Bucking/Surging Epidemic

[Ranger_Rocks]

If you ref post #652 - Mr. Busses - Drive Cycle, post he mentions the fluctuating DPFE Pressure, before replacement, but I do not know if that became stable after Tube & Sensor replacement.

Other than that, from what I see with what was posted - all readings appear normal
The Map & EBP readings appear normal range as well.

BTW: I am trying to figure out how to @ Mr. Busses - highlight that for a mentioned you response to the member or as a reference (quick link) to the members post etc.
Can someone tell me how to do it?

@MrBusses

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[airline tech]

@MrBusses

Ok, thanks I figured it out, I have been trying to R/Click, copy / paste etc..
So, type it and it (autofill's) --

 

[MrBusses]

If you ref post #652 - Mr. Busses - Drive Cycle, post he mentions the fluctuating DPFE Pressure, before replacement, but I do not know if that became stable after Tube & Sensor replacement.

Other than that, from what I see with what was posted - all readings appear normal
The Map & EBP readings appear normal range as well.

BTW: I am trying to figure out how to @ Mr. Busses - highlight that for a mentioned you response to the member or as a reference (quick link) to the members post etc.
Can someone tell me how to do it?

Yes readings became stable

 

[fishy1rt]

Thank you to this forum and thread. Bought the part (about $45) from Napa. Installed after cutting away a couple of pesky hose clamps. The problem has gone away!

 

[Yinzcity]

Yes readings became stable

Interesting. Since mine are still unstable after replacing the sensor, that would seem to suggest maybe something else isn't right.
Would be really helpful if we could figure out what all goes into the calculated value for pressure. It's more than just the voltage output of the sensor since that is remaining stable..

 

[Luke Nukem]

Interesting. Since mine are still unstable after replacing the sensor, that would seem to suggest maybe something else isn't right.
Would be really helpful if we could figure out what all goes into the calculated value for pressure. It's more than just the voltage output of the sensor since that is remaining stable..

If I understand @MrBusses correctly, he is suggesting that those who still have problems after replacing the DPFE sensor try replacing the EGR tube as well (LB5Z-9E469-B).

 

[Yinzcity]

If I understand @MrBusses correctly, he is suggesting that those who still have problems after replacing the DPFE sensor try replacing the EGR tube as well (LB5Z-9E469-B).

Well, I've got both the EGR tube and the pressure sensor that goes into the tube on order. I'll swap the sensor first and see if that stabilizes it. If not, then there has to be some physical issues in the tube itself.

 

[Luke Nukem]

Well, I've got both the EGR tube and the pressure sensor that goes into the tube on order. I'll swap the sensor first and see if that stabilizes it. If not, then there has to be some physical issues in the tube itself.

Let us know how it goes. I'll wait for your results before I spend the money ?

 

[airline tech]

Well, I've got both the EGR tube and the pressure sensor that goes into the tube on order. I'll swap the sensor first and see if that stabilizes it. If not, then there has to be some physical issues in the tube itself.

I looked at your posted results again, other than the Press fluctuating all looks good.
However, all I see is pics of it above idle and trying to determine if you have EGR Flow past the EGR valve when it is fully closed.

From the manual (Ref Value) Specs the voltage does not change much but the pressure does, when it sees (or presumes) EGR flow across the sensor.
At Idle this should be a (-) reading and when EGR Flow is present it should read a (+) number

From what I can tell, the only things that will affect the DPFE readings are:
The DPFE Sensor & Hose Connections / The Orifice Tube & Attach Points / The EGRT12 sensor threads (leaking)
So, any leak or blockage (partial blockage) in the Orifice Tube, will possibly affect the sensor readings as well as the moisture droplets moving around in the tube and setting on the sensor or EGR flow past the EGR Valve in the Closed Position, Vacuum leak at the intake, but you would see this with MAPT sensor readings and would be noted as a rough idle.

In addition to the DPFE sensor readings, showing EGR flow, we have 2 other sensors we can view PID Data for and see a noted increase in the readings.

MAPT Sensor & EGRT12 Sensor, both of these sensors react when EGR Flow is introduced.
The MAPT increases and the EGRT12 Increases

Being that you have a scanner capable of reading these PIDs here are the posted manual PID Ref Values to view

Note: I used 2,000 RPM as a reference parameter to coincide with the manual specs as around 2,000 RPM is the point to which the EGR Valve should be opening (Non-Driving Test - Purpose)
so, this should closely match the 30 MPH specs.

