It sounds like you’re experiencing slow acceleration issues with your Infiniti G35, and it’s accompanied by OBDII codes P0021 and P0011. These codes indicate problems with your camshaft timing, specifically that the Engine Control Module (ECM) is detecting a discrepancy between the intended and actual camshaft angle. Let’s dive into what this means and how to diagnose the problem, especially if you’re also facing issues with your OBDII reader not showing oil temperature, a common concern among G35 owners on sites like g35driver.com.
The Infiniti G35, like many modern vehicles, uses oil pressure to advance the intake camshafts. This system relies on cam actuator solenoids located at the front of the engine. These solenoids rapidly actuate, and as the duty cycle increases, more oil is allowed into the cam sprocket actuator. The ECM controls this duty cycle based on factors like RPM and throttle position. To monitor the actual camshaft position, the system uses cam sensors at the rear of the cylinder head. These sensors read a pickup ring on the rear of the cam, which has notches, and send a frequency signal back to the ECM. This signal informs the ECM about the real-time cam angle, allowing it to adjust the solenoid duty cycle to achieve optimal timing.
Alt text: Location of the camshaft position sensor on an Infiniti G35 engine, critical for accurate cam timing.
When a significant difference arises between the expected camshaft angle and the data received from the cam sensor, the ECM throws codes P0011 (Bank 1) or P0021 (Bank 2), signaling an Intake Valve Timing (IVT) problem. Seeing both codes P0011 and P0021 simultaneously, as you are, often points towards a broader issue affecting oil pressure. With a high-mileage engine, this is a plausible area to investigate. However, it’s also worth considering the cam actuator solenoids themselves, as they contain moving parts and are prone to wear and tear over time.
Fortunately, these solenoids can be tested. After unbolting them from the cylinder heads and removing the actuator assembly, you’ll notice screens designed to filter out debris. These screens can become clogged with RTV sealant, gasket material, or other contaminants circulating within the engine. A more frequent issue is the buildup of varnish and sediment on the moving parts of the actuator, which can physically impede its full operation. You can test the solenoid’s functionality by applying brief, momentary battery voltage. This will allow you to observe the actuator in action and identify any sticking or malfunctioning sections. Remember, these solenoids are designed for rapid duty cycle pulsing and should not be held open for extended periods.
Alt text: Mechanic testing a cam actuator solenoid from an Infiniti G35 with a 12V battery to check for proper actuation.
Numerous YouTube videos demonstrate cam actuator solenoid testing procedures, which, while not always Nissan-specific, are generally applicable due to the similar operating principles across various manufacturers. Given your engine’s high mileage (270k miles), there’s a strong possibility that worn-out cam actuators are contributing to your problems.
To comprehensively diagnose the issue, consider performing the following tests:
- Compression Test: Assess the overall health of your engine’s cylinders.
- Leakdown Test: Pinpoint potential leaks in cylinders, valves, or piston rings.
- Oil Pressure Test: Verify adequate oil pressure to the cam actuators. This is particularly relevant if your OBDII is not reading oil temperature, although these might be separate issues. A mechanical gauge might be needed for accurate pressure readings.
- OBD2 Scan for Real-time Data: Use an OBD2 scanner that can read live data to monitor the actual cam advance. Ideally, cam advance should peak around 40 degrees as RPMs increase. If you’re getting minimal or no advance, it further suggests an issue with the IVT system. Apps like Torque Pro for Android can monitor cam advance, and many full-function OBD2 scanners offer this capability.
To measure oil pressure directly, you may need to install a sandwich adapter and a gauge. Typically, unless your oil pressure warning light is illuminated, you likely have sufficient oil pressure for basic engine operation. However, the ECM has some capacity to compensate for pressure variations by adjusting the solenoid duty cycle. The presence of P0011/P0021 codes indicates that the system is significantly outside of its acceptable parameters.
Considering your described symptom of struggling to reach higher RPMs, the cam actuator solenoids are prime suspects. Testing them is a crucial step to confirm or rule out this possibility. Remember to consult resources like g35driver.com for Infiniti G35 specific advice and community knowledge regarding these issues. While the OBDII not reading oil temperature might be a separate sensor or electrical problem, addressing the P0011 and P0021 codes related to cam timing should be your priority to restore your G35’s performance.
