450 performance issues

6.0 Tech

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Man, it’s been dead in here lately. Let me throw a goofy one at some of you guys, hopefully someone has a thought.

01 f450 pretty much stock

Truck had come to me a few months back, put up pipes, pedestal, and a hydra on it. Php didn’t have the pcm code for their box tunes, so I found a description that was similar to what the truck is, and loaded those up. Ran fine for about a month and a half, then his hpop started pissing, so I put a cnc fab stage 1, and the 2 cnc fab lines, did not do a crossover line. About 2 weeks later he calls me saying it lacks power, and was damn near undriveable. I asked the usual questions, as far as filters go, he cleaned the air filter, and changed both his fuel filters (he’s got a pre filter on it) even though the fuel filters weren’t too old time/mileage wise. I stopped by his house, truck ran pretty good cold, about as good as a 450 boom truck on a 75ish ho tune can run. Then, as it got warm it lost all power, and didn’t have the slight amount of smoke that it had cold. He informed me the injectors came out of his old pickup, and probably had about 225-250 on them, so I sold him some stock replacement full force injectors (to include the long lead injector, as this guy thinks it’s too noisy), motorcraft valve cover gaskets, under valve harnesses, and glow plugs. Changed the oil and filter with a motorcraft filter, and Costco Kirkland 15-40, which I didn’t even know was made. Did not fix the problem. Only code it’s throwing is a 1211 icp higher/lower than desired.

I have checked icp, it is reading correctly koeo, seems to follow desired, but far enough off to not be defaulted, I found its idling at 2.5ish ms on pulse width, at 500ish psi, and 7-11% ipr. Once it gets to around 180 on oil temp, this thing has a solid 3 count once you hit the throttle, then it slowly comes up in rpm. App is reading properly when I press the throttle when this occurs. After having it lack power, the ipr duty cycle will hang around 45-60% still at 2.5ms, and 500ish psi. If I free rev it to about 2500 rpm it acts like it’s got a hard rev limiter, and will bounce from 3ish ms to 600micro seconds for about 10 seconds, it is around 2500psi at this point, then it will smooth out, drop to 1.5ish ms and 1500ish psi. Then when I return it to idle its idling at 2.5ms, 7-11% ipr, and 500ish psi.

Changed the ipr, mainly for s&gs but also figured it may have been sticking when hot, no change.

Base oil pressure is 20 at hot idle, 40 at hot stall on the converter while testing the concern, seemed low to me, but a guy I know who does 7.3s all the time says that’s normal. He is also stumped on this.

Only thing I have found that is absolutely wrong, is fuel pressure, it’s about 35 at hot idle, and drops to 24 while power braking. I know this is bad, but the numbers don’t change from when it doesn’t have any issues vs when it does have the issue. It is also not a suction issue, I ran the suction side of the pump to a 5gal jug tonite with no change.

Planning on trying a cam sensor for s&gs tomorrow, and if that doesn’t fix it borrowed a idm from my buddy to test. Not really leaning towards either fixing it, but it’s a 7.3, if it’s not under valves, icp, or ipr, it’s a cam sensor, right?

I know this is a lot, but I figured all the info I’ve got makes it easier for some else to help diag.

Thanks for any help


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fastersteve

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I had a similar issue, turned out the hose nipple on the MAP sensor was cracked. I only found it when I did a pressure test looking for boost leaks.

Good luck!
 

DEEZUZ

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Have got to fix that fuel psi issue, have you put eyes on the regulator?
 

6.0 Tech

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Have got to fix that fuel psi issue, have you put eyes on the regulator?

No, planning on doing pump and regulator though. The way this one’s going I know if I sell him one it’s gonna be the other.


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6.0 Tech

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That fuel pressure is shit!! Get that to a solid 60psi and see how it runs.

How many miles/hours on said oil?

Fresh oil change with the injectors. So all of 10 miles, and maybe an hour of driving/testing


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6.0 Tech

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I had a similar issue, turned out the hose nipple on the MAP sensor was cracked. I only found it when I did a pressure test looking for boost leaks.

Good luck!

Map sensor and hose are good, no leaks and reading correctly


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6.0 Tech

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Fuel pressure wasn’t it. Have 55 at idle now and 50 under load. Swapped cam sensors for the hell of it, no change, same with idm.


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DEEZUZ

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Can we put a clear line on feed side to make sure we're not getting aireted fuel
 

6.0 Tech

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Can we put a clear line on feed side to make sure we're not getting aireted fuel

That would be kind of a pain in the ass with the setup he’s got. Talked to a tuner, he feels there’s an issue with the hpop, called them and it’s getting sent out tomorrow


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Powerstroke Cowboy

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Was the chip ever removed to see if the problem persists?

It does sound like an hpop problem. Being it's been acting like that so soon around the hpop replacement, it's a red flag.
 

6.0 Tech

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Was the chip ever removed to see if the problem persists?

It does sound like an hpop problem. Being it's been acting like that so soon around the hpop replacement, it's a red flag.

Yeah, I pulled the chip with no change.


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lincolnlocker

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You pulled and replaced injectors and pulled and inspected ipr.. lots more air induced.

Go flog on it wot runs up to 70 like 10 times.

What is voltage doing this whole time?
 

6.0 Tech

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Have you flogged on it on some hard runs. Only 10 miles of driving?

Yeah, my 10 mile road test gets the air out. I usually run it in second until I get to the highway, then, depending on gears, I’ll run 3rd or 4th at hi rpm’s for about 4 miles, it gets hot as ****…. After doing that it’s typically a 2-3 second crank before it fires up.


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lincolnlocker

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Yeah, my 10 mile road test gets the air out. I usually run it in second until I get to the highway, then, depending on gears, I’ll run 3rd or 4th at hi rpm’s for about 4 miles, it gets hot as ****…. After doing that it’s typically a 2-3 second crank before it fires up.


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Right on!
 

6.0 Tech

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Cnc fab got back to me today. Seems the pressure sleeve in the pump came apart. He said it’s not real common, and the ones he has seen this on had completely different issues than what I’ve got. Gonna get one pulled off the shelf and installed tomorrow night, as customer is needing his truck, so waiting on this one to come back is a bit rough for him.


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