327 error code pain

[Iron Weasel]

Coasting is low vacuum, so the voltage is low.
When you're wide open, that's high vacuum so the voltage is high.
When there's a low amount of vacuum on the EVR solenoid, it sends a low amount of voltage to the PCM, and the PCM in turns tells the EVR solenoid to close and restrict vacuum going to the EGR valve causing it to close. During high vacuum, like when you're at full throttle, the opposite is true. High vacuum at the EVR solenoid causes the voltage to raise and the PCM tells it to open and increases the vacuum on the EGR valve causing it to open.

I'm not sure what amount of vacuum there should be at idle, but the purpose of using a vacuum gauge is to make sure that the EGR valve operates smoothly on its own.

Your best bet is to start poking around with the vacuum gauge. Here's DL99, the only step I didn't post yesterday:


Vacuum gauge connected.
Key on, engine running.
Look for an increase in EGR vacuum while performing the following:
With the engine at idle, wiggle the EGR Vacuum Regulator (EVR) solenoid harness between the EVR solenoid and dash panel and between dash panel and Powertrain Control Module (PCM) .
Does the EGR vacuum increase?

Yes -- Isolate and service short in EVR circuit. Remove vacuum gauge. Reconnect all components. Clear continuous memory. See: Reading and Clearing Diagnostic Trouble Codes\Clearing Diagnostic Trouble Codes

Rerun quick test. See: Reading and Clearing Diagnostic Trouble Codes\Reading Diagnostic Trouble Codes\Quick Test Appendix (Detailed Testing Instructions)

No -- Unable to duplicate and/or identify fault at this time. For further diagnosis using the EEC-IV monitor box or Scan Tool, refer to Normal Scan Data Values .

 

[nelwill]

Iron,
Just hooked up the vacuum gauge to the vacuum tree just to get a "default" level set before I get after the EGR components with it.
Measured about 12.5in Hg. at idle and basically 0 under any acceleration.

Not sure what that means but I throw it out as a data point... anybody care to comment? Normal vacuum pressure @ idle?

 

[rickybobby]

12" of vacuum seems quite low, i would expect 16 iirc

 

[nelwill]

R.B.,
I had a bogus measurement for vacuum at idle. Now have approx 17in. Sorry for the fire drill.

Iron, all,

1) Disconnected EGR valve to solenoid vac line. Inserted a "T" inline with a vac gauge and in a "suck" line to EGR valve. With engine running, used lung power to pull 10in.Hg on EGR valve. Held steady at 10in for approx 1min. Engine sounded like it wanted to stall. Released vac. Both gauge and engine smoothed out.

2) "T'd" in a vac gauge between EGR valve and solenoid. Drove with the vac gauge on top of the dash. Two results - a) With CEL on, not much action on the vac gauge. b) With CEL off, gauge would climb to about 5in during acceleration and fall to 0in when the tranny shifted or I let up on the accelerator.

As always, input welcome and thanks given.

 

[Iron Weasel]

R.B.,
I had a bogus measurement for vacuum at idle. Now have approx 17in. Sorry for the fire drill.

Iron, all,

1) Disconnected EGR valve to solenoid vac line. Inserted a "T" inline with a vac gauge and in a "suck" line to EGR valve. With engine running, used lung power to pull 10in.Hg on EGR valve. Held steady at 10in for approx 1min. Engine sounded like it wanted to stall. Released vac. Both gauge and engine smoothed out.

Try the test again but without teeing the gauge in. Plug the line from the EVR solenoid and hook the gauge up to the EGR valve. Also check the vacuum coming from the EVR solenoid with just the gauge hooked up.

2) "T'd" in a vac gauge between EGR valve and solenoid. Drove with the vac gauge on top of the dash. Two results - a) With CEL on, not much action on the vac gauge. b) With CEL off, gauge would climb to about 5in during acceleration and fall to 0in when the tranny shifted or I let up on the accelerator.

As always, input welcome and thanks given.

CEL On = No vacuum
CEL Off = 5" vacuum during acceleration.

