COMMON PROBLEMS
Idle / Hesitation / Kangerooing / Misfire Problems
As idle / hesitation / kangerooing / misfire problems and misfires seem to be a common problem on the S2000, and indeed on most cars, I thought I would construct a thread to aid people in diagnosing their problems.
Aside from an actual problems listed below, these type of problems can just be a passing phase. Your ECU has to cope with changing ambient temps and pressures, and can simply be adjusting. If your problem persists or gets worse then read on....
All this info is based on MY00-05 cars - the 06 has some differences in its setup which im not clued up on (drive by wire throttle etc)
Idle and hesitation / kangeroo problems can be caused by the following:
Loose throttle cable
Failed or failing MAP sensor
Failed or failing O2 / lambda sensor
Air leaks (on the vacuum side)
Blocked throttle lines
Dirty throttle butterfly
Blocked air filter
ISCV / AIC (idle speed control valve) misbehaving
One person (simon prelude) also had a seized aircon pulley which cause a bad idle on his
Hesitation / Kangeroo!
This is a common complaint. You have been driving the car a while, you stop at a junction waiting to pull out, you see your chance, boot the throttle and not a lot happens 
Frustrating at best, dangerous at worst if you roll out in front of someone!
It has been said that the car will kangeroo becuase of the light flywheel - I dont subscribe to that view. No car ive ever owned does it this bad, and the ECU should easily be able to cope with the flywheel weight. The kangerooing I believe is to be ether IAT (intake air temp) or MAP (manifold absolute pressure) heatsoak. I have some logs from my PLX when the car was kangerooing and there was basically no fuel going in, and some very screwy readings from both sensors.
In my case I bought a new MAP sensor and it was fine again, while others have cured it with intake snorkels and cooling mods. An intake snorkle is a good idea anyway as it ensures the airbox only takes air from outside the engine bay.
Some people decide to live with it by revving the car before pulling away, which effectively allows the engine to gulp a lot of warm air and clear the problem.
Misfires are slightly different but can have some similar causes (more often than not its the MAP sensor if above 6000 rpm):
Failed or failing MAP sensor
Blocked injectors
Damaged coil packs
Worn or damaged spark plugs
Valve clearances
Damaged Crank Position Sensor
Corroded ECU wires - this has been found on a number of cars and isnt easy to detect or fix!
Failed or failing O2 or lambda sensor
Air leaks (on the vacuum side)
One thing to note regarding misfire codes is that they can be diagnosed quite nicely by doing the following. If you have an error code on cylinder 1 and 3, then you can find out if its a coil pack by swapping them around (noting where you put them!) and see if the fault follows it. Valve clearance issues and blocked injectors seem to be the main culprit of misfire codes....
There are many others faults which can crop up, but these tend to be the main ones. This guide should either identify one of these problems as a cause, but if not then at least you have narrowed it down and post up what issues you have!
Ok now how to check what is causing the problem, to be checked in this order.... If your car is hesitating, idling badly or misfiring, then the following should be checked, and if you still get stuck then post up - but it would be helpful to check these first!
Have you got a CEL - check engine light?
This is the amber light on your dash that you can see when you turn the ignition on. The CEL is a bloody great invention and can be your best clue at diagnosing a problem. Too many people just reset it and dont get the code...
Should the ECU decide something is wrong, it will light up to tell you there is a problem. These codes can be decoded by a dealer, normally for a charge, or you can get ECU code readers to plug into the diagnostic OBDII port under the passenger side trim. PM if you need a code reader. Quite often you can have a fault with the and no CEL will appear but getting these codes is vital in diagnosing the problem. If the CEL is flashing - DO NOT DRIVE ANYWHERE! If it's just lit then I would say you can drive with caution and get the error code as soon as you can. Some codes will go away once the ECU is happy again, often within about 50 miles. Occasionally with all the things the ECU has to deal with, you may get the odd false CEL which will go away. All codes are stored in the ECU even when the light has gone out.
The list of fault codes is here:
FULL ECU ERROR CODES LIST
The ECU reset!
This leads nicely onto the ECU reset... Dont reset the ECU until you have extracted any codes from it. If the car is misbehaving, an ECU reset can often put things right. The ECU does not learn your driving style, but it does store fuelling trends / trims and idle info etc. By resetting the ECU, it wipes its fuelling trim memory and idle control.
