3. Inspect inside of cone area on cup seating ledge for
nicks or burrs which could prevent cup seating.
Injector Barrel - PT (type D) Injectors
1. Inspect injector barrel plunger bore for scoring. If
injector will pass the ST-990 leakage test, barrel is
useable. If leakage is too high barrel and plunger
must be replaced.
2. Use strong magnifying glass to check for burrs,
Fig. 6-1-19, F60107. Corroded injector cup tip
carbon and distorted radii in orifice. When metering
orifice is damaged, the injector will not function
properly. Do not attempt cleaning with wires, plug
gauges, etc.; use solvent cleaners.
3. Check fuel passage plugs for looseness and barrel
4. Check injector barrel surfaces for mutilation and
flatness in black area as shown in Fig. 6-1-24.
a. Thoroughly clean and dry barrel of all oil film before
Fig. 6-1-20, F60108. Seat pattern of plunger In cup
3. Check injector cup barrel surface for mutilation and
b. Using a surface plate (preferably a lapping plate) and
"bluing," check for surface flatness.
a. For mutilation check in area (black area) as shown in
Table 6-1-6: Cup Contact Area of Barrel
b. Using a flat steel plate (preferably a lapping plate)
and "bluing" to check for surface flatness.
If mutilation or unevenness are found, mark for
Fig. 6-1-21, F60161. Cup surface at body contact area
4. PT (type D) injector cups with black finish, are
Fig. 6-1-24, F60191. Barrel surface at cup contact area
interchangeable with "old-style" stainless steel cups.
If mutiliation or unevenness are found, lap to repair.
d. Do not use crocus cloth or wire brush on barrel and
1. Inspect the threads for damage.
cup contact area.
5. If 5/16 type injector has been overheated, the barrel
2. Check outside cone area for nicks or burrs which
to adapter gasket can melt. Loss of injector cup
could prevent proper seating with sleeve in head.
retainer torque will occur; therefore, the following
items should be suspected: