Crank No Start in Cold Weather - Weak Battery / Low CCA

Electricalbeginner✓ OP Confirmed

Problem

1988 7MGE Supra cranks but will not start in cold Michigan winter temperatures (around -5°F). Engine cranks for extended periods (30+ seconds) without even sputtering. Previously required a jump start and had a rough start.

Engine cranks but does not fire in cold weatherNo sputtering at all during extended crankingPreviously needed a jump startBattery voltage dropping very low during cranking

Root Cause

The original battery (from 2019) only had 590 cold cranking amps, which was insufficient for cold weather starting. In sub-zero temperatures, the battery voltage was dropping so low during cranking that the ECU was not functioning properly, preventing the engine from firing. The cold start injector was also non-functional (JB welded by previous owner), compounding the issue.

Confidence

High confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted January 2024 on SupraForums.com