Engine - Erratic Idle, Loss of Power, or Stalling
90porsche08 May 15, 1990Subject: Engine, Inconsistent Performance
Model Group
911 C2/911 C4 2
Part Identifier Number
24../9750 9005
ATTENTION: Service Manager/Service Technician
This bulletin replaces Technical Bulletin Group 2, Number 9005, dated April 6, 1990.
Models Affected: 911 Carrera 2 and 911 Carrera 4, Model Years 1989 (K) and 1990 (L)
Concern: Inconsistent acceleration, erratic idle, loss of power or engine dies.
Possible Cause: The air flow meter wiring harness protective cover (Figure 1) contacts the engine ventilation hoses (Figure 2) causing current flow interruptions on the plug terminals.
Vehicle Information: The protective cover on the air flow meter wiring harness plug was discontinued from production date February 13, 1990.
VIN's 96 - LS 45 1659 Coupe 96 - LS 46 0409 Targa 96 - LS 47 1072 Cabriolet
Repair Information: 911 Carrera 2 model year 1990 and 911 Carrera 4 model years 1989 and 1990 prior to the above VIN's should be modified when the engine is removed or when working on the air flow meter, even if no engine performance problems are present.
Work Procedure: 1. Remove air filter housing cover and filter.
Figure 6:
2. Push down locking spring on air flow meter wiring plug and disconnect plug (arrow in Figure 6).
3. To gain access to plug, pull wiring harness with plug between air flow meter and idle stabilizer towards rear of vehicle.
Figure 3:
4. Pull back rubber boot and cut protective wire covering using side cutter or similar tool (arrow in Figure 3).
Figure 4:
5. Heat protective wire covering with hot air blower to maximum 110~ C (230~ F). Pull off and discard protective wire covering (Figure 4).
Figure 5:
6. Reinstall rubber boot on plug housing. Loop wiring harness along side of plug and tie wrap as shown in Figure 5.
Figure 6:
7. Reconnect wiring plug. Make sure spring lock is engaged. Figure 6 shows wiring plug connected (engine removed).
Important: Do not use contact spray.
Figure 7:
Work Procedure: 8. Check clearance between wiring harness and vent hoses.
(continued) Distance should be at least 15 mm. If necessary, bend bracket
on right shock absorber mounting slightly forward (arrow in Figure 7). Make sure vent hoses are properly installed on bracket at shock absorber mounting and on bracket in front of air flow meter. The small diameter hose must be routed below the large diameter hose, 9. Reinstall air filter and filter housing cover.
Figure 8:
10. Mark air flow meter with a black paint dot as shown in Figure 8.
Parts Information: Tie wrap: PN 999 513 021 40
Labor Information: Labor Operation: 97 50 19 OA
Damage Code: 97 50 40 000 1
Time Units: Engine installed - 80 Engine removed - 20