My spin on this is to get the car warm then park up. Switch the car off and pull the ECU fuse shown below for about 10 mins (this removes power to the ECU) Replace it, start the car up then go and find a long stretch of road and give it redline through the gears. The ECU will quickly learn where to set its fuelling and ignition timing. The next step is to get the idle sorted. You will notice the car really struggles to idle and tries to cut out (it shouldn't normally cut out, but comes close). To relearn, park up and let the car go through 3 cycles of the cooling fan coming on and off. its then set. It will eventaully learn anyway, but its quicker using the cooling fan method.
Fuse can be found behind the fuse cover inside the footwell:
If you reset and your problem persists then onto the following...
Ok, question time! These are things to check and I have tried to put them into the easiest things first.
1) Have you just had a service or added a modification to the car?
Its quite common that something may have been nocked or not re-connected which will casue you a few problems! Have a double check that all is well uner the bonnet. If a sensor is disconnected it will generally give a CEL. Have any of the vac hoses been pulled off? there are bloody loads of them on the S2000! Quite easy for one to come loose.
2) Is the throttle cable taught?
Notice I didnt use the word tight! The cable seems to slacken off on these cars, which means when you touch the throttle, its not actually opening the butterfly, so the engine doesnt try and pick up. The cable can be adjusted using the nuts on the arm shown below. It should have a 1/4" play in it to allow for temperature adjustment. Info here:
https://www.s2ki.com/...opic=120410&hl=
3) Is the air filter blocked?
Unlikely but worth a check! Unclip the airbox lid and check there arent any small animals, leaves, homeless people or tools left in there
4) The MAP sensor...
The MAP basically tells the ECU how much fuel to put in. They can get gummed up with oil mist etc, as they are after the filter. They tend to be the cause problems with misfires while on VTEC, but also can be the cuse of hesitation / kangerooing. Many have had success by giving the sensor a gentle tap - so this can be worth a try. Its quite difficult to determine if this is broken without removing it and bench testing it to see if it gives a linear output as you bring up the pressure. A new one can be had quite cheaply from HardTopGuy in the US.
How to tap it
https://www.s2ki.com/...howtopic=209708
5)Air leaks...
Can be atotal bast to find but they can cause your idle a lot of problems! Normally a problem after a service or a modification where you might have nocked something off, which is then a lot easier to spot. An air leak can be a problem anywhere after the throttle body, right back to the exhaust, just before the lambda sensor. Good luck finding it!
6) Plugs
Dodgy plugs can give a similar problem to the above one with injectors. There have been a number of issues with Denso plugs (tips coming off) so my advice would be to stick with NGK... Again, plugs can be moved from one slot to another as a fault finding task.
7) Throttle butterfly / vac line cleaning
Quite a good practice anyway but this can cause some rough running. See this thread here for some help on cleaning these bits!
https://www.s2ki.com/forums/index.php?showt...0225&hl=gizzard
8) Is the car using a lot more fuel than normal?
If the lambda or O2 sensor (not these are one and the smae thing!) is damaged then this can be the cause - the sensor will fail to a low voltage which tells the ECU its running lean - so the ECU pours more fuel in to try and compensate. To check this your best bet is go to a dealer with an ECU monitor and ask them to look at the lambda voltage at idle. It should slowly bounce back and forth from 0- about 0.9 volts. if its broken it will either be very sluggish, or just not move at all! if this is the case then buy a new one and reset the ECU. You could also get an emissions check from an MOT place, and if it fails this will indicate the o2 is at fault. You can buy monitors from people like Greddy (Infometer) or Apexi etc and can be useful!
9) Valve clearances
Many people have had misfire codes on the ECU from valve clearances which are out of tolerance. The clearances can be checked yourself, or by Honda or equivalent competent dealer. THere are 2 DIY threads here:
https://www.s2ki.com/...showtopic=93197
https://www.s2ki.com/...howtopic=245555
10) Injectors
A lot of people have recently been having misfire problems, the root cause of which appears to have been blocked injectors. If you have a misfire code on one cylinder, you could test it by removing an injector to a different cylinder to see if the problem moves to that cylinder. A blocked or non firing injector will cause a misfire as the associated cylinder will not be getting any / enough fuel. In terms of replacement, you could buy one from a breaker and get it flow tested / refurbished, buy a new one from a dealer, or buy an aftermarket one (Spoon etc). There are quite a few outfits who will flowtest and refurbish your injectors but the choice is yours as to whether you just go and buy new ones...
11) Idle Control Valve Cleaning
Fir idle only problems (ie no misfires) then your AICV might need a clean. It's good practice to do it every couple of years anyway. Good thread here by UncleFester:
https://www.s2ki.com/s2000/topic/856...roblems-fixed/
12) Lots of weird CEL faults?
