How to: Compression test
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How to: Compression test
Hey guys, I am doing a spark plug change out and while I am in there would like to check the compression. Does anyone know how to do a test? I would like to disable the injectors but dont know which fuse to pull? Any help would be appreciated.
You need a professional type dual unit (2 guages) that goes up to 100psi. The other gauge has the % meter.
you pressure each sparkplug hole one at a time up to 100 psi then stop and wait to see where the loss in % stops...
write it down and move on to the next one...
you pressure each sparkplug hole one at a time up to 100 psi then stop and wait to see where the loss in % stops...
write it down and move on to the next one...
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2001 996TT 3.6L and stock ECU
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2001 996TT 3.6L and stock ECU
9.66 seconds @ 147.76 mph 1/4 mile click to view
160 mph @ 9.77 seconds in 1/4 mile click to view
50% OFF ON PORSCHE ECU TUNING BLACK FRIDAY SPECIAL
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I just have a single gauge leakdown tester.... what is the difference between the single and dual?
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unplug all your coils and make sure ALL your spark plugs are out. turn engine over until the needle stops increasing. shouldn't see more than 15%-20% delta between cylinders, hopefully WAY less.
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when i do this i always do it the same way.
1. remove all the spark plugs so the engine will turn easy.
2. block open the trottle (stick a screwdriver handle into the thottlebody)this will prevent airflow resistance.
3. disable the ignition system to prevent sparks(remove the feed wire to the coil).
4. disable the fuel injection.
5. screw the gauge on with the right adapter in the sparkplug holes.
6. crank the engine and listen for about 5 compression strokes(the needle will move as this happans).
7. Write down the numbers and repeat these steps in all cylinders. if the test fails try adding a little oil to the cylinder and see if the rings are fried if not check head gaskets and valve seats and seals.
1. remove all the spark plugs so the engine will turn easy.
2. block open the trottle (stick a screwdriver handle into the thottlebody)this will prevent airflow resistance.
3. disable the ignition system to prevent sparks(remove the feed wire to the coil).
4. disable the fuel injection.
5. screw the gauge on with the right adapter in the sparkplug holes.
6. crank the engine and listen for about 5 compression strokes(the needle will move as this happans).
7. Write down the numbers and repeat these steps in all cylinders. if the test fails try adding a little oil to the cylinder and see if the rings are fried if not check head gaskets and valve seats and seals.
Hey Mark, I think your referring to a leak down rather than a compression test. I would like to do a compression first and if there is any low #s then I will do a leak down. I just need to know how to disable the injectors really. Im just going to leave the coilpacks unplugged. I figured it would just be a fuse I could pull to disable them?
I just have a single gauge leakdown tester.... what is the difference between the single and dual?
I just have a single gauge leakdown tester.... what is the difference between the single and dual?
re: Fuse
Look for a DIY oil change post on here ?? I remember seeing it there as to crank the engine to prime the oil pump vs firing it straight up after an oil change.
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when i do this i always do it the same way.
1. remove all the spark plugs so the engine will turn easy.
2. block open the trottle (stick a screwdriver handle into the thottlebody)this will prevent airflow resistance.
3. disable the ignition system to prevent sparks(remove the feed wire to the coil).
4. disable the fuel injection.
5. screw the gauge on with the right adapter in the sparkplug holes.
6. crank the engine and listen for about 5 compression strokes(the needle will move as this happans).
7. Write down the numbers and repeat these steps in all cylinders. if the test fails try adding a little oil to the cylinder and see if the rings are fried if not check head gaskets and valve seats and seals.
1. remove all the spark plugs so the engine will turn easy.
2. block open the trottle (stick a screwdriver handle into the thottlebody)this will prevent airflow resistance.
3. disable the ignition system to prevent sparks(remove the feed wire to the coil).
4. disable the fuel injection.
5. screw the gauge on with the right adapter in the sparkplug holes.
6. crank the engine and listen for about 5 compression strokes(the needle will move as this happans).
7. Write down the numbers and repeat these steps in all cylinders. if the test fails try adding a little oil to the cylinder and see if the rings are fried if not check head gaskets and valve seats and seals.
0. Make sure the car is up to running temp before starting. This may make it tough to work on because its hot, but results wont be accurate if its cold.
6.5. After you are dont cranking a set number of times, crank a second time until the needle stops moving.
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