How To Start A Diesel With Bad Glow Plugs [2 Easy Methods]

If your glow plugs have gone bad to start your diesel engine, you should follow this procedure: Turn the ignition key to the start position and crank for five seconds. 

Afterward, allow five seconds to elapse. Crank again for five seconds and wait for five seconds. Repeat this process several times until the engine starts.

1. Start diesel engine with faulty glow plugs

2. Diesel Cold Start Trick

Symptoms of Bad Diesel Glow Plugs

This video explains how to spot signs that your car’s glow plugs fail. Below you will find some clues which point to faulty glow plugs.

1. Trouble Starting the Vehicle

A difficult starting engine is the most common sign of faulty glow plugs. If the combustion chamber does not reach the proper temperature, it will not be able to ignite the fuel, and your engine will fail to start.

Glow plugs should be checked if you have no problems with your fuel or battery, as these are the most common causes of a hard-to-start engine.

2. Black Exhaust Smoke

Black or dark gray smoke is an indication that your diesel vehicle is experiencing a problem with the combustion system.

The combustion system is responsible for converting fuel into energy and powering the engine, so it’s important to pay attention if you notice black smoke coming from the exhaust.

3. Engine Misfiring

If your engine backfires, there’s something wrong. It means that your fuel isn’t igniting properly in the cylinder, and a bad glow plug could cause that.

If you’re having a starting problem, check the glow plugs first.

4. Poor Acceleration

If you’ve been having trouble pushing the accelerator down and nothing seems to be happening, it might be time to replace your glow plugs.

Glow plugs are used to warm up the engine, and if they’re defective, they can affect your vehicle’s performance.

5. Engine Warning Light

When glow plugs become faulty, the check engine light can be triggered. With an OBDII diagnostic tool, you can scan the onboard system and retrieve the error codes.

A P0380 code may appear if any glow plug circuits are faulty.

Frequently Asked Questions

What happens if you don’t replace your glow plugs?

If glow plugs are not replaced, engine performance will decrease, and the operating temperature will not be reached.

Consequently, more power will be required from the engine, which will reduce fuel efficiency.

Can I drive with a bad glow plug?

The diesel glow plug plays a key role in triggering an ignition and achieving normal engine performance.

A misfire is likely to occur if the plug is faulty, and progressive degradation of vehicle performance will become evident if the glow plug doesn’t fire correctly.

What happens when a glow plug stops working?

If one or more glow plugs are damaged or malfunctioning, the engine will be harder to start at lower temperatures.

Also, it will idle roughly and produce white smoke from the exhaust once it is running.

How to Test Glow Plugs From Start to Finish (With a Multimeter) – The Complete Guide

How often should glow plugs be changed?

Their typical lifespan is about 100,000 miles. However, if you hard start frequently or use a lower quality glow plug than recommended, the plugs may fail before their anticipated life span.

How long should I let my glow plugs warm-up?

Glow plugs require a 15 to a 30-second waiting period before the engine can crank. Allow the “Wait to Start” light to illuminate completely.