08 f450 6.4 won't rev above 2300rpm

6.4f450

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I was going on a trip 7hrs away towing my 48 ft enclosed trailer. 1 day Before I left on my trip I changed the oil and the fuel filters I used ford filters. I made it 4 hrs into the trip where I pulled off at a truck stop to get fuel. Filled up never shut the truck off. Heading back on the highway down the on ramp I lost power. Wouldn't rev above 2300 rpm. Got to my destination shut off the truck ran fine. Drove fine all the way home. Now 2 weeks later was running to town and it did it again No engine light or codes. Truck has ******* tuner ******d, erg ****** afe intake. Truck has 130,000 miles on it. Any ideas?
Thanks Brandon
 

6.0 Tech

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Sounds like frp is freaking out. More than likely a sensor, but it could be the harness under the valve cover. Get it to act up again, and monitor frp.
 

6.4f450

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it woul rev to 2300 rpm just fine and rail pressure would be steady. But once it hit 2300 it would cut out. You could hold the pedal floored and it would be like it got no fuel. Once it goes into overdrive it would be under 2300 rpm you could then lay into it to get moving and rail pressure would go up to like 24,000
Thanks Brandon
 

6.0 Tech

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400 seems a bit much, typically it is only 100-150 they bounce. Does i match desired pretty close?
 

sootie

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First thought is chaffed hpfp harness. Second is frp sensor
 

6.4f450

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So you recommend the harness first. Can you get it with the cab on? I am worried that it might be the hpfp.
Thanks Brandon
 

6.4f450

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Do you know the part number or where to get the harness from? Should I do the fuel rail pressure sensor at the same time?
Thanks
 

Black AOD

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Do you know the part number or where to get the harness from? Should I do the fuel rail pressure sensor at the same time?
Thanks

Pretty much anyone who sells the K16 also sells the HPFP harness as well.
Alliant Power comes to mind.

Yes do the sensor too to be safe.
 

6.4f450

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I just checked today and at idle the rail pressure fluctuates about 100-150 psi. Also could it be a fuel filter or the fuel pump down on the frame rail that would make it act up?
Thanks
 

6.4f450

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Was just driving home from work today and got check engine light and wouldn't rev over 2300rpm again. Was code P0088 fuel rail pressure too high. Would that be the hpfp harness?
Thanks
 

sootie

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Was just driving home from work today and got check engine light and wouldn't rev over 2300rpm again. Was code P0088 fuel rail pressure too high. Would that be the hpfp harness?
Thanks

Yep most often that's either the harness or a bad pump.
 

6.4f450

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Ok I'm going to get a pump and the harness is there anything else that I need to put the new pump in? Any parts or gaskets? Also where is the best place to get a pump? I heard the ford ones were not good.

Thanks
 

sootie

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You will need the gasket kit. I can't remember if it comes with the pump or not.
 

Lipka101

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I had the same problem. Replaced pump and harness with no luck. Changed tuner and haven't had any more issues


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sootie

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I had the same problem. Replaced pump and harness with no luck. Changed tuner and haven't had any more issues


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Good point there.....spartun tuned trucks have had issues like that for sure
 

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