A bad starter is a real pain, we’ve all been there, but don’t panic you’re in the right place. This post is designed to fix your problem.
Jump-starting a car with a bad starter motor will not help start the engine. Jump-starting will only boost battery power. A manual transmission car with a bad starter maybe push or tow started but an auto transmission car can not.
In this post, you’ll learn how to easily diagnose if your starter motor is bad. You’ll learn about other starter system components that commonly give trouble how to diagnose them and fix them.
Starter motors do give trouble but in my experience, the cause is a ton more likely to be a battery or connection issue. Starters have a tough job though and yours could indeed be the root cause of the problem. But just before we get to check the starter motor, let’s do a run-through of the more common causes. This will eliminate all the easy-to-fix stuff first, make sense?
The noise your car makes will be the first clue as to what’s going on. The noises are broken into 3 groups. When you turn the key to crank the engine, you hear:
- Repeated click sound
- Single click sound
- No sound
1 Repeated Click Sound
This suggests a flat battery or poor battery terminal or ground connections. Testing the battery and terminals is easy to do and your issue may simply be a flat battery. A boost start is the fastest way to solve this problem. Use a donor vehicle or alternatively consider buying a jump pack.
The little NOCO boost pack is about the best I’ve seen and I’m a mechanic for over twenty-five years. It’s small enough to fit in a glove box powerful enough to start a diesel engine. Anyway, you can check it out here on the Auto electrical tools page.
Using the picture above as a guide, put the jumper cables on in sequences 1, 2, 3, 4.
Start your car and leave the cables attached and your car idling for a few minutes before removing. Now with the engine running, remove the cables in reverse order 4, 3, 2, and 1.
However it’s worth noting, a flat battery may be a symptom of a faulty battery or a battery drain, or of course an interior light may simply have been left on overnight.
Check out the Amazon link below for cracking deals on starter motors delivered right to your door.Amazon Auto Starter Motors
Loose Battery Terminals & Grounds
Loose or dirty battery terminals aren’t the most likely cause of the repeated clicking sound, a flat battery is, but checking the terminals is a simple quick fix if it works. Look at the battery terminals, are they covered in corrosion (white crusty crud), if so they need to be cleaned.
Cleaning is simple, you’ll need gloves and glasses. The acid will burn the skin. Prepare some baking soda in water and pour it over the crusty white acid corrosion. The baking soda will kill the acid and allow you to clean the terminals safely using a wire brush. Apply some petroleum jelly to help prevent future build-up.
Are the terminals tight? Using a glove check and see if the terminals are loose. Loose or damaged terminals will prevent power to flow to the starter.
The ground straps connect from the battery negative side to the chassis, check this connection is clean and tight. The chassis has a second important ground strap from the chassis to the engine, check they’re tight, rust-free, and in good condition. Loose or damaged grounds will cause starter issues and it’s a common problem.
A volt drop test is great for checking this type of problem and you can check it out in this post “Car won’t start but lights come on”.
OK, that’s the easy stuff checked, now let’s look at the most likely cause of the repeated clicking sound.
Checking The Battery
The battery is as you know the most likely culprit, so let’s go ahead and check it first. Two tests are needed to conclusively test the battery – Voltage check and a Crank test. You’ll need a voltmeter to check battery readings.
The following readings represent the state of charge of a battery at rest:
- 12.7 – 13.2 volts is 100% charged
- 12.4 volts is 75% charged
- 12.2 volts is 50% charged
- 12.0 volts is 25% charged
- 0 – 11.9 volts is Discharged (Flat)
A battery could read a healthy 12.65 volts and still be faulty, so we need to load test it to be sure it’s got the power to turn the engine, for that we need the crank test.
2 Single Click Sound
The single-click sound is closely associated with a faulty starter solenoid but it’s by no means conclusive. To check if the starter motor is indeed faulty, we’ll run a test right from your engine bay fuse box. This saves struggling under the hood to access the starter to test or remove, at least for now unless it tests bad of course.
To begin, place your car in park or neutral for manual cars with E-brake on, this is important as we’ll attempt to crank over the engine. Locate the starter relay in the fuse box and remove it.
The relay will have four terminals:
85 – Starter control ground
86 – Starter control power
30 – Battery power
87 – Solenoid feed
The relay is an electro-mechanical device that controls the solenoid (load) circuit using the Ignition (PCM control) circuit. I use a power probe for this type of work and you can check it here on the Auto electrical repair tools page.
Caution engine may turn over – Using a fused jumper wire, we’ll bypass the ignition and PCM/ECM by connecting terminal 30 with terminal 87.
This allows us to test just the starter, solenoid, and main feed wire. If the starter symptom doesn’t change suspect a faulty starter, however, it still isn’t conclusive. A stuck starter motor, hydro-locked engine, or mechanical fault could also cause the click sound.
If the engine now cranks, suspect a faulty relay or PCM to fuse board wiring. You can check the relay as per the infographic below. If it tests OK, check the wiring back to the PCM, but you’ll need a wiring diagram.
If you’re not into all this wiring, check out a simple relay tester here on the Auto electrical repair tools page.
Jammed Starter Motor
Rocking a manual car back and forth should help free up the starter motor. Auto trans cars will need sockets and a ratchet on the flywheel to crank over the engine. A worn starter or starter gear or flywheel ring gear may cause the starter motor to jam.
You might find this post useful “How hard to replace starter motor?”
This happens when a cylinder fills with a fluid (which isn’t compressible), the piston fails to move and so locks up the crankshaft. Remove the spark plugs and try cranking the engine now. Common causes for Hydro-locking include car flooding in extreme weather conditions and failed head gasket.
A mechanical fault is a possibility too, any obstruction inside the engine will cause the engine to lock. Major faults include Dropped valve; Seized camshaft; Seized Crankshaft; Seized Piston; Broken timing chain; Broken Timing Belt.
3 No Sound At All
In this section, we’ll look at the most common reasons your key turns but you have nothing, not even a clink sound. The lack of sound points to the starter circuit not even attempting to engage. We can run a simple test from the driver’s seat to help confirm that.
Turn on the lights and crank the engine, the lights should go dim, if it does, it suggests that the ignition switch circuit is working. If it doesn’t go dim we have a few more items to check.
Here’s that list:
- Security key on dash board – If the security light is on, the transponder inside the ignition key isn’t being read by the receiver. If you have a spare key try using it, but suspect a faulty ignition receiver.
- Place your automatic transmission in Neutral (N) and try starting – This by passes the Park lockout switch. If it works, suspect faulty PRNDL or wiring.
- Check starter fuse – You’ll find the fuse located in the engine bay fuse box listed as starter motor fuse.
- Manual transmission cars fitted with clutch switch – Check the switch is in place and secure. Try disconnected it.
- At this point we’ll need a DVOM, it doesn’t get very technical and you’ll easily follow it. I wrote a whole post about checking the starter circuit and you can take up that story here “Car won’t start but lights come on”.
Repair manuals and wiring diagrams are seriously useful tools when fault finding. A good manual will cover component location and operation, wiring diagrams and repair procedures, troubleshooting section and fastener torque and sequence specs, etc.
Check out the Auto electrical repair tools page for links to the tools I use. Here are a few tools you’ll find helpful on this job:
- Flash light
- Wire strippers
- Test light
Can a completely dead battery be jumped? A completely dead battery will be difficult to start. Modern cars use battery management computers that won’t output a start command unless a minimum steady voltage is recorded. Running a car with a faulty battery may cause damage to the alternator.