Compression test questions
Thread Starter
Instructor
Joined: Feb 2010
Posts: 202
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From: The Chi
Compression test questions
I'm changing the plugs so I might as well do a compression and leak down test but before I start I have a couple of questions.
1. Does the motor have to be warm or cold? I mean the plugs are right next to the header and I might burn myself if the engine is warm. But If it's cold I might get a false reading due to piston slap. What is CF's opinion?
2. If I pull the fuse for fuel and ignition do I have to pull the coil pack wire? I'm guessing no since the fuse will cut off the electricity.
3. What are the actual fuses that cut fuel and ignition?
4. For the leak test, to find top dead center can I just stick a screw driver in the plug hole and manually rotate the motor until the screwdriver hits a low point or is there a better way?
5. Last question, how do I open the drive by wire throttle body to listen for any leaks? Damn electronics, I can't just pull the wire
Thanks
1. Does the motor have to be warm or cold? I mean the plugs are right next to the header and I might burn myself if the engine is warm. But If it's cold I might get a false reading due to piston slap. What is CF's opinion?
2. If I pull the fuse for fuel and ignition do I have to pull the coil pack wire? I'm guessing no since the fuse will cut off the electricity.
3. What are the actual fuses that cut fuel and ignition?
4. For the leak test, to find top dead center can I just stick a screw driver in the plug hole and manually rotate the motor until the screwdriver hits a low point or is there a better way?
5. Last question, how do I open the drive by wire throttle body to listen for any leaks? Damn electronics, I can't just pull the wire
Thanks
Last edited by -DLS-; May 16, 2011 at 09:58 PM.
Thread Starter
Instructor
Joined: Feb 2010
Posts: 202
Likes: 0
From: The Chi
Okay, I have done it since this post.
1. The motor should definataly be cold or you will BURN the **** out of your hands. Theres not much room to work with.
2. I pulled the wire anyway, it was right in front of me. Why not.
3. In the fuse box there are fuses labeled IGN1 and IGN2. They are the ones you can pull to remove spark but they are optional. When cranking the car, if you floor the gas pedal, it cranks but doesn't send fuel or spark. (I pulled the fuses anyway). I don't know which one is fuel, but it is not needed.
4. I didn't do leak down. My compressesion test was okay and I didn't have the tester.
5. I don't know but I was hopeing when I was cranking and holding the gas to the floor that the throttle body would open.
1. The motor should definataly be cold or you will BURN the **** out of your hands. Theres not much room to work with.
2. I pulled the wire anyway, it was right in front of me. Why not.
3. In the fuse box there are fuses labeled IGN1 and IGN2. They are the ones you can pull to remove spark but they are optional. When cranking the car, if you floor the gas pedal, it cranks but doesn't send fuel or spark. (I pulled the fuses anyway). I don't know which one is fuel, but it is not needed.
4. I didn't do leak down. My compressesion test was okay and I didn't have the tester.
5. I don't know but I was hopeing when I was cranking and holding the gas to the floor that the throttle body would open.
