Trying to diagnose and replace whatever is causing your Nissan 1.8L Sentra to Crank but Not Start can have you pulling your hair out. Especially since so many things can cause a no start condition like: a bad fuel pump, a bad crankshaft position sensor, a blown head gasket, and the list can go on.
Well, there is ‘light a the end of the tunnel’ because with a solid diagnostic strategy, you can do it yourself and replace the failed part, whichever it may be (or take it to have it done). In this article I'll show you the basics of testing/troubleshooting such a problem.
Contents of this tutorial:
NOTE: The following real life case study may be a handy read: No Start Case Study 2002 1.8L Nissan Sentra.
Difference Between A No Start And A No Crank Condition
Before I jump into the specifics of troubleshooting a No Start Condition, let me tell you that a no crank and a no start condition are not the same thing. Here's a brief description that'll help you make sense of this tutorial:
Cranks But Does Not Start Condition: Means that your 1.8L Nissan's starter motor is cranking the engine but the engine is not starting. This is usually due to a fault in the ignition system, or in the fuel system, or there's an engine mechanical problem (like a thrown rod, etc.).
Does Not Crank Condition: Means that the engine is not cranking when you turn the key to crank the engine. In other words, the engine doesn't turn over at all. This is usually due to a bad starter motor, bad ignition switch, bad neutral safety switch, or the engine is locked up.
If your Nissan doesn't crank and you suspect the starter motor, here's a tutorial that'll help you test it: How To Test The Starter Motor (Nissan 1.6L, 1.8L).
No Start Condition Basics
The most basic and the most important thing you need to know, to begin troubleshooting the No Start Condition, is that your 1.8L Nissan Sentra's engine needs 3 things to start and run. These are:
When your 1.8L Nissan Sentra Cranks but Does Not Start, it's because one of these 3 things is missing from the mix.
So, troubleshooting the problem requires that you and I check for spark (with a spark tester), check fuel pressure, and if necessary, check the engine's health with a compression test.
I'll go into more specific details in the following headings:
1.) Ignition System
- The ignition system is the one responsible for creating and delivering spark. Without spark, the engine will crank but no start.
- The ignition system of the 1.8L Nissan vehicles covered by this article use a COP (Coil-On-Plug) ignition coil system. In a COP ignition coil system, each cylinder has its own ignition coil; thus eliminating the distributor entirely.
- In my experience, the most common component failures, of the ignition system that cause a no-start no-spark condition are:
- Ignition control module (ICM) -most commonly known as the igniter (if distributor equipped).
- Ignition coil.
- Distributor cap (if distributor equipped).
- Distributor rotor (if distributor equipped).
- All of the above ignition system components can be tested in a methodical way to find out exactly what has failed (if indeed something has).
2.) Fuel System
- The fuel system is the one responsible with supplying the engine with fuel.
- The fuel system component that causes the majority of no-start no-fuel problems:
- Fuel pump relay.
- Fuel pump.
- The fuel pump can be tested to make sure it has really fried using a fuel pressure gauge.
3.) Engine Mechanical System
- The engine pistons and cylinder head valves (and all the other related components like: timing chain, etc.) are the ones responsible for the induction of the fresh air the engine needs for the combustion process.
- Although rare, internal engine mechanical problems can and do cause no-start conditions.
- Possible internal engine problems are:
- Blown head gasket.
- Blown engine.
OK, the list of possible things that can go wrong looks pretty long but it is rare to see (or have) two different components go bad from two separate systems at the same time.
The cool thing is, is that there is a diagnostic strategy that you can use to figure out exactly what's wrong with your particular no-start problem. Let's find out more about it in the next subheading.