Correction

Replace the Fuel Solenoid Driver, after completing the following steps:

1. Check the fuel system for air, fuel pressure and fuel flow. Refer to Engine Controls in the 1998 model year Service Manual for all model years.

2. Check Powertrain Control Module (PCM) and Injection Pump wiring harness for chaffing, and/or loose terminals at the PCM connector, 15 pin connector, Injection Pump connector and Fuel Solenoid Driver connector. Refer to Engine Controls in the 1998 Service Manual for all model years.

3. Check all engine and vehicle wiring harness grounds. Refer to Engine Controls in the 1998 Service Manual for all model years.

4. Check for loss of ignition voltage on circuit 339 at the Fuel Solenoid Driver connection to the injection pump. Refer to Engine Controls in the 1998 Service Manual for all model years.

5. Verify that the condition is still present:

a. If the condition is no longer present, the vehicle is repaired.

b. If the condition is still present, and there are active DTC's set, go to Step 6.

c. If the condition is still present, and there are no active DTC's set, go to Step 7.

6. For active DTC's 35 or P1216, refer to Engine Controls in the 1998 Service Manual for all model years. If the DTC diagnostic table flow chart directs you to replace the Injection Pump, replace the Fuel Solenoid Driver only. Go to Step 9.

7. For stall condition, disconnect the Optical sensor and operate the engine in back up fuel (you may experience an extended crank time during engine start - this is normal). If the condition is still present, replace the Fuel Solenoid Driver only. Go to Step 9.

8. For a no start condition, check injection pulse width with a Tech 1 (1994-1995) or fuel solenoid closure time with a Tech 2 (1996-1998) while cranking the engine (ensure that the batteries are fully charged and engine cranking speed is at least 100 RPM during test). If the closure time is 1.95ms (1994-1995) or 0.01ms (1996-1998), replace the Fuel Solenoid Driver. Go to Step 9.

9. Replace Fuel Solenoid Driver.

a. Remove the intake manifold to gain access to Fuel Solenoid Driver (on the left side of the Injection Pump). Refer to Engine Mechanical in the 1998 model year Service Manual for all model years.

b. Scribe a reference mark on the engine front cover and the injection pump housing to assist in correctly locating the Injection Pump during reassembly.

c. Loosen the Injection Pump retaining nuts approximately 1/2 turn, using Injection Pump Timing Wrench J 41089 or J 41711 (do not remove the nuts).

d. Rotate the pump to the passenger side of the vehicle until it stops, using Injection Pump Adjusting Tool J 33042, and re-tighten the top Injection Pump retaining nut, using Injection Pump Timing Wrench J 41089 or J 41711.

e. Disconnect the Fuel Solenoid Driver wiring connector at the injection pump.





f. Loosen the four Fuel Solenoid Driver mounting screws until free of the Injection Pump housing, using a T15 torx bit. (Figure 1).

g. Remove the Fuel Solenoid Driver, heat transfer pad and mounting screws from the Injection Pump. Discard the heat transfer pad and mounting screws.





h. Remove the Fuel Solenoid Driver Calibrating Resistor using snap ring pliers (Figure 2).

Important:
The Calibrating Resistor is specific to the Injection Pump. Do not damage the resistor

The Calibrating Resistor identification number is located on the front of the Calibrating Resistor (Figure 2).

If the calibrating resistor is damaged, it can be replaced by the identically numbered resistor that is available through GMSPO. A driveability issue will occur with the vehicle if an incorrect resistor is installed. If the resistor is lost and it's number is unknown, the injection pump must be taken to a Stanadyne dealer for calibration.

i. Install the Calibrating Resistor in the new Fuel Solenoid Driver using snap ring pliers (Figure 2).

Important:
If the Fuel Solenoid Driver Calibrating Resistor is missing, DTC 56 (1994-1995) or P1218 (1996-1998) will set.

j. Install Fuel Solenoid Driver.

^ Place the new heat transfer pad on the side of the new Fuel Solenoid Driver and insert the four Fuel Solenoid Driver mounting screws into the Fuel Solenoid Driver.

^ Align the Fuel Solenoid Driver mounting screws with the holes in the pump housing and tighten to 2.75 N.m (23 lb in.).

Important:
Do not install the Fuel Solenoid Driver without a new heat transfer pad. Do not reuse a heat transfer pad. Use a new heat transfer pad only. The heat transfer pad is required to prevent rapid failure of the Fuel Solenoid Driver from overheating.

Notice:
Do not over tighten Fuel Solenoid Driver mounting screws. Damage to the Fuel Solenoid Driver will result.

k. Connect the Fuel Solenoid Driver wiring harness connector.

I. Loosen the upper Injection Pump retaining nut approximately 1/2 turn, using Injection Pump Timing Wrench J 41089 or J 41711 (do not remove the nut).

m. Rotate the pump back to it's original position (using the reference mark made previously), using Injection Pump Adjusting Tool J 33042, and tighten the Injection Pump retaining nuts, using Injection Pump Timing Wrench J 41089 or J 41711.

n. Install the intake manifold. Refer to Engine Mechanical in the Service Manual.

o. Perform Injection Timing Adjustment Procedure. Refer to Engine Controls in the Service Manual.