August 2018 Archives - UnderhoodService
Nissan Variable Compression Engine

The new Nissan 2.0 L VC-Turbo (Variable Compression Turbo) offers similar performance figures to the 24-year-old 3.5 L V6 that it replaces, while providing 4-cylinder fuel economy. The first vehicle to receive the engine in the Nissan lineup will be the 2019 Altima SR. While it might be a few years before this engine is in your bays, the preparation and training needs to start now, not when you are stumped with a problem.

Pulse-Width Fuel Pump Diagnostics

You will see only one fuel line going to the fuel rail on most late-model vehicles. Instead of using an engine vacuum routed to a pressure regulator under the hood, returnless systems use engine data and vary the speed of the electric pump to meet fuel pressure and volume requirements without having to bleed off and return it to the tank when the engine does not need it.

Understanding Hyundai TPMS

Hyundai TPMS has an auto relearn function, but if a shop is initializing a sensor or doing a manual relearn, you will need a TPMS tool that can capture the sensor IDs and program them into the TPMS module.

Diagnosing Intelligent Cooling Systems

The majority of cooling systems on the roads react to what is happening inside the combustion chamber. After the engine is stressed, the heat causes the thermostat to open. Increases in temperatures will also cause the cooling fans to come on. The heat carried by the coolant is the trigger for operation of the fans and thermostat.

VANOS Variable Valve Timing Diagnostics

Diagnosing a VANOS system does not require that you speak German. What it does demand, however, is knowledge of how the actuator adjusts the camshaft, how the solenoid controls the actuator and when the engine control module changes camshaft timing. As for tools, you will need the appropriate tool set to lock the crank and camshaft. You will also need a scan tool and a scope to observe the crankshaft and camshaft signals to accomplish more advanced diagnostics.

Locking Down The Engine For Timing Belt Replacement

The relationship between the cam and crank is a critical one. You might say they are heavily dependent on each other for their survival because any slip-up and their union ends in catastrophe. Locking down engines for timing service is a necessity anytime you remove the crank or cam pulley or have to replace the belt itself.

Oil And Start-Up: Why Oil Temperature Matters

A cold start is one of the most traumatic things that can happen to an engine. For the first few minutes that the engine is running, it is virtually blind, has poor circulation and is waterlogged. The goal of the engine module is to get the engine up to temperature quickly so emissions can be controlled. The oil in the crankcase plays a critical role in this process.

Fuel Injector Diagnostics: Thinking Through The Problem

There is almost no way to inspect the spray pattern of the fuel injector while it is on the vehicle, and it is impossible to inspect on a vehicle with direct fuel injection. You can, however, witness the symptoms of a bad injector.

Subaru Stretch Belt Inspection & Replacement

If you see a belt on a late-model Subaru that does not have an automatic tensioner and runs between only two or three components, it’s probably a stretch belt. These types of belts typically are used to turn the A/C compressor on the 2.5L four-cylinder engine in 2008 and later models.