Idle RPM spec — cold vs. warm engine

Tags: #cold-start

Cold-start idle and warm-up curve (one report). One community discussion gives FAW X80 normal cold-start idle as 1000-1100 RPM, dropping to 700-800 RPM once the engine is fully warmed. A variation of ±100 RPM around these figures is considered normal. The stated mechanism: cold air has higher oxygen content, so the engine runs a richer mixture and a higher idle speed at start; RPM gradually decreases as coolant temperature climbs toward 90°C¹²³⁴⁵⁶.

Warm idle and "weak idle" threshold (separate, later report). A separate, later discussion gives somewhat lower figures: normal cold idle around 800 RPM, with warm idle 700-750 RPM considered acceptable, and a broader normal band of 600-1000 RPM depending on how warmed-up the engine is. Idle below 600 RPM is flagged as weak/abnormal. This source also notes the dashboard tachometer display is less precise than the actual RPM, and that slight idle fluctuation is normal⁷⁸⁹¹⁰. Conflict: the two reports disagree on the cold-idle figure (1000-1100 RPM vs. ~800 RPM) — this may reflect different ambient temperatures, engine variants, or simply different owners' dashboards/tachometers; both agree the idle drops as the engine warms and that some fluctuation is normal.

Related pages

• Cold start and fuel pressure troubleshooting
• Manual transmission — cold start and clutch
• Engine oil — spec, viscosity, and brands
• Engine operating temperature and fan engagement
• Cold-start hard cranking — LPG and valve clearance

Sources

This page is compiled from 10 community messages. Every fact carries a numbered reference to its original author and message.

Last updated: 2026-07-24