808style

I got a compression check done this past weekend after I was convinced my car was definitely not running up to par. I dyno'd the car bone stock a few weeks ago and it put out a dismal 183whp and 125 lb-ft tq. I also rode in a friends MY00 that had 18" ssr sp1s and it felt like it pulled harder than my car with stock rims. Here are the results of the compression check:

Cylinder #1: 210
Cylinder #2: 200
Cylinder #3: 220
Cylinder #4: 180

Obviously something is wrong with cylinder #4. I am going to try and take the car in to Honda this week to see if they can figure out what exactly is wrong. What are some of the possibilities? I just want to prepare myself in case they try to BS me. The car is still under warranty (barely) although from reading this forum it seems highly likely I will end up getting screwed with a fat ass bill. Any insights or opinions would be greatly appreciated!

yogi

Was that with oil in the chamber, or was that dry? The difference between cylinders can be up to abou 30 psi (I think) and you're not too far away from that. Double check it by pouring a capfull of oil into the combustion chamber before you attach the gauge. If it jumps a significant amount, you've probably got ring/cylinder wall issues. I don't remember when Honda fixed the cylinder 4 failures, but this could be the start of that problem. Have them scope that cylinder to inspect the cylinder walls.

808style

No oil was added when doing the compression check. Are you supposed to do that for more consistent readings? The compression check was done immediately following a half hour drive on the highway. Cylinders were tested in sequential order 1 thru 4 in about a 45 minute time span.

CoralDoc

Yes, there isn't a lot of disparity between cylinders, but it is more than is optimal.

Another very helpful diagnostic procedure is a leak-down test. Basically, you pressurize each cylinder with compressed air through the spark plug hole when that piston is at TDC and see how much air leaks. Usually some does, and a healthy engine will have less than 5% leakdown. You can also discover where the pressure loss is from by listening at the intake, exhaust or oil filler. If air is escaping through the intake it's a problem with intake valves, likewise, sound in the exhaust suggests an exhaust valve problem. If air is coming out the oil filler, then air is leaking past the rings. I have 35% leakdown in one cylinder in my Miata, and the engine is down about 10% in power compared to more healthy engines.

This type of test should cost aroung $50 and will help you pinpoint where the problem is. For your sake, I hope it's the valves.

808style

If it's the valves though, that means I'll be paying all out of my pocket for repairs right?

yogi

Probably, yea.

mwy23

compression per helms manual

Nominal: 228psi
Minimum: 135psi
Maximum Variation: 28psi

9kFever

I had problems with my 2002 as well. I took it in for a popping dipstick and they ended up doing a leak down. I was covered by the warranty for new piston rings, head gasket, valve seats, and some other stuff. Good luck

808style

^ well that's promising. hopefully i can have the same good fortune as you!

swtazn97

Current odo: 39,000mi.

Did a compression check 6,000mi ago before a valve adjustment. Here are my results.

Cylinder #1: 240psi
Cylinder #2: 240psi
Cylinder #3: 230psi
Cylinder #4: 240psi