What to Do If Your Car Running Rough After Washing Engine? [4 Simple Fixes!]

As a car owner and enthusiast, I know the irritating feeling every car owner feels listening to strange noises coming from the motor post-engine wash. There can also be a chirping noise from engine when cold due to post-engine wash with cold water. Most of the time the problem can be easily resolved.

But the question is, why might it happen, and what to do about it? Washing engines with a high-pressure hose can make water enter the important electrical components. Water can also damage the mass airflow sensor. Cleaning the sensor will help you with the problem. Drying the engine for 30 minutes to several hours post-wash is advisable.

Throughout this guide, I am going to describe the causes, solutions, and symptoms you might need to know about post-wash engine troubles. Let’s not waste any more time and get started.

6 Signs Your Engine Is Running Rough

Before we jump into the solutions, you need to know the symptoms of a rough-running engine post-wash. If these symptoms are not there, you’re good to go.

1. Interrupted engine operation with power delivery pauses and uneven acceleration due to improper air-fuel ignition.
2. Misfires are caused by water intrusion or electrical disruptions during washing.
3. Excessive vibrations indicate a rough-running engine. You may also hear a whining noise when revving engine in neutral.
4. Indicative of misfiring cylinders or combustion imbalance.
5. Noticeable decrease in mileage
6. Check Engine light comes on indicating potential issues after washing the engine.

4 Ways to Fix a Rough-Running Engine After Washing. Which One Is Right for You?

As we mentioned before, there are several reasons that cause a rough engine after washing. Below I have discussed them in detail. Also, I have provided their potential solutions to address them promptly.

1. Water intrusion into sensitive components

When water enters areas of the engine where it shouldn’t be, such as electrical connections, sensors, or ignition components, it can disrupt their normal functioning.

Water can interfere with electrical signals, leading to misfires, poor ignition, or other issues that result in a rough-running engine. Additionally, water can cause corrosion or short circuits, further compromising the performance of the engine.

It is important to be cautious while washing the engine, avoiding excessive water spray and directing water away. Especially from sensitive areas to prevent water intrusion and subsequent engine roughness.

Fix

I would suggest starting by inspecting all electrical connections and components within the engine bay. Look for any signs of water intrusion or loose connections. Ensure that all connections are secure and dry.

If you notice any corrosion or damage, clean the affected areas and consider repairing or replacing the damaged components. Also, do allow the engine bay to dry thoroughly before starting the engine.

Use a clean and dry cloth or compressed air to remove any remaining moisture. Pay close attention to areas where water may collect, such as crevices or electrical connectors.

It’s essential to ensure that the engine bay is completely dry to prevent water-related issues that can contribute to a rough-running engine.

Also, do not forget to carefully inspect the spark plugs for any signs of moisture or damage. If you notice water droplets or corrosion, use a clean cloth or compressed air to dry the spark plugs. Ensure that they are clean and free from any debris.

If the spark plugs are severely damaged or worn out, consider replacing them (Our recommendation: Autolite Platinum AP5263). Properly functioning spark plugs are vital for efficient combustion, preventing misfires and contributing to a smooth-running engine.

2. Damaged ignition coils

The faulty ignition coils or wires disrupt the spark delivery to the cylinders, resulting in rough engine operation. Water intrusion is often an overlooked cause of ignition coil damage.

In certain vehicles, the accumulation of A/C condensation can result in water dripping directly onto the ignition coils. It leads to the filling up of spark plug holes with water.

This can have detrimental effects on the ignition system, impacting engine performance and reliability. It is important to be aware of this potential issue and take preventive measures to avoid water-related damage to the ignition coils.

Fix

Examine the ignition coils and wires for evidence of wear, corrosion, or water entry. Examine the area for cracks, rust, or broken connections. If any issues are detected, replace the affected ignition components.

3. Contamination of air intake or fuel system

Engine roughness after washing might be caused by contamination of the air intake or fuel system. Water, dirt, or debris might get into the air intake or fuel system components during the cleaning process.

Air filter contamination can interfere with the proper flow of air or fuel, affecting the engine’s combustion process and leading to rough operation. Water or debris in the air intake can cause a lean or rich air-fuel mixture, resulting in misfires or hesitation.

Contaminants in the fuel system can clog fuel filters or injectors, affecting fuel delivery and engine performance.

