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.
1990 Audi 100 Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Engine Compression
Check engine compression with engine at normal operating temperature at specified cranking speed, all spark plugs removed (on dual plugs, remove exhaust side only) and throttle wide open.
NOTE:
Connect coil high tension wire to ground before cranking engine for compression test.
4-CYLINDER COMPRESSION SPECIFICATIONS
| Application | Specification | |
|---|---|---|
| Compression Ratio | 10.4:1 | |
| Compression Pressure | ||
| Normal (New Engine) | 152-196 psi (10.7-13.7 kg/cm2 ) | |
| Minimum | 109 psi (7.7 kg/cm2 ) | |
| Maximum Variation Between Cylinders | 44 psi (3 kg/cm2 ) | |
5-CYLINDER COMPRESSION SPECIFICATIONS
| Application | Specification | ||
|---|---|---|---|
| Compression Ratio | |||
| 2.2L Turbo | 7.8:1 | ||
| 2.3L | 10.0:1 | ||
| Compression Pressure | |||
| 2.2L Turbo | |||
| Normal (New Engine) | 100-130 psi (7-9 kg/cm2 ) | ||
| Minimum | 72 psi (5 kg/cm2 ) | ||
| 2.3L | |||
| Normal (New Engine) | 145-203 psi (10.2-14.3 kg/cm2 ) | ||
| Minimum | 116 psi (8.2 kg/cm2 ) | ||
| Maximum Variation Between Cylinders | 44 psi (3 kg/cm2 ) | ||
Factory Service Tools
Use the Manual With the Right Hardware
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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.