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.
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HOMESERVICE MANUALSPONTIAC1987FIREBIRD BASE, 2.8 S, AUTOMATICREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSIS1987-88 COMPUTERIZED ENGINE CONTROLSSCAN TESTER - TEST DATA PARAMETERS
1987 Pontiac Firebird Base, 2.8 S, Automatic
Scan Tester - Test Data Parameters
1987 Pontiac Firebird Base, 2.8 S, AutomaticSECTION Scan Tester - Test Data Parameters
NOTE:
Information in the following table is typical readings taken on vehicle with engine idling, upper radiator hose hot, closed throttle, transmission in Park or Neutral, "closed loop" status achieved and all accessories off (except as noted in tables). Data parameters are updated every 1 1/4 seconds. On systems using P-4 computers, parameter updates are virtually instantaneous. Not all devices & systems are used on all models.
THROTTLE BODY INJECTION
| Tester Position | Units Measured | Nominal Data Value |
|---|---|---|
| A/C Clutch | On/Off | Off (On with A/C). |
| A/C Request | Yes/No | No/Yes (with request). |
| AIR Divert Sol. | On/Off | On (air to switching sol.). Off (air to atmosphere). |
| AIR Switching Sol. | On/Off | On (to exhaust manifold). Off (to catalytic converter). |
| BARO | Volts | 3-4.5. |
| Battery Voltage | Volts | 13.5-14.5. |
| Block Learn | Counts | 118-138 (128 normal). |
| Brake Switch | On/Off | On when engaged. |
| Canister Purge Sol. | On/Off | On/engine cold (idle some). |
| Clear Flood | On/Off | ***See tester manual**. |
| Coolant Fan | On/Off | Off below 216°F (102° C). |
| Coolant Temp. | °C | 85-105° (norm.temperature). |
| Crank RPM | RPM | 100-900 |
| Cross Counts | Counts | 0-255. |
| Cruise Cont. Sw. | On/Off | when engaged. |
| EGR Solenoid | On/Off | On when energized. |
| EGR Duty Cycle | 0-100% | 0/closed-100/fully open |
| Fan Relay | On/Off | On when energized. |
| Fan Request | On/Off | On with request. |
| Fuel Backup | Yes/No | Yes when engaged. |
| IAC | Counts | 0-50. |
| Ignition/Crank | On/Off | On with ignition/crank. |
| Injector Pulse Width | Mil./Sec | .8-3.0. |
| INT (Integrator) | Counts | 110-145 (128 normal) |
| Knock Retard (ESC) | Counts | 0-255. |
| Knock Signal | Yes/No | Yes when knock exists. |
| MAT Temperature | °C | 10-90°. |
| MAP | Volts | 1 (idle) to 4.5(WOT). |
| Open/Closed | N/A | Closed/Open during |
| Loop Status | Ol/Cl | extended idle. |
| O2 Sensor | Millivolts | 100 (lean) to 999 (rich) |
| P/N Switch | P/N/RDL | Park/Neutral. |
| P/S Switch | Norm/Hi | Normal. |
| PROM I.D. | PROM # | Original factory number. |
| RPM | RPM | Spec. +/-25 RPM Drive (Auto.). Spec. +/-50 RPM Neut. (man.). |
| Spark Advance | # of Deg. | Varies. |
| TCC | On/Off | Off (On with command). |
| TPS | Volts | 1.25 (idle) to 5.0 (WOT). |
| Throttle Angle | 0-100% | 0 (idle) to 110 (WOT). |
| Trouble Codes | Code # | No Codes. |
| Turbo Boost | On/Off | On when activated. |
| Upshift Light (Man. Trans.) | On/Off | Off |
| VSS | MPH | 0-actual. |
| 3rd Gear Switch | On/Off | On/3rd & 4th gear. |
| 4th Gear Switch | On/Off | On/4thgear. |
RENDER: 1.0x
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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.