There have been quite a few reports of reccuring CEL codes popping up and general car misbehaviour, caused by corossion of the ECU wires. I think at least 2 UK owners have had this problem. Can be checked by resetting the ECU, getting the car stable at idle, then wiggling the wires to the ECU in the engine bay, or under the passenger footwell.
Engine management stuff
Next part is more for info, for those who are interested, to try and explain how some of the components uder the bonnet function, which will help you understand why the car will misbehave.
Attatched to a modern engine are various sensors which all feed into the ECU. The ECU lives under the passenger footwell as shown below. All the sensor wires form into a loom, which comes through the bulk head into the ECU.
The engine sensors mostly work on sending voltage outputs to the ECU, which allows it to determine things like how much fuel to put in, how much ignition timing to add or subtract, and to diagnose faults. Its an extremely complex device and never fails to amaze me!
The main sensors are as follows:
MAP - Manifold Absolute Pressure sensor
This is the sensor that gets the most attention on the S2000 It lives on top of the inlet manifold as pictured, and is a v important bit of kit. The ECU uses this as an indication of engine load, and will use it to decide how much fuel to put in.
Some cars use MAF (mass air flow) to tell the ECU how much work the engine is doing, but we use a MAP. Within the ECU are fuelling lookup tables, so for a given MAP voltage (combined with inputs from the TPS, knock, AIT and coolant temp) the ECU known what amount of fuel to put in for optimal fuelling. It would seem that these sensors, like any, can have a limited life and I know replacing mine really imporved the behaviour of the car. By now you can probably guess why im not a fan of this MAP whack business! You can also probably appreciate why the car can hesitate when pulling away or misbehave on VTEC if this sensor has a fault... A failing MAP very rarely seems to give a CEL.
O2 or Lambda sensor
The S2000 has 2 of these. One in the exhaust manifold and one in the catalytic convertor. The one in the cat has no input other than to tell you if it thinks the 1st one is causing fuelling problems. The one in the manifold is the more important one for us, as it has a big input into fuelling and idle control. The sensor is there to tell the ECU how rich or lean the fuelling is based on oxygen content, so it feeds back a signal to the ECU, from 0-1v volt, 0 being lean and 1 being rich. On our, and many cars the sensor is heated and takes about a minute to become live when you start the car. If your issues (idle etc) happen before this sensor is warm and active, its not the O2 sensor which is at fault.
At idle or cruise the ECU tries to achieve "stoichiometric mixture" which is 14.7 parts of air to 1 part fuel for normal pump fuel. To do this the ECU bounces back and forth either side of this figure to try and get to optimum.
This sensor is running all the time but only controls the fuelling when your are at idle or part throttle / cruise. Once you put your foot down a bit, the ECU purely iuses the MAP sensor to dictate its fuelling - and the O2 becomes passive. This is where the fixed fuelling lookup tables come it!
When the O2 sensor is being used, it is called "closed loop" fuelling, and when the MAP alone is being used it is called "open loop" fuelling. A broken O2 will often give a CEL.
TPS - Throtle position sensor
This sensor is bolted to the other side of your throttle body and has a rotary spring inside it, as pictured below. When you
have your foot off the throttle, the throttle butterfly is closed, and the TPS will give a voltage of about 0v to the ECU. When fully open, the spring turns and the resistance changes in the sensor and it will go to around 5v. The ECU uses the position of the TPS for various functions.
IAT - Air Intake Temperature sensor
This beasty provides input into the ECU for fuelling control too. The problem with just using manifold pressure to tell how much air is being used, is that the volume of air changes depending on ambient temps. So on a how day the air is less dense
than a cold day. By adding this input into the ECU it will help judge the air volume right, therefore the fuelling will be more precise The IAT is the white sensor plugged into the intake manifold, between the 3rd and 4th manifold branch.
There is also some great DIY info here:
https://www.s2ki.com/...howtopic=108435
Disclaimer - Im not responsible for any damage or injury caused by you or anyone acting on this information so its taken at your own risk! Im not a trained auto technician - just an enthusiast trying to help
Thanks to MB for this excellent post. You can follow the thread that it came from here... https://www.s2ki.com/forums/index.php?showt...0&#entry9913298
Spring Spacers
To prevent the S2000 settling excessively on it's suspension during shipping, Honda insert spacers in the suspension springs all round. They are supposed to be removed by the dealership as part of the the pre-delivery prep. It's not unknown for this to get missed or for not all of them to be removed.
This is the card that Honda UK leaves in the car for the dealers
If the suspension feels overly hard or the steering response is vague, then check to see if you have any or all of the spacers left in!
