paul2011s2000

Been out in my 1999 S2000 tonight (69000 miles). The engine seems to have quite alot torque up to 4000/4500 rpm, but then it goes kind of a little flat until VTEC at 6000rpm. Is this normal, if so can anything be done to improve it?

SpitfireS

What about maintenance?
Oil, sparks, air filter, you know: the basics.
Get a 4.56 or 4.77 diff. The flat spot will be passed before you know it.


Maybe do an ECU reset / relearn.
See if this changes anything.

paul2011s2000

Thank you for your reply. Oil and filter was done about 1000 miles ago, air filter was done about 250 miles ago. I haven't done the plugs yet, they are on the to do list. I've had the car about three months now and it's been the same since day one. I'll do plugs but what about valve clearances, could they cause the flat spot? Also, normally I'd do a fuel filter but these cars don't seem to have one that is a service item.

Can I do ECU reset/relearn somehow?

paul2011s2000

Ok,so I think I found the main problem here. I changed the plugs the other day. When I removed the coil pack from cylinder number 4, I noticed the rubber seal was left attached to the plug. I know the plugs had been changed before as I have the bill for it. So I measured the depth to the top of each plug with my calipers and sure enough, plugs 2 and 4 weren't screwed all the way in, they were at least 2/3 threads from correct depth! When I tried to fit the new plugs they wouldn't screw in either. I didn't have a tap handy so I cut a slot in one of the old plugs with a grinder, put some grease in the slot(to catch the bits) and used it to clean out the threads. All the plugs then screwed in to the correct depth. However, number 2 seems as if it has a couple less threads than the rest, but it torqued down ok so I'm not going to worry about it. There was no difference off the bat, but once the car had done 20 miles or so it seemed a lot better. I've now done aprox 500 miles since changing all oils, air filter, clutch and plugs, and it's such a different car than it was when I first had it. Just the IAC valve to clean now, as it sometimes, almost stalls when the revs drop back to idle.

Froth.

To ECU Reset simply disconnect the battery for 15min or so then hook it back up. This will change everything back to "default" mode and it will start over from there, if you had a CEL it will likely be erased. Glad you figured it all out and are happy with the car!

I would look into getting the valve lash adjusted/checked. It can lead to a number of problems.

paul2011s2000

Sorry, forgot to put that on my list, valve clearance was done at Christmas.

SpitfireS

A reset is not a re-learn.
Re-learn is: cold start, start, not touch anything (but start button ) and do not drive and let engine warm up until the 2nd heat fan cycle (off-on-off(1)-on-off(2))

@ paul2011S2000: Thank You for updating your post.
There are way (WAY!) to many unfinished posts around here and for you making yours not one of them.

rob-2

There is a feeling of lack of power just before the vtec cross over. Maybe this is what you're referring to?

paul2011s2000

Yes, I notice from looking at peoples standard dyno power curves, that there is a little drop off before 6000 rpm, but mine sometimes felt like it took forever to get to that magic rpm without changing down. I also noticed that the old plugs in cyclinders 2 and 4 were a little bit too much on the white side of brown for my liking. Not sure if this has anything to do with the depth of the plugs but seems like a strange coincidence to me otherwise??