report

My Engine Won't Turn Over

An engine no-crank condition can by hard to diagnose sometimes.
An engine no-crank condition can by hard to diagnose sometimes. | Source

An engine-won't-turn-over issue is a common engine performance problem. The root cause may range from a loose wire to a more serious mechanical issue. Fortunately, most of the problems that may prevent your engine from turning you may diagnose at home. Others are more difficult, for example when dealing with an electrical short or a component you won't think could affect the starting system.

Thus, you can soon hit a road block trying to repair the starting system without knowing what to do next, while missing important clues. The purpose of this guide is to help you find those clues so you can find and follow the potential path that most likely will lead you to the source of the problem.

So let's see how you can speed up your diagnostic process.

Index
WARNING: Your Oil Pressure May Be Low
How to Use This Guide
I. I Hear the Starter Motor Rotating
II. My Starter Makes a Noise
A) I Hear a Click Sound
B) I Hear a Chattering Sound
C) I Hear a Grinding Noise
III. I Don't Hear Any Noises
Using Your Headlights as a Diagnostic Tool
Starting System Current Draw Test
Voltage Drop Test
Engine Seize Test

WARNING: Your Oil Pressure May Be Low

As a safety measure, some vehicle models won't allow the engine to start if the oil pressure has dropped. If your vehicle has this feature, make sure you have enough oil and check the interlock switch, if necessary. Consult your car owner's manual and the repair manual for your vehicle model to make these checks.

A starter motor will fail after miles of service.
A starter motor will fail after miles of service. | Source

How to Use This Guide

Although the engine not turning over is obvious—since the crankshaft is not rotating—the symptoms may manifest in different ways, depending on the source of the problem. For example, an undercharged battery will probably will produce just a click or no click at all when you try to start the engine; on the other hand, a loose starter or problems with the flywheel will probably produce a screeching sound every time you try to start the engine.

So one of the first things to do to speed up the diagnostic process, and the fixing of the problem, is to gather as much information surrounding the issue so that you can narrow down the potential sources to the minimum.

This guide is divided into three main sections, plus three main tests referred to by one or more sections. The section headings describe general potential symptoms your starter may be producing. Some sections are further divided into more specific symptoms.

Identify the section heading that closer describes the symptoms your engine is showing and go over the steps under that section to help you troubleshoot your engine no-crank condition.

I. I Hear the Starter Motor Rotating

Often, when the starter motor seems to work fine but the engine doesn't turn over, the starter motor is at fault.

  • Failed starter overrunning clutch
  • Starter mechanism fails to engage pinion gear
  • Pinion gear teeth worn out or broken
  • Flywheel teeth worn out or broken


The overrunning clutch allows the pinion gear to only rotate in one direction to turn the flywheel; than, it lets the gear spin freely when the engine has reached running speed.

Remove the starter motor, use a standard screwdriver to turn the pinion gear. It should turn in one direction only; check the gear teeth for wear and damage. Or take the starter motor to your local auto parts store. They can bench test the starter for you without charge.

If the starter motor turns out fine, check the flywheel for missing teeth or damage to the ring gear or similar problems. The Engine Seize Test section below describes a couple of methods you can use to turn the engine so you can check the flywheel ring gear, if necessary.

Make sure the battery terminals are clean and tight.
Make sure the battery terminals are clean and tight. | Source

II. My Starter Makes a Noise

Clicking, chattering, and loud grinding noises, other than a regular starter motor operating, usually mean trouble in the starting system. The problem could lie with the starter motor itself, a component in the starter system, the connecting wires or the battery.

A) I Hear a Click Sound
A single, solid click sound usually means a problem with the starter motor, the starter solenoid, or a seized engine. You can remove the starter motor and take it to an auto parts store and have them test it. If the starter motor works fine, try turning the engine manually. Refer to the section below Engine Seize Test, which describes how you can turn the engine manually.

B) I Hear a Chattering Sound
1. First, make sure that you have a charged, healthy battery. Even if you're reading above 12 DC volts from your battery with your multimeter, it doesn't mean it can deliver the required amps for the starting system to work. Take your battery to an auto parts store to have it checked, or check the battery yourself with a hydrometer.

2. After checking the battery, visually inspect the starting system connections, at the battery terminals, at the starter solenoid or starter remote relay. Loose, corroded (white, greenish or blueish crud) or damaged connections will resist electrical flow and prevent the starter motor to function properly.

