About a month ago I started chasing a general lack of power and responsiveness. A Throttle Position Sensor has helped the responsiveness a bunch but I still have a gap between the MAP and EBP.

I have a replaced the EBP sensor and tube. I thought that would have closed the gap in the MAP and EBP difference as it remains high at a difference of 3 PSI. Borrowed a MAP sensor from a friend and the MAP read 12 vs 11.5. Still a wider gap than it should be. I have checked for boost leaks and resealed a couple boots but nothing major...

Any ideas or am I chasing a ghost?

My truck is stock except for 6637 intake. I'm getting the following readings on 4/11 in Denver approx. 5000 ft:

April 11
KOEO
MAP 11.5
EBP 14.2
IPR 14.8

WOT:
MAP 25.0
EBP 38.9
IPR 39.5
ICP 2773.6

May 6 after the new tube and boost fixes etc
KOEO
MAP 11.5
EBP 14.6
IPR 14.8

WOT:
MAP 26.7
EBP 35.3
IPR 39.1
ICP 2722.3

Thanks,
Wink

 

Your MAP sensor is closer to where it should be than the EBP sensor. Standard pressure at 5000 ft elevation is 12.2 psi, depending on weather systems, etc. The manual says a deviation of 3 psi from the barometric pressure is the threshold for replacing a MAP or EBP sensor, IIRC.

 

Wink,

What are you using to measure MAP & EBP? You should be comparing MAP, Barometric Pressure & EBP at KOEO.

Like Pikachu said the standard pressure at 5,000 feet is 12.2. Here is the table, look for your altitude and cross reference to PSIA. This is what your Baro sensore, MAP and EBOP should be close to on a cold engine at KOEO.

 

Have you ever been to se Rocky out at Rockin "S" Diesel Performance in Fort Lupton? He's about 45 minutes from you - great guy if you get stuck and need to have someone look over your truck.

Rockin 'S' Diesel - Home Page

 

I have been using Torque Pro. The pid calculations are from a couple threads that Tugly has been sharing info re the TP app.
One odd thing is I have never gotten TP to give a Baro reading, at all. So not sure what that indicates.
As I understand my 2000 f350s baro is part of the PCM vs a stand alone part. So I'm hopeful that is not the reason things are out of whack.
The EBP is new and reads the same as the one I replaced due to me stripping the threads.
Thanks
Wink

 

I have verified my Torque Pro readings by comparing them with AE, and my new OEM sensors read bang-on throughout operation. Maybe a typo in the formula, or you have a non-OEM EBP?

Factory spec is much tighter than 3 PSI from BARO. I've seen 0.2 in the PC/ED, but that's unrealistic. I'd say if you're off by about .7 PSI or more from BARO, you can't trust the sensor to work correctly at a higher pressure. What if it's not off by just one all the way up the scale... what if it's off by 10% all the way up? This effects fueling and shifting.

When you figure 1 PSI is 2000ft in elevation, isn't that relevant to proper fueling?

 

You got me thinking about it and I thought I would check mine. [IMG][/IMG]
I was considering removing the ebp tube to clean it but would these numbers lead me to believe its operating well and clean ? Or does it not necessarily correlate that way?

 

Is that engine off?

 

Ok, looking for a possibility to your power loss. Comparing your boost readings a WOT for both tests.

I am assuming your baro sensor is reading 12.2 psi (standard press at 5,000 feet elevation).

Boost = MAP - Baro.

In the first WOT test you were at 12.8 lbs of boost., the second WOT run you were at 14.5. So if you did everything the same during both WOT runs then it appears you did correct/fix something since you increased your boost by almost 2 psi.

I have no experience with Torque Pro but I would get with Tugly and make sure your formula is set correctly and ask how to read Baro Pressure through that app as well. Did you purchase an OEM EBPV sensor or is it an aftermarket one?

Once you can see baro pressure then you can compare MAP & EBP to that and see a clearer picture....

 

The spec for MAP sensor diagnosis is +/- 0.3 volts from expected voltage for the altitude-adjusted pressure. That translates to about 2.75 or so psi.

 

Me or Jwink? If you meant me the truck was running in park in the driveway after a short drive. Maybe 5miles

 

I went back through and re-re-verified that calculations and they match yours exactly.

Yes I do have a non-OEM EBP. It was the only thing available the weekend I twisted off the old OEM part. It seemed OK in my mind as the reading from the old and the new were within .2 of each other. I thought I had the EBP nailied when I found the compression fittine loose at the manifold due to corrosion. Put in the new fitting, tube and (nonOEM) EBP and got no joy as the reading was the same as with the old parts.

I have a friend that I can swap the MAP and EBP sensors with this
weekend, 1 at a time to see the impact.

You had mentioned that in a different post the the BARO is calculated automatically. I can't get the BARO gauge read any value at all does your's come up blank as well? How can I validate that the BARO is working within the PCM, or do I even need to. It's also entirely possible that I have a lot more to learn!

Thanks, Wink

 

I need to learn the logging function with this app to better capture the WOT aspect. I was manually taking a screenshot of the gauges based on rpm so given your boost comparision , it made me think I added some serious "human factor" that should not be included.

The EBP is after market but reads the same as my OEM that i physically broke.

Thanks,

Wink

 

This may or may not be relevant. In Torque, I'm pretty sure I read that BARO() is the barometric pressure reading on your device, not from the PCM. If your device doesn't have a barometric pressure sensor, you won't get a reading from BARO(). You might be able to get it from the PCM too, but I don't know what the PID would be for it. I would assume however, that the Ford specific boost PID uses the PCM's barometric reading for the calculation.

 

You could disconnect the MAP sensor hose and that will give you Baro Pressure.....then you could check that against your device.