Matt21

Hello,

I've just bought my first honda s2000 a week ago and have started to have a few issues.
It's a 2002 Japanese import AP1

On a warm day I went for a drive and after a while I noticed while in vtec there was a bit of a farty stutter, mainly noticeable in 2nd and 3rd.
Normal driving was fine, no lumpy idle or any issues with part throttle etc.

I did a bit of searching and found some threads about the MAP sensor and it was sounding like this was my problem, so i went and gave it a tap, plus another for good luck and had a test drive, it seemed fine for about 3 miles then started again (whether it was just the engine bay warming up I'm not sure)
So i returned home and removed it, gave it a blow and a squirt with carb cleaner and another tap.
Then I went for a test drive, still the same, however after a while it started bogging down while I was at lower revs, around 2500rpm seems the worst. Setting off is also horrendous, the engine is cutting out and you just end up bouncing down the road (nothing to do with the way I'm driving, its like the fuel is being cut), it's also still doing it when cruising along at normal speeds too.

Today I cleaned up the throttle body and checked the plugs, I found one to have the end of the 'hook' snapped off at the bend, so fitted a new set of NGK laser platinums, went for a test drive and the stutter in vtec seems to be cured! (I'm hoping the little bit of plug has passed through the engine without causing issues?!
However the lower rpm bogging is still very much an issue.

Any one have any ideas on this?
Could I have damaged the MAP sensor by blowing into it?!
I've ordered one to pick up tomorrow as it seems odd that it started after I tinkered with the MAP.
Anything else I should be checking?

Nottm_S2

I would be worried about that bit of plug

Not sure on map issue, never had it. They can bog down when hot with standard airbox as it grabs hot air from near the rad

lordys2000

When I had the MAP issue, it tended to be at higher revs when booting it and was like the engine was stuttering. I never replaced it, but the connector is now tightly held in place with some zip ties - the issue was it was a loose connection:





The bogging down issue is something I get, but it tends to be when it's hot, in stop start traffic, and when setting off. As per the technical FAQ, a quick rev before setting off avoids the issue,

noodels

As above,as the piece of plug may be stuck in the valve train area.
Check valve clearance to see if any tight ones<on the failed plug cylinder>
Compression test to eliminate low compression.
Coil ok ?
No fault code ?
EMS oem ?
What plugs did you take out , Bosch ?

s2konroids

It'll either be stuck in the valve seat (doubtful) most likely passed out it'll have burnt up and smashed into peices and made its way on exhaust stroke.

noodels

^^
Made a mess in my combustion chamber when had a broken tip,also may have gone down cylinder wall on mine.
A replacement engine was needed.
Worth checking though.

s2konroids

Yup you can be unlucky abs that's happen too

Nottm_S2

You could get a boroscope down there to have a look I guess?

Good garages have em but USB ones are cheap now too.

Good luck

Matt21

It's odd that the car runs fine when booting it though. You'd think if the bore was scored or something in the valve then it would run bad all the time.
setting off a high rpm is fine too

Its only when setting off normally and when cruising along at normal kind of speeds. It's pretty violent and what most would call undriveable

someone has also said it may be the o2 sensor?

I don't want to start replacing any more bits willy nilly but stuggling to decide what to do next. I wish there was a fault code!

Matt21

Here's a video of it
setting off is a problem then you can see when I get to 2500rpm it does it again.

https://youtu.be/YMaBaj2UlA8