Engine Controls - Hard Start/Long Cranking Time
Article No.3-21-32
10/06/03
HARD START/LONG CRANK - VEHICLES EQUIPPED
WITH AFTERMARKET MODIFICATIONS AND 7.3L
DIESEL ENGINE
FORD:
1997-1999 ECONOLINE
Article 98-26-9 is being republished in its entirety as part of a consolidated 7.3L diagnostic aid booklet.
ISSUE
Some vehicles equipped with aftermarket modifications may exhibit a crank but no start or a hard start/long crank condition. Some 7.3L Econolines with aftermarket modification to the electrical systems may exhibit "chattering" of the Injector Driver Module (IDM) relay. This may be caused by modifications to the vehicle which may not provide enough electrical current to maintain the function of the IDM relay.
ACTION
Run a dedicated power source to Pin 85 of the IDM relay. This action will isolate the IDM relay power circuit from any circuits that may have aftermarket equipment connected to them. Refer to the following Service Procedure for details.
SERVICE PROCEDURE
1. Check for 12V at Pin 87, Circuit 876 in Start or Run, and during cranking. If 12V is present in Start, Run, and during cranking, proceed with normal diagnostics. If 12V is not maintained during cranking, proceed to Step 2.
2. Check Powertrain Control Module (PCM) ground wire connection for corrosion or poor contact. Ground in the circuit is G101 on Page 151-10 at location E1 in the 1998 and 1999 Econoline Electrical and Vacuum Troubleshooting Manual (EVTM). Ensure proper contact. If concern is not resolved, perform Step 3.
3. Run a 10 gauge wire from the starter motor relay post (Battery +) to the engine compartment fuse box.
4. Install a 30 amp sealed fuse in the 10 gauge wire.
5. Cut the wire that attaches to Pin 85 of the IDM relay (Relay F) in the engine compartment fuse box ensuring that enough wire is left to splice in the new 10 gauge wire from Step 2. The wire to be cut is Circuit 361 (non-electric fuel pump) or Circuit 16 (electric fuel pump).
6. Attach the new 10 gauge wire to Circuit 361 (non-electric fuel pump) or Circuit 16 (electric fuel pump) using solder and heat shrink tubing. Cover the unused end of Circuit 361 or Circuit 16 with heat shrink tubing to prevent shorts.
7. Secure all wiring and test vehicle ensuring that 12V is present at Pin 87, Circuit 876 in Start, Run, and during cranking.
OTHER APPLICABLE ARTICLES: NONE
SUPERSEDES: 98-26-9
WARRANTY STATUS: INFORMATION ONLY
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