A Challenge to the Technical Wizards out there

[N40GL]

Can someone explain to me, using words of less than one syllable, how a bad EGR/DPFE can cause a transmission to make jerky shifts, or cause general jerkyness (is that a word?) in the drivetrain in general?

Yeah, I read a lot of the stuff Google uncovered, but I still don't get it.

[Blackened300a]

In modern Ford vehicles the EGR flow rate is determined by monitoring the pressure across a fixed metering orifice as exhaust gasses pass through it. This system is called Differential Pressure Feedback ( DPFE ) system. The pressure sensor monitors upstream ( before ) and downstream ( after ) exhaust backpressure. This backpressure coefficient is relayed to the PCM and the correct amount of EGR ( duty cycle ) is applied to the EGR vacuum regulator control ( EVR ). By calculating the difference between the two pressures, the PCM determines exactly the EGR flow rate at all driving conditions.
The DPFE is more accurate than early systems because the ECM doesn't have to guess at the upstream pressure coefficient to determine EGR flow rate as the engine drives through various road conditions such as hard acceleration, downshifting, engine misfire, poor fuel combustion etc. All of these conditions will cause the exhaust backpressure to vary and requires more strict and responsive EGR control to limit NOx emission levels. Note that in this particular system when the check engine light comes on due to EGR system malfunction, most of the time is due to a malfunctioning DPFE sensor.
Too much EGR flow tends to weaken combustion, causing the engine to run rough or stop. When the EGR flow is excessive, the engine can stop after a cold start or at idle after deceleration, the vehicle can surge at cruising speeds or the idle may be rough. If the EGR valve remains constantly open, the engine may not idle at all.

http://www.howstuffinmycarworks.com/Ford_EGR_systems.html

[N40GL]

That helps. I also found the item (below) on the NAPA site. But (other than the valve snapping open) how can the EGR/DPFE system cause transmission bucking?
============================== ==============
SYMPTOM: Repeated PFE-DPFE Sensor Code
APPLICATION: FORD, All With PFE-DPFE Sensor

Ford vehicles equipped with a Pressure Feedback EGR Sensor, (PFE) or a Differential Pressure Feedback EGR Sensor, (DPFE) may experience repeated occurrence of false EGR system codes and possible incorrect replacement of components due to limitations of the factory diagnostic procedures. While the Ford "H" manual does include reference to the EGR valve as a possible source of an EGR PFE Sensor code it does not address valves that "Hang" momentarily.

Our testing has found that contaminant build-up in the area of the EGR pintle shaft, or pintle seat may cause the valves on these applications to be slow in opening when the PCM commands additional vacuum be applied to the valve. Sensing that insufficient EGR is occurring, the PCM commands for more vacuum to the EGR valve. When the valve does pop open, the combination of valve inertia and vacuum build-up cause the valve to over travel. This creates the sensed excessive EGR condition that triggers the false code.

Drivers’ complaints usually include a bucking or trailer hitching condition during shifting or initial off-idle acceleration as part of the drivability complaint, which can be especially noticeable on manual transmission equipped vehicles. EGR valve replacement is the recommended service.

A similar false code may also occur if the metering orifice located in the intake below the EGR valve and DPFE sensor is restricted. This type of problem will not create a trailer hitching condition but loss of fuel economy will be noted. Cleaning the orifice will correct this condition.

[Bluerauder]

In modern Ford vehicles the EGR flow rate is determined by monitoring the pressure across a fixed metering orifice as exhaust gasses pass through it. This system is called Differential Pressure Feedback ( DPFE ) system. The pressure sensor monitors upstream ( before ) and downstream ( after ) exhaust backpressure. This backpressure coefficient is relayed to the PCM and the correct amount of EGR ( duty cycle ) is applied to the EGR vacuum regulator control ( EVR ). By calculating the difference between the two pressures, the PCM determines exactly the EGR flow rate at all driving conditions.
The DPFE is more accurate than early systems because the ECM doesn't have to guess at the upstream pressure coefficient to determine EGR flow rate as the engine drives through various road conditions such as hard acceleration, downshifting, engine misfire, poor fuel combustion etc. All of these conditions will cause the exhaust backpressure to vary and requires more strict and responsive EGR control to limit NOx emission levels. Note that in this particular system when the check engine light comes on due to EGR system malfunction, most of the time is due to a malfunctioning DPFE sensor.
Too much EGR flow tends to weaken combustion, causing the engine to run rough or stop. When the EGR flow is excessive, the engine can stop after a cold start or at idle after deceleration, the vehicle can surge at cruising speeds or the idle may be rough. If the EGR valve remains constantly open, the engine may not idle at all.

http://www.howstuffinmycarworks.com/Ford_EGR_systems.html

The above ^^^^^ response exceeds the one-syllable criteria where noted. Please go back and edit your post to substitute little tiny words per the OP guidance. Thank You for your cooperation. ;)

[RF Overlord]

Mark, that diagram in your sig is not for a supercharger. Anyone with any aptitude at all can clearly see that it shows how Congress works.

