Originally posted by Contouraholic:
You probably can't suck hard enough to operate the EGR




Of course you can. It takes less effort that does drinking a milkshake through a straw.

5.1:

The 327 IS an electrical problem. You are close to the right track, but you have a slight misunderstanding of how the EGR system works.

In a nutshell, here is how it is supposed to work:

1. PCM tells EVR (EGR Vacuum Regulator) solenoid to open, applying manifold vacuum (restricted) to the EGR valve.

2. EGR valve opens, allows exhaust gas to pass through air tube, EGR valve, and intake.

3. The exhaust gasses pass by an orifice in the air tube enroute to the EGR valve. There are sample tubes connected to the air tube on each side of the orifice. When there is EGR flow, there is a difference in pressure/vacuum between the two sides of the orifice.

4. These tubes are connected to the two inputs of the DPFE ( DIFFERENTIAL Pressure Feedback EGR) sensor. The DPFE sensor outputs an analog voltage that is proportional to the difference in pressure/vacuum between the two sample tubes. This voltage is fed back to the PCM as an input to tell the PCM how much EGR flow is taking place.

5. The PCM can, under its programming, vary the duty cycle to the EVR solenoid, which varies the EGR flow rate which is reported back to the PCM by the DPFE sensor.

Basic closed loop feedback control system.


Now to your 327 code:

This indicates that the output voltage of the DPFE is below the lower limit of 0.2 V when there is no EGR flow (lower limit is around 0.45 V).

There is a simple test to see whether the fault is due to the DPFE sensor or an external fault, however, the physical location of the DPFE sensor and its connector on the 2.5L makes it a challenge to perform.

1. Key off. Disconnect the connector from the DPFE sensor. Jumper the Vref wire in the wiring connector to the DPFE circuit (consult your schematics for exact wire color codes for your year/model - I can't read the wire color codes on my service CD drawing) on the wire harness connector.

2. Re-run the KOER test and watch what codes are output.

3. a: No codes generated - wiring harness or PCM fault

b: 337 code - DPFE sensor bad

c: 327 code again - check Vref circuit to the DPFE sensor for an open circuit (loss of Vref to the DPFE sensor)

There you go - the tools to DIAGNOSE the 327 code you are encountering. Good luck.

FWIW, my bet is that after you fix the 327 problem, you will still have at least one additional problem code that will then crop up. Unfortunately, you will have to fix this problem first.

Steve

98 Contour SE Sport 2.5 Duratec ATX The wifey's car 89 Taurus SHO - 246K miles 94 SHO ATX - 190K 1997 F-150 5.4L ATX - The Workhorse 150K. ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!