Mechanics

SERVICE SOON ENGINE LIGHT ON

1998 Ford Escort

Engine Performance problem
1998 Ford Escort 4 cyl Two Wheel Drive 132, 01 miles

My service soon engine light came on.
I changed the gas cap and upgraded my gas for two fill ups. The light never went off.
Had a dignostic test done, The code was P0401. EGR System Insufficient Flow Detected.
The Differential pressure feed back unit was repleased.
Also a poor vacumm hose was found in the PCV system. Replaced hoses and PCV Vale. After driving the vehicle about 30 miles the service soon engine light back on.
Could you please tell me wear the problem might be.
My vehicle has an Electronic Fue Inj
Thanks

Rick
Avatar
Rick1944
October 18, 2008.




Read code again and if you get the egr again then test egr valve and the egr selonoid here is the way to test and if eather one false testing replace

Operation

The Exhaust Gas Recirculation (EGR) system is designed to reintroduce small amounts of exhaust gas into the combustion cycle, thus reducing the generation of Nitrous Oxides (NOx). The amount of exhaust gas reintroduced and the timing of the cycle varies by calibration and is controlled by various factors such as engine speed, altitude, engine vacuum, exhaust system backpressure, coolant temperature and throttle angle.

A malfunctioning EGR valve can cause one or more of the following:

Detonation
Rough idle or stalling on deceleration
Hesitation or surge
Abnormally low power at wide-open throttle
COMPONENT TESTING

Before performing any test on the EGR system components, make sure the hoses are not kinked or damaged, any electrical connection are loose, corroded or damaged.

Exhaust Gas Recirculation (EGR) Valve

See Figure 1
Fig. 1: Some EGR valves may be tested using a vacuum pump by watching for diaphragm movement
Start the car and let the engine reach normal operating temperature.
Turn the engine OFF and connect a vacuum tester (pump) to the EGR valve vacuum source port.
Turn the engine ON and idle the engine.
Slowly apply 5-10 in. Hg (16-33 kPa) of vacuum; if the engine idles roughly or stalls, the EGR valve is functioning properly.
If the engine does not idle rough replace the EGR valve.
EGR Vacuum Regulator (EVR) Solenoid

See Figure 2
Fig. 2: EVR solenoid wiring schematic
Unplug the EVR solenoid electrical connection.
Using a high impedance Digital Volt Ohmmeter (DVOM), probe the terminals of the solenoid.
The resistance should be 20-70 ohms on 1991-96 models, or 26-40 ohms on 1997-99 models.
There are two types of EVR solenoids used. One is a normally open solenoid and the other is a normally closed solenoid. Follow both testing procedures to determine which type of solenoid you are testing.

For a normally open solenoid, test it as follows:
Trace the hose that runs from the solenoid to the EGR valve and unplug the hose from the solenoid.
Using a hand pump, apply 10-15 in. Hg (33-50 kPa) of vacuum to the solenoid. The vacuum should hold.
Apply 12 volts to the solenoid and the vacuum should be released.
For a normally closed solenoid, test it as follows:
Trace the hose that runs from the solenoid to the EGR valve and unplug the hose from the solenoid.
Using a hand pump, apply 10-15 in. Hg (33-50 kPa) of vacuum to the solenoid. The vacuum should not hold.
Apply 12 volts to the solenoid, then re-apply 10-15 in. Hg (33-50 kPa) of vacuum and it should hold.
If the solenoid does not meet the specifications outlined in the tests, it may be defective and must be replaced.
Pressure Feedback Electronic (PFE)/Differential Pressure Feedback Electronic (DPFE) EGR System

See Figure 3

The PFE type system is a subsonic, closed loop EGR system that controls EGR flow rate by monitoring the pressure drop across a remotely located sharp-edge orifice. With a PFE system, the EGR valve only serves as a pressure regulator, rather than as a flow metering device. The Differential Pressure Feedback EGR (DPFE) system operates in the same manner, except that it also monitors the pressure drop across the metering orifice. This allows for a more accurate assessment of EGR flow requirements.

Fig. 3: PFE/DPFE sensor wiring schematic
Unplug the PFE/DPFE sensor electrical connection.
Turn the ignition key to the ON position, but do not start the engine.
Using a high impedance Digital Volt Ohmmeter (DVOM) set to read voltage, probe the DPFE/PFE terminal of the sensor. The voltage should be approximately 0.45 volts.
Using a hand held vacuum pump, apply 8-9 in. Hg (27-30 kPa).
The voltage should be above 4 volts.
Quickly release the vacuum from the sensor and the voltage should drop to less than one volt in three seconds.
If the readings are not as specified, the sensor may be defective and should be replaced.
REMOVAL & INSTALLATION

EGR Valve

Loosen the Exhaust Gas Recirculation (EGR) valve-to-exhaust manifold tube nut at the valve.
Unplug the EGR valve hose.
Unfasten the EGR valve bolts.
Remove the EGR valve and gasket.
Clean the old gasket material from the EGR valve mounting surface.
To install:

Install a new gasket and the EGR valve.
Tighten the valve retaining bolts and connect the hose.
Tighten the EGR valve-to-exhaust manifold tube nut at the valve.
EGR Vacuum Regulator (EVR) Solenoid

Disconnect the negative battery cable.
Unplug the EVR solenoid's electrical connection.
Tag and disconnect the hose(s) from the EVR solenoid.
If equipped, loosen the retainers and remove the EVR solenoid.
Installation is the reverse of removal.
Pressure Feedback Electronic (PFE)/Differential Pressure Feedback Electronic (DPFE) Sensor

Disconnect the negative battery cable.
Unplug the PFE/DPFE sensor electrical connection.
Tag and disengage the hose(s) from the sensor.
Unfasten the retainers and remove the sensor.
Installation is the reverse of removal.
Fig. 1


http://www.2carpros.com/forum/automotive_pictures/52960_0900c1528008dc1b_1.jpg


Fig.2


http://www.2carpros.com/forum/automotive_pictures/52960_0900c1528008dc1c_1.jpg


Fig.3


http://www.2carpros.com/forum/automotive_pictures/52960_0900c1528008dc1d_1.jpg


Jnovack
Oct 18, 2008.


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