Can bad ground cause a car to not start?

A car may not start for various reasons, but could a bad ground be the cause? and what can we do to fix it, if so? Let's find out.

This article will help you recognize the symptoms of a possible bad ground, confirm if a bad ground is really the culprit, and fix the problem so you can start your car again.

So, Can a car not start due to poor grounding? Yes, it can.  Grounding is critical to the correct operation of the vehicle's electrical system.

Below I will teach you how to recognize the symptoms of a bad ground and how to re-establish a good connection.

What is grounding?

First of all, what is grounding? Vehicle grounding refers to the connection of the negative (-) battery terminal to the vehicle body and engine. Although the main ground cable is usually black, you may find that a separate ground wire was used to connect the negative terminal to the vehicle chassis (body ground wire).

Maintaining a good ground is important because the electrical circuit in a car is a closed loop system. It flows from the positive (+) battery terminal to the negative (-) terminal, with all vehicle electronics connected to this circuit. A continuous and uninterrupted flow of electricity is necessary for the normal operation of all vehicle electronics.

What makes a bad ground

When you have a bad ground, there is no longer a continuous and uninterrupted flow of electricity for the car's electronics. In this situation, the current seeks another return path to battery ground. This disruption or variation in flow is often the cause of many electrical problems.

A bad ground will not usually drain the battery, but it can cause it to not charge properly and cause the car to give incorrect signals. This can lead to difficult starting, loose or faulty spark plugs (gasoline engine) or relay or heater problems (diesel engine). Bad grounding can affect a car's entire electrical system, including its sensors and coils, and severe damage can require costly repairs.

Symptoms of bad grounding

If you notice any of these symptoms, it may indicate a bad ground:

Electronic failures

An electronic failure occurs when you notice, for example, that the warning lights on the dashboard come on for no apparent reason, or all the taillights turn on when you intended to give only one signal. Even if the car is turned off, poor grounding can cause the lights to turn on. Anything unusual, abnormal, or erroneous in electronics indicates a failure.

If you notice any malfunctions in your car's electronics, it may be due to poor grounding, although there may be another serious reason. If you notice a pattern in the failure or the appearance of a specific DTC, this may provide a clue to help you resolve the situation.

flickering headlights

Dim or flickering headlights are the visible symptom you notice when you turn your headlights on. If they flicker or pulsate, this may be due to uneven generator voltage.

Generator low voltage

The alternator voltage is low when the reading is well below the normal range of 14.2-14.5 volts. You may only recognize this symptom after checking the alternator voltage.

heavy cranking

Hard starting occurs when the starter cranks when the ignition is turned on to start the vehicle. This is a serious condition.

Engine misfires or won't start

If your car's engine is misfiring or won't start, it could be due to a bad ground. This is a clear sign that something is wrong and the car needs further inspection.

Other symptoms

Other symptoms of poor grounding include intermittent sensor failure, repeated fuel pump failures, vehicle difficulty starting or vehicle not starting at all, ignition coil failure, battery draining too fast, radio interference, etc.

General Checks for Bad Grounding

If you suspect there may be a bad ground preventing your car from starting properly, look for the following things to fix the situation:

Check out the repaired area

If you have recently performed repairs and the symptoms of poor grounding only appeared after that, you should first check for the problems mentioned below.

Check for free contacts

The connection may loosen or come loose due to the constant vibrations the vehicle experiences or after doing some mechanical work. Look at the connections between the battery, car body and engine, especially nuts and screws. Tighten them if you notice any loose contacts, or replace them if their threads are damaged.

Check for damage

Check for damaged cables, clamps, wiring and connectors. If you notice a cut or tear on the cable or strap, a damaged connector, or a broken wire end, it could be a bad ground.

Check Contacts Rusty

All metal contacts are subject to rust and corrosion. Typically, a car battery is protected by placing it high up in the engine bay and using protective caps on nuts and screws. However, these measures do not guarantee complete protection against rust or corrosion.

Inspect the battery terminals for signs of corrosion. Look at grounding cables, clamps, and wire lugs at their ends. All of these points are usually located below where they are subject to contact with water and moisture, as well as dirt and grime.

Careful check for poor grounding

If the above general checks fail to identify the cause of a bad ground, get ready for more thorough checks. For this you will need a multimeter.

First, find the electrical, chassis, engine, and transmission of your vehicle. You may need to refer to your vehicle owner's manual. We will check these grounds in the same order.

Before we begin, however, remember that when testing for grounding, connect the terminals to bare metal, i.e., an unpainted surface.

Check electrical grounding

Check the electrical ground by connecting the remote starter switch to the positive (+) battery terminal and the other end to the "s" terminal of the starter solenoid (or starter relay, depending on your vehicle).