Pic 1 shows a spacer in situ in a rear spring.
Pic 2 shows a spacer having been removed.
This is potentially highly dangerous and it's worth querying with your dealer at the outset to see if this has been done!
Seizing Suspension Geometry Adjustment Bolts
As this is turning out to be such a major issue, this section has been replaced by a full Definitive Suspension Bolt/Bush FAQ.
Please scroll down or Click Here to see this section.
MAP Sensor
Symptoms: Engine Stuttering, lack of VTEC engagement, and general intermittent engine problems.
Solution: The MAP sensor is a small piece of plastic that sits on top of the engine and has the words MAP Sensor printed on it. Normally a couple of light knocks with a rubber hammer will sort any problems out. You can also remove it and blow on it to remove any dirt build up.
Some MY04 and MY05 cars that have a problem with engine stuttering can get the MAP sensor replaced free of charge. Please contact your dealer for details
Another problem with similar symptoms is this...
A 'flat' spot when starting it after it had been standing for 15-45 minutes after it had been warmed up. It refused to respond to the accelerator, kangarooed, jerked and lost ALL power. The solution to this was...
A corroded wire near the scuttle on the passenger side, which was replaced.
Auto Window Function Fails
When your battery is disconnected, the auto function on the drivers window can stop working, this is because it then needs to be reset.
The car has to be started!!
1. push and and hold the window button down all the way until its completly down.
2. when its completely down, let go and push it down again and hold for 2 to 3 seconds. then let go
3. now pull and roll the window up until its all the way up.
4. when its up let go
5. pull the button up again for 2 to 3 seconds.
(after step 2, he said you should be able to hear or feel the motor or something inside reset.)
6. now then your autoscroll should work correctly.
Premature Wearing of Roof
A number of cars are suffering with premature roof wear. There is a guide below with some preventative measures.
It seems the arm that is doing the damage can only do so when the hood is right down and it is pressed against the hood.
Operation of the hood and the movement of the car then causes it to rub against the hood and wear through, possible bigger problem for those with hardtops.
My first idea was to add a piece of black gaffa tape at the wear point to protect the hood.
Then I made a sleeve to go around the 'elbow' of the frame that seems to cause the problems:-
Added velcro hooks down the edge of a piece of black bass box cloth 12 x 14cm and wrapped this around the elbow.
Looks OK and covers any rough edges
Heavy Clutch
For over a year now my clutch has been getting stiffer and stiffer, but initially started as being a slight sticking point when released. It got to the point where my left leg would ache after a drive, especially when encountering traffic (every morning to work along the M1 now).
I mentioned it a few times to the dealer over that period and got responses of
1) Will have to take the clutch out to have a look.
2) Clutch is on its way out and will probably need replacing.
3) Probably need to replace the Clutch Master Cylinder.
Having read in Under the Hood about sticky clutches various people have had Master, Slave cylinders replaced and still have had the same problem. Others have sprayed WD40 into the clutch housing (not recommended) and problems have gone away for a while, but always come back (WD40 doesn't have a high enough temperature range for the job and also dissolves grease!!). And others have managed to re-grease the release fork, pivot and bearing (contact point with release fork) through the release fork hole in the side of the gearbox using a piece of wire.
With all this in mind and not wanting to pay the dealer to diagnose and hence cost more than is required, I set about systematically solving the problem myself.
1) Replace and bleed clutch fluid. It was looking pretty black anyway, so needed doing just to eliminate this as a problem. Still the clutch was stiff.
2) So next day down to dealer to get some high temp grease, and it just so happened that night on one of the US forums someone had posted a service bulletin for 00-04 S2K, Clutch Stiff and Squeeky (or something like that).
This basically says, remove slave cylinder and pull-out release fork. Grease release fork pivot, release fork which comes into contact with release bearing and release fork to slave cylinder connection point.
With grease in hand, slave cylinder removed in 5 mins, and a quick tug on release fork (note: release fork
will not come out of gearbox!!). Using a flashlight and I went ....my god as dry as a bone, no grease to be
seen anywhere. So using a piece of wire (from a coat hanger) I applied grease to the relevent points and attempted to add some to the release bearing guide, but it was very tight and you generally end up doing it blind. I done the best I could and put everything back together and suddenly I had what felt like a brand new clutch. Smooth action when applying the clutch and releasing, its amazing how such a small thing makes driving easier and more pleasurable (yes! it was pissing me off).
So now I am and all it cost was £20 and my time (including clutch bleed).
