A compression test can give you valuable insight into your Toyota Camry engine's health. It's a key diagnostic step to figure out if low compression in one or more cylinders is causing issues like misfires or check engine light trouble codes.
This test can also help determine if a no-start issue is related to a broken timing belt or internal engine damage, giving you a clearer picture of where the problem lies.
In this guide, I'll explain how to perform the compression test step by step and, most importantly, how to interpret the results so you can troubleshoot your engine effectively.
Contents of this tutorial:
APPLIES TO: This tutorial applies to the following vehicles:
- 2.0L Toyota Camry: 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001.
Important Tips And Suggestions
TIP 1: Warm up the engine slightly. If your Camry's engine starts and runs, let it idle for about 15 minutes to warm up—just don't let it get to full operating temperature. A slightly warmed-up engine helps produce more accurate compression readings without being too hot to handle safely.
TIP 2: Prioritize safety. Always take safety precautions when working near an engine that's cranking. Use common sense, stay alert, and ensure you're thinking about safety at all times.
TIP 3: Be careful with the spark plugs. The cylinder head in your Camry's 2.0L engine is made of aluminum. To avoid damaging the spark plug threads, never remove the spark plugs while the engine is hot (normal operating temperature). Always wait for the engine to cool to a safe, warm level before starting this step.
Symptoms Of Low Or No Cylinder Compression
Engine compression problems usually show up in two main ways:
- The engine runs but has a rough idle or misfire.
- The engine cranks but won't start.
Let's break these down:
1. Rough idle or misfire from low compression
Low compression in one or two cylinders can make your 2.0L Toyota Camry idle roughly or misfire, causing noticeable vibrations or shaking.
Interestingly, this issue often improves or disappears when you rev up the engine or drive at higher speeds.
2. Engine cranks but fails to start
When two or more cylinders have no compression, the engine may crank but won’t start. If all four cylinders lose compression, you’ll likely notice these symptoms:
- Faster cranking: The engine turns over much quicker than usual, signaling a major internal issue.
- Spark is present: You’ll find all cylinders are sparking properly, ruling out problems with the ignition system.
- Fuel is reaching the engine: The injectors are delivering fuel. You can check for this by:
- Using a Noid light to confirm the injector pulse.
- Inspecting the spark plugs—wet, fuel-soaked plugs indicate fuel is being injected.
Common causes of zero compression across all cylinders:
- Blown head gasket: This can cause compression loss between cylinders.
- Broken timing belt: A snapped belt stops the camshaft from turning, halting compression.
- Thrown connecting rod: Severe internal damage that disrupts engine operation entirely.
Which Compression Tester Should I Buy?
There are lot of engine compression testers to choose from and many places to buy them. I'm gonna' make two recommendations to you:
1) Which one to buy: The engine compression tester that I have always used is the Actron CP7827 Compression Tester Kit. My only complaint about this engine compression tester is that it does not come with a case to store it in.
2) Where to buy: You can buy an engine compression tester just about anywhere, but you'll end up paying more for it (especially at your local auto parts store). The above links will help you comparison shop. I think you'll agree it's the better way to save money on the compression tester!
TEST 1: Dry Compression Test
The first we're gonna do is a dry compression test. This test will let us know the compression of each cylinder. Once we have all four values, we can interpret the test results.
CAUTION: Be careful and be alert at all times since you'll be working around a cranking engine.
NOTE: If your Toyota's engine is hot, wait for it to cool down before removing 4 spark plugs. Removing the spark plugs from a hot engine can damage the spark plug threads in the cylinder head.
Alright, these are the test steps:
- 1
Disable the ignition system by disconnecting the ignition distributor from its electrical connector. This will prevent the ignition coil from sparking during the test.
- 2
Remove the spark plugs from a slightly warmed up engine (if it starts and runs). Remember, the engine can not be hot!
When removing the spark plugs, be careful not to drop any of them on the floor, or you run the risk of having the spark plugs porcelain insulator crack and then you'll have a misfire on your hands.
If the engine does not start, don't worry about it being warmed up. - 3
Thread the engine compression gauge into the spark plug hole for the number 1 engine cylinder. Hand tighten the compression gauge only! Do not use any type of tool to get it tight.
- 4
Have your helper crank the engine till the needle on the compression gauge stops climbing.
- 5
Now, record on paper the value at which the needle stopped and the number of the engine cylinder on a piece of paper. Release the pressure on the gauge and repeat this step one more time.
- 6
Repeat this test step on the remaining 3 cylinders.
Let's take a look at what your test results mean:
CASE 1: You go 0 PSI compression on all 4 cylinders. This is not good and tells you that one of the following conditions exists
- Timing belt problem.
- Blown head gasket.
- Blown engine.
Any compression value below 100 PSI (even if it does not 0 PSI) means internal mechanical engine trouble.
CASE 2: Some, but not all, of the cylinders had a low compression value. Up to a certain point this is normal -especially if the engine has a lot of miles.
What is NOT normal is if the values vary too much. With a bit of math we can find out if the lowest compression values are normal or not. Go to: Interpreting Your Compression Test Results.
The rule of thumb is that the lowest compression value cannot vary more than 15% from the highest value you recorded. Any cylinder with a compression value lower than 15% of the highest will misfire.