Uphill acceleration problems
Hello everyone I got a question I have been battling up hill acceleration for a long time now trucks got good fuel pressure as it was tested more then twice tank was cleaned out and reinstalled injectors are decent and in a scanner everything seems normal from a few trusted diesel techs anyone got any ideas what’s going on. Truck is a 2003 Ford F-350 with an 01 7.3 powerstroke
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Measure fuel pressure while the engine is under load, climbing the hill. It will show good pressure all day long at idle, but that's basically useless information in diagnosing a power loss as you are describing. Mine was fine, but dropped to 20 psi at the first hill I came to. The factory fuel pump has a screen inside the inlet side of the pump that greatly hinders fuel volume which is critical for maintaining good fuel pressure when the volume demand is high. Once I got the volume issue ironed out, I hardly ever have to shift down on a hill any more while pulling the trailer. 4% grade or less, it just goes up and over.
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The screen inside the fuel pump gets clogged, then fuel volume drops off, then the engine power drops off as well.
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Originally Posted by Kwikkordead
(Post 20638289)
Measure fuel pressure while the engine is under load, climbing the hill. It will show good pressure all day long at idle, but that's basically useless information in diagnosing a power loss as you are describing. Mine was fine, but dropped to 20 psi at the first hill I came to. The factory fuel pump has a screen inside the inlet side of the pump that greatly hinders fuel volume which is critical for maintaining good fuel pressure when the volume demand is high. Once I got the volume issue ironed out, I hardly ever have to shift down on a hill any more while pulling the trailer. 4% grade or less, it just goes up and over.
had the truck fuel pressure tested many times under load while driving all tested good especially after I changed the fuel pump and dropped the fuel tank and cleaning everything out |
The 01 motor in the 03 truck, is that from a van? What's your oil level?
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Originally Posted by Jared0099
Hello everyone I got a question I have been battling up hill acceleration for a long time now trucks got good fuel pressure as it was tested more then twice tank was cleaned out and reinstalled injectors are decent and in a scanner everything seems normal from a few trusted diesel techs anyone got any ideas what’s going on. Truck is a 2003 Ford F-350 with an 01 7.3 powerstroke
Originally Posted by Jared0099
(Post 20638302)
had the truck fuel pressure tested many times under load while driving all tested good especially after I changed the fuel pump and dropped the fuel tank and cleaning everything out
We are willing, eager and capable of helping you, but we need very specific information and a lot more details. |
What makes the injectors good?
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Originally Posted by Wes444
(Post 20638310)
The 01 motor in the 03 truck, is that from a van? What's your oil level?
truck had an 03 7.3 powerstroke motor but I had some issues with that one with some broken push rods and a bunch more so I got a donor installed and oil level is perfect |
Originally Posted by Sous
(Post 20638440)
We are willing, eager and capable of helping you, but we need very specific information and a lot more details. had a rebuttable diesel shop out into in the coast install the motor, injectors weren’t taken out fuel tank was and cleaned out and reinstalled injectors were buzz tested they passed, motor passed contribution test and dirty diesel drove the truck around on a scanner and told me everything looked and was acting normal don’t know number as exact details as I don’t have a scanner my self, and last time I got fuel pressure checked I was above 55 pounds ripping around town and when wot |
What Sous said. Need specific information if you're going to get any real help here.
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Originally Posted by Jared0099
(Post 20638579)
had a rebuttable diesel shop out into in the coast install the motor, injectors weren’t taken out fuel tank was and cleaned out and reinstalled injectors were buzz tested they passed, motor passed contribution test and dirty diesel drove the truck around on a scanner and told me everything looked and was acting normal don’t know number as exact details as I don’t have a scanner my self, and last time I got fuel pressure checked I was above 55 pounds ripping around town and when wot
Lastly, we are willing, eager and capable of helping you, but we need very specific information and a lot more details. Although, you have to help us help you. We need details, units of measurement and questions answered. Otherwise, the thread will die and you will be going right back to the "reputable" diesel shop that could not resolve the issue. |
Originally Posted by Sous
(Post 20638651)
Lastly, we are willing, eager and capable of helping you, but we need very specific information and a lot more details. Although, you have to help us help you. We need details, units of measurement and questions answered. Otherwise, the thread will die and you will be going right back to the "reputable" diesel shop that could not resolve the issue. my fuel tank was full of mud and dirt cleaned that out purged all the fuel lines changes filters and fuel pump and went from dropping under 20psiof fuel pressure under load to above 55 60 psi or more at wot. The gentleman who installed the motor owns a shop in the coast called redneck truck parts and he installed everything and ran test on motor before dropping in, reseal and runtime to make sure everything was solid and I’m working order. Was also having these problems with the last motor but I took it the motor was hurt and down on power so hence why I dropped a donor in. As far as wiring harness I’m not sure if that was changed. And I’m going to dirty diesel today so I’ll get them to plug a scanner in to it and see what it’s reading, I’ll take some pictures |
That would be the uphill fuel restriction valve kicking in. It is there to prevent excessive EGTs when going up hills.
Conversely, there is a downhill fuel feed valve to lubricate the cylinders while engine-braking down a grade. </YouTube 7.3 “expert”> :-X03 |
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