What causes idle surge on a Honda Accord?

What causes idle surge on a Honda Accord?

When the valve fails, it causes idle surge. Here’s how to check it out. 1) Start by making sure the cooling system is filled with coolant and there’s no air in the system. If it’s low on coolant, that can trick the fast idle valve.

How does a Honda car know its idle speed?

What you have is a computer that’s literally “chasing” a good idle speed. Techs call this a surge. Honda uses most of those same components to determine idle in their vehicle. However, they use a fast idle valve that has engine coolant running through it.

What are the symptoms of an idle air control valve?

One of the most common symptoms commonly associated with a problematic idle air control valve is irregular idle speed. The idle air control valve is programmed to regulate and maintain the engine idle speed at a constant rate.

Where is the idle air control valve on a Honda?

5) Finally, check the idle air control valve. There’s a port in front of the throttle plate. That port feeds the idle air control valve and the base idle screw.

When the valve fails, it causes idle surge. Here’s how to check it out. 1) Start by making sure the cooling system is filled with coolant and there’s no air in the system. If it’s low on coolant, that can trick the fast idle valve.

5) Finally, check the idle air control valve. There’s a port in front of the throttle plate. That port feeds the idle air control valve and the base idle screw.

What you have is a computer that’s literally “chasing” a good idle speed. Techs call this a surge. Honda uses most of those same components to determine idle in their vehicle. However, they use a fast idle valve that has engine coolant running through it.

Can a failed IAC cause engine stalling at idle?

A problem with the IAC should throw a P0505 code. A failed/problematic IAC can cause engine stalling when off-throttle, and/or excessively high engine rpm, particularly at idle. The IAC, signaled by the ECU, controls the throttle opening at idle.

Where is the idle air control valve on a Honda Accord?

You will find it at the back center of the under hood area, near the throttle body (TB) and mounted on the rear of the intake manifold (IM). You will have to remove the TB intake hose in order to gain access to area of the IM that is connected to the IACV. Remove the Honda idle air control valve.

What to do if your Honda has a bad fast idle valve?

There should be NONE. If there’s vacuum on that line, check the coolant hoses at the fast idle valve. They should be HOT. If the lines are hot and you ARE getting vacuum on that removed vacuum line, you can suspect a bad fast idle valve.

Are there any problems with the Honda Accord?

The upshot is when your Accord won’t start, that’s never good, but especially bad when it’s just a few years old. Also once again, owners are complaining that the 2014 Honda Accord seats are uncomfortable. Uncomfortable seats has been a significant complaint with the Accord since the 2008 model year. Click on a category below for details.

Are there any recalls on the 2014 Honda Accord?

Based on information received from our latest subscriber survey, our reliability history charts give you a rundown on how used vehicles are holding up in 17 potential trouble spots, ranging from the engine, transmission, and brakes to power equipment and the electrical system. The 2014 Honda Accord has been recalled 2 times by NHTSA. View Recalls

Why does my car run worse when the accelerator is not applied?

That increases the idle speed. Knowing that the accelerator isn’t being applied (by reading the throttle position sensor) the computer sees a high idle as a problem and commands the idle air control valve to close. That makes the engine run worse. So the computer either opens the idle air control valve again or adds fuel.

What does a fast idle valve on a Honda do?

Honda uses most of those same components to determine idle in their vehicle. However, they use a fast idle valve that has engine coolant running through it. Inside the valve is a wax pellet (just like a thermostat) that opens and closes a vacuum line that allows additional air to bypass the closed throttle plate at cold idle.

Why is the idle air control valve still open?

If the electrical connector to the idle air control valve is removed and the base idle screw is turned all the way in (count the turns if you’ve already adjusted base idle so you can return the screw to the proper position) and there is STILL airflow through the upper port, then the idle air control valve is stuck OPEN.

Why does my Honda Accord stall all the time?

