Jump Start A Car With Bad Starter? – Fix it now!


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.

Can you jump start car with bad starter? 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 may be 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.

Starter Noise

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 though job though and yours could indeed be the root cause of the problem. But just before we get to checking the starter motor, lets do a run through of the more common causes. This will eliminate all the easy to fix stuff first, make sense?

Diagnoses

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:

  1. Repeated click sound
  2. Single click sound
  3. 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.

Jump starting

Using the picture above as a guide, put the jumper cables on in sequence 1, 2, 3, 4. (It’s not important which car has the flat battery)

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.

Loose Battery Terminals & Grounds

Battery terminal check

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. 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 clean the terminals safely using 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.

Ground straps

Car ground strap

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 problem and you can check it out in this post “Car won’t start but lights come on”.

Ground strap

OK, that’s the easy stuff checked, now lets look at the most likely cause of the repeated clicking sound.

Checking The Battery

Battery testing

The battery is as you know the most likely culprit, so lets go ahead and check it first. Two testes are needed to conclusively test the battery – Voltage check and a Crank test. You’ll need a volt meter to check battery readings.

Voltage test

The following readings represent 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 its got the power to turn the engine, for that we need the crank test.

Crank test

diag

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.

Starter test

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.

Relay

The relay will have four terminals:

85 – Starter control ground
86 – Starter control power
30 – Battery power
87 – Solenoid feed

Control module starter circuit

The relay is and electro mechanical device that controls the solenoid (load) circuit using the Ignition (PCM control) circuit. Caution engine may turn over – Using a jumper wire we’ll by pass the ignition and PCM by connecting terminal 87 with terminal 30.

Hot wire starter motor
Do not attempt this without applying the E-brake

This allows us 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 info graphic below. If it tests OK, check the wiring back to the PCM, but you’ll need a wiring diagram.

Relay testing

Jammed Starter Motor

Rocking a manual car back and forth should help free up the starter motor. Auto trans cars will need socket and ratchet on the flywheel to crank over the engine. A worn starter or stater gear or flywheel ring gear may cause the starter motor to jam.

Hydro-locked Engine

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.

Mechanical Fault

Valve damage

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

Car fuse box

In this section we’ll look at the most common reasons your key turns but you have noting, 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 drivers 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 a list of items to check:

  • Security key on dash board – If the security light ids 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”.

Tools Used

Here’s a few tools you’ll find helpful on this job:

  • Flash light
  • Wire strippers
  • Test light
  • Dvom

Related Questions

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.

John Cunningham

John Cunningham is an Automotive Technician and writer on Rustyautos.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write articles that help fellow gear-heads with all aspects of classic car ownership, from tires to roof aerials and everything in between.

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