Symptoms Of Bad Suction Control Valve (SCV) In Common Rail Diesel Engines
Suction Control Valve (SCV) is one of the components in a common rail diesel engine installed on the supply pump. The function of the SCV (Suction Control Valve) regulates the fuel pressure in the delivery pipe (rail), so the fuel pressure is always stable according to the ECU target and engine needs.
The ECU controls the Suction Control Valve (SCV) directly and works dynamically according to the conditions that occur inside the engine. Because the ECU directly controls the SCV, when a problem occurs with this SCV component, it will generally cause the Malfunction Indicator Lamp (MIL) to light on.
A bad SCV may occur due to low-quality diesel fuel, for example, long stored diesel fuel or contaminated with other fluids.
For bad SCV, the ECU shows up diagnostic codes P0089 (Suction Control Valve stuck), P0628 (Suction Control Valve open), and or P1275 (Supply Pump exchange). As a side note, the above DTCs found in Montero sports vehicles from the 2010-2016 production date (data may vary for other car brands).
However, on several occasions, there was also a bad SCV but the check engine light did not light on. Well, below are the symptoms of bad SCV that often occurs in common rail diesel engines.
1. The engine like to shut down suddenly
The first symptom of a bad SCV that often occurs is the engine shutdown suddenly. Some stop quickly after being turned on (engine runs while starting then stop), while others have been running for several minutes and then suddenly stop.
The Suction Control Valve (SCV) is an actuator in the common rail system regulating the fuel pressure inside the delivery pipe (rail). When the SCV is damaged, the fuel pressure needed by the engine will vanish.
As a result, the rail will lose fuel pressure, and the injector cannot properly inject the fuel. It is why the common rail diesel engine will eventually stop suddenly.
2. The engine is hard to run even it's easy to start
The symptom of a bad SCV that often appears in common rail diesel engines is the engine is hard to run even it's easy to start. This condition may occur because the fuel supply that should be injected by the injector into the combustion chamber does not happen.
After all, the fuel inside the delivery pipe (rail) does not have sufficient pressure to produce a fuel mist that matches engine needs. Sometimes, the engine still has time to start, but generally, it will stop immediately after the current fuel pressure drops and cannot be maintained at the required pressure.
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3. The engine rpm is stuck at 1500-2000 rm even the gas is fully open
The last symptom of a bad SCV often found on common rail diesel engines is that the engine rpm stays stuck at 1500 - 2000 rpm when fully gassed. This condition generally occurs without any strange signs on the engine.
When starting, the engine is easy to start, the idling rpm is in the normal position, and it shows no symptoms of bruising, limping, or hunting. However, when driving the car, the engine rpm is stuck at 1500-2000 rpm, even though we have fully stepped on the gas pedal. Also, engine power becomes less powerful.
Yes, this condition will occur because the fuel pressure inside the rail pie is not proper for a common rail diesel engine. There will be a drastic change in pressure from the normal pressure set by the manufacturer, causing the mismatch of the actual fuel injection amount with the computer set. Therefore the engine becomes low power, retained rpm, and is not powerful even though the gas pedal pressed fully.