So I offered to help a neighbor compression test his 2003 Civic Hybrid as it's burning oil and the dealership he reliably gets his oil changes done at told him they didn't care. To be honest it's not clear where the oil is going, but it's dropping about a quart every month. Since I have a high end Sears compression test tool I figured we'd check that first. But the Civic Hybrid has 8 spark plugs in four cylinders? Can someone who has done a compression test on a newer engine like this explain the process? I'm thinking I would just take out the four spark plugs that are easy to get to, and leave the other ones in. Any problem with that? I'd be disconnecting all the spark plug wires and injectors and doing one cylinder at a time. Any pointers appreciated.

 

If there are two spark plugs per cylinder, then I would think that yes, you'd need to leave one in (or else all of your pressure would be lost). Just make sure they're not firing (which you are, by unhooking the plug wires).

I don't think this is applicable, but on my '97 Civic I fried the ignition module in the distributor when I did a compression test, because I didn't unhook it. The wires weren't giving spark to the plugs, but enough energy built up in the ignition module during the test that it popped it. I'm not sure how the hybrid works.

 

Thanks Koko4 for the advice and encouragement. As it turns out on the 2003 Civic Hybrid there is 1 ignition coil per spark plug, instead of a distributor and plug wires. We needed to pop off two plastic motor covers to see all 8 ignition coils. Then we unclipped the electrical connections from all 8 ignition coils, unbolted and removed only the front four coils and plugs, one at a time, and threaded in the compression test tool. I also pulled fuse #6 to kill the fuel injectors (in the manual/top of fuse box diagram, this was the ECM fuse). Found 3 cylinders really close to 150 psi and the cylinder closest to the driver side was around 135.

The CEL was lit up after putting everything back together, but disconnecting the 12V cleared that.

Probably took us 20min to do the whole job on this car.

 

That doesn't sound too bad. If I remember correctly, the cylinders need to be within 10% of each other, so 15psi difference is right at that threshold. I don't know what the optimal PSI should be, but I think mine were closer to 170ish when I tested? I could be wrong, and it could be different for the hybrid!