Hey guys- have an 01 with 49k on it- run mobil 1 synthetic-here is the deal- the car (after driving it for a little bit) my throttle response goes out the window. My typical day - go to work around 5:30 in the morning- car runs great. vtec slams, car sounds great- for about 20 minutes. then when i accelerate- especially from 4k on up- the car is slower. Vtec takes forever, does not sit you back- almost feels like an rx-8 when i get into vtec (little to no diff when it gets in the higher revs). It makes all the vtec sounds though. bought the car with 44k on it- here is everything i have done

tranny fluid change
diff fluid change
spark plug change (oem plugs)
valve adjustment (only 1 valve was SLIGHTLY out of spec)
timing chain tensioner (last week- toned down some of the noise)
new pcv valve

I had Honda do a compression check 2 weeks ago- 212, 212, 212, 214 cylinders 1,2,3,4 respectively. All this has been done in the past 6 weeks (when i noticed the problem.) Dark_sub_rosa drove it a few weeks ago and noticed it wasnt pulling as hard as it should as well. I figured the timing chain tensioner would take care of it- i am tapped out. I have no clue what else it could be. Also- with the car running slow- sometimes in the same drive it will pick up speed again i.e. running slow for a few miles, runs fast for a mile, goes back to slow or vice versa. any help would be appreciated

 

Try the MAP Whack.
https://www.s2ki.com/forums/index.php?showtopic=209708

 

is your cat clogged by chance? try running a test pipe if possible and seeing if that helps you.

 

It appears that you've checked all of the right things. If a map sensor whack doesn't help, you might want to invest in an OBDII data log sensor & software for a laptop. You can drive the car with this thing hooked up to your car, and it can tell you what's happening.

Other things that may be suspect: dirty throttle body, and an oxygen sensor that is going bad.

Good luck.

 

thanks guys- is there a way to check the throttle body without taking apart allot of stuff under the hood? (not mechaniically inclined). also- the 02 sensor... would that throw a code? is there a way to visually inspect it? (sorry honda has taken pretty much all my spendding money for the next few months)

Thanks!

 

The throttle body is pretty easy to get to. I personally haven't done it, but you should be able to remove the intake from the air filter and take a peep inside. You can remove it to clean it well or you can spray throttle body cleaner (or gumout, STP, etc), and try cleaning it with a brush or rag. If you do a search, you will find posts of people that have done it. Just make sure you don't spray a bunch and hydrolock your engine.

The oxygen sensor will set off a CEL if the voltage is out of its specified range. If it is starting to go bad, it may still send a signal but not an accurate one. You can't tell by just looking at it even if you remove it. There are two oxygen sensors on our car, and they aren't cheap. You could hook your car up to an OBDII scanner and see what kind of signal your sensors are putting out when you're running with a warm engine. Then you can compare it to the signal put out by another S2000. That would be the best way of telling if there's a problem.

If you can't afford a scanner right now, you may want to post something in a regional forum and find out if someone in your area has one. They might be willing to help you out for a couple of beers

In my opinion, it is probably not your oxygen sensor. I was just mentioning it as a possibility.

 

thanks for the info- ill check the throttle body. Not sure why the car would run great sometimes and not so good others...

 

MAP Whack.

The problem with the MAP is that the thing can vibrate loose a bit and doesn't make good contact. That would explain why it's intermittent.

 

i have been searching- anybody got the tape mod for the map sensor? i wacked it (hmmm) and it rab strong all day till right before i got home.. i am assuming i should tape it down.

 

hardtopguy sells the revised map sensor with a zip tie built into it, about 50 bucks.