Engine Controls - Poor Driveability/Idle, Engine Surge
86chevy16NUMBER: 86-B-105
GROUP: 6 - Gasoline Engine
DATE: July, 1986
SUBJECT: THROTTLE POSITION SENSOR - HEAT SHIELD SERVICE KIT
MODELS: 1985-86 S/T TRUCKS AND M VANS EQUIPPED WITH THE 2.5L L4 (VIN CODE E) ENGINE
Some 1985-86 S/T models and M vans equipped with the 2.5L L4 engine may experience reduced engine performance, poor idle, and engine surge and may also set a Code 22.
Figure 1 - Heat Shield Service Kit P/N 17111750:
This condition may be caused by an intermittent electrical signal from the throttle position sensor (TPS). If this condition is encountered and the vehicle has been properly diagnosed using the procedures in Section 6E2-C1 of the service manual, replace the TPS with Part Number 17078274 (AC is cast on the housing) and at the same time, remove the factory installed TPS heat shield attached by the EGR bolt and replace it with a new heat shield service kit, Part Number 17111750 (See Figure No. 1). The contents of the service kit are:
Screw Assemblies - 2 Each (Hex Head) Heat Shield - Stainless Steel Graphics - Instruction Sheet
Whenever a new TBI assembly is purchased from WDDGM, check to be sure it includes the AC TPS and the stainless steel heat shield. Units which were not received with these pieces must be retro-fitted to include the new service parts listed above. Use applicable labor time and labor operation numbers.
Figure 1 - Heat Shield Service Kit P/N 17111750:
RECOMMENDED PROCEDURE:
1. REMOVE AIR CLEANER ASSEMBLY
2. REMOVE AND DISCARD OLD HEAT SHIELD ATTACHED TO EGR MOUNTING BOLTS BY REMOVING ONE BOLT ONLY, AND REINSTALL THE BOLT BACK INTO THE EGR. TORQUE TO 34-44 N-m. (25-32 FT.LBS.).
3. REMOVE AND DISCARD OLD TPS ATTACHING SCREWS.
4. INSTALL NEW TPS (1) AND HEAT SHIELD (3) USING NEW ATTACHING SCREWS (2) PROVIDED WITH TPS HEAT SHIELD SERVICE KIT.
^ TIGHTEN ATTACHING SCREWS TO 2.0 N-m.(18 IN.LBS.).
5. INSTALL AIR CLEANER ASSEMBLY