1.) Engine Mechanical System
- The engine pistons and valves (and all the other related components like: timing chain. camshaft, etc.) are the ones that get the air into the cylinders to mix with the fuel (and then explode in combustion when the spark hits this mix).
- Although rare, internal engine mechanical problems can and do cause no-start conditions (especially after severe overheating or running the engine with no oil).
- Possible internal engine problems are:
- Blown head gasket.
- Blown engine.
By now, you might be thinking that a no-start condition may be too difficult to diagnose but nothing could be further from the truth.
Also, it's very rare to have two different components from two different systems fail. For example, the odds of having a bad fuel pump and a bad crank sensor at the exact same time are astronomical.
Now, since 'knowledge is power', knowing the three major problem areas (or systems) will help you develop a diagnostic strategy of what to test and how to test it, which in turn increases the likelihood of finding the exact cause of the no start issue.
No Start 1: Checking For Spark
My recommendation is to test for spark and fuel right from the beginning.
Testing for spark should always be done with a dedicated spark tester and testing for the presence of fuel should be done with a fuel pressure gauge.
For this part of the article, let's assume for a moment that you have tested for spark and you got one of the following two results:
CASE 1: Spark was present in all of the cylinders. Depending on the type on whether your Ford has a distributor or a coil pack ignition system, this results tells that:
- Distributor Type Ignition System:
- The PIP Sensor (which is what Ford calls the crank sensor) is functioning correctly.
- The ignition coil is good.
- Coil Pack Type Ignition System:
- The crank sensor is functioning correctly.
Your next step is to verify fuel pressure. Go to: No Start 2: Checking Fuel.
CASE 2: Spark was NOT present in all of the cylinders. The next step is to make sure that you do have fuel pressure with a fuel pressure gauge just to make sure the fuel pump is not a secondary issue.
Now, with no spark in any of the engine cylinders, this what I would suggest:
- On a Distributor Type System:
- Check for spark directly on the ignition coil tower using a spark tester.
- On occasion, the distributor cap and/or rotor stop distributing spark. The best way to test them, is to check for spark directly on the ignition coil tower.
- If you do get spark coming out of the ignition coil tower, you now know beyond a shadow of a doubt the distributor cap and rotor must be replaced.
- Distributor Type Ignition
- ...Testing the ignition coil continued:
- If no spark is firing from the ignition coil, then the next step is to verify that the ignition control module is activating it. This is a pretty simple test.
- You can find the ignition coil here: How To Test The Ignition Coil (Ford 2.9L, 3.0L, 3.8L).
- If the PCM is not activating the ignition coil, this usually means that the ignition control module is fried.
- Distributor Type Ignition
- Test the ignition control module.
- If the ignition control module tests OK, then the next step is to test the PIP sensor.
- The PIP sensor is at the heart of everything that is involved with starting the vehicle. For example, if the PIP sensor has failed:
- The PCM will not activate the fuel injectors.
- You can find the ignition control module Test and PIP sensor test here:
- Coil Pack Type Ignition
- In my experience, it's rare for the coil pack or crank sensor to fail in this type of ignition system, although this is not an absolute truth.
- The most common problem that I've seen is a lack of power going to the coil pack, causing a total no-spark condition.
- This lack of power (12 Volts) is usually due to a blown fuse or some electrical issue in the wiring.
- You can find a complete coil pack troubleshooting guide here: How To Test The Coil Pack (at: easyautodiagnostics.com).