How to Fix Honda Fit Rattling Noise on Cold Starts

Understanding and Resolving the Honda Fit Cold Start Rattling Noise

Many Honda Fit owners have reported experiencing rattling noises on cold starts. Fortunately, there are several potential solutions to address this problem. In this article, we’ll explore the common causes of a Honda Fit Rattling noise cold starts and provide step-by-step instructions on how to fix them

Let’s start with the Honda Service Bulletin That Directly Addresses The Cold Start Rattling Problem

Honda has issued a service bulletin #16-088 to address a Honda Fit rattling noise on cold starts on the vehicles listed below. Honda has determined the cause to be a faulty variable valve timing control (VTEC) actuator. The rattle begins at a cold start and sounds for about 2 seconds. The rattle may be intermittent and usually occurs when the engine has been off for 6-8 hours

Vehicles affected by Honda service bulletin #16-088

2015-16 Honda Fit All trims, All VINS

Understanding VTC Actuator

What is VTC?

The Variable Timing Control (VTC) is a system used in Honda engines to optimize the timing of the intake valve opening and closing events. By adjusting the timing based on engine speed, load, and other conditions, the VTC system helps improve overall engine performance and efficiency.

The VTC actuator is a crucial part of the VTC system. It is a hydraulically operated mechanism located at the end of the camshaft. The actuator adjusts the camshaft’s position relative to the crankshaft, thereby changing the timing of the intake valves. This adjustment allows the engine to operate more efficiently under various driving conditions.

How Does the VTC Actuator Work?

The VTC actuator works in conjunction with the engine control unit (ECU) and other components to adjust the camshaft timing. Here’s a step-by-step look at its operation:

• Signal from the ECU: The ECU monitors various engine parameters, such as speed, load, and temperature. Based on this data, it sends a signal to the VTC actuator solenoid.
• Actuation of Solenoid: The VTC actuator solenoid controls the flow of oil to the VTC actuator. When activated by the ECU, the solenoid opens or closes to regulate oil pressure.
• Hydraulic Adjustment: The oil pressure acts on the VTC actuator, causing it to rotate the camshaft. This rotation adjusts the timing of the intake valves.
• Optimized Timing: By advancing or retarding the camshaft timing, the VTC actuator helps optimize engine performance for different driving conditions, such as acceleration, cruising, and idling.

This is the replacement VTC actuator listed in the service bulletin

Common Issues with VTC Actuator

While the VTC actuator is designed to be reliable, it can develop issues over time. Here are some common problems:

• Rattling Noise on Cold Start: A common symptom of a failing VTC actuator in the Honda Fit is a rattling noise during cold starts. This noise is typically due to a worn or malfunctioning actuator that struggles to adjust the camshaft timing correctly.
• Check Engine Light: If the ECU detects a problem with the VTC system, it may trigger the check engine light. • Diagnostic trouble codes (DTCs) related to the VTC system can be read using an OBD-II scanner.
• Poor Performance: A malfunctioning VTC actuator can lead to poor engine performance, reduced fuel efficiency, and increased emissions.

Parts required to fix Honda fit cold start rattle

VTC Actuator 14310-5R1-013
Fuel Joint Pipe Set 16012-5R1-315
0-Ring 91311-5R1-J01
Intake Manifold Gasket 17105-5R0-004 (4)
Throttle Body Gasket 17107-5R0-004
EGR Port Gasket 17108-5R0-004
Sealing Washer (12 mm) 16705-5R1-J01
Fuel High Pressure Pump Base 0-Ring 91304-5R7-A01

Fix the Honda Fit rattling noise on cold starts using this step-by-step procedure

1) Disconnect negative battery cable
2) Remove the air cleaner assembly
3) Remove the throttle body (you can leave the coolant lines attached)
4) Remove the intake manifold
5) Remove the ignition coils
6) Remove the valve cover
7) Rotate the crankshaft to #1 cylinder TDC. ON the intake side, mark the chain where the arrow on the VTC is pointing to. On the exhaust side, mark the camshaft sprocket to the timing chain and secure the chain to the camshaft sprocket using zip ties.
8) Remove the high-pressure fuel pump
9) remove the high pressure fuel pump cover
10) Raise the vehicle and remove the right front wheel and lower splash shield and timing chain tensioner cover.
11) Rotate the crankshaft counterclockwise a few degrees to compress the auto-tensioner. Align the hole in the lock and auto-tensioner and insert a .05″ diameter lock pin. Rotate the crank back to TDC and remove the timing chain tensioner. Then lower the vehicle.
12) Remove the five intake side camshaft caps. Keep them in order and set them aside. Tip-up the camshaft and remove the timing chain from the VTC teeth.
13) Remove the intake camshaft and VTC actuator and secure the chain
14) On a workbench hold the camshaft while using an open-end wrench to remove the VTC actuator mounting bolt. Separate the VTC actuator and discard it. Swap in the new VTC.
15) Hold the camshaft while tightening the VTC actuator bolt to 85-ft/lbs.
16) reinstall the camshaft and reverse the disassembly procedure.

Camshaft cap torque to 4-ft/lbs, then to 10-ft/lbs starting in the middle and working out

The timing chain tensioner torque is 9 ft/lbs.