While a DIY project can save you time and money, less experienced owners or cars with more complex problems may require a trip to the dealership. Here are some reasons your car may be stalling, along with possible solutions. V6 Accord’s are particularly prone to bad ignition coils.

Why is my Honda Accord engine running poorer?

An informal way to test the strength of the coil is to unplug them one at a time while the car is running. If all of your coils are strong, this will cause the engine to begin to run poorer. If you pull a plug and there is only a minor difference or no difference at all in the engine’s performance, that coil is likely dead and requires replacement.

Why is my Honda Accord making a clunking noise?

After removing the unit, a faulty FPR will typically have enough fuel pressure going through the fuel rail until the key is turned to the ‘accessory’ setting. A bad injector may also make unusual noises, such as clunking. If removing the fuel rail isn’t your thing, you can also test the pressure output of the regulator with a pressure gauge.

Honda uses most of those same components to determine idle in their vehicle. However, they use a fast idle valve that has engine coolant running through it. Inside the valve is a wax pellet (just like a thermostat) that opens and closes a vacuum line that allows additional air to bypass the closed throttle plate at cold idle.

A problem with the IAC should throw a P0505 code. A failed/problematic IAC can cause engine stalling when off-throttle, and/or excessively high engine rpm, particularly at idle. The IAC, signaled by the ECU, controls the throttle opening at idle.

What do you do when your Honda engine is at idle?

An easy way to find one of these faulty PCV valves is to pinch off the supply line to the PCV valve with a pair of pliers while the engine is at idle. If the idle smoothes out when you do this, replace the PCV valve with an OE unit.

Why does my car idle all the time?

If the computerized engine control system is faulty, high idling can be one symptom. A vacuum leak in any of the hoses can be the culprit—inspect them all for leaks. A bad idle-speed control unit can cause the problem; it may need to be replaced.

Can a FITV cause a Honda to idle?

The FITV is not the only thing that can cause an idle issue with your Honda so be sure to follow ALL the steps first before making that adjustment. If playback doesn’t begin shortly, try restarting your device.

What should I do if my idle air control valve is not working?

If the idle air control valve checks out and the fast idle valve doesn’t, then replace the fast idle valve. It’s a little hard to get to, but replacing it is just a matter of loosening the screws, removing the coolant hoses, and replacing the valve.

What to do when your Honda engine is idle?

If you’re sure you don’t have any vacuum leaks, and you’ve bled the air out of the cooling system, and you still have a problem, then check the IAC (Idle Air Control valve). You can do this by tapping on it with the butt of a screwdriver while the engine is running.

Why does my Honda Civic idle too high?

When cold you just get an idle that is too high like up around the 1200-1500rpm range or higher. The second video shows a vacuum leak that I found on a Civic using a ‘safer’ method for checking for vacuum leaks. Both work but the important thing is that you check for vacuum leaks if you have a Honda idle problem.

Why does my Honda have a surging idle?

If you have a Surging idle on Honda, read this post. Most computer controlled vehicles rely on the coolant temperature sensor to tell the computer whether the engine is cold and needs a rich mixture. The computer then commands the idle air control valve to open to the correct setting. However, any vacuum leak in the system can screw this up.

One of the most common symptoms commonly associated with a problematic idle air control valve is irregular idle speed. The idle air control valve is programmed to regulate and maintain the engine idle speed at a constant rate.

How to test the fast idle valve on a Honda?

3) Once the engine coolant is above 90 degrees F, you can proceed to test the fast idle valve. Start the engine and remove the vacuum line on the lower portion of the throttle body. Check for vacuum. There should be NONE.

What to do if your fast idle valve is bad?

If there’s vacuum on that line, check the coolant hoses at the fast idle valve. They should be HOT. If the lines are hot and you ARE getting vacuum on that removed vacuum line, you can suspect a bad fast idle valve. But continue with the tests before you replace it.

If there’s vacuum on that line, check the coolant hoses at the fast idle valve. They should be HOT. If the lines are hot and you ARE getting vacuum on that removed vacuum line, you can suspect a bad fast idle valve. But continue with the tests before you replace it.

