Why is my diesel engine surging up and down?

Why is my diesel engine surging up and down?

Even without problems like algae, a boat that hasn’t had its fuel tank polished in a while and is normally sailed in calm weather will often exhibit this behavior when it gets rough. When a fuel filter starts to clog, the engine will idle fine since not much fuel is required then but it will have trouble with loads since it is fuel starved.

What causes the engine to surge at low speeds?

Idle Speed Control Issues On some models, a faulty or fouled idle speed control (ISC) motor [or idle air control (IAC) motor] may cause the engine to surge at idle or at low speeds. A common problem is carbon buildup. It prevents air to bypass the throttle plate as commanded by the car’s computer.

What to do when engine surges at idle?

Fill fuel supply tank. Check / adjust low idle screw setting. Bleed fuel system and check for suction leaks. Clean or replace pre-filters and screens, check for fuel line restrictions. Check / replace injectors.

What causes an engine surge during fuel injection?

In combination with the camshaft position sensor (CMP), the CKP signals are used by the ECU to manage fuel injection and spark delivery. A faulty CKP (or CKP circuit) can easily cause an intermittent misfire, which naturally results in what the driver may perceive as a surging effect.

Even without problems like algae, a boat that hasn’t had its fuel tank polished in a while and is normally sailed in calm weather will often exhibit this behavior when it gets rough. When a fuel filter starts to clog, the engine will idle fine since not much fuel is required then but it will have trouble with loads since it is fuel starved.

Fill fuel supply tank. Check / adjust low idle screw setting. Bleed fuel system and check for suction leaks. Clean or replace pre-filters and screens, check for fuel line restrictions. Check / replace injectors.

Idle Speed Control Issues On some models, a faulty or fouled idle speed control (ISC) motor [or idle air control (IAC) motor] may cause the engine to surge at idle or at low speeds. A common problem is carbon buildup. It prevents air to bypass the throttle plate as commanded by the car’s computer.

In combination with the camshaft position sensor (CMP), the CKP signals are used by the ECU to manage fuel injection and spark delivery. A faulty CKP (or CKP circuit) can easily cause an intermittent misfire, which naturally results in what the driver may perceive as a surging effect.