No Start After High Impedance Injector Swap - Bypass Injector Resistor Pack

Fuel Systemintermediate✓ OP Confirmed

Problem

After swapping from low impedance RC 550cc injectors to high impedance 550cc injectors from eBay, the 7MGTE would not start. Fuel pressure would not climb past 40psi despite having previously reached 60-80psi with the old setup.

Engine will not start after injector swapFuel pressure stuck at 40psi and cannot be increased via FPR adjustmentFP B+ diagnostic trick does not raise pressure above 40psiNo diagnostic codes - CEL just flashes indefinitelyPreviously ran but leaned out (AFR climbing to 18+) before injector swap

Root Cause

The 7MGTE's factory injector resistor pack was still in the circuit. This pack is designed to add resistance for low impedance (~2.5 ohm) injectors. When high impedance (12.5 ohm) injectors were installed, the combined resistance was too high, preventing the injectors from opening properly and flowing enough fuel.

Confidence

Moderate confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted March 2024 on SupraForums.com