Bucking/Surging Epidemic

[TJC]

Thanks for the explanation.

Next question (I promise that this is the last one on this subject!).

Can the water simply be removed from the sensor, or does it permanently damage the sensor?

I have 2 sitting in the 2020 Ranger parts bin.

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[airline tech]

Thanks for the explanation.

Next question (I promise that this is the last one on this subject!).

Can the water simply be removed from the sensor, or does it permanently damage the sensor?

I've got 2 sitting in the 2020 Ranger parts bin.

That is the unknown at this point - as we do not know if the moisture itself is causing the sensor failure or the acidic nature of the moisture damaging the sensor.

 

[airline tech]

To highlight the Tube Assy:


Ref: The DPFE Sensor

The Right Hose is the Downstream Press (Intake Side)
The Left Hose is the Upstream Press (Exhaust Side or EGR Flow)

If you picture a restriction (inside the tube) this is the orifice (<=) and it is located between the (2) pick-up tubes on the tube assembly (roughly the location of the smaller pick-up tube (finger clamp)

When the EGR valve is closed, you have equal press on both pick up tubes, this is the Intake Manifold vacuum. (Low Pressure)

When the EGR valve opens (it creates a press differential) higher pressure on the Downstream (smaller pick-up tube) which routes to the Left Hose @ the DPFE

So now you have a pressure acting on both sides of the (Orifice)

The Pressure Difference

Now the sensor is seeing a High Pressure (on the small pickup tube) that feeds to the Left Hose on the DPFE (Upstream Pressure)
and
On the Larger Pickup Tube is seeing the (Downstream Pressure) (Ref) for the EGR Flow, it is measuring the pressure drop (as compared to the Upstream Press reading)

This differential pressure in the Orifice is how the EGR Flow is measured

A clog in the Orifice can throw the sensor reading askew or the small pickup tube

A leak from the increased pressure of EGR Flow anywhere along the tube can throw the sensor askew. (pressure bleed off)


Note: with all the pics posted of the DPFE water (it's always in the Left Hose on the DPFE) this is the High-Pressure side of the Orifice.

So, we have to determine if the water droplets can temporally block the Orifice and cause the fluctuating readings or accumulate on the High Press side (Upstream) of the sensor and throw the readings off.
Once it reaches the sensor, it has nowhere to go but evaporate if and when the Exhaust Flow has less moisture content.
any moisture that makes it past the Orifice and enters the Downstream side of the tube, it will be forced into the intake stream. Thats why we don't see any moisture in the smaller tube on the DPFE sensor (Right Hose)

 

[Woods22250]

To highlight the Tube Assy:


Ref: The DPFE Sensor

The Right Hose is the Downstream Press (Intake Side)
The Left Hose is the Upstream Press (Exhaust Side or EGR Flow)

If you picture a restriction (inside the tube) this is the orifice (<=) and it is located between the (2) pick-up tubes on the tube assembly (roughly the location of the smaller pick-up tube (finger clamp)

When the EGR valve is closed, you have equal press on both pick up tubes, this is the Intake Manifold vacuum. (Low Pressure)

When the EGR valve opens (it creates a press differential) higher pressure on the Downstream (smaller pick-up tube) which routes to the Left Hose @ the DPFE

So now you have a pressure acting on both sides of the (Orifice)

The Pressure Difference

Now the sensor is seeing a High Pressure (on the small pickup tube) that feeds to the Left Hose on the DPFE (Upstream Pressure)
and
On the Larger Pickup Tube is seeing the (Downstream Pressure) (Ref) for the EGR Flow, it is measuring the pressure drop (as compared to the Upstream Press reading)

This differential pressure in the Orifice is how the EGR Flow is measured

A clog in the Orifice can throw the sensor reading askew or the small pickup tube

A leak from the increased pressure of EGR Flow anywhere along the tube can throw the sensor askew. (pressure bleed off)


Note: with all the pics posted of the DPFE water (it's always in the Left Hose on the DPFE) this is the High-Pressure side of the Orifice.

So, we have to determine if the water droplets can temporally block the Orifice and cause the fluctuating readings or accumulate on the High Press side (Upstream) of the sensor and throw the readings off.
Once it reaches the sensor, it has nowhere to go but evaporate if and when the Exhaust Flow has less moisture content.
any moisture that makes it past the Orifice and enters the Downstream side of the tube, it will be forced into the intake stream. Thats why we don't see any moisture in the smaller tube on the DPFE sensor (Right Hose)

 

[Woods22250]

This forum is great! I changed my sensor and it fixed my issues. I turned it over and water came out, about half a thimble full, which cannot be good as water and computers/electricity do not mix well.

