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Harley Davidson High Idle Problems: Solutions & Causes Reviewed

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Chase Manhattan

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Owner and Editor at The Wrench Network

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Hey y’all, it’s Chase Manhattan! I’m a life-long automotive and motorcycle enthusiast with a knack for diagnostics that I hope to share with you! I spend a lot of time trying to cover every angle in my articles, but if you need more info feel free to ask in the comments or contact me directly. I hope you enjoy the read, and if you find it helpful, please share it via your preferred social media and like my Facebook page as it really helps independent creators like me. Cheers!

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Fuel injected Harley Davidson motorcycles are designed to provide optimal performance and efficiency. However, there are times when these bikes might experience high idle issues. High idle can be caused by various factors such as incorrect throttle body settings, stuck throttle cables, leaking intake hoses, faulty temperature sensors, or simply the condition of the fuel. In this article, we will discuss the reasons behind high idle in fuel injected Harleys and provide solutions to address these issues.

Harley Davidson High Idle Reset

If your fuel-injected Harley is experiencing a high idle, you can try resetting the idle settings. To do this, follow these steps:

  1. Turn the ignition switch on for 10 seconds (do not start the engine).
  2. Turn the ignition switch off for 10 seconds.
  3. Repeat this process a total of four times.

This process should reset the original throttle position, allowing your Harley to idle at the correct RPM.

How To Adjust The Idle on A Fuel Injected Harley Davidson

If your Harley’s idle is still too high or too low after resetting the throttle position, you may need to adjust the idle setting manually. This can be done by adjusting the idle speed on the throttle body.

How To Adjust Idle Speed On The Throttle Body

To adjust the idle speed on a fuel-injected Harley, follow these steps:

  1. Locate the idle speed screw on the throttle body.
  2. Use a flathead screwdriver to turn the screw clockwise to increase the idle speed or counterclockwise to decrease the idle speed.
  3. Make small adjustments and check the idle speed with a tachometer.
  4. Continue adjusting until the idle speed is within the recommended range specified in your Harley’s user manual.

Locating The Idle Speed Screw

The idle speed screw is typically located on the side of the throttle body, near the throttle linkage. It may be covered by a protective cap, which you will need to remove to access the screw. Consult your Harley’s service manual for the exact location of the idle speed screw on your specific model.

Warning: Adjusting The Idle Isn’t Always The Solution

While adjusting the idle speed can sometimes resolve high idle issues, it’s essential to remember that this is not always the solution. In some cases, high idle can be caused by other underlying problems, such as vacuum leaks or faulty sensors or even bad gas. If adjusting the idle speed does not resolve the issue, it’s essential to investigate other potential causes. As a reminder, I always suggest using the manufacturer’s recommend fuel for your motorcycle.

Related: Harley Davidson Starting Problems

Hey you! Keep your Harley Davidson running in tip top shape with these suggestions:

[Harley Davidson 103 Engine Problems You Should Know About] [Are Harley Motorcycles Reliable?] [Got A Clogged Harley Fuel Injector?] [Harley’s Notorious Fuel Pressure Regulator Problems] [Bad Gas in A Harley Symptoms] [Harley Bad Compensator Symptoms Get Revealed]

Other Potential Causes of A High Idle

Stuck Throttle Cable or Cold Start Lever

A stuck throttle cable or cold start lever can prevent the throttle valves from closing completely, leading to a high idle. To fix this issue, follow these steps:

How To Fix

  1. Inspect the throttle cable and cold start lever for signs of binding or damage.
  2. Lubricate the throttle cable and cold start lever to ensure smooth operation.
  3. Replace any damaged or worn components.
  4. Adjust the throttle cable and cold start lever according to your Harley’s service manual.

Leaking Rubber Intake Hoses

Leaking rubber intake hoses between the throttle body and cylinder head can cause a high idle by allowing unmetered air to enter the engine. To fix this issue, follow these steps:

How To Fix

  1. Inspect the rubber intake hoses for signs of cracks, damage, or leaks.
  2. Replace any damaged hoses with new ones.
  3. Ensure that all hose clamps are tight and secure.
  4. Check for vacuum leaks using a smoke machine or a spray bottle with soapy water.

Faulty Temperature Sensors

Faulty oil or water temperature sensors can cause a high idle by sending incorrect information to the fuel injection ECU. To fix this issue, follow these steps:

How To Fix

  1. Check the temperature sensors for signs of damage or corrosion.
  2. Test the temperature sensors using a digital multimeter according to your Harley’s service manual.
  3. Replace any faulty sensors with new ones.
  4. Clear any diagnostic trouble codes related to the temperature sensors.

Vacuum Leaks In the Manifold

Vacuum leaks in the manifold can cause a high idle by allowing unmetered air to enter the engine. To fix this issue, follow these steps:

How To Fix

  1. Inspect the intake manifold for signs of cracks, damage, or leaks.
  2. Check for vacuum leaks using a smoke machine or a spray bottle with soapy water.
  3. Repair or replace any damaged components as needed.
  4. Ensure that all manifold bolts are tight and secure.

In conclusion, high idle issues in fuel injected Harley Davidson motorcycles can be caused by various factors. By following the steps outlined in this article, you can diagnose and resolve high idle problems, ensuring that your Harley runs smoothly and efficiently. Remember, always consult your Harley’s service manual for specific information related to your specific model and engine type.

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