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Mustang Cranks But Won't Start Checklist

Created by Jay Walling / 6 min read
Date Created: 12/8/2020
Last Updated: 12/22/2023

In this article, LMR covers some of the common problematic issues that can cause no-start conditions. Check out our Mustang Cranks But Won't Start Checklist!

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Mustang Cranks But Won

There is nothing worse than hopping in your Mustang, and you go to fire it up and it just cranks over. In this article, LMR goes over some of the common problematic issues that can cause these no start conditions. For any engine to run you really only need 4 main things: Air, Fuel, Timing, and Spark. Throughout this checklist, we will cover each of these factors in detail so that you can better diagnose your specific issue.


Jump To: Air | Fuel | Timing | Spark

AIR

Mustang Cranks But Won

Starting off with the air intake system, this is pretty simple. Check over all of your main intake components. This would include any blockages within the intake track that could be starving the engine of fresh air. Clogged or dirty air filters are the main thing to look at here. Normally if the engine is starving for air, this is the first place to check out.

Mass airflow sensors will be another air-related area. Make sure that your MAF is not dirty. Any build-up of dirt, debris, or oil/contaminants can cause these issues as well. Check over any missing or misaligned gaskets. Again, any blockages that could hinder air from entering the engine is key here.


FUEL

Mustang Cranks But Won

Next, moving over to the fuel section. The first thing is do you have gas? I know this may sound silly, but you never know if you may have a faulty level sending unit or just simply ran out.

If you have access to a fuel pressure gauge you can normally hook this up to your factory Schrader valve (if equipped) and verify proper fuel pressure. This can help you determine if you may have had a fuel pump fail. If your fuel pressure is not up to spec, things to look at are going to be the pump, the electrical system including wiring and relays, or any blockages in the line that would not allow fuel to reach the engine.

Depending on the application, you may look at any DTC’s or codes in the system. This can also help you with the diagnosis of your no-start condition.

Quality of fuel is another area. If your car has sat for an extended timeframe, you may want to consider draining this and starting fresh. E85 is another one that can be time-sensitive. It is not a good practice to let ethanol sit too long in the tank.


TIMING

Mustang Cranks But Won

Timing is a key area when it comes to starting. If the timing is off, there can be many different problems. If you have recently installed a camshaft or other valvetrain-related components, you may want to go back over your install. If timing is too far advanced or retarded, this can cause hiccups upon startup.

Ignition timing needs to be up to par as well. If the ignition timing is too far off then this can cause your starting problems as well.


SPARK

Mustang Cranks But Won

Everything we have covered so far has to have the spark to complete it all. Without spark, you will never have a running engine. Some ignition systems can be complicated. The ignition system normally has many different parts that can be the culprit. Distributors, coils, plugs, wires, sensors, computers, and the list can go from there.

Your proper firing order will need to be correct. If not, then this can cause a no-start condition. Especially if multiple cylinders are mixed up. One quick way to start off with is to just pull a plug wire or coil and ground it out against the engine. This way, you can physically see the spark if it is firing.

As we mentioned earlier in the timing section, ignition timing has to be set correctly for the engine to start. Depending on the application, this can be done manually or some need the use of tuning or a computer to do this task. Now we do want to mention that there are other things to factor into the “no start” condition. This can include some of the following items below:

  • Battery- Low battery voltage is one of the electrical system's first things to look for. A good rule of thumb here is 12.5V or higher, to begin with.
  • Engine Compression- If your engine compression is low, this can hinder the engine from starting and running properly.
  • Starter- The starter system includes your battery cables, ignition solenoid, and the starter; all need to be checked out for proper operation.
  • Aftermarket Ignition Systems-Aftermarket ignition systems usually run in series through the factory ignition system to enhance them. One quick thing to do here is temporarily remove this from the system to eliminate this as the issue.
  • Other Electrical Components (Fuses, Wiring, PCM, etc.)- Go over all fuses and relays to ensure no opens or popped fuses and that all relays are in working order. This can also include items like a neutral safety switch on automatic cars, and a clutch pedal position switch for manual applications.
  • Ignition Switch-The ignition switch inside of the car is one common issue on a lot of Mustangs. Check over the switch and associated wiring to ensure there are no issues at hand.
  • Exhaust (Possible Clogs/Restrictions)- Inspect the catalytic convertors to ensure there are no obvious restrictions here.
  • Grounds- Dirty ground cables and cable ends are a common problem with any vehicle. If the ground side is not making contact, starting issues can happen due to this.
  • Ignition Coils- The ignition coil is integral to any ignition system. If this is not working, then the spark can be affected.
  • TFI Module (If Equipped)- The TFI module found on some of the Fox Body Mustangs is a known culprit for causing no-start issues. There is no real repair for these other than to replace them. Heat is the number one killer of these modules.

Just to give a quick recap, this is a basic guide for things to look over. This will not be the same for every year of Mustang, but overall, these are the places we would recommend to start with. We at LMR hope this checklist has better helped you diagnose your issue and can get you back on the road!


Thumbnail image of the author of this article, Jay Walling.

About the Author

Jay has written content for Late Model Restoration for over 10 years, producing over 120 articles. Jay has an extensive 25-plus-year background in automotive and is a certified Ford Technician. Read more...