Patrick L

Hey Guys,

So I got a CEL and had it checked out at the mechanic. They took the readings, changed the spark plugs, and 3/4 of the misfires went away. The misfire on the #1 cylinder is still present. They ran a compression test, and the #1 cylinder tested @ ~180 PSI (wet). I was told this number should be around 240psi.

I went through the "Misfire Thread" to get more information, and did a little digging around the web.

The mechanic told me I was looking at $1,000 to get it diagnosed fully, plus the cost of repairs.

I came across the "Drip Test" online and was planning on getting my car and testing the change in compression with the drip test. (Dropping oil down the cylinder to help create a seal with the cylinder and the ring)

Has anyone come across this issue before? Do you have any suggestions for me as to how I should proceed?

Something similar happened 3 years ago and it cost me around 3k to rebuild. Any input appreciated.

Thanks!

mugen_rsx09

Drip test is the wet compression test. Dry Compression test is with no oil

humbucker87

One random, and relatively cheap, thing to try is a valve adjustment. If the valves are tight they may not be sealing completely especially if the engine is cold. Especially since the number isn't catastrophically low. It's certainly much cheaper than $1000 and it's a relatively easy DIY if you're up to it.

Also a leakdown test will let you know exactly which piece (exhaust valves, intake valves, head gasket, etc) is leaking compression and should be way cheaper than $1000....maybe a new mechanic is in order.

franky

If the tech is telling u that its gonna be $1000 to diagnose it properly than he is ripping u off. The next test is a leakdown test n it will tell u whether u have bent intake valves or bent exhaust valves. it doesn't cost $1000 to ran a leakdown test on one cylinder period n it will only take less than 30min.

Patrick L

Thanks for the help, I really appreciate it.

$1k seemed stupidly high for a diagnosis. I'm going to look into humbucker's suggestion, and find an alternative mechanic. I will look into the bent valves, as well as symptoms for each one (exhaust/intake).

Glad to have something to go off.

cdelena

Have you swapped the coil packs around to see if the misfire moves?

sillyboybmxer

what were the other cylinders at?????

YELLOW JACKET

according to the official s2000 shop manual,130 is the minimum. 180 is not great but not bad either. new spec is 235. no more than 50 difference between any of the cylinders is allowable. this is straight out of my official Honda s2000 manual. mine got down to 180 and added 4 cylinder restore to the oil. next oil change they were 200 to 210 on a engine with 233k on the clock. stuff works! but I would check the valves for good measure. the misfire code could be some thing else causing it. hope this info helps.

Patrick L

The other cylinders are at: 210, 235, and 240.

I haven't done anything to the car yet. I will look into figuring out what it is, then determine the next move.

Yellow Jacket, I'm assuming this is the engine restore stuff you were talking about? Link

The compression for the cylinder in question is at 130 dry (180 wet). The other cylinders had no where near this amount of change.

I've been reading into the issue, from what I've uncovered so far I think it might be:

Cracked Retainer

Bent Valve

Valve guide (I was told the valves were sticking last time I got a CEL. Stuck once, triggered the CEL) i remember the mech telling me that replacing the springs might help.

Thoughts?

Thanks again for everyone's help

humbucker87

Hmm, the massive increase in compression given the oil actually starts to make it sound like worn piston rings. How many miles on the engine?

Can adding oil affect compression on the top of the cylinder (valves, seals, etc)?