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 MANUALSSAAB1987900 BASE, 2D HATCHBACK, 2.0 J, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMFUEL INJECTION SYSTEM - CIS (8-VALVE)TESTINGPREPARATIONCONTROL PRESSURE (WARM ENGINE)
1987 Saab 900 Base, 2D Hatchback, 2.0 J, Automatic
Control Pressure (Warm Engine)
1987 Saab 900 Base, 2D Hatchback, 2.0 J, AutomaticSECTION Control Pressure (Warm Engine)
- Connect plug to control pressure regulator. Leave auxiliary air valve sensor plugs disconnected (if equipped). Place valve for pressure gauge in open position and operate fuel pump.
- After about 5 minutes, control pressure should rise to specified level. See CIS (LAMBDA) FUEL PRESSURES table. On models with vacuum hose connected to control pressure regulator, leave hose connected to read pressure.
- Start engine and allow to idle. Pressure should remain same or rise slightly. On models with control pressure regulator vacuum line, remove and plug hose. Pressure should drop.
- If pressure does not reach level specified, disconnect plug at control pressure regulator. Check for voltage across terminals with test lamp or voltmeter. At least 11.5 volts should be present. If not, check wiring. If voltage is present and pressure is not correct, replace control pressure regulator.
CIS (LAMBDA) FUEL PRESSURES
| Application | Specification | |||||
|---|---|---|---|---|---|---|
| Saab 900 | ||||||
| System Pressure psi (kg/cm2 ) | 68-78 (4.7-5.4) | |||||
| Control Pressure (Warm)(1) psi (kg/cm2 ) | 50.55 (3.4-3.8) | |||||
| Residual Pressure psi (kg/cm2 ) | (2) 22 (1.5) | |||||
| Injector Opening Pressure psi (kg/cm2 ) | 44-55 (3.0-3.8) | |||||
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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.