The engine compression test on the 3.3L Nissan Frontier, Pathfinder, or Xterra is not too difficult.
In this tutorial, I'm gonna' explain how to do the engine compression test and I'm also gonna' explain how to interpret your test results.
You'll be able to find out if your Nissan has an engine compression problem or not.
Contents of this tutorial at a glance:
APPLIES TO: Quite a few Nissan vehicles are equipped with the 3.3L V6 engine. This tutorial applies to the following vehicles:
- 3.3L Infiniti QX-4: 1997, 1998, 1999, 2000.
- 3.3L Nissan Frontier: 1999, 2000, 2001, 2002, 2003, 2004.
- 3.3L Nissan Pathfinder: 1996, 1997, 1998, 1999, 2000.
- 3.3L Nissan Xterra: 2000, 2001, 2002, 2003, 2004.
Symptoms Of Low Or No Engine Cylinder Compression
You usually see one of two types of compression problems. Either the engine compression problem is causing the engine to crank but not start.
Or the engine compression problem is causing a rough idle or a misfire problem. In other words, the engine starts but idle rough (at a traffic light, etc) or has a cylinder misfire that lights up the check engine light with a misfire trouble code.
The following list is a list of the most common symptoms you're gonna' see when the engine has a compression problem:
- P0300: Random Cylinder Misfire.
- P0301: Cylinder #1 Misfire.
- P0302: Cylinder #2 Misfire.
- P0303: Cylinder #3 Misfire.
- P0304: Cylinder #4 Misfire.
- P0305: Cylinder #5 Misfire.
- P0306: Cylinder #6 Misfire.
Besides a cylinder misfire condition (or a rough idle condition), your 3.3L Nissan Frontier, Pathfinder, or Xterra is gonna' suffer from bad gas mileage. You're also gonna' notice a heavier exhaust smell coming out of its tailpipe. Also, since the engine is not running optimally, it's not gonna' be as peppy as it was once.
Important Tips And Suggestions
TIP 1: Do not remove the spark plugs from a hot engine. Removing the spark plugs from a hot engine can result in damage to the spark plug hole threads.
If your Nissan's engine has been running for any length of time let it cool down completely before removing the spark plugs.
One method that I have used to cool the engine down in a matter of 15-20 minutes is placing a box fan on top of it to cool it down.
TIP 2: The engine has to be cranked to test the compression, for this reason take all necessary safety precautions while working around the engine when it's being cranked.
TIP 3: Have your helper wait outside of the vehicle till you're done setting up the test. This way you'll avoid having your helper accidentally crank the engine while you're installing the compression tester.
TEST 1: Finding The Dead Cylinders
As mentioned earlier don't remove the spark plugs from your Nissan's engine if the engine is hot.
Also as you're removing the spark plugs, examine them to see if you see any obvious damage on them.
One other recommendation is to label the spark plug wires so that you can put them back in their proper places.
If you don't have a compression tester you can run down to your local auto parts store and buy or borrow one from them. If you're interested in buying one, then take a look at my recommendations here: Which Compression Tester Should I Buy?
NOTE: Disable the ignition system before doing a compression test. You can easily disable the ignition system by disconnecting the distributor from its electrical connector.
OK, these are the test steps:
Disable the ignition system by disconnecting the distributor from its electrical connector. This will prevent the ignition coil from sparking during the test.
Remove the spark plugs. 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 plug's porcelain insulator crack and then you'll have a misfire on your hands.
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.
Have your helper crank the engine till the needle on the compression gauge stops climbing.
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.
Repeat steps 3 through 5 on the remaining cylinders.
Let's examine your test results:
CASE 1: All six cylinders had 0 PSI. This test result tells you that the engine has an internal mechanical problem.
The most common cause of this condition is a broken timing belt.
Your next steps should be to check the condition of the timing belt. I would also recommend that you check for a blown head gasket.
CASE 2: One or more cylinders had a low compression value compared to the others. This could be normal or it could be causing a problem.
To find out the next step is do some math and see if the low compression value is lower by more than 15% of the highest compression value you got. To find a detailed explanation of this calculation go to: Interpreting The Compression Test Results.
CASE 3: All six compression values were similar and above 120 PSI. This lets you know that a compression problem is not behind the no-start or misfire problem you're trying to troubleshoot.