MCU - Quick Test Revision
Article No. 86-25-11MCU - QUICK TEST - 5.8L POLICE/CANADIAN TRAILER TOW VEHICLES
FORD 1984-87 FORD
LINCOLN-MERCURY 1984-87 MERCURY
The MCU Quick Test has some directions that could cause a wrong diagnosis. Following is a revision to the MCU Emission Diagnosis Shop Manual, Page 23-18, Test 6 to aid in proper diagnosis. This revision needs to be added to your Manual.
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: "INFORMATION ONLY"
Quick Test
6
TEST STEP RESULT ACTION TO TAKE
6.0 SPARK KNOCK, ONLY AT WIDE
OPEN THROTTLE, AND/OR POOR
PERFORMANCE/MILEAGE.
PERFORM STEP 6.3 ON VEHICLES
WITH KNOCK SENSOR ONLY
^ Disconnect knock sensor. Yes RECONNECT
ignition module, and
^ Verify initial timing per emission decal. go to Step 6.1
- Reset to correct timing if necessary.
^ Verify vehicle is at normal operating No REPLACE ignition
temperature. module, and repeat
- Disconnect the two wire ignition all of Step 6.0
module connectors (yellow wire,
Circuit 324 and black/white
wire, Circuit 60) from vehicle
harness.
- Jumper these two wires together at
the ignition module.
- Read and record ignition timing.
^ Remove jumper wire.
- Reread ignition timing.
^ Did timing retard 16-20 degrees when jumper was removed?