nodisguise

Today, I went inside my friend's house for like 2 minutes and left my car running outside. When I came back, I noticed there was a LOT of valvetrain noise, even more than usual (I noticed a little extra noise recently but haven't had time to get an adjustment as I just started school, and have had a schedule change at work.) Well, I started to drive home and noticed that my engine was very lumpy, power delivery was stumbling, I could hear an intermittent tapping, and after a bit, my check engine light came on. By the time I got home, my car smelled, and it was running like absolute crap. I did drive very, very slowly the whole way home.

So do you guys think it's just a valve that's gone all the way loose? How much damage do you think there is? It didn't go loose at high rpm or anything, so I wouldn't think the piston needs to be replaced (opinions?). Will the valve probably be needing replacement? Like I said, I just started school, and My S is my daily driver. I need it to get to work and school, and really can't afford the downtime involved in a head removal, so I'm trying to avoid that if it's at all possible. I'm thinking I'll just pop off the valve cover tomorrow morning and look around, see if it is just one valve that's loose, tighten it up, and then take it in for a full adjustment (I've never done a valve adjustment before). Bad idea?

I'd appreciate any input and any ideas you guys might have on any of this. Thanks a lot.

xviper

I think you are getting way ahead of yourself. Since you have a CEL, the first thing you should do is to pull the code so you have a bit of an idea of what you're dealing with. Don't start tearing into the motor until you pull that code. You may be making a mistake by assuming it's a valve.

Billman250

Words of wisdom. This should be like stickied all over the UTH forum. IF a valve adjuster nut has come loose, it could make it way into the engine and do major damage. Misfire codes could mean you have valve trouble. I'd bite the bullet and flatbed it to the dealer to do a scan and pull the codes. Unless you can get ahold of a code reader and post the codes here.

nodisguise

I'm going to try to get a hold of a code reader tomorrow. I may be jumping the gun, but I just couldn't think of anything else that would make the same erratic noises and have the same symptoms, plus I know my valves were out of whack before. Then again, I'm no expert. I'll post up the results of the code reader tomorrow morning, unless I can't get a hold of one, in which case, I'm just going to go ahead and pull off the valve cover (it's not that hard, my brother and I have done it many times on his b18c) and look around.

Can you guys think of anything else that might cause the same noises/symptoms?

Oh, also, I should add that the car was definitely misfiring, when the CEL came on.

marcucci

A valve adjustment is much harder on the F20C since the head is deeper than on a B18 and the fuel rail is jammed up so close on the intake side.

Valves don't just "come loose" like that so I think the possibility of that being the problem is slim. If it is stumbling and power delivery is affected I would think of a more serious mechanical problem. You definitely need to pull the code, any auto parts store should be able to do it, and definitely any dealer.

Billman250

I was telling nodisquise on IM that it is prolly unlikely he has loose nut and adjuster, unless the valves have been adjusted before and they didn't torque the locknuts properly.

alexf20c

My car backfired out the exhaust yesterday. I think I threw a rod.

Billman250

CoralDoc

I agree with marcucci - it is very rare for valves to become loose that rapidly and dramatically.

I also agree that you should pull the code and then start trouble shooting.

Here's one other possibility:
A loose or poorly connected spark plug can also cause these symptoms. Since you have a MY 2000 car, did you have the spark plug TSB performed? It addresses this concern. It is relatively easy to check the plugs, but you may want the dealer to "discover" the problem if you want to pursue warrantee coverage. Even if the car is out of warrantee, you may be able to get a good faith repair done if it's the spark plugs since there is a documented problem with them.

nodisguise

Bingo. The code was reading missfire. I pulled out the plugs, one of the thingies that connects to the plugs was half incinerated. How much do those guys cost? Do dealerships stock those? Everything's closed today.