EGR Sensor

[Con Seann3ry]

Reason this is in Explorer 911 is because I'm working on this right now and I would like responses as fast as possible.

A couple days ago I decided to finally chase down my check engine light. I went to Autozone and they read the codes and said "It's most likely a bad EGR valve" - so I bought a replacement and put it in. Once I put it in though I noticed that it's running very lean (and CEL came back on.)

I bought my own scanner at that time and just ran the codes. I got 327 in both the KOEO codes and the continuous memory.

My questions are: If my EGR valve was good and I replaced it unneccesarily then why would it change the way the engine ran?

I've also heard about this problem being mostly caused by a faulty DPFE sensor - My local Ford dealership wants 120 for this, but I've heard you can get them for 60 from Fordpartsnetwork. Is there a way I could test this sensor to be fairly certain it's the cause of my problems?

 

[Con Seann3ry]

Anyone?

 

[Con Seann3ry]

Should these holes be open like this?

I tried covering those with duct tape and it ran fine for a little while - eventually the gasses burned through the duct tape and I could hear it running lean again and the check engine light came back on

 

[yosh18981898]

wouldn't be first time autozone sold someone a bum part.

 

[MrShorty]

One mistake the folks at Autozone made is that a KOEO code, because it's set without the engine running, is almost always an electrical fault. "By the book" we look at the code from the KOEO perspective. 1st check would be the wiring between the EGR position sensor and the PCM. Second check would be vacuum hoses, to make sure one of those isn't plugged. Then a check of the sensor output.

 

[Con Seann3ry]

wiring and vaccum hoses are fine - how do I check the sensor output?

(ps. if a mod could move this out of the 911 forum that would be fine as I dug my old part out of the trashcan and put it on and it is no longer an emergency)

 

[pmcmaster]

If this is any help - test from Haynes.
EGR tests Disconnect harness to EGR vacuum regulator, with ignition on there should be voltage at the harness end. With ohmmeter check resistance of regulator - for DPFE systems should be 26-40ohms (PFE systems should be 20-70ohms). Voltage at the harness end of the DPFE terminal VREF should be 4-6 volts (ignition on engine not running). DPFE test, at the DPFE connector identify the SIG and GND wires that run to the PCM. backprobe these wires with voltmeter, with engine running COLD (No EGR) there should be 0.75 - 1.25 volts (black plastic DPFE) or 0.35 - 0.8 volts (aluminium DPFE). As engine warms and EGR is called the voltage should increase to 4.0 - 6.0 volts. If tests values are incorrect - check the vacuum source to the DPFE if ok the DPFE is probably faulty.

Pat McMaster

 

[Con Seann3ry]

Thanks Pat - I took my DPFE off today and it was all corroded...I took it apart by drilling out the rivets but the inside is so gross that I decided to just buy a replacement (70 bucks at Carquest) which was the cheapest I could find other than 60 bucks from Fordpartsnetwork (I hear)...anyways - going to buy some new tubing (because that was gross too) and then it should be all fixed. Thanks for your help guys.

 

[Con Seann3ry]

Update

Ok, so I no longer see the 327 code anymore after replaceing the DPFE and it takes longer for the check engine light to come on...but sure enough...after 5 minutes of driving or so it comes back on. Now I am getting a 332 code in the continuous memory (EGR flow too low). When I replaced the EGR sensor there was some funkyness occuring. First they gave me the wrong one, then they gave me another and said it was one from a 95...it looks the same on the outside. It is a Wells with the nubmer EGR270....on my one before that it shows B70 - Are these the same ones? Also, if you don't think that is it are there any other sensors I should be checking?

Thanks,
-Kevin "Wanting this damn check engine light gone" Blackmore

 

[newbi]

The DPFE controls a solinoid activated vacumn switch. Shold find it to the rear of the DPFE, will have 2 small vacumn lines on the bottom and power wires to the top. Check to see that the vacumn line are attached securely. You can then attach a section of tubing directly to the EGR valve and give er a suck Should open the valve. If these check out, the EGR could need cleaning or replacement.

