I have a 2002 s2000 with 47,000 miles. Check engine light came on and was running a little rough. Took it to dealership and they said it was the plugs and needed a tune-up. After tune-up check engine light on again. They said valves misfiring. Now they say bent valves. Took it for a second opinion and they disagree but don't know what the problem is. Any suggestions?

 

Diagnostic found codes p0302, p0303 and p0300. They found a misfire on #2 cylinder so they switched the coils and cleared the code. #2 returned. MAP sensor was at 1.11. Compression test results found #2 at 140 PSI and #1 at 205psi. Valve clearance was loose. Adjusted valves and performed leak down test and #2 was losing about 70% . I have had the vehicle for the last 10,000 miles and have not pushed it to performance limits. Cold engine idles just fine. Runs rough once engine warms up. Purred just after tune-up but that did not last long. Any ideas? One mechanic says I need to replace intake and exhaust valves. Another says that it is not the valves but something else. Also, the Car revs and excellerates when I put clutch in as I come to a stop.

 

Did you misshift at one point? sounds like bent valves to me as well. You might was well re-do the whole head with aftermarket springs, retainers, valves, guides, seats. Good luck

 

i have the same codes and problems.... ive been researching and researching and everyone says the same shit bent valves and crack retainers and we might of spun the main bearings.... just to rebuild the head costs 2500... new motor 3-4k

 

Get a leakdown test done ( different to a compression test). It will tell you which valves are leaking or if its a ring/piston problem.

If the valve clearances were loose this can be a sign that the valves were bent. When the valve heads are tilted slightly the valve clearances open up.

 

I did not misshift. They quoted me around $2200 to replace all the valves. I have been pretty gentle with the car so I am a bit frustrated with this. Could the previous owner bent the valves and it is just becoming evident after 10.000 miles of driving? Initially the dealership said all it needed was a tune-up. changed out the fluids. i agree it is looking more like a bent valve. thanks

 

It unfortunately sounds like you have a valve or sealing issue in that cylinder. Was a leakdown/compression performed prior to the valve adjustment or just after? You've chosen all the correct avenues for diagnoses thus far.

What is your location btw?

 

If the valves are bent you need to think more about how it happened. If you have had the car since new and never mechanically over revved the engine then the valves shouldn't be bent. Leak down test see what happens if cylinder 2 is leaking you should be able the air escaping from some where. Then move on from there.

 

I'll sell you a completely built head for less than that. Bolt on and be safe for up to 11, 000 rpm (head wise), plus you will still have your original head to sell.

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I realize he is rocking an AP2 but i have an AP1 if you could get me a new head for less then that it sounds super good what kind of valve train are you using.