3. If everything looks fine, do a Voltage Drop Test on the starting system connections as described in that section below. You may have a corroded or broken cable or wire. Follow that test with the Starting System Current Draw Test.

C) I Hear a Grinding Noise
A loud, chattering metallic noise, usually means one of three things:

  • The starter motor mounting bolts are loose
  • The pinion gear is damaged
  • The ring gear around the flywheel is damaged.


1. Check and tighten the starter mounting bolts to the torque listed in your vehicle repair manual.

2. If the starter motor bolts check OK, remove the starter and check the pinion gear.

3. If the pinion gear seems in good shape, check the teeth at the flywheel ring gear for damage. You may need to use a flywheel turner or turn the crankshaft using a breaker bar to inspect the whole ring gear. Refer to the section Engine Seize Test below.

Use your headlights as a diagnostic tool.
Use your headlights as a diagnostic tool. | Source

III. I Don't Hear Any Noises

Sometimes, the starter motor won't produce any sounds, not even a click, when you try to start the engine.

* This could mean the pinion gear got stuck at the flywheel ring gear. With a manual transmission, it's easier to verify this. Set the transmission to gear and rock the vehicle a few times. Then try to start the engine. On an automatic transmission, hit (but don't damage or dent) the starter with a hammer or rubber mallet to rattle and unstuck the inside mechanism. Then try to start the engine.

* It's possible you may have an electrical short or bad connection somewhere in the starting circuit. To start checking the circuit, if you turn the ignition key to the On position and you don't see the dashboard warning lights come on, but your headlights, radio and other accessories work fine, look for a possible blown ignition circuit fuse. To find the fuse, look for a 'power' box under the hood, or behind a fuse panel cover under your dashboard (driver's side or passenger side). Also, check the ignition relay (check your repair manual for the location, then test the relay.

High resistance pose another problem for the starting system circuit. But this calls for some specific tests:

Using Your Headlights as a Troubleshooting Tool

1. Turn on the headlights, windshield wipers and radio. If they fail to work, you may have a discharged or failed battery, or corroded battery terminals (white crud stuff around them), one or both battery terminals are loose, or the ground connection (the thin wire that runs from the black battery cable to the car body) is corroded or loose. Turn off the ignition, headlights, windshield wipers and radio. Once you've checked your battery and the connections, proceed to the next steps.

2. Stand in front and to one side of your vehicle so that you can see the headlights clearly.

3. Ask an assistant to turn on the headlights and try to start the engine while you observe the headlights.

A) If the headlights remain bright, check for a possible short in the starting circuit.
* First, check the starter solenoid. If the starter solenoid on your starter seats on top of the motor, you can take the starter motor to your local auto parts store for a quick check.

NOTE: When testing the starter solenoid, if you don't detect voltage at the control circuit wire, probably your neutral safety switch (automatic transmission) needs an adjustment or has failed (newer vehicles now use a Transmission Range [TR] sensor instead and may set a trouble code in the computer memory when it fails); also, there could be a problem with the clutch interlock switch (manual transmission). Another possibility is an open at the wire connecting the fuse panel to the control circuit terminal at the solenoid, or an open or failed ignition switch.

* Then, using a multimeter, check for battery voltage along the positive (red) battery cable. For this test, your battery has to be fully charged. If you don't own a digital multimeter, you can get an inexpensive one from your local auto parts store or online. It's an indispensable tool for automotive troubleshooting.

1. Set your voltmeter to 15 or 20 DC volts. Then connect the black meter probe to the negative (-) battery post, and the red meter probe to the positive (+) battery post. You should read above 12 volts, otherwise, charge and have the battery checked at your local auto parts store.

2. Leave the black meter probe connected to the negative side of the battery, and connect the red meter probe to the terminal connected to the positive side of the battery.

3. Then, move the red probe to the next connecting point along the red battery cable, until you reach the terminal and connection at the starter motor.

4. At every point along the battery cable, you should read battery voltage. Otherwise, check for an open or damaged cable or connection between the point where you found no battery voltage and your previous check point.


B) If the headlight brightness dimmed when your assistant tried to start the engine:
1. Check the battery cables at the battery terminals, solenoid or relay, and ground connections for corrosion, loose or broken wires.

2. Make sure the starter is properly mounted, otherwise it won't be properly grounded and electric current won't reach the starter.

3. Check voltage drop on the battery cable that connects to the starter motor as described in the section Voltage Drop Test below.

