Engine / Fuel / Intake

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Changing Belts Changing the Fuel Filter Changing the Fuel Injectors Changing the Oil Cleaning the Throttle Body Cold Idle Fix Idle Speed Adjustment MAF Sensor Grounding Motor Mount Extravaganza (by John Heer)

Motor Mounts (comments & pics) Replacing Motor Mounts Replacing the Oil Pressure Switch Replacing the Power Steering Fluid Replacing the Timing Chain Tensioner Replacing the Water-Pump Synthetic or Dino Oil? Tuneup and Troubleshooting Guide

About Ignition Timing About Airflow sensors About Idle Air Control Valves Bosch Platinum vs. NGK Platinum Spark Plugs Bowling's Automotive Programs Break-In FAQ ECU Trouble Codes Engine Block Preparation Guidelines Engine Oil Bible Fuel Injectors Gasoline FAQ How to make your own AFR Meter Missing Oil Syndrome	More info on Oil More info on Fuel Oil FAQ Oil Filter Analysis Platinum vs. Copper NGK spark plugs Snake Oil Info Some interesting info on Slick-50 Spark Plugs and Ignition Systems Specialty Spark Plugs The Limit of Bolt-Ons TPS Voltage Adjustment Torque vs. HP
Info on Other SR Engines	Nissan Engine Designations

Open Loop vs. Closed Loop

Comments by Dan Thompson

In automotive terms, "closed loop" refers to the mode of operation whereby the ECU monitors input from all sensors and trims fuel delivery and timing maps to optimize engine performance. During "open loop" operation, all but a few critical sensors (TPS, MAF, coolant temp and Crankshaft Position Sensor on our cars) are ignored, and fuel delivery and timing are based on pre-programmed maps.

High port versus low port

Comments by Dan Thompson

To set the record straight, 'high port' or 'low port' describes the intake manifold's entry point into the cylinder head. If the cylinder head's intake ports are located toward the top of the head, it is considered a high port head. If the ports are located toward the bottom, it is a low port head.

The high port head was in all NX2000s as well as the '91 thru '93 Sentra SE-R. The switch to the low port head on U.S. Nissan models (I'm not sure about Infinitis) occurred in 1994. All SR20DE engines installed in Nissans from 1994 to present have been the low port model.

If you're *still* not sure whether you have a high port or low port head, look between the valve cover and the firewall. If you see an object that looks kind of like a log (which is the surge tank), you have a low port head. If you see 4 "tubes", you have a high port head.