Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSPONTIAC1987SUNBIRD BASE, 4D SEDAN, AUTOMATICREPAIR AND DIAGNOSISENGINE PERFORMANCEIGNITION SYSTEMIGNITION SYSTEM - HEI-ESTTESTINGESC PERFORMANCE CHECK
1987 Pontiac Sunbird Base, 4D Sedan, Automatic
ESC Performance Check
1987 Pontiac Sunbird Base, 4D Sedan, AutomaticSECTION ESC Performance Check
NOTE:
Perform these checks only after checking ignition timing, MAP, EGR operation or if engine overheats.
- Connect tachometer to engine. Place shift lever in "P" (auto. trans.) or NEUTRAL (man. trans.). Run engine at fast idle (about 1500 RPM). With engine at normal operating temperature, tap engine block in area of detonation sensor. If RPM drops, system is operating properly.
- If RPM does not drop, disconnect ESC controller (located in engine compartment) and check for RPM change. If there is no change in RPM, proceed to step 5). If RPM drops, run engine at 2000 RPM. Unplug controller harness. Connect a digital voltmeter between ESC harness connector terminals "E" and "D". Voltage should not exceed .08 volts on the AC scale.
- If voltage reading is correct, problem is a faulty ESC connection or ESC controller. If voltage is not correct, check for an open in wire from ESC controller connector terminal "D" to ground.
- Repair wire if an open is found. If no open wire is found, check for an open or poor connection between detonation sensor and ESC controller connector terminal "E". If circuit is okay, replace detonation sensor.
- Inspect "CHECK ENGINE" light. If light is on, problem is most likely a faulty ESC controller or detonation sensor. If light is off, turn ignition switch to "ON" position (engine not running) and check voltage from ground to ESC terminal "C".
- If voltage is under 2 volts, replace ECM. If voltage is over 2 volts, repair short in wire from ESC terminal "C" to ECM terminal "L".
NOTE:
A knock sensor-to-controller wire that is routed too close to spark plug wires may cause retarded timing due to a false signal.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.