s2k_abe

The other day i was driving my s2000 and my check engine goes on. The second day i started my car it was running rough, so i check my oil, and it was at low, i add oil and it sill runs the same. So i check my spark plugs 3 are good except 1 is black and smells like gass. My friend tells me change all four plugs, so i do that and it still runs the same. I talk to my mechanic and he says do a compresion test, so i did that 3 valves where at 185, and 1 was at 65. What dose that mean, i asked a couple of friends they say it might be a bent valve or something eles.
Help me out guys.
Thanks
ABe

CaptainMike

What does your mechanic say? There are several possible reasons for bad compression in a cylinder. Most of them probably involve a top end rebuild unfortunately, unless you have a valve that is WAY out of adjustment or has a bad retainer. There are many relevant threads in the UTH forum which is where you should have posted this, hopefully a moderator will move it for you. (you could PM a mod to move it for U) I would advise you NOT to drive the car the way it is or you could make a bad problem much worse. Which cylinder had the bad compression reading? (I'm guessing #4) You need to pull the CEL code as well and post that info.

Amer

You need to give more background info about the car's mileage, has it been mishifted, are you the original owner, etc.

negcamber

Have a mechanic do what is called a "leak down test". This will tell you if it is rings or valves...and give a clue if it is a head gasket.

s2k_abe

my car has 43.000 miles, i have had it for about a 5 months and i never misshifted, i am not the 1st owner.
But my car wasnt driven for a while, its been parked, and i went to the dealer today and told them my problem, they told me try lucas lubricants, so i did that like 1 hour ago and, i let it run for about 40 min, it sounds better at idel but when i drive it a bit i dosent sound good and it feels like it choking.
and the honda dealer told me its not a bent valve because the compr is at 65 psi.

CaptainMike

You NEED to find out WHY one cylinder is bad. Lubricants are not going to fix a mechanical problem. I would NEVER let that dealer near my engine again.

As Negcamber mentioned a leakdown test will help isolate the problem, you might try a borescope as well to see if the piston sleeves are scored, could be that, or bad rings, or a bad headgasket, or a slightly bent valve, or a cracked retainer, or a worn valve seat, or incorrectly set clearances, you see where I'm going with this?

What did the CEL code pull as? Please tell me the dealer at least pulled the code?
Did the plug that came out of the bad cylinder look OK? As in was ALL of it still there? How does the new plug look that is in the bad cylinder? Is it getting spark? You should probably post up in your local Forum to see if anyone can recommend a decent mechanic.

jeggy

please dont judge that dealer negatively based on what that one person told you. chances are you talked to a servive writer. his job is to pass on your complaints to the mechanic who then goes on to fix your car. the fella that told you to try lucas additive to fix your low compression problem would not be the person working on your car. also he probably was just busy and wanted to be rid of you for the moment. any service writer would see someone in your situation as $$$ and try to get your car in the shop. that was obviously not this fellas' intention.

as stated above there are many things that can cause low compression and there are still a few more things you can do yourself before you drop big money to have it looked at.

s2k_abe

i took my car over 9 grand and it was still normal untill the next day, but i drove it for another hour after i parked it,it it was normal.

CaptainMike

Kyushin

Id seek out a reputable shade tree mechanic because i do not trust dealers either, i have had bad experiences with 3 dealer ships and those are all listed on other posts... not just one negative instance but several. Thank God i found 2NRwerks, those guys are awesome and their work is amazing, i will never go to a dealer again. I agree with the suggestions here for the diagnostic tests needed.