 

[Con Seann3ry]

Ok, that was kind of late when I posted. The EGR valve position sensor is new and the EGR valve is new too. I'll go check that vacumn switch...I'm assuming it is that little black plastic thing that has the wire that connects to the nipple on the EGR valve. I noticed that inside this there is a long tube with fittings for a socket at the top...is this adjustable? How tight should it be?

 

[newbi]

non adjustable. What this switch does is when the solinoid is activated, it will allow vacumn to pass THROUGH the switch TO the EGR valve and open it. The DPFE(amongst other sensors), feed the ECM, which contols the electrical signal to this switch. Example- the EGR will not open till the engine is warmed up
PS- that "wire" to the EGR valve is actually the vacumn tube. It looks like a wire though.

 

[pmcmaster]

When you replaced the EGR did you check that the number stamped on top was the same? most important that the replacement has the same code stamped on it. Code 332 also means 'EGR valve not opening'. Just realised something, is yours a 94 model? if so there not fitted with a DPFE system, 95 and earlier (+96 5.0L) are fitted with the PFE system. Very similar but the PFE has only one connection for exhaust pressure (downstream pressure) while the DPFE has two connections (downstream & upstream pressures). Several other sensors effect the operation i.e. MAF, TPS, ECT as the EGR system only activates when; the engine temp is above 113 F, throttle pos is at part throttle and MAF sensor is at 'mid-range' position. Make sure the vacuum pipe to the EGR is good.
Pat McMaster.

 

[Con Seann3ry]

I think 91 was the only year with the PFE, because mine definately has a DPFE...it is different than the one on later models though, mine is all metal construction while the 95+ models use a plastic one. I did, however, get the code off. I replaced the new EGR with my old EGR valve because it didn't have enough markings that I was sure it was the same one...then I cleaned some little sensor (driver side with one plug going into it...about the size of a spark plug) it had a bunch of crap on this little red thing, so I sprayed it with carb cleaner and used some q-tips to get all that crap off...and I just drove for a half an hour - the light went on twice for like a second, but then turned off...I hadn't reset the computer yet, so, hopefully with the computer reset it will be good.

 

[newbi]

My 94 has the DPFE system also. The Haynes manuel is wrong on thier years for this system.

 

[Con Seann3ry]

Ok, so after a few days of driving. The check engine light is off, but randomly, it has turned back on for 5-10 seconds (332 in CM) and then turned off twice now. Anyone know what this is about? Also, I have my old EGR Valve in there.

 

[lonestar]

Should these holes be open like this?

I tried covering those with duct tape and it ran fine for a little while - eventually the gasses burned through the duct tape and I could hear it running lean again and the check engine light came back on

NO, there shouold be no holes or vaccum leaks in the EGR valve. Basically the EGR (exhaust gas recirclulation) opens as your RPM increases in order to recirculate exhaust from the exhaust manifold back to the intake.

Tha valve is operated with a vacuum, and the DPFE senses the vavle position. If there are vacuum leaks, or the vavle fails to close at idle, it will run lean, give rough idle, or will not idle.

The CEL will also come on if the DPFE is bad, or the EGR fails to open. Atleast it will run fine if it stays closed.

WELLS has some good tech tip advice on most electronic engine controls.

 

[pcbytes]

I drilled a hole in a nickel and screwed it onto the egr valve to cover the hole. Works fur me...... I had same codes it was my DPFE wish I had found a cheaper one up here it cost me 179.00 plus GST.

 

[Con Seann3ry]

ouch, i got my DPFE for 94 bucks.

as for that EGR valve, i returned it and got the right one

 

[pcbytes]

Well our Canadian dollar is not as strong as the US money but I am sure the Ford dealer up here did not give any deals. As for the right EGR valve well according to the same dealer and a NAPA the only egr valve they could find had the holes.