Note these are not (dead specific) they are TYPICIAL (average)
Note: These readings are for engine at (Operating Temp)

DPFE:
KOEO- Same as Idle Readings
Idle: ------ 1.48 Volts - (-0.39 KPA) or (-0.06 PSI)
30 MPH --- 1.49 Volts - (+0.95 KPA) or (+0.14 PSI)
55 MPH --- 1.48 Volts - (+0.63 KPA) or (+0.09 PSI)

Note how you have a (Neg) Pressure Reading until the EGR Valve opens.
Note: The manual bench test (checks for sensor readings (Min / Max) and reaction time

Note: Fluctuating Pressure readings (may) be the EGR Valve (opening & closing) a small amount (steps) during a driveway test as the engine is not under a driving load, would be curious if it did the same in a drive test.

MAPT:
KOEO: -----1.54 Volts - (100 KPA) or (14.50 PSI)
Idle: ------ .53 Volts - (34 KPA) or (4.93 PSI)
30 MPH --- 1.22 Volts - (79 KPA) or (11.46 PSI)
55 MPH --- 1.48 Volts - (96 KPA) or (13.92 PSI)

So, a higher MAP reading at Idle, could be an indication of EGR Flow at Idle, so flowing past the valve or the valve is being commanded open.
You MAPT sensor is reading normal with EGR flow, but I cannot see what the reading is at idle.
Note how the MAPT increases when EGR is flowing (30 MPH)

EGRT12: (EGR Temp Sensor) (Flow as it exits the EGR Cooler) after the EGR Valve
KOEO: -----1.08 Volts - (96.9 D/F) or (36 D/C)
Idle: ------ 1.03 Volts - (104 D/F) or (40 D/C)
30 MPH --- .72 Volts - (125.6 D/F) or (52 D/C)
55 MPH --- .60 Volts - (140 D/F) or (60 D/C)

Note how the EGRT12 sensor increases when EGR is flowing, this is another sensor to look at to see if you have EGR flow at idle.
Note: This sensor is mounted on the Orifice Tube by the DPFE Sensor.

Here is the verbiage from the manual for the EGRT12:

The EGRT12 sensor (if equipped) measures the exhaust gas temperature downstream of the EGR cooler and is monitored by comparing the EGRT12 sensor calibrated value to the actual EGRT12 sensor value. The EGRT12 sensor is primarily used for EGR flow calculation and is also used for EGR cooler diagnostics.

So, yet another sensor looking at EGR Flow


EBP: (Exhaust Back Press Sensor)
KOEO: --- .96 Volts - (98.7 KPA) or (14.32 PSI)
Idle: -----1.01 Volts - (102.3 KPA) or (14.84 PSI)
30 MPH - 1.49 Volts - (96.6 KPA) or (14.01 PSI)
55 MPH - .99 Volts - (100.9 KPA) or (14.63 PSI)

Note the pressure drop when the EGR flow is commanded at 30 MPH
The manual description is vague on what this sensor does other than it is used for EGR cooler monitor (effectiveness) and exact verbiage

The EP sensor (if equipped) measures the exhaust pressure by comparing the EP sensor calibrated value to the actual EP sensor value. The EP sensor is used primarily to determine EGR cooler effectiveness and is also used for converting EGR flow to EGR valve position.

So, I take this as - feedback of the EGR Vlave Position vs measured flow

Note: This sensor is mounted beside the EGR Valve and the Fitzstick mount point.


EGRVP:
KOEO: .94 Volts
Idle / 30 & 55 MPH -- .93 Volts

There are no Data Ref Specs for the EGR valve itself other than the voltage spec above, I believe this is due to the parameters vary by the PCM controlling the Open / Close of the valve.
This varies greatly by the input parameters (mostly) engine load and temperature.

But so far it appears that the EGR Valve only opens 10 to 15 % under normal driving conditions and loads from the posted test results so far, this appears to be the normal range we need to see above idle.

Here is the verbiage of EGR system inputs:

The EGR system uses inputs from the engine coolant temperature (ECT) sensor or cylinder head temperature (CHT) sensor, the intake air temperature (IAT) sensor, the crankshaft position (CKP) sensor, the manifold absolute pressure (MAP) sensor, exhaust gas recirculation temperature bank 1, sensor 2 (EGRT12), exhaust pressure (EP) sensor, differential pressure feedback EGR sensor and vehicle speed to provide information about engine operating conditions to the PCM.

