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.
1991 Audi 100 BaseFACTORY OEM SERVICE PROCEDURE
Idle Speed, Co Level & Ignition Timing
Ensure idle speed and ignition timing are within specification. See the IDLE SPEED & CO LEVEL SPECIFICATIONS and IGNITION TIMING tables. For adjustment procedures, see the appropriate ADJUSTMENTS article in this section.
IDLE SPEED & CO LEVEL SPECIFICATIONS
| Application | Idle RPM | CO Level % | |
|---|---|---|---|
| 2.2L | |||
| A/T | 670-770 | .3-1.2 | |
| M/T | 750-850 | .3-1.2 | |
| 2.3L | |||
| Checking Value | 720-860 | .3-3.0 | |
| Adjusting Value | 720-860 | .6-1.0 | |
| 2.8 L V6 (Checking Value) | 720-860 | .3-1.2 | |
IGNITION TIMING
| Application |
Degrees BTDC @ RPM | |||
|---|---|---|---|---|
| 2.2L | ||||
| A/T | TDC @ 670-770 | |||
| M/T | TDC @ 750-850 | |||
| 2.3L | ||||
| Checking Value | 13-17 @ 720-860 | |||
| Adjusting Value | 14-16 @ 720-860 | |||
| 2.8L V6 | (1) * | |||
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Factory Service Tools
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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.