Fix

Examine the fuel system components, including fuel filters, injectors, and lines, for any signs of contamination. If you suspect water or debris in the fuel system, it’s important to address it promptly.

Clean or replace fuel filters if they are clogged, and use fuel additives designed to remove moisture or contaminants from the system. Here are a few simple steps you can follow;

• Disconnect the battery. It will make sure the car won’t get started while you work on the filters.
• Locate the fuel filter just along the fuel line on the bottom of the car, just past the fuel pump. Or it can be in the engine bay on the line that leads to the fuel rail.
• Remove the clips holding the fuel filter in place using a flathead screwdriver to pop them out of the holes they are in. These clips are made of thin plastic and may break as you remove them. So be ready with the replacement clips along with your fuel filter.
• Remove the fuel lines from the filter and now you can slide the fuel filter out of the bracket.
• Pre-check and replace the old one with a new one. Make sure the one you just removed is a match with the new one.
• Place the new filter in the bracket and slide the plastic clips through the holes to secure the line in place on the fuel filter.

Check out this youtube video to understand the steps visually:

Next, you must check the air filters for any signs of dirt, debris, or water contamination. If the filters appear dirty or wet, clean them or replace them accordingly.

• Remove the air filters from their housing.
• Tap the filters gently to remove loose debris.
• Use compressed air or a vacuum cleaner to further clean the filters.
• If the filters are washable, rinse them with water and mild soap.
• Allow the filters to air dry completely.
• Once dry, reinsert the filters into their housing.
• Ensure that the filters are properly seated and secure.
• Clean air filters ensure optimal air intake and promote smooth engine operation.

Check out this youtube video to understand the steps:

4. Damaged or degraded engine components

This can also contribute to engine roughness after washing. The forceful application of water or improper washing techniques can potentially cause physical damage to engine components. This damage may include;

• cracked or chipped parts
• worn seals or gaskets
• degraded insulation

Damaged or degraded components lead to air or fluid leaks, inadequate compression, or poor combustion, resulting in a rough-running engine. Regular inspections and maintenance are important to identify and address any damaged or degraded engine components promptly.

Fix

Repairing or replacing these components as needed can help restore smooth engine operation after washing and prevent further issues.

Here’s a step-by-step fix for addressing damaged or degraded engine components after washing:

• Conduct a visual inspection of engine components for any visible cracks, chips, or other damage.
• Check seals and gaskets for wear or deterioration, paying close attention to areas prone to water exposure.
• Inspect insulation around wires and connections, looking for any signs of degradation or damage.
• Address any identified issues by repairing or replacing the damaged or degraded components.
• Ensure proper installation and tightness of seals, gaskets, and insulation during replacement.
• Conduct a thorough leak test to verify the effectiveness of the repairs.
• Perform regular inspections and maintenance to promptly identify and address any new damage or degradation.

Preventive Measures: Protecting Your Engine During Washing

Follow these preventive measures for protecting your engine during washing:

1. Cover sensitive components with protective covers or plastic bags.
2. Use proper techniques for engine washing. Check out the quick steps below:

• Prepare the engine. Ensure a cool engine temperature.
• Protect air intake, electrical connections, and exposed wires by covering them.
• Use a gentle engine cleaner or degreaser.
• Avoid high-pressure water
• Spray cleaner onto dirty areas.
• Gently scrub engine surfaces with a soft brush.
• Rinse thoroughly with water to remove cleaner and debris.
• Dry the engine. Allow air drying or pat dry with a cloth.
• Carefully take off the protective covers from sensitive components.
• Check for moisture and start the engine to ensure proper operation.

3. Be cautious with water pressure to avoid damage or water intrusion.
4. Allow sufficient drying time before starting or operating the vehicle.
5. Consider professional car wash services for a safe and reliable engine cleaning experience.

Concluding Notes

To conclude, engine washing is essential. It helps to keep it running smoothly and prevent corrosion. If you want to keep your engine safe during and after an engine wash, ensure the engine is cool enough to not show any fumes.

Other than this making sure of proper washing procedures are a must. Apart from your car running rough post-engine wash, you may also hear squeaking noise from engine when idle.

I have tried to put all the necessary steps and suggestions to fix and prevent the problem of the car running rough after washing the engine. I hope this will help.