Put the truck in neutral with the parking brake on and see if you can duplicate the results with the gauge hooked up to the EVR solenoid and the EGR valve disconnected.

 

[nelwill]

Iron,

From my earlier post - "1) Disconnected EGR valve to solenoid vac line. Inserted a "T" inline with a vac gauge and in a "suck" line to EGR valve. With engine running, used lung power to pull 10in.Hg on EGR valve. Held steady at 10in for approx 1min. Engine sounded like it wanted to stall. Released vac. Both gauge and engine smoothed out."

From your response(first part of your question) -"Try the test again but without teeing the gauge in. Plug the line from the EVR solenoid and hook the gauge up to the EGR valve."

I may have been unclear. 1) The components on the "T" I refered to were 1) EGR valve 2) Vac gauge 3) my lungs. "T" was not connected to EVR solenoid. EVR solenoid line was plugged. Does this answer the first part of your question or am I just confused?

From your response(second part of your question) "Also check the vacuum coming from the EVR solenoid with just the gauge hooked up."

Will do.

 

[nelwill]

CEL On = No vacuum
CEL Off = 5" vacuum during acceleration.

Put the truck in neutral with the parking brake on and see if you can duplicate the results with the gauge hooked up to the EVR solenoid and the EGR valve disconnected.

Will do also. Thanks.

 

[nelwill]

Also check the vacuum coming from the EVR solenoid with just the gauge hooked up.
QUOTE]

Just tried. Gauge reads 0in untill engine warms up. Varies between 0in and 5in after it warms up depending on tranny shifts and my acceleration.

 

[nelwill]

Also check the vacuum coming from the EVR solenoid with just the gauge hooked up.
QUOTE]

Just tried. Gauge reads 0in untill engine warms up. Varies between 0in and 5in after it warms up depending on tranny shifts and my acceleration.

Forgot to mention that CEL was constant on.

 

[Iron Weasel]

OK..when you said you teed the line off, I thought you still had everything hooked up but added the gauge in-line. Disregard all that stuff then.

I'm poking through all the diagnostics and using all the information you've provided to work through it and see if I can come to a conclusion. So far though, everything I've done tells you to replace you've already replaced, so that's not much help.

The only new bit of information is that the CEL is staying on constantly now, right?
If so, you need to check the codes again and see what's causing the KOER hard code.

 

[nelwill]

CEL is currently constant on (don't forget that I still have the EGR valve disconnected and the EVR solenoid hooked to the vac gauge).

Should I take the codes in this configuration or return all to normal?

Im pretty sure that under "normal" config the CEL will play off/on again, since I have not really done anything.

Thanks much

 

[Iron Weasel]

If everything is still disconnected, don't worry about pulling codes again. I was under the assumption you had everything back in the stock configuration.

I'm still looking through the diagnostic procedures to see if I can find anything new. I'll edit this post in a few minutes......

Edit time:

Verify your wiring matches the diagram.



BR/LG should be Pin 27 at the PCM connector.
GY/R should be Pin 46 at the PCM connector.
BR/W should be Pin 26 at the PCM connector.

Key "OFF".
Pressure Feedback EGR (PFE) / Differential Pressure Feedback EGR (DPFE) sensor disconnected.
Key "ON, engine "OFF".
Measure voltage between VREF circuit and SIG RTN circuit at the PFE/DPFE sensor vehicle harness connector.
Is voltage between 4.0 and 6.0 volts?

 

[nelwill]

Iron,
Can do. Have to run a quick errand but should have the answer within an hour. Stay tuned...

 

[nelwill]

Iron,
5V.

 

[Iron Weasel]

Key "OFF".
Pressure Feedback EGR (PFE) / Differential Pressure Feedback EGR (DPFE) sensor disconnected.
Disconnect Powertrain Control Module (PCM) . Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
Install breakout box, leave PCM disconnected.
Measure resistance between PFE/DPFE circuit at the PFE/DPFE sensor vehicle harness connector and test pin 27 at the breakout box.
Is resistance less than 5.0 ohms?