Check Chassis Ground

The chassis ground test reveals resistances in the vehicle's chassis used as a common ground by electrical components. Here are the steps:

Step 1: Turn off the ignition

Turn off the ignition (or fuel system) to prevent the engine from accidentally starting during this test.

Step 2: Install the transmission

Set the gear/transmission to neutral (or park if using an automatic).

Step 3: Connect the multimeter leads

Set the multimeter to DC. Connect its black wire to the negative (-) battery terminal and the red wire to any clean spot on the chassis, such as a bolt or cylinder head.

Step 4: Start the engine

Crank the engine for a few seconds to get a reading. You may need an assistant to turn the crankshaft while you check the readings. It should be no more than 0.2 volts. If the multimeter shows a higher value, this indicates some resistance. In this case, you will need to further test the chassis ground.

Step 5: Change the lead connection.

Disconnect the red wire from the current point on the chassis to another point as the main ground terminal.

Step 6: turn on the ignition

Turn on the vehicle ignition (or fuel system), start the engine and let it idle.

Step 7: Turn on the electrical component

Turn on major electrical components such as car headlights, auxiliary lights, wipers, or heater.

Step 8 Reconnect the multimeter leads.

Disconnect the red wire from where it is connected on the chassis to the vehicle's firewall and recheck the multimeter reading.

It must be equal to or less than 0.2 volts. You may need to repeat this step for different points until you notice a higher voltage at one point and a voltage drop at another. If this happens, the high resistance point will be between the last two points where you connected the red wire. Look for loose or broken wires and connectors in this area.

Check engine ground

Check the motor ground by taking a voltage drop reading to determine any resistance on the return path. Here are the steps:

Step 1: Turn off the ignition

Turn off the ignition (or fuel system) to prevent the engine from accidentally starting during this test. Either disconnect and ground the cable from the distributor cap to e.g. engine bracket/bolt with a wire jumper, or remove the fuel pump fuse. Check your vehicle owner's manual for the location of the fuse.

Step 2: Set the multimeter to DC

Switch the multimeter to DC voltage and set a range that covers but exceeds the battery voltage.

Step 3: Connect the multimeter leads

Connect the multimeter's black lead to the negative (-) battery terminal and its red lead to any clean surface on the engine.

Step 4: Start the engine

Crank the engine for a few seconds to get a reading. You may need an assistant to turn the crankshaft while you check the readings. The reading should be no more than 0.2 volts. If the multimeter shows a higher value, this indicates some resistance. In this case, you will need to additionally check the mass of the engine.

Step 5: Change the lead connection

Disconnect the red wire from the motor surface to the motor end as the main ground terminal.

Step 6: Start the engine

Start the car engine again to measure the voltage again.

Step 7: Repeat the last two steps

If necessary, repeat the last two steps, reconnecting the multimeter's red lead to different points on the motor, until you get a reading of no more than 0.2 volts. If you notice a voltage drop, there will be a place of high resistance between the current and the last point where you connected the red wire. Look for loose or broken wires or signs of corrosion in this area.

Check transmission ground

Check the transmission ground by taking voltage drop readings to determine any resistances on the return path.

As with previous ground tests, check for voltage drop between the car battery negative terminal and points on the transmission case. The voltage should be 0.2 volts or less, as before. If you notice a voltage drop, you will need to check between these two points connected by the red wire for any damage, as you did before. You may need to remove rust, paint or grease. If you see any damaged ground straps, replace them. Finish by cleaning all gearbox bases. (1)

Summing up

Suppose you notice any of the symptoms mentioned in this article, especially if they occur frequently or if several of them appear at the same time. In this case, your vehicle's ground may be bad. Things to look for (such as loose contacts, damage, and rusty contacts) will confirm if this is the case. If confirmed, the problem should be resolved to avoid possible negative consequences.

Check all ground connections by tracing the negative terminal of the car battery to where it connects to the car body and from there to the car's engine. If you notice electronic failures, check all peripheral ground connections, including the connectors in the engine compartment or wherever they are located.

Maintaining a good ground connection is essential to prevent poor connection problems and to ensure smooth starting of the vehicle. (2)

Take a look at some of our articles below.

• How to connect ground wires to each other
• How to test a low voltage transformer
• How to Use a Cen-Tech Digital Multimeter to Check Voltage

Recommendations

(1) paint - https://www.elledecor.com/home-remodeling-renovating/home-renovation/advice/a2777/different-types-paint-finish/

(2) bad connection - https://lifehacker.com/top-10-ways-to-deal-with-a-slow-internet-connection-514138634