schwanny30

I recently did some work on my car, replaced the EGR valve, and cleaned injectors, new coil pack and replaced some vacuum elbows and hoses. A week later I started getting P1506 error code idle air cntrl overspeed error. I am also getting a pending code P0401 EGR flow insufficient. I have used a hose to listen for leaks and to be honest I can't find any. Does anyone know if these are linked and if they are would it be in my best interest to start with the DPFE valve? If so I understand this to be buried in the back? Anyone have a pic of this location?

I should probably also mention that when I drive with the heat or air conditioning on I feel small jerks as I am driving at 55-60mph. Mostly with defrost only.

Sterling_Six

Hello and good day:

First may I suggest you just replace DPFe sensor first then the IAC (idle air control valve) if needed.

The Following was taken of the Website: WikiAnswers - Where to find and how to replace a DPFE sensor on a Taurus - Sable
What does it look like...

• Rectangular box about 3" tall x 5" wide x 1" thick (very rough estimate)
• 2 vacuum hoses going upwards into the left side of the bottom
• Wiring connection goes into right side of the "face"

Where to find it on the 24v Duratec engine


First, let establish that the front of the engine has the serpentine belt - the opposite end is then the back.
The DPFE sensor then is mounted to a plate on the top right on the back of the engine.

It is below the Throttle body and above the transmission dipstick height.


Where to find it on the 12v Vulcan engine

• Mounted to the backside of the Intake Manifold - and basically faces the firewall - about 2/3s the way towards the front of the engine.
• Readily accessible and easy to replace
• Don't forget to label the hoses as you take them off

How to replace on a Duratec engine...

• Looking at my 98, I'm going to suggest it might be just as easy to remove the throttle body or upper intake manifold (UIM) to get access to the DPFE sensor.
  
  Removing the UIM might be overkill, but having done it to change sparkplugs, I can say it's really not that big an effort. Disclaimer: I haven't changed a DPFE, so I'm somewhat speculating about access being difficult - just observing what it looks like )
• Remove the 2 mounting nuts
• LABEL the 2 vacuum hoses before disconnecting them from the DPFE
• Remove wiring connector
• Reverse to install (surprised? )

Is there a way to test a DPFE sensor?


Yes, but too involved to try and repeat here.

Visit Autozone.com and do the FREE registration for their Z-Net membership. This provides free access to the photo/illustrated/detailed Chilton's Online Repair Guide - or buy a manual.

It is behind the upper intake between the intake and the firewall. Hard to get to without removing the upper intake. Remove the eight 8MM bolts holding down the upper intake, loosen the hose clamp connecting the intake tube to the throttle body, and unbolt the EGR valve. Then move the upper intake out of the way while disconnecting the 3 vacuum lines under and to the rear of the intake near the throttle body.
Answer


The DPFE sensor is located below the throttle body and intake plenum, near the fire wall on the back side of the engine. It will have two places for vacuum hose connection. both pointing downward and a electrical connector on it's face pointing towards the drivers side of the car.
Answer

There is actually 2 different V6 3.0 liter engines. One is a 12 valve and one is a 24 valve. On the 12 valve the dpfe is behind the upper intake manifold, between the engine and firewall close to the middle of the car. On the 24 valve it is down below the throttle body area, almost completely hidden by hoses and wires and stuff. Look right below where the air snorkel attaches to the throttle body, toward the friewall slightly. It's down in that area on the 24 valve engine.

__________________
Good Luck and good repairing Sterling_6
"You know, just like in that Book, When Jesus beats up Moses to get Religion!!"

schwanny30

Found the DPFE, thanks for the help. I will give it a shot and see what happens. Car has 187,000+ so it can't hurt to check it out. We'll see where that takes me.

tomw

For what it is worth, a lot of DPFE sensors take a vacation when the engine gets to about 60k miles. There is corrosion from the exhaust gas fumes over time. I think it happens more on the 3.8, but wouldn't bet the farm.
The action you describe is called 'trailer hitching', and indicates the engine is misfiring enough for you to notice it. When the selector is on "defrost", the A/C compressor engages to dehumidify the incoming air, so it is just the same, loadwise, as having the A/C engaged.
tom

schwanny30

Replaced DPFE valve, doesn't seem to run any different. Car still trailer hitches when driving. I erased the codes that I was having will see if they return. Haven't really driven it enough to see if they come back. Any other suggestions on the trailer hitching? I have attached data from my code reader if this helps, I am not really sure of all of the data, but maybe someone can tell me if something looks out of wack.

Attached Files

Global OBDII1.doc (40.0 KB, 9 views)

tomw

If the A/C compressor was being engaged/released because of limited load, that could cause a slight hesitation or surge. Try leaving the system on 'vent' or switching from vent to defrost and back when you are experiencing the trailer hitch. If it comes and goes with the setting, you know what it is.
Looking at the numbers on your readout, two things I noticed were 1) the RPM, at idle, I presume, was pretty high and 2) the LT and ST fuel trim numbers are different by what looks to me to be a significant amount. One is a whole lot higher than the other. I would check again for air leaks and loose vacuum lines, etc.
I admit a whole lot of ignorance on OBDII readouts, but the two sides of the engine should have similar numbers...
tom

Bert

How many times did you run the test? Are these all one after another?

schwanny30

My ODBII reader takes readings I would say probably one every 5 to 10 seconds and records them. Yeah you will see the rpm higher in some of them because I was rev-ing the engine to try and see the differences at higher to idle rpm's. There was a total of 35 cycles taken, so this is about half of them.

Good new though I have driven the car for 3 days now and the error codes have seemed too disappeared for good. I will try switching back and forth with the vent /defrost to see if that is what it was. I had a buddy at work suggest that maybe my refrigerant was low causing the compressor to cycle more. That checked out ok.

Thanks