford has to say on the matter.
Anybody have the part number for that tee at the back of the motor? I have not been able to find one using search engines. However, I did find the part number for the return line check valve at the filter head - the best and latest design, with a check ball, is F2TZ-9K061-A, if you wanna keep your return line to the filter head.
Anybody have the part number for that tee at the back of the motor? I have not been able to find one using search engines. However, I did find the part number for the return line check valve at the filter head - the best and latest design, with a check ball, is F2TZ-9K061-A, if you wanna keep your return line to the filter head.
#21
Join Date: Feb 2002
Location: Greater Austin, Texas
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Anybody have the part number for that tee at the back of the motor?
#22
TSB 92-10-9
This may be what you are looking for:
Article No.
92-10-9
May 6, 1992
<table border="0" cellSpacing="2" cellPadding="1"><tbody><tr vAlign="top" align="top"><td>^</td><td>FUEL SYSTEM - 7.3L DIESEL ENGINE - DIAGNOSTIC PROCEDURE FOR DETECTING AIR LEAKS
</td></tr><tr vAlign="top" align="top"><td>^</td><td>HARD START - 7.3L DIESEL ENGINE - FUEL SYSTEM AIR LEAKS
</td></tr><tr vAlign="top" align="top"><td>^</td><td>POOR PERFORMANCE OR LACK OF POWER - 7.3L DIESEL ENGINE - FUEL SYSTEM AIR LEAKS
</td></tr></tbody></table><table border="0" cellSpacing="2" cellPadding="1"><tbody><tr vAlign="top" align="top"><td>LIGHT TRUCK:</td><td>1988-92 E-250, E-350, F SUPER DUTY, F-250, F-350
</td></tr></tbody></table>ISSUE:
Hard starting and poor engine performance may be caused by air leaks in the diesel fuel system supply lines. Hard start concerns may also be caused by air leaks in diesel fuel system return lines. In some cases, air leaks have resulted in unnecessary fuel injection pump replacement.
ACTION:
If service is required, use the following diagnostic procedure and a Rotunda One Hand Vacuum Pump 021-00037 or equivalent to detect air leaks in the diesel fuel system.
Cheers,
Fred
Article No.
92-10-9
May 6, 1992
<table border="0" cellSpacing="2" cellPadding="1"><tbody><tr vAlign="top" align="top"><td>^</td><td>FUEL SYSTEM - 7.3L DIESEL ENGINE - DIAGNOSTIC PROCEDURE FOR DETECTING AIR LEAKS
</td></tr><tr vAlign="top" align="top"><td>^</td><td>HARD START - 7.3L DIESEL ENGINE - FUEL SYSTEM AIR LEAKS
</td></tr><tr vAlign="top" align="top"><td>^</td><td>POOR PERFORMANCE OR LACK OF POWER - 7.3L DIESEL ENGINE - FUEL SYSTEM AIR LEAKS
</td></tr></tbody></table><table border="0" cellSpacing="2" cellPadding="1"><tbody><tr vAlign="top" align="top"><td>LIGHT TRUCK:</td><td>1988-92 E-250, E-350, F SUPER DUTY, F-250, F-350
</td></tr></tbody></table>ISSUE:
Hard starting and poor engine performance may be caused by air leaks in the diesel fuel system supply lines. Hard start concerns may also be caused by air leaks in diesel fuel system return lines. In some cases, air leaks have resulted in unnecessary fuel injection pump replacement.
ACTION:
If service is required, use the following diagnostic procedure and a Rotunda One Hand Vacuum Pump 021-00037 or equivalent to detect air leaks in the diesel fuel system.
Cheers,
Fred
#25
#29
I meant if the updated fuel delivery set up would work with a turbo or does having a turbo make no difference. Yeah i know its old, i was diggin last night. But these trucks are 30years old so im sure its still useful ino
#30
I've modified my trucks; I put single-ended return caps at the back, bring the return lines forward, and tee everything together at the IP, right at the front of the engine. I then run rubber fuel line from there, across over to the driver's fender well and down along the frame, totally eliminating the stock metal return line going back across the intake manifold.
This helps keep it away from the turbo, as well as being a lot easier to work on - no messing with leaks or hoses at the back of the motor.