EGR issues

[seth959ci]

i've been getting really crappy fuel mileage and a buck/shutter at lower rpms(2300 and lower), as well as a high idle. scanned the ecm and i've got a code 31.I put a different but not new egr feedback sensor and no change. I pulled the vacuum line off the egr while it was idling and it did not have any vaccuum. is it supposed to have vacuum? any other suggestions?

 

[jmcleek]

CODE: 31 (KOEO) - EVP circuit below minimum voltage. Vref (5 volt reference voltage supplied by the computer) missing or broken wire or bad connection in circuit. Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or MAP sensor located on the firewall near the center of the car. Use the black/white wire for the ground for the DVM.
With the sensor removed from the EGR and still connected, press the plunger and watch the voltage change on the brown/lt green wire. Pull the passenger side kick panel and measure the voltage at the computer. You will need to remove the plastic cover over the wires and probe them from the backside. A safety pin may prove very useful for this task. Use pin 27, EVR input (brown/lt green wire) and pin 46, signal ground (black/white wire) to measure the voltage. The orange/white wire is Vref and should always be 5 volts -/+ .25 volt. Be sure to measure Vref at the EGR sensor to rule out any broken wires or bad connections.
Measuring the voltage at the computer helps you spot broken wiring and intermittent connections.
The code descriptions below are general
descriptions to help you understand the system.
Look up your code definitions in the appropriate
service manual when diagnosing a vehicle.
DTC 31/327 typically means that the
PFE signal is less than the self test minimum
voltage. This can be due to a bad PFE sensor, a
bad PFE hose, improper reference voltage, a bad
connection or a bad computer.


I also have a code 31 that I am trying to resolve, above are some things that I found that maybe helpful.


The EGR will not opperate under 2000 RPM or before the engen reaches opperateing temp. there also has tobe a moderit load on the engen. The computer works the EGR by grounding the ege control solenoid (yellow wire pine 52 on the computer) and the EGR purge soleniod (dark green pine 33 on the computer). These 2 solenoids are 1 part and located on passinger side between the air cleaner and fender. Red plastic vac line is vac feed from intake. green opperates the EGR.

 

[seth959ci]

thanks for the input, just picked up a DVM, so ill give it a whirl tomorrow

 

[seth959ci]

how do you measure voltage at the ecu? ive never tried it.

 

[jmcleek]

There is a plasic cover on the back of the plug that the bolt that holds the plug to the computer goes through, it has 4 tabs that holds it on. remove it and look for the same wire you checked under the hood. Ues a pin to get through the wire insolation.

ECU pin out http://oldfuelinjection.com/?p=35


Hear another like for you http://oldfuelinjection.com/?p=35