My 97 F-350 has developed a strange characteristic in which it will not accelerate rapidly as it should. It also seems to take longer to start. It shifts normally but feels like it is towing a large load. On occasions this problem will disappear and the normal acceleration returns.
I ran the codes and got PO344, Camshaft Position Sensor Circuit Intermittent (bank 1/1 sensor). The second code was PO470, Exhaust Back Pressure Sensor Circuit Error.
It would seem that the first step to correct my problem is to replace the cam position sensor. What is the opinion of the group on this approach and what do I do about the PO470 code?
TIA

pbgsho2

 

Both of these issues could be contributing to your symptom. The EBP sensor may be calling for the EBPV to close when it should not be. This will cause the exact thing you are describing and is usually associated by a distinct hissing / blowing noise. Just unplug the valve. It is a two wire connector under the turbo. It won't cause any trouble to have it unplugged, and many of us run with them unplugged anyway.

Also, the CPS is a known issue in these trucks and WILL leave you stranded at some point. Get yourself another one at either the Ford dealer, on an International dealer and keep it in the glove box as a spare, along with the 10mm (or maybe 11mm) wrench needed to replace it. They're cheap and it's an easy fix if that is the issue. Or you may just want to swap it out now, but carrying a spare is still a good idea.

Good Luck!

 

DIY Mechanic, I am willing to bet your first suggestion is possibly the problem and will try that first. I have been down the cam position sensor failure road and ever since have carried one of the grey ones in my glovebox. Will try the simple fix first and if that doesn't work will replace the cam position sensor.
Thanks for the response and will report back with the result.

pbgsho2

 

Sounds good, let us know what happens.

 

When you're working on it check your wiring leading to the cam sensor just for curiosity. Have seen a few cases of the wires chafing real bad.

 

I would inspect both sensor systems that are giving you trouble codes and replace them if no other problems with them are evident.

 

you know i am also having this same problem, mine is a 95 but i dont know if they are any different but the plug on the driver side of the turbo on mine is broke and i just had the wires pluged in, i am going to unplug them and see if it helps.

 

Occasionally it is proven that thinking about the problem rather than twisting wrenches may be a better approach. Several years ago I had added an exhaust brake since I carry a very heavy slide in camper. In reviewing the installation instructions today, I found that the exhaust brake closes when the weather is cold so it performs the same function as the exhaust back pressure valve. The EBPV I found, was removed when the brake with the new turbo housing was installed. This I verified with the manufacturer.
DIY Mechanic, I believe your analysis was right on but it was the exhaust brake and not the EPVB. I will be able to see tomorrow when I drive the truck. Believing that I have a problem with the computerized brake controller, I bypassed the solenoid valve to allow vacuum to hold the brake open which should temporarily solve my problem.
Thanks to all who replied and will confirm if my problem is solved.

pbgsho2

 

I have just got a power stroke A 97 were is the cam sensor located ?

 

In front of the motor above the balancer at about the 10 oclock position.

 

I agree with all that was written above, but I also would check the TPS.

 

This is a followup to my original post. As I mentioned in a previous post, I do not have an exhaust back pressure valve since it was removed when an exhaust brake was installed.
1. As I mentioned, I bypassed the solenoid valve to assure that the brake was open and drove the truck but the condition continued, No improvement.
2. I replaced the cam position sensor and drove the truck but there was no improvement. The truck started more quickley and the PO344 code, Camshaft Position Sensor Circuit Intermittent, disappeared.
3. Since I was running a Tow/Haul program I returned the computer to stock thinking that this might be impacting the computer. There was no improvement but this time when I ran the codes I got PO470 and PO603. The 603 code is Internal Control Module KAM error.
4. I retuned the computer to the Tow/Haul program and ran the codes and got the same PO470 and PO603 codes.
Apparently reading the codes is not always a way to a solution. I have three gauges showing EGT, boost and tranny temp. While driving down the street I noted that there was no turbo boost so I think that this is the problem. The question is, if there is no boost is the turbo toast? If so and I need to replace it, are there better alternatives than the stock turbo?

pbgsho2

 

The 603 code could come from unhooking the batteries, or something of the like. I don't think that is an issue. Have you visually checked the turbo? Remove the intake and take a look at the wheel and check for play. Unplug the elec. connection for the map sensor and take it for a drive first, see if it improves. Also check the hose for the map for cracks or plugging.

 

The back pressure sensor will not tell the EBPV to close no matter how it fails. It's job is to tell the PCM that the ebpv is closed or not. It just reports the state of the valve. That's it. I have never seen any time when the back pressure sensor caused a driveability problem. If there is a code for the cam sensor then it needs to be checked. Other things can cause that code too. Bad wiring that was chewed on or whatever, loose or dirty connector. Lots of stuff. You all replace too many good sensors.