Hi everyone,
im new to the site but have read the threads here before looking for advice. Here's my problem. I have a 2002 F350 7.3L crew cab. It has a K&N intake, 4" downtube and exhaust, fuel tank mod and pre-pump filter installed and a TS Performance 6-Position chip. I installed the chip about 8 months ago and it was awesome. But for the last 2 months or so it seems to have lost power on all the tunes. Basically the 120hp tune feels more like a stock engine and if i put it on the stock setting it has little or no power. It still accelerates on the stock setting but is slow to do it. On 120hp setting it will still blow a little black smoke but nothing like it did when i first installed the chip. I did notice the ICP sensor has a little fuel in the plug so i know thats not good and i need to replace it but im asking if that sounds like my problem? or is it something else.
I know its a lot of reading but i trid to remember everything i could about what the truck is doing. If you have any other questions let me know. Thanks for the help in advance.
EDIT: Forgot to add that i have aftermarket gauges and the fuel pressure holds right around 68-70 psi. I changed the frame fuel pump about 2 months ago also but my problem started before the new pump. This new pump is louder than the stock one and it sounds like it revs up and down. I have read about IRP sensor also. Just looking for advice on where to look.
Here are the results of what i tested and changed. I moved the fuel pressure sensor to the output side of the fuel bowl and the pressure is the same as the input side. So that rules out a fuel issue. I cheaned the exhaust backpressure sensor and it had a little carbon buildup in the tube but wasnt clogged. I removed the intake from the turbo and there is very little movement in the turbo shaft and the compressor wheel feels fine with no evidence of it being dusted. Although now that i am paying attention to boost pressures i think the truck used to boost at a lower RPM than it does now, and the truck fuel mileage went down as well. I was getting around 18 in town and 22 on the highway. I have a spare turbo from a early 1999 truck that has the wicked wheel installed in it, the wheel is fresh but the turbo could use a rebulild. So im going to rebuild it and port it and see if it changes anything. Unless anyone has any other ideas on what to look at. BTW where is a good place to get a rebuild kit along with the gaskets to re-install on the truck.
Before you go tearing out your turbo to replace with the early 99, keep in minf they are different turbos. The WW will change out to your turbo easy enough, but to change out the whole unit may be problematic. If I recall right, the outlet is smaller and it's also a different ratio overall. Let KLhansen or RT chime in and confirm this, or do a search.
On the EBP line, are you sure there isn't a hole in the line? Mine had one and it wasn't really visible, but using a can of brake cleaner showed it as a drip.
Im pretty sure there wasnt a leak. I cleaned the line with brake cleaner and even pushed a wire through it to help loosen the carbon. Then i filld it with cleaner and let it sit for about an hour before blowing it out with the compressor and re installing. i didnt see any leaks and im pretty sure i tightened the ends down good. I can remove it again this weekend and check it again if necessary. Would a leak in that line really cause the truck to not smoke as much as it did when i first installed the chip?
You can't just put an early 99 turbo on a later truck. It just won't fit. Like Tom said, the compressor outlet is smaller, so wouldn't mate up with your spider that directs the air to/from the intercooler and into the intakes. You can however rebuild your turbo and put the early 99 compressor wheel on it.
Did you crawl under the truck and look for soot at the exhaust manifolds and along the up-pipes to the turbo inlet wye. The donuts mentioned earler are at the top end of the up-pipes and they can wear and make the up-pipes hourglass shaped. Any evidence of soot is going to reduce the performance of the turbo, because with leakage, there won't be as much exhaust pressure driving the turbine side.
I think you're chasing the problem in the wrong place with the EBP sensor tube. You should check that the EBP valve is in the correct position (actuator rod fully extended and the crank for the valve against the stop.) You can take that out of the equation by unplugging the wiring to the intake air sensor at the filter housing. That will cause a fault and the EBP system won't work, keeping the valve open.
15-16 psi boost isn't bad in stock tune. They're supposed to be limited to 17 psi by the wastegate control. That might be something you should check. You can disable it (somewhat) by pulling the tube off the wastegate actuator at the rear of the turbo. The spring in the actuator will still allow it to open at higher boost, but the pressure tube is the main control.
Have you also checked for leaks in the intercooler boots and other parts of the intake? You can do that with a 4" ABS plastic pipe cap with an air hose connection adapter in the center. Clamp it into the intake hose of the turbo and apply air pressure (5-10 psi) and listen for leaks at the boots, etc.
I did crawl underneath the truck and used a mirror to check the up-pipes and didnt see any evidence of soot on the pipes. I will look again to be sure.
The EBP valve is the one on the underside of the turbo. Correct? It would be the larger "butterfly valve" inside the exhaust side of the turbo housing.
But where is the air intake sensor? Is it the brass sensor that is in the cast aluminum "y-pipe" where it connects to both heads?
I can do the pressure test like you described to check the intercooler boots.
If you have a stock air filter box, the intake air sensor is plugged into the back of it. If your air filter is a tymar type open filter, then where the sensor is is anyone's guess, but it should be connected to the wiring harness in the same vicinity toward the rear of the fender liner.
Ok. I have a K&N system on it now. I know they dont have a good reputation but i have them on every toy i own and have never had a problem with them. Plus I keep them pretty clean. I found the sensor but didnt get a chance to unplug it. I will do that after work and see if anything changes.
I have noticed but dont know if its related or not. But before when everything was working great and the truck would blow black like crazy, that if i eased into the throttle and let the truck blow black, the RPMs would slowly rise and the black would slowly stop. But now if i do the same thing, the truck automatically downshifts into the next lowest gear. Like i said, it might not be related or maybe its just a cause of what im currently trying to track down. IDK.
Thanks for the help.
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