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Can't Get Rid Of The PO0327 Codes

T

TorkMonster

New CEG'er
Joined
Apr 20, 2008
Messages
15
On a 1995 2.5l Auto (LX)

I can't seem to get rid of this code.

I replaced both the DPFE sensor and the EGR valve as well as the EGR selenoid.

Ran the car about a week and pulled the EGR again. The EGR tube side was rusty - no soot. exhaust had not been running through the EGR valve! I cleaned out the EGR tube with pipe cleaners and compressed air. I found no blockage, but the tube is clean! The DPFE hoses are properly connected from the EGR valve.

I connected my multimeter to the EGR selenoid lead ant took a test drive. My meter read 13.2 volts for the entire drive. So the vacuum selenoid never opens for the EGR to open up. The selenoid voltage should vary depending on the load of the engine as long as the car is moving.

The wiring looks good - no cracks or missing insulation anywhere.

The question is why?

If the DPFE fails it's test, would'nt the EGR selenoid continue to operate? Anyone had the same experience?
 
Did you clean the passages in the UIM? Put a hose on the vacuum input to the EGR valve and at idle either suck hard or use a vacuum pump on it. The engine should stumble. If you take the EGR off you can also look in to see the piston move when you suck on the vacuum input. You can start the car without the EGR valve installed and see if you get exhaust gass out the pipe. You can also put a vacuum gauge on the input to the ERG valve and see if it's getting a vacuum. Do you have vacuum at the input to the solenoid?
 
twocontours said:
Did you clean the passages in the UIM? Put a hose on the vacuum input to the EGR valve and at idle either suck hard or use a vacuum pump on it. The engine should stumble. If you take the EGR off you can also look in to see the piston move when you suck on the vacuum input. You can start the car without the EGR valve installed and see if you get exhaust gass out the pipe. You can also put a vacuum gauge on the input to the ERG valve and see if it's getting a vacuum. Do you have vacuum at the input to the solenoid?
Click to expand...

I cleaned the EGR portion of the upper intake manifold with pipe cleaners and air. When pressurized with the air hose air would move through the manifold and throttle body if opened.

I pulled the vacuum line from the EGR and installed my hand powered vacuum pump. The valve did open as vacuum was applied and the engine stumbled. The EGR valve got hot due to the exhaust gases moving through.

So I know that the EGR valve will operate if it will get some vacuum. The darn selenoid just won't open!
 
twocontours said:
Are you sure you have vacuum to the solenoid? since it's a 95 how does you wire harness look any cracks?
Click to expand...

I do get vacuum to the selenoid.

The wiring harness looks fine - no cracks or missing insulation. The car has had the recall performed.

My next step is to pull the harness, visually check, then check continuity on every wire. I was hoping that I was missing something simple. In two months time I have replaced the entire cooling system including the fans, replaced the valve cover, timing cover, and oil pan gaskets, replaced the O2 sensors, and replaced the intake gaskets. I hate to tear into it that far again. My hands are worn to nubs! :laugh:
 
With 13 v on the solenoid and vacuum it should be working. Did you check the ground on the solenoid? It might also be a measurement problem with the meter you used. The control signal is a 0 to 12 volt pulse that varies the on/ off ratio to control the vacuum. Some meters will just read the peak not the average. You might want to try an old analog meter instead of a newer digital (but I don't really think that's the problem) Are you sure the vacuum hoses are OK?
 
There you go. Does that solenoid have 2 wires? One powers up at 12 volts from power relay and the other is grounded intermittently by PCM to cycle solenoid. If you can tell which wire is positively the 12V one then take the other wire and find a good ground and ground that wire. Please have the ground lead unplugged from the harness to prevent any damage to PCM. Have the engine up and idling and ground that other lead only a second or two to avoid burning out the solenoid, it's only intended for partial load not 100%. If solenoid cycles engine should mess up from EGR switching on just like EGR valve test. That means solenoid itself is good, look for a problem in the wiring harness that prevents a good clean amount of power getting back to the PCM through the ground. Or else the PCM itself has a problem recognizing it should be switching that ground on and off. What is that dtc code? Technically with '95 model car should only be 3 digit EEC IV system, not OBD II. That means you can pull codes just with the jumper wire, no scanner needed.
 
twocontours said:
With 13 v on the solenoid and vacuum it should be working. Did you check the ground on the solenoid? It might also be a measurement problem with the meter you used. The control signal is a 0 to 12 volt pulse that varies the on/ off ratio to control the vacuum. Some meters will just read the peak not the average. You might want to try an old analog meter instead of a newer digital (but I don't really think that's the problem) Are you sure the vacuum hoses are OK?
Click to expand...

I use a Fluke 87 multimeter. It's normal to read +-13 volts when the engine is running. Engine off came right to 12v. I get good vacuum - I also checked all of the vacuum lines when I removed the intake (and replaced a few). When I unplug the seleniod vacuum connector there is suction on the lower line.

amc49 said:
There you go. Does that solenoid have 2 wires? One powers up at 12 volts from power relay and the other is grounded intermittently by PCM to cycle solenoid. If you can tell which wire is positively the 12V one then take the other wire and find a good ground and ground that wire. Please have the ground lead unplugged from the harness to prevent any damage to PCM. Have the engine up and idling and ground that other lead only a second or two to avoid burning out the solenoid, it's only intended for partial load not 100%. If solenoid cycles engine should mess up from EGR switching on just like EGR valve test. That means solenoid itself is good, look for a problem in the wiring harness that prevents a good clean amount of power getting back to the PCM through the ground. Or else the PCM itself has a problem recognizing it should be switching that ground on and off. What is that dtc code? Technically with '95 model car should only be 3 digit EEC IV system, not OBD II. That means you can pull codes just with the jumper wire, no scanner needed.
Click to expand...

Interesting. I am getting 12v on both sides of the connector (negative lead to chassis ground)! I am guessing that the connector gets 12v on one lead all of the time and the PCM supplies ground as necessary? The code is 327 btw. I will check on the operation of the selenoid this afternoon.
 
Last night I isolated the EGR selenoid and manually engaged it and found that it works ok.

I also pulled the ECM and cleaned it as well as the main ECM harness plug (whoever decided that it would be a good idea to place the ECM under the power steering tank should be flogged). While I was at it I checked continuity on the selenoid wiring and it checked out ok. The selenoind just never gets a signal.

Looks like the ECM may be the culprit. :nonono:


On a side note, the blower motor and rear tail lights quit working this morning - blew fuse #23 on the cabin fuse box. Replaced the fuse and everything worked for about 30 seconds. This thing is really testing me! :dizzy:
 
check your vacuum lines, I had a similar issue getting an EGR code, turned out one of my vacuum lines had been disconnected, with a 10+ year old car, I am willing to bet one of those lines broke or has degraded, throwing this code.

if you have any vac leaks, you should be able to hear it with the motor running and the hood poped.

I didn't read the rest of the thread, so I dont know if this was ruled out or not, if it had been... Just ignore me then.
 
Code 327

Code 327

You should not be getting 13 volts on both sides of the connector. The brown wire goes to the pcm ground. If you are getting 13 volts you most probably have a short to a hot wire.

The brown wire goes to a common connector before it goes to the pcm. There are a multitude of sensor wires that go to this connector, any one of these wires could be shorted

good luck in finding the short
 
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