 

[TJC]

That is the unknown at this point - as we do not know if the moisture itself is causing the sensor failure or the acidic nature of the moisture damaging the sensor.

Well, I guess it is time to experiment a little bit. I have 2 known good units and the suspect one on my truck. I'll pull just the sensor and use hose clamps to secure the new one. Drive truck and see if the slight stumbles/jerks disappear.

I'll dry out the original unit and reinstall, and see if the problem returns.

I'm not quite sure what I will do if the new part doesn't correct the problem.

The question is should I change the spark plugs before running this experiment? I've got a set of NKG iridium plugs waiting to go in.

 

[RangerBill]

Well, I guess it is time to experiment a little bit. I have 2 known good units and the suspect one on my truck. I'll pull just the sensor and use hose clamps to secure the new one. Drive truck and see if the slight stumbles/jerks disappear.

I'll dry out the original unit and reinstall, and see if the problem returns.

I'm not quite sure what I will do if the new part doesn't correct the problem.

The question is should I change the spark plugs before running this experiment? I've got a set of NKG iridium plugs waiting to go in.

I would wait to change the spark plugs so you don't introduce another variable into your test.

 

[TJC]

That is generally my thought process as well. Change 1 thing at a time. I may well do that. The plugs can wait a day or two.

 

[Woods22250]

Well two days later I know have a check engine light and an alert in fordpass. Did I get a Bad sensor?

 

[Woods22250]

Well what an idiot I am. I plugged in forscan and it said hoses reversed. Lol

 

[airline tech]

Well what an idiot I am. I plugged in forscan and it said hoses reversed. Lol

,

Check to ensure that they are in fact reversed, Ref diagram below for correct routing.

 

[Marc S]

Well two days later I know have a check engine light and an alert in fordpass. Did I get a Bad sensor?

I just got this warning today after getting my Ranger back from the dealer for a regular maintenance! Bringing it back in the morning.

 

[mang5927]

My truck threw the P139C code today. 57,685 miles. Felt a few bucks/surges running errands then the check engine light came on. Plugged in my scanner at home and it had the code listed twice. Checked this thread and went to the ford dealership for the sensor. Just replaced the sensor (what a pain in the butt) and it drives wayyyy better. I've had sluggish acceleration for months at full or heavy throttle and now it's like new again. Guessing the sensor was the reason for that.

I do have a question though. I cleared the code with my cheap innova scanner I got from autozone and the check engine light is not on when the truck is running, but it is on when the key is in the "on" position. It also flashes after 10-15 seconds if I leave the key in the "on" position without the engine running, but goes off once I start the truck. Do you all think this is an issue with using the innova scanner? Would clearing the code on forscan fix it?

 

[airline tech]

My truck threw the P139C code today. 57,685 miles. Felt a few bucks/surges running errands then the check engine light came on. Plugged in my scanner at home and it had the code listed twice. Checked this thread and went to the ford dealership for the sensor. Just replaced the sensor (what a pain in the butt) and it drives wayyyy better. I've had sluggish acceleration for months at full or heavy throttle and now it's like new again. Guessing the sensor was the reason for that.

I do have a question though. I cleared the code with my cheap innova scanner I got from autozone and the check engine light is not on when the truck is running, but it is on when the key is in the "on" position. It also flashes after 10-15 seconds if I leave the key in the "on" position without the engine running, but goes off once I start the truck. Do you all think this is an issue with using the innova scanner? Would clearing the code on forscan fix it?

Not the scanner nor code related - Normal Ops for the IPC, the Flashing of the light appears out of norm I think - but did you have the Scanner hooked up at the time? if so, you are still in communication with the scanner, and that's the reason.

 

[mang5927]

Not the scanner nor code related - Normal Ops for the IPC, the Flashing of the light appears out of norm I think - but did you have the Scanner hooked up at the time? if so, you are still in communication with the scanner, and that's the reason.

I did have the scanner hooked up at the time, but have tried it hooked up and not hooked up and it's still flashing. Same with forscan. I cleared the DTC log and no codes or DTCs are showing up. Could this be because I unhooked the DPFE sensor and the emissions system needs to run through a full "cycle" to completely reset everything? Asking because the check engine light stayed on in our jeep grand cherokee after replacing a couple emissions system parts and it took x amount of miles until it reset itself even though I had cleared the code.

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