The thing was I had the clutch replaced under warranty (54 clutch), so its not just a problem straight from the
factory. Honda know its a problem, hence service bulletin, and my guess is their installation instructions may have been wrong at dealers and factory. Either that or the areas in question get too hot for the grease and it just
disappears over time.
Whatever you do don't let the dealer fool you into thinking it is something else before this remedy is tried.
With ramps etc, it should only take 30 mins to complete..not a new Master Cylinder!!! The other thing to mention is that due to the restricted access it is very difficult to ensure everything gets greased, so at a later date
it may need to be done again.
Clonking Suspension
Symptons: Suspension making anything between a clicking and a clonking noise at low speeds on rough ground.
Solution: There can be many causes of this but the first and cheapest thing you should be looking to do with this problem is retorquing the suspension bolts. My dealer did this for free, and it's a good thing to rule out before playing with dampers etc
Squeaking Dashboard
Symptoms: A very annoying squeek that has been compared to having a mouse in the dashboard!
Solution: Check and oil the bonnet catch and also check the rear view mirror.
Puddle in Passenger Footwell
There is a pipe connected to the bottom of the aircon unit in the passenger footwell that takes the condensation out the car and drops it on the road. This can become disconnected (probably kicked off) , takes 15 seconds to replace and problem solved.
Rattling Roof Catches
My S HAD the most annoying little clicking/rattling sound coming from the strikers/roof latches. I understand that this is a common problem/fault with many s2k's out there.
Get yourselves down your local fish tank stockist and ask from some Fish tank tubing . . . .it is a clear flexible 6-8mm diameter plastic tubing. I had to buy a whole metre . . . . but who damn cares it only cost 49p. Basically you only need about 2cms of the stuff.
All you need to do is slip this over the small metal knobbly bit (technical jargon) that protrudes from the striker (the part that is fixed to the roof) quite difficult to explain really, but if you look at it, you will see where I mean. This simply prevents a metal to metal contact, the small about of plastic is just enough to tighten up the seal.
PLEASE NOTE You can get both striker plates for around £50 from a dealer and fit them yourself, saving almost £400. See this thread for details
https://www.s2ki.com/forums/index.php?showt...0&#entry4635854
054/055 Clutch
The clutches on the earlier cars, numbered 054, can make quite a lot of noise when decelerating in gear. These clutches can be replaced by the 055 clutch under warranty.
The part number for the 055 clutch is 22105PCX325
Alloy Wheels
Honda is aware of a corrosion problem with the wheels on the MY99 – MY01 They should replace corroded wheels under warranty. the warranty for the wheels on earlier cars was extended to 5 years. This is at Honda UKs discretion, so please talk to your dealer or HUK directly.
Locking Wheel nuts
Make sure these are removed and greased every six months to avoid seizing
Gearbox
It is not unheard of for S2000s to have gearbox problems, especially with the syncromesh in the higher gears. Honda's fix for this is usually a new gearbox.
Annoying 04 Headlamp Washers
MY04 cars come with the fantastic feature that means the headlamp washers come on when you clean the windscreen, causing the passengers to get a soaking!
There is a bulletin that covers the change from 03-04 model year.
The symptom it corrects is when you activate the screen washers, the headlamp washers also work, irrespective of whether the headlamps are on or not.
Only certain chassis ranges are afftected and the fix is customer complaint only and only for the duration of the manufacturers waranty.
If the sympton is one you are experiencing and your car is still under warranty, ask your dealer to look up bulletin HUK 521 dated 02.12.04.
This bulletin does not apply for 05 model year on as they are already modified.
Disabling the Headlamp Washers
MY99 - MY01 & MY04 - MY05
On the MY99 - MY01 the headlamp washer button is in a ridculous place so that you can soak yourself or your nicely washed car by leaning on the button 
Honda solved this problem on the 02 model but in their wisdom re-introduced it on the 04 model in a different guise. When you press the windscreen washer on an 04 it also activates your headlamp washers - brilliant
To disable the headlamp washers on all models follow these instructions (stolen from Frenchie!)
Open up the bonnet. Look up by the windscreen on the passenger side; there's a black box about 6" x 3" with its top just below the level of the wing, between the battery and the wing.
Squeeze the ends of the box to free the clips and lift off the top. In the box, towards the front, is a 20 amp and a 30 amp fuse
Pull the 30 amp fuse out and store it in the empty space at the opposite end of the box.
Replace the lid - job's done!
Please take good care of your S2000, keep it by your side for long and enjoy it from the bottom of your heart. And share the quality and legacy of the S2000 with many friends so that the legend of the S2000 will continue for long