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.
Fuel Injection System - BOSCH LH: Description: Notes
The Bosch LH Jetronic (LH standing for hot wire airflow system) fuel injection system is a further development of the Bosch L-Jetronic Fuel Injection System. The Bosch LH system has a hot wire air mass sensor instead of a conventional sensor plate for measuring airflow. The hot wire air sensor is installed between the air cleaner housing and throttle housing.
The LH injection has a microcomputer which can process a multitude of engine signals. The microcomputer can calculate and trigger the most favorable injection timing. In this manner optimal control of the entire combustion system is possible. This guarantees optimal fuel consumption and performance in all operating conditions.
Major components include the fuel pump, fuel filter, 2 fuel pressure dampers, fuel injectors, pressure regulator, fuel cooler throttle housing, hot wire air mass sensor, LH control unit and oxygen sensor. Incorporated with the injection system is the EZF ignition system
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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.