Ignition System - Knock Detector Cable Replacement
88saab09FILE IN S.I. Man VOL. I
SEC. A-3 PG. 111
SUBJECT: REPLACING THE KNOCK DETECTOR CABLE ON THE EZK IGNITION SYSTEM
APPLICATION: 1986 - 88 900S MODELS
ISSUE: 10/88-1085
If EZK ignition system fault tracing indicates that the knock detector cable may be allowing interference or an open circuit the cable can be replaced without replacing the entire engine wiring harness. For EZK fault tracing information see 900 Service Manual Section 3:1.
This procedure outlines how to remove the faulty knock detector cable from the engine wiring harness and then reroute and connect the new cable in the engine compartment.
Parts Required:
Knock Detector Wire PN 95 61 804
Cable Terminal PN 85 71 804
Tool Required:
Electrical Crimping Pliers PN 30 14 222
(Both the cable terminals and the crimping pliers are contained in Electrical Connector Kit 30 05 212)
Knock Detector Wire Removal
1. Disconnect the negative (-) battery lead and cover the terminal post on the battery.
2. Remove the bracket for the EZK system control unit from the fender and unplug the 25 pin connector.
3. Disconnect the bottom hose from the AIC valve.
FIGURE 1 - REMOVING THE INSULATOR STRIP FROM THE 25-PIN CONNECTOR.:
4. Open the 25-pin connector by removing the rubber seal. Then cut off the cable tie and slide back the rubber boot (Figure 1). Remove the single external screw and pull out the connector block. Remove both pin insulator strips (Figure 1).
NOTE
Pin numbers are molded into the connector block.
NOTE
The original knock detector cable on M86 - 87 models has two wires. The replacement procedure is the same as M88 models with the three-wire cable.
FIGURE 2 - DISCONNECTING THE WIRE LEADS.:
5. Disconnect the following leads complete with terminals from the connector block (Figure 2).
Connector Block for M86 - 87 Models
Wire Number 488, Pin 13, GN (Green) Wire Number - , Pin 12, Black (Shielded ground) Wire Number - , Pin 20, Black (Shielded ground)
Connector Block for M88 Models
Wire Number 488, Pin 13, GN (Green) Wire Number 489, Pin 12, BR (Brown) Wire Number - , Pin 20, Black (Shielded ground)
FIGURE 3 - CUTTING OFF THE LEADS.:
6. Cut the terminal off the end of the black wire removed from pin 20 of the connector block. Then strip approximately 10 mm of insulation from the end of the black wire.
7. Cut off the green and brown leads (brown lead only on M88) where they enter the wiring harness sheathing (Figure 3). Cut off the black lead from pin 12 (M86, M87 only) where it enters the harness sheathing. Discard the leads.
FIGURE 4 - CUTTING OFF THE KNOCK DETECTOR WIRE.:
8. Unplug the two-pin connector from the knock detector (Figure 4).
9. Cut off the knock detector wire where it enters the wiring harness sheathing near the starter motor (Figure 4) and remove the wire.
Knock Detector Wire Installation
1. Install the new knock detector wire by first plugging it into the knock detector. Then install tubing such as fuel line over the terminals on the control unit end of the knock detector wire and secure with tape. This prevents damage to the terminals and facilitates routing of the harness.
FIGURE 5:
2. Run the knock detector wire alongside the engine harness at the starter motor See Figure 5).
3. Secure the detector wire with cable ties (Figure 5), but do not overtighten them. Overtightening can damage the coaxial knock detector wire.
4. Pass the end of the wire lead through the rubber boot and the connector cover. Remove the tubing and tape from the terminals. NOTE
Pin numbers are solded into the connector block.
FIGURE 6 - FITTING THE WIRE LEADS.:
5. Install the green and brown wires in the connector block (See Figure 6).
6. Cut the terminal off the end of the black wire in the new knock detector harness. Then strip approximately 10 mm of insulation from the end of the black wire.
7. Insert both the black wire from the engine harness (previously stripped during knock detector wire removal) and the black wire from the new knock detector harness together in cable terminal PN 85 71 804. Crimp both wires securely in the terminal with electrical crimping pliers PN 30 14 222.
FIGURE 6 - FITTING THE WIRE LEADS.:
8. Install the terminal with the two black wires into the connector block as shown in Figure 6.
FIGURE 7 - REFITTING THE PIN INSULATOR STRIPS.:
9. Install the pin insulator strips in the connector (Figure 7). Push the connector block inside the cover and secure the connector block with its screw. Slide the rubber boot into position and secure with a cable tie. Install the rubber seal.
10. Plug the connector into the control unit for the EZK system and bolt the control unit bracket to the fender.
11. Reinstall the bottom hose on the AIC valve.
12. Reconnect the battery.
13. Test drive the car and ensure that the EZK system is functioning properly.
Warranty Information: For warranty claims, use Failure Coding 37130-63-0- 01-05. Labor allowance is 0.8 hour in straight time.