What kind of compression test does a 1998 Subaru do?
I did a compression test on 1998 2.5 L DOHC EJ25 engine with 109,000 miles on it. I was only able to do the test cold, as I can’t start the car.
How much compression does a Subaru engine need?
An engine is essentially a self-powered air pump, so it needs good compression to run efficiently, cleanly and to start easily. As a rule, Subaru engines should have 142 to 170 lbs. of cranking compression with no more than 10% difference between any of the cylinders.
What does low compression mean on a Subaru Outback?
It will tell you if your engine has good compression. As a rule, Subaru engines should have 142 to 170 lbs. of cranking compression with no more than 10% difference between any of the cylinders. Low compression in one cylinder usually indicates a bad exhaust valve.
Can a compression test be done without spark plugs?
The results correlate well with actual gauge readings and can be completed in a matter of minutes without having to remove any spark plugs. What’s more, the analyzer prints out the results of the compression test making it easy to see and compare the actual numbers.
What causes spark plugs to get wet and foul out?
According to AA1Car.com, this occurs when the spark plug fails to fire, or fouls out. This can be caused by a number of variables, such as engine flooding, or excessive moisture build up. Failed vehicle starting attempts eventually lead to wet spark plugs, according to E3 Spark Plugs.
Why does my engine burn during a wet compression test?
Wet Compression Test. Exhaust valves burn due to hot gases passing through. Intake valves have the advantage of being cooled by the incoming fuel. Valve timing : When all of the cylinders are low and inserting oil into the cylinder does not increase compression, the camshaft timing is likely off.
Why does the intake valve not increase compression?
Intake valves have the added advantage of fuel flow, keeping them cooler. Valve timing: When all of the cylinders are low and inserting oil into the cylinder does not increase compression; the camshaft timing is likely off. The timing belt can slip on the sprockets resulting in staggered and low compression results.