97 low on power.

Petro · May 30, 2013

Alright Guys, One of my buddies has a 97 F250 EXT Cab Short Box 7.3 5 speed. He bought it a few years ago with Swamps 175/30 injectors, a dominator 66, full fuel system, Adrenaline HPOP, Has BDP tuning, a boost fooler and a few other small mods. The truck was a running son of a b!tch up until a few months ago when it seemed to lose 3/4 of its power. It sounds like a totally different truck now, Turbo doesnt seem to whistle at all anymore, but before you could hear it screaming inside the cab, The overall tone of the engine sounds different and it smokes black like crazy. I started trouble shooting it, and swapping in known good parts trying to find the problem before I had access to a scanner. There are no boost leaks or exhaust leaks. The truck holds a constant 60 psi of fuel pressure. We tried a CPS, ICP sensor, IPR, IDM, and a different PCM. We ran it both with and without the chip and its the same thing. I threw a scanner on it last nite, Duty cycle never went over 40% at WOT with 2600 to 2800 ICP. With a buzz test, I pulled up several injector codes with high and low voltage numbers. Im not really sure that that means? I was also told It may be a compression problem, But the Truck only had 140,000 miles, Starts right up on the coldest days and doesnt smoke blue or grey at all. It idles great, and never misses or feels like its missing at idle or WOT. It just feels like the higher it gets into the power band the less power it has. It feels like it is never lighting the turbo, but the turbo spins freely, has very little shaft play and no in and out play. The only sensor we havent replaced is the map sensor. When driving it yesterday, I stopped and unplugged the map sensor. It didnt run any worse but maybe a tad bit better ( Could Have just been in my head, It was that slight). Does this indicate the map sensor is bad? Im at a complete loss with this truck. Any help would be much appreciated.
Thanks and sorry for the long post, I was trying to cover everything but probably forgot a few things.

Powerstroke Cowboy · May 30, 2013

Do you have a boost gauge?? If so what does it say? If you are not getting boost it will not have any power. Did you check the Exhaust back pressure sensor line?

POWER-STRUCK · May 30, 2013

you might try running it without the boost fooler and a new map sensor line

Petro · May 30, 2013

He hasnt had a boost gauge on it recently. He put one on it today but he said he didnt want to drive it out of his new shop because it rained an inch last nite and they dont have gravel on the driveway yet. He said parked at redline it made 6 psi and he is going to drive it tommrow. We replaced the Y pipe boots, and the O ring inbetween the Y pipe and turbo. Even if it had a boost leak, Why would the turbo just stop whistling? It whistles through the tail pipe, there is just no whistle in the cab anymore. I replaced the map sensor line yesterday and ran it without the fooler and it was the same.

Petro · May 30, 2013

Forgot to mention, The EBPV arm is not hooked up and the valve is open. The up pipes are newer and there is no soot on any of the joints or any other signs of leaks.

Powerstroke Cowboy · May 30, 2013

Is the valve wired open?

Petro · May 30, 2013

Yes, I made sure of it.

Powerstroke Cowboy · May 31, 2013

Sounds good. I really would like to know what it makes for boost under full throttle and load.

That will tell a lot.

Petro · May 31, 2013

He ran it this morning. He said it is making a max of 10 psi so again I'll be looking for a leak, but I'm pretty sure it doesn't have one. There are only so many places the stock Y pipe can leak and I thoroughly looked it over and inspected it. I'll report back with my findings.

Powerstroke Cowboy · May 31, 2013

Sounds good. That would be the problem. Did he by chance happen to check what the back pressure is?

Petro · May 31, 2013

Nope, he didn't. I'll have to bring the scanner home from work and watch ebp also.

Powerstroke Cowboy · May 31, 2013

If your BP is good then you would know that the up pipes are not leaking for sure.

Right now my brother is having the same problem but his is not as bad. He will see a max of 16 to 18 PSI of boost but will see 33 to 34 PSI of back pressure. With the low boost reading we thought the up pipes were leaking. But that was not the case.

Does your friend by chance have a IC on the pickup? If so what one does he have?