Dis Diagnosis Equipment; Dis Diagnosis Procedure - Ford VSG-411 Service Manual

26-05 Ignition System
26-05
DIAGNOSING AND TESTING DIS
DIS
DIAGNOSIS EQUIPMENT
To accurately diagnose DIS, certain diagnostic equipment and
tools are required: In addition, the suggested diagnostic equip-
ment may make the job easier and more convenient.
Prior to diagnosing DIS, obtain the following test equipment or
equivalent.
l
DIS diagnostic harness PPOlll429 or equivalent
l SPARK TESTER, NEON BULB TYPE (CHAMPION CT-336
OR EQUIVALENT)
There is no need to disconnect a plug wire: just place this spark
tester on a spark plug wire to determine if spark is being provided
to the plug. This is especially useful for those hard to reach plug
wires.
. SPARK TESTER. GAP TYPE (SPECIAL SERVICE TOOL
D81P-6666-A OR EQUIVALENT)
Connect this gap type spark tester between anv spark plug wire
and engine ground to instantly determine if spark is being pro-
vided to the plug. A spark plug with a broken side electrode is not
sufficient to check for spark and may lead to incorrect results.
l
VOLT-OHMMETER (ROTUNDA 014-00575 OR
EQUIVALENT)
A volt-ohmmeter is essential for gathering system operating data
during diagnosis, testing, and engine servicing procedures. This
digital volt-ohmmeter (DVOM)+can also be used for general
purpose electrical troubleshooting on conventional starting and
charging systems.
FIG. 10 Volt-Ohmmeter
l
12-14 VOLT TEST LAMP
TIMING LIGHT (ROTUNDA 059-00006 OR EQUIVALENT)
This timing light uses an inductive pickup for convenience and
safety on 12 volt systems. This timing light includes a tachometer
which reads from zero to 3000 RPM (Figure 11).
Identify the engine harness Ford part number and use the follow-
ing electrical harness part number sketch that corresponds to the
engine harness part number being checked.
FIG. 11 Timing Light
The first check will test the engine harness, connectors and
sensors for both continuity and resistance.
1. Remove the 12 pin UESC harness plug from the UESC
module. Pins 1 and 5 are not used, therefore, do not have
' female connectors in the 12 pin harness connector plug.
2. Check the following circuits with the voit-ohmmeter (with
the sensors connected) per the following chart with
reference to pages; 2B-06 through 2B-15.
If the DIS Engine Harness checks are not to the chart
specifications (page 2B-Lil),, complete the following:
l Remove the wire harness connector to the UESC
l Remove each sensor or component from the harness
l Using a high impedance digital volt-ohmmeter (DVOM)
check each wire for continuity or resistance (ref. 2B-A)
for wire numbers & coiors for the harness being used.
l If the wire harness has open circuits or resistance higher
than specifications repair or replace the harness.
l If the wire harness checks are to specifications - reconnect
each sensor and component and complete another DIS
Engine Harness check (ref. page 2B-/i\)
l If the same sensor or component circuit does not test to
specifications -
replace that sensor or coil.
l If the engine will not start and/or run install a new module
and make a normal start.
A
1 Use the electricai sketch that corresponds to harness part
number reference pages 2B-06-2B15 and
fold-out page.