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I have a f150 txrd that is off about 1000 rpm's at WOT. However it runs perfect and doesn't miss or sputter at any rpm. It use to run around 5800 and now only runs about 4800. The fuel pump in the vst locked up, so I put a new pump in the vst and cleaned the screen, when I put it in the lake it was off 1000 rpm's. Then I had the injectors cleaned. I replaced the fuel line and both fuel filters on the motor. I also checked the pickup in the fuel tank. I replaced the spark plugs, changed the gear lube and water pump and changed the engine oil and filter. I even went from a 17 pitch to a 15 pitch prop just to see and it still only wants to run around 4800. At WOT my butterfly's are open 87.4 degrees and the tps is at 4.086 according to the computer. I know the range on the TPS is up to 4.5, so should I adjust it so it at or very near 4.5 at wot? this is the only thing I can see on the computer that is not 100% within spec. Although I suspect at 4.086 it has already gone to full timing and such, but maybe not. I pulled the plugs and it seems to be running a little lean by the plugs. I have cheked the fuel pressure on the rail it is it about 42 at idle and 46-48 under a load. It holds 46-48 from take off to WOT. Also the compression is fine on every cylinder. Any suggestions or what to look for would be greatly appreciated. I have access to YDS and am fairly knowledgeable with these motors, but this one has me stumped. Oh and the motor has 90 hours on it if that matters.
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leave all the adjustments alone, fight the fuel issue. -
I drained the tank even though the fuel seemed fine. I checked the pickup in the tank. I have pulled fuel samples after refilling the tank. I am at a loss. Unless someone can provide some insight I am gonna pull the injectors and have my buddy clean and flow them again. If that doesn't help I guess I should go back into the vst? If a low pressure pump was weak or bad would i still have 46-48 lbs of fuel pressure at wot? It seems like lack of flow would cause the pressure to drop especially on an extended run under a load.Comment
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a failed injector OR a failed plug will drop about 1000 RPM.
electrical/ign failures are incredibly rare.Comment
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I had the injectors professionally cleaned and back flowed, I have actually changed the plugs and then removed them again after it didnt run correctly and checked them for cracks and the gap. They all looked a little lean, but not to the point of being chalky or anything.Comment
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I had the injectors professionally cleaned and back flowed, I have actually changed the plugs and then removed them again after it didnt run correctly and checked them for cracks and the gap. They all looked a little lean, but not to the point of being chalky or anything.Comment
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still trying, maybe this info will help someone
ok, so had time to mess with this hunk of junk again today. Checked low pressure pumps and they seem to be fine. Unhooked sensor on the top of butterfly's and the motor would not take any fuel and cut off, unhooked the IAC and didn't see much difference in the way it runs or crank, although when I cut the key off I can hear it close. Unhooked the other sensor on the top of the intake and with the motor running the motor cut off, but when it restarted it the motor ran fine and didn't seem to lose any power, it may have even gained a little, but it was virtually the same. So all that was inconclusive, but maybe someone reading can make sense of it
The one thing I have noticed is the fuel level in the front main filter is about 1 inch from the top, basically at the bottom edge of the element. This may be normal, but I have seen others that always seem to stay full. You can pump it full with the bulb, but once you crank the motor, it returns to about 1 inch from full. I have removed the filter and checked the seal and spring and all seems to be fine, but again maybe someone can put some insight into if this is correct or not.Comment
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did you check the shift position switch?Comment
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fuel filter and low power
was wondering if you found a fix to your problem. Looks like i am having similar issues now. I have F150 (2006) and noticed the samething with the fuel filter, fuel is always at bottom of the element and ball get soft. I just wish i would have noticed what the filter looked like before my problems, i wouldn't think that is normal, makes sense that it is starved for gas. Let mekno if you have figured it out.Comment
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