Hi All,

Not sure how to describe this problem but I'm looking for some advice on a possible cause for this. The car has about 125k km (99 AP1).

What's happening is my S2K starts to choke and struggle to accelerate.
The problem occurs at low rpm to mid rpm at light or medium throttle pressure.
It's extremely difficult to drive in traffic (start/stopping) as the car tries to cut out, not when its just idling, but when starting to accelerate from stand still). At low speeds say about 60-70kph in 4th the car sometimes struggles to accelerate.

It's gotten a lot worse no it's starting to get cold and car is becoming undrive-able. I had the Idle Control valve cleaned and this had no affect so I thought the problem might be elsewhere or the valve needs to be completely replaced. Up until today the car never had an issue under idle. It stayed fairly consistent (i.e. no hunting).

Does anyone have any similar experience of this type of problem and was it the IACV that caused this behavior?

Thanks.

Jeff

 

have you done the map sensor trick and the tps sensor. Change your spark plugs to NGK if not and get a valve adjustment.

got any mods? or Check engine lights?

copied from another forum not mines

DISCLAIMER - I do not guarantee any procedures or products demonstrated below are the best for your specific situation, as I cannot be there beside you to watch your every move. Please Read Very Carefully, feel free to PM me with Questions.
So basically what I'm trying to say is - if you screw something up - it's not my fault.

December 3, 2004 Service Bulletin 04-073, "Intermittent Hesitation During Hard Acceleration". Install new map sensor and holder kit � by: S2K Mayhem

Items Needed:

• Phillips Screw Driver
• 2 zip ties or *Honda Zip Tie (#14)
• Wire Cutter
• Possible new MAP Sensor (if you are replacing the old one about $45-$55)

The �MAP Whack� (with an ECU Reset � See Link Below) can be a simple, quick fix for all kinds of odd behaviors the S2000 can produce. Although it may not be a permanent solution for all problems, it is worth the try and could save you a trip to the �stealership�.

The MAP sensor (#8) sits on top of your throttle body:

[PHOTO=489345]
[PHOTO=489346]

• 2 Small Screws(#2)
• 1 O-Ring (#1)
• MAP Sensor (#8)
• Honda Zip Tie (#14)

Pinch the clip on the top of the wiring harness and slowly wiggle it back and forth to remove it. (At this time you may want to use some electrical plug cleaner, yes there is a specific name for this stuff but I can�t remember it. If you have Honda Brand Brake Cleaner, it will work � that�s what I use - if you do not do this step first be sure there is plenty of time for it to dry thoroughly)

[PHOTO=489348]

It�s finally time for the �Whack.� Using your screw driver, give it a few firm taps. Remember �your break it you buy� :LOL: well the same goes for here, don�t break it into pieces, but give it enough to free up any debris built up.

[PHOTO=489347]

Next we are going to insert the plug back into the sensor. Give it little wiggle and make sure the clip snaps back in place.

Now if you have the Honda Zip Tie attach it.

[PHOTO=489344]

If not you can use Two like so:

[PHOTO=467308]
(Make sure you put the horizontal one on first - get it under the clip - get it snug but not all the way tight. Next add the "vertical" one over lapping the first one. get it snug. Now, takes a little patience, just tighten one back and forth until it's good and tight.....reason behind this is the zip ties can slip off when tightening - so it can be a Pain. When you are finished cut off the excess with the wire cutters and you're good to go)

After you have to MAP sensor secured with the zip tie(s) you are finished. BUT if you are wanting to clear/reset the ECU, this is the time to do it before you start the car. If you are doing so because the car was �acting up� you might as well do it � it can only help.

Link to Resetting the ECU

************************************************** ********************

If you are replacing the MAP sensor continue to read.

Remove the plug same as described above.
And now remove the two screws

[PHOTO=489346]

-Careful not to drop or lose the two little screws(#2) or o-ring (#1) that holds it into place.
Now swap the two sensors. Careful not to lose the rubber o-ring that is seated on the throttle body itself.

[PHOTO=489349]

When tightening the screws down, do so evenly � tighten one side � of the way, then the other, then swap, until it�s tight. You don�t want to tighten one screw down all the way, then the other.

After you have to MAP sensor secured with the zip tie(s) you are finished. BUT if you are wanting to clear/reset the ECU, this is the time to do it before you start the car. If you are doing so because the car was �acting up� you might as well do it � it can only help.

Link to Resetting the ECU


Ultimate Lurker's post on the "infamous" MAP sensor: Here



Here is the TPS Sensor

So I was having the jerky hesitation problems that many have reported, but the car would never throw a DTC. Mine would occasionally stumble only when cold and only between 2500-3000 rpms. After it warmed up it was fine. I checked TPS V at idle and WOT, MAP, PHOS, every piece of the secondary air injection, plugs, coils, fuel - all checked fine. Finally I checked the TPS again, but this time I slowly rotated the sensor and monitored the voltage - found a ratty section that was very unstable. So now I start looking for a new TPS, but you have to buy the whole throttle body :banghead: . The local dealer wanted $550, and majestic (online) gets $476. That's alot of coin for a 0-5V potentiometer. So instead I bought an OmniPower TPS for $75, and buzzed off the flanges so that I could rotate it to .30V at idle. Works great and voltage at WOT is correct also.

[PHOTO=525610]

 

thanks ! i have Ap1 and it does this.

 

No CEL showing on dash.
Only engine mod is AEM V2.
Plugs are NGK.

With the cold weather were having here the problems are pretty severe with hesitation now around the 2-3.5k rpm range and all of a sudden idling has become erratic with the car hunting badly.

I'm going to try to swap the IACV with another car just to see if that works as they're expensive to buy new.

I haven't tried that Map sensor "Whack" trick at all. If the IACV swap doesn't work then I'll look at swapping the Map and TPS sensors. It seems like the TPS symptoms described in your post above are very similar to what's happening to my car so could be onto a winner there.

 

Just swap out one at a time to make sure. Check your plugs again to make sure. Reset your ecu before changing out though parts too. Just pull the 7.5 back up fuse, change the parts, then crank it up. Let it idle until it warms up, then drive it. dont give it gas or anything and make sure your ac, radio is off.

 

pull the fuse for about 5 minutes just to make sure it resets.

 

I bet its your vacuum lines check and make sure theyre connected correctly
use this as a reference http://www.s2ki.com/forums/index.php?showtopic=171067