I'm just copy / pasting. I know you don't have a breakout box, so you'll have to test at the PCM connector.

 

[nelwill]

Iron,
Have done it twice now. Once with a very aggressive "jiggle" of every cable/connector I could find. Both times they were dead solid connected <1ohm.

Was thinking back to this though, as I also replaced the DPFE with a Duralast. Your thoughts are greatly appreciated.

I'll chime in with my 327 experience. (94 Ex Sport)

I was having no luck with the 327 code, did lots of reading through the threads to find that many people were having problems with auto-parts-store DPFE's (mine was a Duralast). I swapped it out with a Standard Motor version...code went away and hasn't returned.

At the very start I was getting 335, 336 codes with my original very old DPFE. Swapping with the Duralast cleared those but added the 327 code. Then, swapping that with the Standard Motor version cleared everything.

If all the other troubleshooting doesn't do the trick, it might be worth trying...

 

[Iron Weasel]

Yeah, I know you've done it several times, but I'm literally going step-by-step through the entire procedure since I'm honestly out of ideas at this point.

FWIW, Autozone parts are cheap for a reason. If you have the spare cash, you might want to head to Napa or even your closest Ford dealer and see if you can pick up a Motorcraft unit.

Key "OFF".
Pressure Feedback EGR (PFE) / Differential Pressure Feedback EGR (DPFE) sensor disconnected.
Breakout box installed, Powertrain Control Module (PCM) disconnected.
Measure resistance between test pin 27 and test pins 40, 46 and 60 at the breakout box.
Is each resistance greater than 10,000 ohms?

 

[nelwill]

Iron,
BWD replacment part at Advance Auto Parts $46.00. Plastic version. Any experience?

 

[Iron Weasel]

I've had decent luck with BWD stuff before, but I somewhat question why that particular unit is plastic. Reason I notice that is because the 94's came with either a plastic DPFE sensor or a metal one. Mine has a metal one which uses the D-shaped connector. Ones equipped with the plastic one have an oval connector.

I looked at the DPFE sensor at Advance Auto and it has the same D-shape plug, but I still wonder why it's plastic. Check Dead Link Removed and do a search for part# CRB 219108.

That's the metal one that I have. I'm basically just wondering if there's enough of a difference in construction or internals that would cause the PCM to not recognize it.

EDIT:

Somewhat related.
I have a 94 Oldsmobile 88 that I picked up for $500 a couple years ago because it wouldn't run. Eventually I tracked down the problem - it was a bad crankshaft position sensor, so I ran down to Autozone and picked one up. Replaced it and it ran, but really rough and threw codes. I tore my hair out for at least a week troubleshooting damn near everything I could think of and everything came up OK. Almost ready to admit defeat, I had a neighborhood service station hook it up to an analyzer and the Autozone crank sensor was working, but the electrical signals were off just enough that it caused the ECM to freak out. Went down to Napa and got a new crank sensor, slapped it in, and the car has been running fine since.

Not saying that's the case here, and I really hate just throwing parts at a problem without diagnosing it. Admittedly, it's hard to diagnose a vehicle with 100% accuracy over the internet, but I still hate to see people waste money just throwing parts at it regardless.

At any rate, every single diagnostic routine for KOEO, Continuous Memory, and KOER DTC 327 points you / me to replace parts that you've already replaced. The only thing you haven't replaced is the EGR, but again I hate to advocate randomly throwing parts at it, so I guess it's really up to you on what to do. If nothing else, I can copy EVERYTHING for that DTC and put it all in a file for you and let you look through it.

 

[Iron Weasel]

OK, I went ahead and copied ALL the steps for each "type" of DTC 327.

Link to document here.

A few things before you go tearing through it.

If 327 is showing up as a KOEO code, start at DL1
If 327 is showing up as a CM code, start at DL22
If 327 is showing up as a KOER code, start at DL90

Many of the steps are the same thing but with a different DL# - those are redirects from other DTC's so just ignore them.