I cannot start my car after engine cools

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 : It’s curious that you don’t seem to have a code in the ECM. Usually if you have a malfunction that prevents the car from starting, there will be a code resulting. That being said, it sounds like you may have an issue with a crank position sensor or an ignition control module. Both of these have a history of failing when they are hot and coming back to life again when they are cold. A bad crank sensor will almost certainly result in a code, but an ignition module might not. It’s hard to say what the issue is about the door lock, but it is probably not related.

Both of those pieces are pretty expensive, so I don’t recommend just replacing them to see if it works. Your best course of action would be to have a mechanic check it out so you don’t replace anything you don’t need. YourMechanic can send a technician to your home to diagnose the starting problem firsthand and recommend an accurate fix.

ANSWER : Your MAP sensor is an important input for your computer. It helps determine the load on the engine to calculate the correct amount of fuel to inject. It sometimes takes a few seconds for the vehicle to realize that the sensor is not producing a good signal.

At that point, it will use other methods to determine the fuel rate, such as pre-programmed fuel maps, throttle position, etc. I would suggest replacing the MAP sensor and retesting. If you would like to have it checked first, a certified technician from YourMechanic will be able to scan your vehicle and test components to determine the root cause of your starting issue before making a repair.

ANSWER : The first thing I would do is have the turbo/intake system ’smoke’ tested or visually inspected for any leaks. Without a smoke machine, you could spray your engine and turbo system with brake cleaner and listen for idle changes to help determine if there is a leak. The brake cleaner method is not as effective as using a smoke machine.

Next, checking your fuel pressure is in order to see if you lose fuel pressure as it sits or if the fuel pump in the tank is weak. If the fuel pump in the tank is weak or losing pressure, it would cause the engine to crank as you mentioned. Performing a fuel pressure test is not easy and requires a special tool. If you want to have this looked at a technician from YourMechanic can come to your car’s location to diagnose your stalling issue.

ANSWER : Hi there:

Unfortunately, there is no exact reason we can offer to you as to why the vehicle won’t start now after your overheating issue; without first inspecting the vehicle. However, if the vehicle overheated on the highway there is a high possibility that major engine damage has occurred, which is possibly why the vehicle won’t start now. This damage could include head gaskets being blown, which can cause coolant to enter the internal portions of the engine and lead to additional damage. The best thing for you to do is have your vehicle towed back home, then contact YourMechanic.com to have one of our professional mechanics complete a car is overheating inspection.

ANSWER : Hello, thank you for writing in. It is difficult to determine the issue without some more information. To start, when the check engine light illuminates, you want to scan the vehicle for diagnostic codes. These are what set the check engine light off, and are meant to tell the driver what the computer has detected is wrong. Codes can be pulled at most automotive parts stores, and by most technicians. Once you have that information you can focus in on one component or system. If the engine is truly overheating, then you want to start by checking your coolant and fluid levels. For more help with diagnosing and resolving the issue, contact our service department to schedule an appointment.

ANSWER : Hi and thanks for contacting Your Mechanic. If sometimes your vehicle will start with the new alternator and sometimes it won’t, then there is a loose connection in your charging system. Check all of the wires to the alternator and to the battery. Make sure that the battery cables are clean and tight. Make sure that the wires to the starter are clean and tight. A loose ground to the ignition system will cause the vehicle to not crank over. Check all of the ground wires from the battery to the starter. Make sure that they are clean and tight. If you need further assistance troubleshooting your no start situation, then seek out a technician, such as one from Your Mechanic, that can assist you.

ANSWER : Hi there:

Sometimes when you have problems starting an engine initially it is caused by a restriction in fuel flow; caused either by clogged fuel injectors or the throttle body that needs to be cleaned. Once the fuel starts to flow and engine warms up, it’s much easier to start. However, it could also be an air filter, EGR valve or other components that causes this issue as well, which is why it’s best to have a professional mobile mechanic complete a car is hard to start inspection so they can pinpoint the source of this issue.