4. If voltage drop is OK, go over the section Starting System Current Draw Test below.

5. If your starter draws too much current but voltage drop is fine, either your starter has failed or your engine has a mechanical problem (you can take the starter motor first to your local auto parts store for a quick check if you prefer). Check to see if you can turn the engine manually. Refer to the section Engine Seize Test below.

6. If the engine rotates smoothly without difficulty, replace the starter.

Some vehicle models, like the Chevy Silverado shown in the video below, have some common issues with the starting system.

Starting System Current Draw Test

You can perform a starter system battery current draw test yourself using an inductive pick-up meter. Consult the repair manual for your particular vehicle make and model, if necessary.

1. For this test, disable the ignition system (unplug the ignition coil cable that connects to the distributor and connect it to ground using a jumper cable) or disable the fuel system (remove the fuel pump fuse).

2. Connect the ammeter to the positive or negative battery cable (read the ammeter manufacturer instructions).

3. Ask an assistant to try to start the engine for about ten seconds.

4. On a 4 cylinder engine, a healthy starter motor will draw about 110 amps; a 6 cylinder or small V8 engine you'll see the motor pulling about 200 amps; a large V8 engine will probably draw close to 250 amps. When amps differ much from what the manufacturer specifies check for problems with the starter motor, solenoid, connecting wires or cables.

A multimeter is an indispensable tool to diagnose starting system problems.
A multimeter is an indispensable tool to diagnose starting system problems. | Source

Voltage Drop Test

1. Set your multimeter to 15 or 20 Volts DC.

2. Disable the ignition system (unplug and ground the ignition coil) or disable the fuel system (remove the fuel pump fuse) to prevent the engine from starting.

3. Connect one meter probe to the connection you want to test (for example, a battery post), and connect the other voltmeter probe to the terminal that connects to that connection.

4. Have an assistant try to start the engine for about 10 seconds or less.

5. You should get no more than 0.1 to 0.3 volts at any connection along, for example, the battery path to the starter motor, if those are the connections you're testing.

6. A voltage drop test between the battery positive terminal and the connection at the starter solenoid where the battery cable connects to, should not go over 0.5 volts.

7. Any reading above those indicated above means a problem with that connection. Make sure the connection is clean and tight, and that the wire or cable is not broken or filled with corrosion at the terminals.

Engine Seize Test

Although not as common, mechanical problems can also prevent your engine from turning over. The easiest way to check whether your engine has seized is to manually turn the engine. To turn the engine, you have two alternative methods: You can use either a flywheel turner or a breaker bar. Let's check the former method first.

A) Using a Flywheel Turner
1. Remove the bell housing cover to gain access to the flywheel. On some models, you can access this cover from above the engine compartment. On other models, you'll need to raise your car on jack stands to reach the cover from underneath.

2. Block the rear wheels to prevent the car from rolling.

3. Set the transmission to Neutral and engage the parking brake.

4. After removing the access cover, turn the flywheel with the tool.


B) Using a Breaker Bar
Another option is to use a breaker bar and the appropriate socket size to turn the crankshaft. You do this by turning the large, center bolt that holds the crankshaft pulley at the front, lower side of the engine.

1. Raise and safely secure the car on jack stands.

2. Remove the passenger side front wheel.

3. Block the rear wheels to prevent the car from rolling.

4. Place the transmission in Neutral and engage the parking brake.

5. Now try turning the crankshaft using the breaker bar, extension and socket.

6. If you can't turn the engine, or it's difficult to turn, you may have a mechanical problem.

7. If you can turn the engine, but nothing turned wrong in your previous diagnostics, check the flywheel teeth for damage by removing the flywheel cover at the back of the engine and examine the ring gear as you turn the crankshaft.

NOTE: If you have difficulty turning the engine, remove the spark plugs (number the plugs and wires first so you can replace them in their correct place), then try turning the engine again. If you still can't turn the engine, or it's difficult to turn, you definitely have mechanical problems.

Starter system problems are common and that includes no-crank issues. However, trying to find the culprit behind the fault can be tricky at times. This guide helps you get to the root of the problem by following a systematic approach. So you stand a better chance to repair your car and get back on the road faster.

More by this Author


No comments yet.

    Sign in or sign up and post using a HubPages Network account.

    0 of 8192 characters used
    Post Comment

    No HTML is allowed in comments, but URLs will be hyperlinked. Comments are not for promoting your articles or other sites.


    Click to Rate This Article