Why do cars retard timing?

Why do cars retard timing?

When it comes to turbocharged or supercharged engines that are running at higher levels of pressure, retarding the timing of an engine can be more beneficial. Retarding the timing on these kinds of engines helps compensate for denser air and fuel mixtures and allows them to run more efficiently.

Does the ECU control timing?

Fundamentally, the engine ECU controls the injection of the fuel and, in petrol engines, the timing of the spark to ignite it. It determines the position of the engine’s internals using a Crankshaft Position Sensor so that the injectors and ignition system are activated at precisely the correct time.

Can timing cause erratic idle?

An engine slightly out of time can idle roughly since the spark is not in sync with the cylinders. Too much timing advance or retardation causes serious drivability problems. Many problems may upset timing. However, the most common is an overstretched timing belt or chain, or a bad tensioner after miles of operation.

Can a knock sensor retard timing?

What are knock sensors? Basically a knock sensor is a glorified microphone that listens for the unique sound that knock makes. A little piezoelectric doohickey. When it detects that knock sound – if it’s severe enough – the computer retards the spark timing and the knock goes away.

What should spark advance be at idle?

In addition, the WSM says spark advance should be between 6 to 18 degrees BTDC at idle.

How do I stop knock retarding?

To electronically eliminate KR, and thus detonation, it is necessary to reduce the heat in the cylinders. Heat is a byproduct of power, so to reduce heat, the power must be reduced. The PCM can reduce power electronically by retarding the overall ignition timing.

How much knock is OK?

Typically 0.5 degrees is a good starting point. If you are using multiple knock sensor on different banks of the engine (for example in a V6 or V8 application) then there are individual long term knock trim maps for each bank of the engine.

What happens when the ECU is not working?

The ECU is related to this because it controls the timing of the spark plugs. If the computer is not working properly then it can impact when the spark plugs fire or stop them from firing altogether. If the vehicle is not getting spark, then it will not run.

How does the ECU control the ignition system?

The information relayed by the crankshaft position sensor is used to control fuel injection, the ignition system, and general engine timing which are all essential for the cylinders to fire properly . The ECU is responsible for many areas of the vehicle that control whether or not the vehicle starts.

How does retarding the ignition timing affect horsepower?

Turbocharged, supercharged and nitrous-injected engines are already running higher pressures and temperatures than normally aspirated engines, so the consequences of advancing your timing can be more severe. Retarding the timing on these engines compensates for the denser fuel-air mixtures by firing the plugs later in the compression cycle.

How to diagnose a bad engine control module?

The best way to diagnose an engine control module fault is to understand its main responsibilities. Once you are aware of these primary functions, it becomes easier to determine what symptoms are bad PCM symptoms.