Rebuilt 351w EFI problem.
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Rebuilt 351w EFI problem.
I have a 1989 
F-150 XLT Lariat with a rebuilt 351w EFI in it. Been having trouble finding out why it has so little power. I mean i can barely get it up hills going 50 mph in 3rd gear. Idles pretty rough. When i spray carb cleaner in the throttle body idle picks right up and idles very nice. Im thinking it is running lean. Not sure what is causing it, maybe a bigger cam then original? Truck came from the factory with the 351w so computer must be calibrated correctly. Checked timing, and got it set to spec. Compression tested. Ran injector cleaner through it on 2 occasions. Not sure what to do next. Im thinking last resort try putting a carburetor on it. Would rather not do that. If anyone can help me or guide me in the right direction it would be greatly appreciated. I love my truck, and really want her feel better. Thank you.
F-150 XLT Lariat with a rebuilt 351w EFI in it. Been having trouble finding out why it has so little power. I mean i can barely get it up hills going 50 mph in 3rd gear. Idles pretty rough. When i spray carb cleaner in the throttle body idle picks right up and idles very nice. Im thinking it is running lean. Not sure what is causing it, maybe a bigger cam then original? Truck came from the factory with the 351w so computer must be calibrated correctly. Checked timing, and got it set to spec. Compression tested. Ran injector cleaner through it on 2 occasions. Not sure what to do next. Im thinking last resort try putting a carburetor on it. Would rather not do that. If anyone can help me or guide me in the right direction it would be greatly appreciated. I love my truck, and really want her feel better. Thank you.
Logistics Pro
Joined: Aug 2010
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From: Chillicothe
Your best bet is to run the code test and see what the computer tells you and go from there.
http://www.corral.net/tech/maintenan...-koeokoer.html
Give you an idea if you don't know how
http://www.corral.net/tech/maintenan...-koeokoer.html
Give you an idea if you don't know how
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Joined: Oct 2005
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From: Kentucky
Speed Density control is very sensitive to LSA <114 degrees. Anything less causes issues.
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I am not sure if it has a different cam then original or not. I am just assuming it might. I have not done anything major to it. Bought it because previous owner couldn't get it running good and gave up and sold it to me for a steal.
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C6 trans i believe. 3 speed auto. 33 inch all terrains all the way around. stock exhaust with no muffler. Just bought two flowmaster 44's mufflers. Getting ready to put a dual exhaust set up straight to mufflers with no cat or anything in between.
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Did you pull the spout plug when setting the timing?
Stock exhaust is a concern on something this old, those cats are well beyond their due date. Is the exhaust still super quiet even with the muffler gone? I'd also suggest you do an old school test and pull the plugs to see what color they are after a good run, that will confirm if it's running lean or not.
Stock exhaust is a concern on something this old, those cats are well beyond their due date. Is the exhaust still super quiet even with the muffler gone? I'd also suggest you do an old school test and pull the plugs to see what color they are after a good run, that will confirm if it's running lean or not.
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