My stock 2002 F-350 has lost most of the boost it use to have along with low power, hi EGT's and poor mileage. My boost, on average, is around 2 - 5 psi. I rarely get over 10 psi, even when pulling a 7k lbs trailer up a grade. Even when empty and I stand on the pedal, I can almost hit 12 psi. I used to feel the truck surge with power when the turbo boosted up just driving without any kind of load in/on the truck, now I don't feel it any more even when empty. Pulling a grade with the trailer, I can barely stay at 40 - 45 mph while keeping the exhaust temps below 1,200 degrees. Sometimes I've even dropped to 30 mph up a 6% grade. Cruising on flat highway, the temps are around 650 - 700 degrees.

I've been all over these forums and the internet as well, trying to figure out the problem. My last resort is here, hoping you guys can give me some suggestions on what to look for/do before I take the truck to the Stealership and have them work on it.

Here's what I've done so far:

- I've done a boost leak test. No obvious leaks found. Any other places to look for leaks besides the usual boots?

- I've replaced the up-pipes since they were leaking and in bad shape with the bellowed kit. Doesn't seem to have made much of a change. Checked for exhaust leaks at the collector and manifolds after the upgrade...didn't find any.

- Replaced the EBP Sensor with a brand new one. Still getting a P0470 code. Engine seems to run better, but still low boost/power and mpg.

- Cleaned the EBP tube and bracket.

- Changed fuel filter (the one on the engine). Haven't taken the fuel tank apart to inspect the screens yet. Not really wanting to IF I don't have to.

I haven't checked the fuel pressure yet since I don't have a gauge.

Any suggestions/thoughts? I'm getting pretty frustrated not being able to figure out the problem. Any help or insight would be greatly appreciated.

(I apologize if my post is scattered and doesn't make much sense. I thought I'd post this before getting some sleep.)

 

The screen in the tank has a bypass, so if it does plug up it will bypass, so I dont think thats it. low fuel pressure would act more like air in the system, noise from the engine, white smoke, does your truck have a cat? some of the 99 and up's had them, everything you said sounds like a restriction in the exhaust system. that would explain the pcode for the EBP sensor, no one put a banana in the tailpipe trick did they? Check to make sure your EBPV is not stuck closed, some time the e-ring falls off the lever and the valve stays shut. Happy hunting

 

Starting with that code... code reader or scan gauge/tool? What does your EBP read? If you can't get an actual reading off the EBP, it would behoove you to get a scan gauge/tool to see what's going on. There is AE for laptops/netbooks, Torque Pro for Androids, Dash Command for iOS, and there are dedicated scan gauges for the dash... like Interceptor or Edge. Portable devices need a OBDII port adaptor - most are Bluetooth, but some are wired or are wireless network.

The intake plenums can leak - that's what happened to me. We had a member recently discover both his intake plenums were letting more air out than holding it back.

 

David - Not sure if it has a cat...didn't look for one yet. No noise in the engine and no white smoke. The EBP valve is good and the clip is on. The turbo is good to, no play at all and the vanes are in great shape.

Tugly - I don't have a scan tool, can't afford one yet. The only thing I have is an Edge monitor (not the programmer version) that came with the truck. It shows EGT, trans temp, battery voltage and boost as well as trouble codes. Would a boost leak test (attached at the air intake) show a leak in the plenums? I didn't hear anything there when I did my last test a few days ago.

 

You would hear it whisle all the way down the street, nothing got sucked up into the airbox did it? Thats were you have to look, Air in, exhaust out. I was going to say fuel filter but that usually gives ya stalling, hard starting, noise in the engine. Double check all your charge hoses and clamps and its easy enough to loosen the banjo clamp on the turbo and take a ride wide open turbo

 

A boost leak test will show a leak in the plenums but its also hard to get down there. I recommend, at a minimum, a set of plenum inserts, for any user worried about boost leaks. I got my set fro. RiffRaff and was very pleased. I had done a boost leak test and I still recovered some lost MPG and boost when installing the inserts.

 

Clean air box and new filter a few days ago too. I think all of my boots and pipes are good. When I had them apart a few weeks ago, I did the hair spray trick when I put them back together. Haven't heard anything from them and no bubbles when I use soapy water when I do my boost leak test.

 

Ya your good there, check the exhaust and see were she leads.