The PCM uses the sensor inputs to determine the desired amount of EGR gas flow and controls the EGR valve to achieve the desired EGR flow rate.

Note: What the manual is lacking and that is a detailed description on how the PCM determines the amount of EGR flow, all that is known is the Typical Ref Data and that the EGR valve should be closed at idle and opens around 30 MPH or near 2,000 RPM's.
EGR Flow (percent) ties into Fuel Control and Trims as well as timing advance.

Now the manuals do not break down exactly what to look for with drivability issues, it's all by experienced based Live Data Monitoring as the manuals are geared toward the T/Shoot of a code and even then, it drives wiring checks


Hope the information helps, so we can possibly get to a pinpoint resolution for this, other than shot-gunning parts (which I hate doing) but sometimes necessary.
Then you factor in Fuel, Ignition or PCV or Transmission issues than can have a similar drivability issue only complicates it even more.
This is where viewing - the STFT and LTFT are helpful (Fuel Trims) and the Misfire Monitor Counts.

 

[airline tech]

Out of curiosity, I hooked up my Autel and did a drive monitor.

Noted:

That the EGR Valve opens and closes (0-15%) cycles while you drive, this was at 55 MPH

Plus: the DPFE Pressure - fluctuates along with the RPM, this makes sense as the exhaust flow is also fluctuating (fluctuation is minimal)

The EGR Valve cracks open @ around 1200 RPM (on average) and when you come off the gas pedal at (whatever) RPM you are at the EGR Valve closes

So, in short, with my drive cycle and @MrBusses drive cycle, the highlighted difference is the amount the EGR Valve is commanded open during the drive.

This is dependent upon the DPFE reading EGR flow, when the EGR valve is open you should see a (+) reading and it will hold steady on the (+) side, now when the EGR valve closes w/I a few milliseconds you should see the DPFE reading go back to (-)

Since I cannot see his frame by frame it appears his DPFE was switching (+) to (-) when the EGR valve was open.
It is normal for you to see the switching, but the EGR Valve has to follow suit.

So, I believe what is happening is that the DPFE is not reading flow, the PCM continues to command the EGR valve open to get the response from the DPFE sensor it is looking for (Feedback) this ends up at a percentage greater than the engine can handle and it stumbles as a result.

Again, my normal drive level roads with Stop Signs & Roundabouts and highway speed of 55 MPH the most I saw on the EGR Valve (open percent) was 16%, mostly stayed under 15%

 

[MrBusses]

You are correct on my drive EGR would be open up to 50 60% and then DPFE would read a negative pressure then a positive pressure and fluctuate back and forth with EGR open which it can't do that the sensor was bad.

Everyone else that has replaced the sensor and still having problems unless you are providing data from recorded Drive session there's not much help I can give you are throwing darts in the dark. Chances are your problem is not DPFE related if you have replaced the sensor already you have other issues going on besides the sensor, probably transmission related or spark plugs.

At this point it's time to bite the bullet and pay the professionals.

 

[Luke Nukem]

You are correct on my drive EGR would be open up to 50 60% and then DPFE would read a negative pressure then a positive pressure and fluctuate back and forth with EGR open which it can't do that the sensor was bad.

Everyone else that has replaced the sensor and still having problems unless you are providing data from recorded Drive session there's not much help I can give you are throwing darts in the dark. Chances are your problem is not DPFE related if you have replaced the sensor already you have other issues going on besides the sensor, probably transmission related or spark plugs.

At this point it's time to bite the bullet and pay the professionals.

I think where I am confused is that the DPFE replacement fixed my problem but then it came back 3 months later with the same symptoms. Could that still be related to spark plugs or transmission?

 

[MrBusses]

I think where I am confused is that the DPFE replacement fixed my problem but then it came back 3 months later with the same symptoms. Could that still be related to spark plugs or transmission?

Obviously it did not fix the problem or it fixed part of the problem. Could he an issue with valve, could be the tube is clogged. Without data who knows?

Could be plugs could be transmission, could have a bad injector maybe low compression, maybe the brakes are dragging. How much money do you want to waste on guessing?

 

[VAMike]

Could be plugs could be transmission, could have a bad injector maybe low compression, maybe the brakes are dragging. How much money do you want to waste on guessing?

The problem is that there's no option to wasting money on guessing; all the ford dealer will do is swap parts at shop rates.

 

[Muffin1]

Does this part/problem not fall under the emissions warranty?
Just for my own memory bank if it happens to my truck.

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