What are the symptoms of a failing IAC valve?

Symptoms of a failing idle air control valve. Your check engine light is on: The computer monitors the IAC valve to make sure it’s working correctly. If something’s wrong, it will turn on the check engine light. 3. The car stalls: A faulty IAC valve can prevent the engine from getting enough air to idle properly. As a result, the car may stall.

How does Idle Air Control ( IAC ) valve work?

The engine’s computer controls the valve by sending voltage pulses to it. This causes the motor inside the IAC valve to move and direct airflow around the throttle plate to control idle speed.

Can a faulty idle air control cause a problem?

A faulty idle air control (IAC) valve can cause a number of problems with your vehicle: 1. Incorrect idle speed: An IAC valve that sticks in the closed position will create an idle speed that’s too low.

If the electrical connector to the idle air control valve is removed and the base idle screw is turned all the way in (count the turns if you’ve already adjusted base idle so you can return the screw to the proper position) and there is STILL airflow through the upper port, then the idle air control valve is stuck OPEN.

If the idle air control valve checks out and the fast idle valve doesn’t, then replace the fast idle valve. It’s a little hard to get to, but replacing it is just a matter of loosening the screws, removing the coolant hoses, and replacing the valve.

3) Once the engine coolant is above 90 degrees F, you can proceed to test the fast idle valve. Start the engine and remove the vacuum line on the lower portion of the throttle body. Check for vacuum. There should be NONE.

That increases the idle speed. Knowing that the accelerator isn’t being applied (by reading the throttle position sensor) the computer sees a high idle as a problem and commands the idle air control valve to close. That makes the engine run worse. So the computer either opens the idle air control valve again or adds fuel.

Why does my Honda engine not rev up?

EASY FIX ON HONDA AND ACURA VEHICLES. – YouTube ENGINE WILL NOT REV UP PAST 2000 RPM ? EASY FIX ON HONDA AND ACURA VEHICLES. If playback doesn’t begin shortly, try restarting your device.

What causes Honda Accord 4cyl to stall when warm?

I had a different idle problem two months ago that I never got to root cause on, see writeup here: 2005 Honda Accord 4cyl low idle and stalling when warm. Troubleshooting steps performed: Suspected poor air-flow. I removed and inspected the air filter. Air filter was fine.

What causes high idle on a Honda Accord?

Its called the FITV (Fast idle thermal valve) Its a simple little thing like this that can cause a lot of idle issues, Such as, Idle bouncing around, Idle surge, It can also cause a high idle. Its a simple little fix and could save you alot of money in the long haul.

I had a different idle problem two months ago that I never got to root cause on, see writeup here: 2005 Honda Accord 4cyl low idle and stalling when warm. Troubleshooting steps performed: Suspected poor air-flow. I removed and inspected the air filter. Air filter was fine.

Why is my Honda Accord revving when parked?

Continue reading to diagnose why your Accord’s engine is revving while it is parked. This article applies to the Honda Accord (1990-2002). Your Accord’s engine should be at a constant low idle when parked and should not be revving or fluctuating. Having an idle problem is always something you want to take care of as soon as possible.

There should be NONE. If there’s vacuum on that line, check the coolant hoses at the fast idle valve. They should be HOT. If the lines are hot and you ARE getting vacuum on that removed vacuum line, you can suspect a bad fast idle valve.


When does the idle air control valve change?

When the engine is running but the vehicle is not moving, this means the engine is idling. During this time, the number of revolutions per minute (RPM) inside the engine will change. The idle air control valve is responsible for managing the engine idle speed.

What happens when the PCV valve fails on a Honda?

Usually if the PCV valve fails in this manner, you’ll experience a ‘high’ or ‘hunting’ idle. An easy way to find one of these faulty PCV valves is to pinch off the supply line to the PCV valve with a pair of pliers while the engine is at idle.