A buddy sent this to me...I don't know where he got it but it worth the read...


For those of you experiencing intermittent surging at idle and while driving at steady speed, excessive smoke, rough running, stumbles,lack of power, stalls, cutting out, erratic idle, bucking, noisy engine operation, oscillating engine noise level, and erratic EGR valve operation, the problem may be the exhaust backpressure sensor. The EBP sensors are failing internally and causing an erratic signal to the computer, or a reading that is too high or low for local altitude.

This is also the part causing the check engine light to come on with a low boost code P2263 (03 and early 04) or P0299 (late 04). Usually these codes are set at idle or at low vehicle speeds/low RPM when boost would not be present anyway. In some cases the EBP is causing EGR flow codes.

Chances are the sensor won't be acting up when you bring the truck into the dealership. The technician should check to see if the EBP base reading is the same as the MAP and BARO sensors when the key is on and the engine is off. I have found that tapping on the sensor bracket can cause the reading to change if the sensor is faulty. Sometimes starting the engine and turning it back off results in the sensor reading a different base pressure than before.

On a test drive I had an EBP drop the reading 3 PSI below what base was, when normally it's 2-3 PSI higher at idle--it's like the EBP though the truck suddenly went over 5000 feet above sea level. I have had severa trucks that would only cycle the EGR on and off while at a steady speed. If it is doing it mildly you can hear the engine cycle between cackly and quiet. If it is severe you can actually hear the turbo coming on and off and feel it surge. Keep in mind there have also be cases of the EGR valve itself sticking and causing
it to cycle open and closed as the computer tiires to get the EGR position sensor where it wants it.

If the EBP is more than 0.5 PSI above or below local atmospheric pressure, or if the signal changes when the bracket is tapped, or if the base reading changes as the engine is turned on and off or as the engine temperature changes, or if the technician can verify the above symptoms, the EBP should be replaced.

At this time there is no bulletin or even an offical notice out on this problem. A revised sensor is being tested, but is not available. In the meantime the only thing that can be done is replace the EBP with the current level part as a temporary fix until a revised part is released.

 

Is there a test we mere mortals can do, like with a voltmeter, to see if our EBP is erratic before taking it to a dealer?

Duncan

 

Good stuff TwoBallsleft...

 

Also, that would sure explain a lot of things about the sometimes Jekyll/Hyde nature of these trucks. Even if a particular truck isn't having any problems, it might explain why some people think their 6.0 is the greatest engine ever put in a pickup, while others are convinced that Satan is living in their engine. (I bet some purchasing person cost-reduced the engine by going to a different vendor on the sensor than they used in initial testing...seen it sooooooo many times...)

Duncan

 

Exactly what I was thinking when I read it...seems like all the intermitent anoying issues are covered here......you know those times when you suddenly look at the person in the passenger seat and say "Did you feel that?"...or... "Listen, hear that?"...and they look at you like you have two heads!... ...maybe we're not crazy after all...

 

Well the only way we can verify that's what's causing all the running issues is to take a known working truck and suddenly take it from sea level to 5000 feet above sea level and then back again, in a few milliseconds, and see if that causes the same symptoms.

Duncan, not volunteering to be driving it at the time.

 

Ummmmm...

A simple test is to disconnect the EGR and the quiet idle and stumbling clears right up...

and many on this forum has proven that was the problem in that when they changed the EBP sensor, the symptoms cleared up...

or maybe I'm just on a sleep deprived bing from watching the lections last night and this morning

 

Just to clarify is it the EBP sensor or the BP sensor (Barometric Pressure)?

Sounds more like the BP sensor from the description:

http://www.backglass.org/duncan/ps60...l/ps60_051.jpg

The Backpressure sensor (they call it the EP sensor) shouldn't be affected by altitude:

http://www.backglass.org/duncan/ps60...l/ps60_058.jpg

Duncan

 

Actually there are several references to the EBP sensor in the Ford Service Bulletins. Go to http://www.intellidog.com/dieselmann/60bulletin.htm and search for EBP.

--------------------
F250SD 6.0L PSD ext. cab, 4x4, 5 speed auto, 3.73 diff. Raven cap. Apr 2, 03 build, Mar. 27, 03 engine

 

I can agree with this my last go around before Ford decided to replace my truck this sensor was replaced and my surge at steady pedal disapeared. I had this problem for about 5 months and it was gone after this sensor was replaced. To bad this was not the only problem but it did take care of this problem.

 

Do you think the EBP could cause a truck to consistently stall when you try to accelerate after a cold engine start up at an elevation of 9000 feet. It acts like it is cutting out for maybe 10 to 60 seconds an then takes off. Seem's to act worse if you let the truck idle for a few minutes. If the truck is warmed up already, it doesn't act up. The truck has never stalled at my home which is at an elevation of about 7,500 feet even from a cold start at about 20 below zero. The truck that i am talking about is a 2004 F350 PSD crew cab.

 

Could be. If the EBP reading is below that of the BARO sensor, one of the two could cause the problem. There are quite a few sensors that input into the PCM. There are barometric pressure, exhaust pressure, mass air flow, intake air temp (pre-turbo), manifold absoute pressure, manifod temp (post turbo), fuel pressure, etc. Any one of those could throw it off at altitude.

 

Check this site for a diagram of the input to the PCM:
http://dan.prxy.org/Truck/Engine/Sen...ors_FRAME.html

 

Assuming that the EBP (EP) sensor is designed to linearly produce 0-5 volts between 0-54 psi, you should be able to test the sensor by removing it and attaching it to a compressor with a psi guage, then measuring the voltage output with a voltmeter. Each ±11 psi increase should result in a 1 volt increase.

 

Exhaust Pressure Signal
0.9 = 14.7 psi
4.7 = 53 psi

The diagnostics on the EP are complex and I don't know how to do it without the test equipment the dealer service has. Moebdick has it pretty close.