F 150 4WD Pickup V8-302 5.0L (1986)
Ignition Control Module: All Technical Service Bulletins
Engine - Spark Knock Diagnostic Procedure
Article No.
93-13-10
06/23/93
SPARK KNOCK - SERVICE BAY DIAGNOSTIC SYSTEM PROCEDURE - THICK FILM IGNITION SYSTEM (TFI) - 1985-93 VEHICLES WITH
5.0L EFI ENGINES AND 1988-93 5.8L EFI ENGINES
LIGHT TRUCK:
1985-93 BRONCO, ECONOLINE, F-150-350 SERIES
ISSUE:
Spark knock may be caused by variability in ignition PIP (Profile Ignition Pick-up) output due to a combination of engine torsional vibrations and
distributor electrical characteristics. A spark advance spike is generated which repeats every eight firings.
ACTION:
Perform the following Service Bay Diagnostic System procedure and, if necessary, replace the distributor.
NOTE:
THE FOLLOWING SBDS PROCEDURE MUST BE USED TO VERIFY IF THE SPECIFIED CONDITION EXISTS ON A GIVEN EFI/TFI
5.0L/5.8L ENGINE. DISTRIBUTORS ON ENGINES THAT HAVE A DETONATION CONCERN AND THAT DO NOT PASS THE SBDS TEST
MUST BE RETURNED THROUGH WARRANTY WITH A "BEFORE AND AFTER" PRINTOUT OF THE SBDS IGNITION GRAPH (WITH THE
SPIKING CLEARLY SHOWN) TO QUALIFY FOR REIMBURSEMENT.
SERVICE BAY DIAGNOSTIC SYSTEM PROCEDURE
1.
Use SBDS 60 pin roadtest monitor/record. Select parameters PIP and Spout.
2.
Start the warm engine and idle for at least two (2) minutes to allow EEC IV to learn and correct for normal PIP variance.
a.
Record data using PVA pendant.
b.
Store the data in a buffer.
3.
Upload the data to the Cart and go to the playback graph mode.
4.
Select Digital PIP and analog spark. Move the cursor to the smoothest (least noise) section of the spark curve, Figure 1.
