Diesel Engine - Hard Start/No Start Condition
Article No.98-4-20
03/02/98
ENGINE - 6.9L - GLOW PLUG CONTROL SYSTEM UPGRADE
LIGHT TRUCK:
1983-86 E-350, F-250, F-35O
ISSUE:
A no start or hard start condition may occur on some vehicles due to the glow plug control system.
ACTION:
Replace the glow plug control system with a revised glow plug control system. Refer to the following Service Procedure for engine-to-body harness retrofit details.
SERVICE PROCEDURE
NOTE:
FOR ALL APPLICATIONS INSTALL EIGHT (8) GLOW PLUGS (F2TZ-12A342-A), ENGINE WIRING HARNESS, AND MODULE RELAY. REFER TO FIGURE 1 FOR LOCATIONS AND PROPER HARNESS ROUTING.
WAIT LAMP
If 1983 vehicle with latching and after glow relay:
1. Locate latching relay under dash (approximately 152 mm (6") passenger (right) side of steering column and approximately 51 mm (2") right of diesel lights warning module). Reference 1983 Electrical and Vacuum Troubleshooting Manual (EVTM).
2. Using a jumper wire, jump Pin 2 (orange) with Pin 5 (black with pink stripe) (Figure 2).
3. Leave remaining pins open (Figure 2).
If late 1983 or 1984 and later vehicle (no latching relay, Wait lamp on every time glow plugs energized):
1. Remove blue wire from power relay (right inner fender well) and install it on the electronic module terminal that feeds the glow plugs.
2. Remove blue wire from chassis-mounted power relay and install on engine-mounted control module glow plug feed terminal (Figure 3).
AT CHASSIS-MOUNTED POWER RELAY (Right Inner Fender)
1. Connect power lead (black with yellow dots on early 1983 or red on late 1983 or 1984 and later) on the same post as the glow plug lead wires. This now makes the glow plug lead wires the battery supply for the Solid State System. These are the wires on the two (2) large posts (Figure 4).
2. All that the vehicle-mounted power relay is being used for is a junction block. Remove and tape back all other leads. Remember the blue wire on late built 1983 or 1984 and later vehicles was removed in the previous Step (Figure 4).
ENGINE-TO-CHASSIS HARNESS CONNECTORS
Early 1983 vehicle with latching relay:
Remove 8-way connector from engine harness supplied with new 7.3L engine. Remove connector on old engine and put the following wires in the appropriate locations (on new solid state wiring harness) (Figure 5).
Late 1983 or 1984 and later vehicle:
Has 8-plug connector already on chassis. From engine harness, remove fuel heater lead and wait-to-start light lead (Figure 6).
FUEL HEATER
Tape connector provided with solid state engine harness back into harness and use connector provided in chassis harness.
TEMPERATURE SENDERS
On early 1983 vehicles, they are provided with the chassis harness. Use these and tape leads back into harness.
On late 1983 and 1984 vehicles (eight (8) wire plugs only), all sender wires will be utilized.
PART NUMBER PART NAME
F2TZ-12A342-A Glow Plugs (8 Req'd.)
FOTZ-12B533-A Module Relay
E7TZ-9A451-A Engine Wiring Harness
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 602300, 603300