My car starts fine but always like once a month it doesn’t start it cranks ok but it will not start if I let it sit for 6 hours

ANSWER : Hi There,
What you are describing sounds like an ignition coil that may be failing. Ignition coils are prone to this type of erratic functioning or heat cycling when they are beginning to fail due to the temperature fluctuations under the hood which ultimately cause them to shut down causing the car to only run after cooling down for 30-40 minutes. Ignition coils are coated with a varnish-like insulation that becomes brittle over time after being stretched then contracted repeatedly The insulation develops small fractures that open when heated and close when cooled. When open, they allow shorting of coil windings and decrease or eliminate the coil’s ability to function. This process will repeat itself continuously until the coil ultimately fails completely and must be replaced. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your ignition system.

ANSWER : The issue you are having is probably due to an intermittent fault in the starter motor itself or a deficiency in the starter electrical circuit, for example a large voltage drop due to a poor ground or a high resistance connection. These issues can be readily diagnosed and resolved on a mobile basis if you request a hard starting diagnostic. If you request that diagnostic, the responding certified mechanic will get this resolved for you promptly. Based on Toyota’s Factory Service Manual, the battery should not be disconnected if the vehicle engine is running. The battery acts as a large resistive voltage sink and consequently taking the battery out of the circuit, while the alternator is still running, can create a voltage spike on the car’s electrical system which is not good for voltage sensitive components such as the engine computer. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : First, let’s make sure about some terminology before I proceed. I will assume the motor is actually turning over. If the car is trying to start, the motor has to be turning over or it is not trying to start. This is an important distinction when diagnosing the starting system. As a technician, I go to different parts of the system based on this description.

If the key is stuck in the start position, this is a ignition lock cylinder issue and the reason the starter continues to turn the motor over. If the starter is turning but the motor is not, then the starter is likely the problem. Either that or the teeth on the flex plate are all gone. This would require removing the transmission to repair.

If the car runs intermittently, this can be a big challenge. And it also means the starting system is working. It will need to be diagnosed when it is failing. A working car cannot be diagnosed because there is nothing wrong. Where you park your car should not have any affect. It certainly could be a wiring problem. Wiring problems hide really well and can happen anywhere in the miles of wires that are in your car. Isolating the system that is failing is really important here. At the moment I am unsure which system is failing. Starter system, ignition lock cylinder and or ignition switch electrical or something with the engine control system.

When the car is failing, you need to check for spark and fuel pressure. If neither is present, this is a clue. Usually the crank sensor will do this. Does your car have a tachometer? If so, does it move at all when cranking. This is a clue whether or not the cam and or crank sensor is working. Is there a Check Engine Light on with the key on? If there is a Check Engine Light, the code or codes can be used for specific diagnosis.

All of these concerns will send you down a diagnostic path. Be sure not to confuse yourself by misinterpreting multiple system failures. If the key does stick in the start position, this would be the first problem to solve. After that, does the motor actually turn when the starter turns? After that, the question of "Why won’t it start?" is first answered by finding what the motor is lacking. Fuel, spark etc… Good luck.

If you need assistance with these checks, contact a certified mechanic who has the tools and experience needed to properly diagnose this starting issue with your car.

ANSWER : Hello, thank you for writing in. If you are in a position of having to push start the vehicle, you need to replace your starter motor. The diesel leak may be contributing to the malfunction of the starter. If this is the case, the diesel leak will need to be resolved before the replacement is made. The diesel fuel can deteriorate and foul the electronics within the motor. The new starter will likely fail prematurely as well and it will cost you more money in the long run. Typically push starting a diesel vehicle is almost impossible, specially in colder weather. Push starting the vehicle is very hard on the engine and you should have the starter replaced as soon as possible. For more help with this repair, you may contact our service department.

ANSWER : Hi there:

Usually this issue is cased by low cranking amps inside the battery. If you’ve recently had the battery replaced, it’s possible that an electrical component that makes up the charging system might be damaged or faulty. It’s also quite possible that the main electrical relay or the starter relay is giving you fits. To know for certain what the exact issue might be on your 1989 Toyota Camry, you should have a professional mobile mechanic complete a car is hard to start inspection, so they can pinpoint the source of your issues and recommend the right repairs.

ANSWER : Hi there, thank you for writing in and providing a detailed description. I’d be happy to give my insight on what to do next.

I would make the same conclusion about the neutral safety switch. I think Pep Boys made the right call. I admit, I don’t like to call a part bad without being able to duplicate the problem, but anytime a customer states their car starts in neutral but not park, we replace the neutral safety switch. I can’t recall a time that this move was wrong.

The intermittent nature of your problem does’t change this diagnosis either. The same electrical connection can work one moment and not the next. Electricity works at the atomic level that we as humans can’t directly observe, which is why we have tools to do electrical testing. Your tow truck driver got it correct.

Hope this helps and best of luck! If you’d like help replacing your neutral safety switch, consider having one of our expert automotive technicians come to your home or office to do it for you.

ANSWER : With the randomness of the codes you are pulling, it is hard to determine what they have in common. When diagnosing mechanical errors like this, keep it simple. Due to the loss of power and stalling issue, I would like you to look at the one component that may have a huge effect over all of theses parts.

The ELD is a unit which measures the amount of power coming from the battery. It allows the alternator to adjust the field, and the amount of power generated by it. If you are experiencing issues with the ELD, which allows the battery and alternator to behave incorrectly, the other electrical components in the vehicle will not work. You may have more than one issue that is all coming to a head at once.

You can test the ELD with a multimeter, but any electrical testing can be dangerous, and we recommend you proceed with caution. If you’re not comfortable with this repair, consider YourMechanic, as one of our mobile technicians can come to your home to diagnose the stalling issue firsthand and help you make the necessary repairs.

ANSWER : Hi there. An intermittent no start condition, can be difficult to diagnose. Replacing the fuel filter would not hurt anything, especially if it hasn’t been replaced in the last 30,000 miles. Diagnostic procedures should be performed, at the time of no start, to confirm whether there is a loss of fuel, of spark or both.

Assuming the Check Engine Light is not coming on, leads me to believe the ECM (engine control module)/computer is not recognizing the fault. There are many possibilities for a no start condition: a faulty ignition switch, fuel pump relay, fuel pump, ignition coil, ignition module, crankshaft position sensor, camshaft position sensor.

Replacing components without diagnoses can be expensive and time consuming without resolution. I recommend having your vehicle’s intermittent no start diagnosed and repaired by a certified technician, such as one from YourMechanic, so that this can be repaired correctly.