Mechanic Exsteven

Mechanic Exsteven Welcome
(2)

10/18/2025

Mechanic Technique 👍💯

🔹 Sensor 1 – Upstream / Before the Catalytic Converter / UpstreamThis sensor is located before the catalytic converter, ...
10/16/2025

🔹 Sensor 1 – Upstream / Before the Catalytic Converter / Upstream

This sensor is located before the catalytic converter, usually on the exhaust manifold or just at the beginning of the pipe. Its main function is to inform the ECU of the actual air/fuel ratio, so that the injection system can adjust the injection timing in real time (closed loop).

Main variants:
➡️ Narrow band: oscillates between 0.1 V and 0.9 V.
➡️ A/F Sensor or Wideband: accurately measures the air/fuel ratio (±3 mA current).

Failure symptoms:
🔸 Unstable idle, increased fuel consumption, black smoke, or loss of power.
🔸 Check Engine Light with codes such as P0130 to P0135.

Detection Method:
🔹 On the scanner, the voltage should fluctuate constantly (0.1–0.9 V) or the wideband current should vary around zero.
🔹 If the signal remains fixed, there is element contamination, internal damage, or loss of heater reference.
🔹 It can be verified with an oscilloscope; it should show rapid switching (2 to 4 times per second).

🔹 Sensor 2 – Downstream / After the Catalytic Converter / Downstream

This sensor is mounted after the catalytic converter and does not regulate the mixture; its task is to monitor the efficiency of the catalytic converter by comparing its reading with that of sensor 1. If both signals are very similar, the catalytic converter is not storing oxygen properly.

Main variants:
➡️ Conventional zirconia or 4-wire planar sensor.
➡️ In some modern systems, wideband downstream is used for advanced OBD-II diagnostics.

Failure Symptoms:
🔸 Check Engine light on, codes P0136 to P0141.
🔸 Slight loss of power or high consumption if the system enters open mode.

Detection Method:
🔹 On the scanner, the voltage from sensor 2 should remain stable between 0.6 and 0.8 V if the catalytic converter is in good condition.
🔹 If it oscillates the same as sensor 1, the catalytic converter is degraded.
🔹 On the oscilloscope, a slow or almost flat signal is observed; if it remains fixed at 0.45 V, there may be an open circuit or contamination.

All camshaft companies list the operating clearance — or lash — in the specs. Usually, those specs are for a hot engine,...
10/16/2025

All camshaft companies list the operating clearance — or lash — in the specs. Usually, those specs are for a hot engine, or one that has reached its normal operating temperature. The reason for this is that all engines grow or expand as operating temperature rises. Conversely, a cold engine will contract. This temperature change only accounts for a minor swing in lash specs, but when assembling a new engine with a solid lifter, you want to be as close as possible to the desired hot specs once the engine comes up to operating temperature.

If the engine is all-aluminum, it will grow by close to 0.012 inch. You might want to check the piston-to-valve clearance at both specs and make a decision based on your findings. The cold lash setting will be the clearance when the engine first starts and then will increase with the wider clearance once the engine warms up.

Where this gets interesting is with tight-lash camshafts requesting a hot lash clearance of 0.014- to 0.020-inch on a hot engine. If that cam is used on an all-aluminum engine, this comes very close to producing a zero lash package with a cold engine. It’s important that the lash not be too tight once the engine cools down or it may leave the intake or exhaust valve open. That can lead to potentially burning a valve on a cold start, as the valve does not have the chance to cool between lift cycles. Just something to think about especially with cold engines.

Cylinder Head Parts and Names ✅
10/16/2025

Cylinder Head Parts and Names ✅

The image displays the components of a leaf spring suspension system, commonly found in vehicles, particularly trucks an...
10/16/2025

The image displays the components of a leaf spring suspension system, commonly found in vehicles, particularly trucks and heavier vehicles, to absorb shocks and support weight.
Hydraulic Shock Absorber: This component dampens oscillations and controls the movement of the springs, preventing excessive bouncing.
Vehicle Frame: The main structural component of the vehicle to which the suspension system is attached.
Auxiliary Spring: An additional spring, often used in conjunction with the main spring, to provide extra support under heavier loads.
Frame: Another term for the vehicle frame, emphasizing its role in supporting the suspension system.
Bearing Plates: These plates, often with rubber stops, prevent the spring from directly contacting the frame, reducing noise and wear.
Torque Rod: A rod designed to control axle wrap and maintain proper alignment of the axle relative to the frame.
Main Spring: The primary leaf spring, composed of multiple layers of metal leaves, which supports the vehicle's weight and absorbs road impacts.
Shackle: A link that connects the leaf spring to the vehicle frame, allowing for changes in the spring's length as it flexes.

Address

Jackson Street
Dallas, TX
75202

Website

Alerts

Be the first to know and let us send you an email when Mechanic Exsteven posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Shortcuts

Share

Category