Good Tips From Experts For The Upcoming Vehicle Maintenance Season

Published On September 15, 2019

It’s at the end of summer and the beginning of autumn, it’s a very important time for vehicle maintenance. Not only can the damage caused by the use in summer be repaired in time, but also the preparation for the coming cold winter can make you driving safer.

Now, let's look at 2 points of car auto parts maintenance.

1. Direct-Injection (GDI) High-Pressure Pumps

When working on GDI vehicles, please be careful not to make any mistake about which pump is faulty and which one needs to be checked first. To figure this problem out, we need to know that a high-pressure pump installed under the hood generates the high pressure of the fuel while the conventional electric pump located in the tank transport the fuel from the tank to the high-pressure fuel pump.

Generally speaking, when a mechanical failure appears on a GDI pump, the pressure in the system will diminish and the high-pressure will not match its name "high". "LIMP" mode on the dashboard or something alike relying on the manufacturer is a common sign of pump failure. The LIMP mode is set for keeping the vehicle running at a safe speed so that the driver will not impair the engine further. Then How to repair it?

Make sure the vehicle is scanned and the fault diagnosis code is read. In most cases, as long as the vehicle goes into limp mode, a code is recorded. This will give you a good understanding of the faulty parts.

If for some reason no code is recorded, you should ensure that the problem does not come from the traditional fuel pump in the tank. If the electric fuel pump does not work properly and cannot provide the fuel as expected, the GDI pump will not work properly.

Once it is determined that the pump in the tank is working properly, the fuel pressure from the high-pressure pump must be tested, just like that from the conventional fuel system. If the pressure does not meet the specifications, a new GDI pump is required.

2. Oxygen Sensor Failure

Once the oxygen sensor fails, the computer of the electronic fuel injection system will not be able to get the information of oxygen concentration in the exhaust pipe, so the air-fuel ratio cannot be controlled by feedback, which will increase the fuel consumption and exhaust pollution of the engine, and the engine will appear idle instability, lack of fire, surge, and other fault phenomena. Therefore, it is necessary to troubleshoot or replace it in time. Now, let's discuss some common symptoms of oxygen sensor failure.

1. The Car Starts Slowly.

It could have started in five seconds, but it took a long time to start the car, and the speed was unstable. This shows that the front oxygen sensor has problems, ECU has no way to strictly control the oil output, there will be no or too few cases, the result is that the engine performance is unstable, jitter, but also damage the life of the engine.

2. If these three faults occur

at the same time, most of them indicate that the oxygen sensor needs to be cleaned, but there are also preconditions.

I. Engine Failure Light on

Generally, when sensor faults occur, such as water temperature sensor, airflow meter, oxygen sensor and so on, the engine fault lights will be on, which is one of the preliminary bases for judging whether the oxygen sensor has problems.

II. Increased Emissions of Tail Gas Pollution

This is mainly manifested in the annual inspection, the exhaust environmental protection will not qualify, because the pre-oxygen sensor failure will be the same as the three-way the catalytic converter, resulting in excessive emissions.

III. Engine Idle Instability

Pre-oxygen sensor failure, ECU cannot accurately control fuel injection volume, easy to cause the air-fuel ratio error can be manifested in engine idle speed instability, jitter.

The problem of the oxygen sensor caused by carbon deposits can be solved by cleaning carbon deposits. Generally, cleaning with a three-way catalytic converter can be considered. The cleaning operation is also very simple, you can choose to use oxalic acid solution or other cleaning agent cleaning.

Oxygen sensor failure is not entirely caused by carbon deposition. It may also be caused by physical faults such as lead poisoning, heating sensor failure or breakage. If the latter three faults are involved, the cleaning will be ineffective and you should replace a new oxygen sensor.