Quick Test

Fig. 41 Quick Test Connections:

NOTE: When performing this test, make sure that the air intake hose between the air flow sensor and the turbocharger is connected, otherwise no EGR signal will be sent to the EDS control unit.

1. Connect on-off ratio tester, Fig. 41, press the 100% IR button, and run engine at 1200 rpm for at least 5 seconds.
2. Check the operation of the gauge by momentarily touching test lead 1, Fig. 41 to battery ground. Needle should sweep the scale and then return to 0%.
3. Increase engine speed above 1200 rpm for at least 5 seconds, if no problem is present, the tester will read 0%. If there is a problem present, the needle will be at 100%.
4. If the meter stays at 100%, momentarily touch test lead 1, Fig. 41 to battery ground.
5. After the test lead is removed from ground, the needle on the on-off ratio tester should go to 0% and start to sweep at regular intervals, ending at 100%. A movement from 0% to 100% to 0% constitutes one sweep. Count each sweep and see chart below for needle sweep vs faulty circuit comparison. For test proceedures see appropriate section under "QUICK TEST RESULTS" section.



Number of needle sweepsAreas to be checked


1 RPM sensor
2 Fuel rack position sensor
3 Air flow sensor, electrical fault
4 Altitude correction capsule
5 EGR circuit - electrical and mechanical faults***
a. EGR valve
b. Vacuum transducer
c. Air flow sensor
8 Coolant temperature sensor
9 Air temperature sensor, in air flow sensor
10 Reference resistor, EGR
11 Trimming plug, electronic idle speed control

***Reading only at 1200 rpm at least 5 seconds