[Bluerauder]

.... can clearly see that it shows how Congress works.

Wouldn't it be wonderful if Congress worked that well. Very organized but nothing much productive comes out of it. Congress has the same result with disorganization.

[crouse]

Hmmmmm. I get a slight surging or bucking at light throttle at highway speeds and I have a slight rough idle. I know where the EGR is, but not sure where the DPFE sensor is or where the orifice is that they talk about cleaning?

[Blackened300a]

Hmmmmm. I get a slight surging or bucking at light throttle at highway speeds and I have a slight rough idle. I know where the EGR is, but not sure where the DPFE sensor is or where the orifice is that they talk about cleaning?

The EGR and the DPFE sensor is all one unit on the Marauder.

[Joe Walsh]

Mark, that diagram in your sig is not for a supercharger. Anyone with any aptitude at all can clearly see that it shows how Congress works.

LOL,
So each blue ball (no pun intended) must represent 1 Trillion dollars worth of taxpayer's money?

[Bluerauder]

LOL,
So each blue ball (no pun intended) must represent 1 Trillion dollars worth of taxpayer's money?
And the blue balls get dumped into oblivion at the bottom of the process. Just like real life. :rofl:

[SpartaPerformance]

I don't be lieve that the jerk in ess is from the trans miss ion, if E G R flow is exc ess ive this will cre ate im prop er com bust ion cause ing in bal ance in cyl in ders feel ing like jerk in ess. :D

[ImpalaSlayer]

didnt read everything but:

my 91 ranger had the egr solenoid go bad (was a slightly diff setup then the mm) and man i thought the friggen trans took a ****, it jerked and bucked like crazy.

if you need an egr, i might still have one left, pm me

[69ranchero351c]

if its stuck open its a huge vacuum leak so it will cause all kinds of bucking and jerking. just happend to my dads grand marquis, smacked it with a hammer a few times to break the carbon loose and been workin for the last 2 weeks. but dont expect that to be a permanant fix.

[Mr. Man]

The EGR is the little spaceship looking thing on the rear of the PS cam cover, correct?

Marc your car is shuddering and jerking about because it is trying to shed the SB and release the monster Black car it is at heart.:P:D

[justbob]

Most EGR issues lead to a tear in rubberish elastic diaphram inside and is easily fixable by opening it up and simply swiping a few coats of liquid electrical tape across the tear.

This technical free repair was brought to you by the people for justbob for president.

[Joe Walsh]

Most EGR issues lead to a tear in rubberish elastic diaphram inside and is easily fixable by opening it up and simply swiping a few coats of liquid electrical tape across the tear.

This technical free repair was brought to you by the people for justbob for president.

That's What She Said!.....:eek:

[Mr. Man]

Most EGR issues lead to a tear in rubberish elastic diaphram inside and is easily fixable by opening it up and simply swiping a few coats of liquid electrical tape across the tear.

This technical free repair was brought to you by the people for justbob for president.
Great tip but I can't vote for a guy who is still living in 1977. Disco Sucks:D

[N40GL]

Even more amazing - if you make multiple copies of this .gif and line them up top, bottom and sides, they all feed each other endlessly.

Like Congress!


And the blue balls get dumped into oblivion at the bottom of the process. Just like real life. :rofl:

[Bruce Wayne]

Anybody have the part number for the EGR on our Marauders, I think mine is faulty, causing hard starts. Thanks

[Ozark Marauder]

ERG Valve, DOHC

3W4Z 9D475 AC

[Blackened300a]

Just in case you are wondering what issues can occur from the EGR valve. I experienced a few this weekend after the header install.
My EGR tube didn't reach very well so they put all kinds of pressure on it and did what they could with it to get it to work, but never tightened the tube into the valve and the two bolts into the manifold. The results were a rough idle, a RPM surge with the A/C on in park, a hissing noise coming from the valve, a puff of black smoke at WOT, and a CEL with a O2 bank 1 pre-heat malfunction, and a pending lean code on bank 1. My power seemed a bit down as well.
Yesterday we massaged the tube to mate up and tightened everything up. No more noise and no more codes. The power is back and the idle is completely smoothed out. This stupid valve can cause all kinds of issues if its leaking or not working properly.

[RF Overlord]

I think mine is faulty, causing hard starts. The EGR valve isn't active during startup.

[Shaijack]

Mine bucks and seems to go from idle to WOT alot. I think it my foot and brain not working together.

[drobin]

Shaijak,

You should consider going to a smaller shoe size or install a smaller accelerator pedal.

drobin