Hi all, after a year of trouble free motoring a new issue has come to light.

To start with, about 3/4 months ago, the car started to really struggle to idle. A/C on or off, it was the same. Rev the car and the idle would go down to around 350~ and shudder the car, it would then after time return to around 900.

This then got worse, where if you came to a stop the engine would just stall out completely.

The garage I went to then went over the car, replaced the MAP sensor (i believe the wrong one was on there), i understand there was an adjustment on the TPS, and yet the problem continued. Then the idle control valve was replaced.

This started a new issue!

Now it idles in a new and strange way, when coasting it sit at about 2k rpm, below 2k rpm and the car is in gear you can feel it driving against the brakes which is a little strange.

If you are at a stand still and the car is warm, it idles perfectly, if you rev the car as long as you are not moving it returns to 900rpm.

If you put the A/C on now, it shudders and dips RPM, also a noticeable dip when even doing the windows up!

Lastly, if you come to a stop, it sits at 1500~2000 rpm for about 2-3 seconds before settling down.

Car has been checked for any vacuum leaks and other than this weird idle issue, runs perfectly...

Any help would be fantastic, as I am not overly knowledgeable and the place i got to is not local at all, its getting quite costly!

Thanks in advance

*Update*

Just drove home from work and had a bit of a play around, with as little load on the engine (AC off, stereo off, no lights) it idles around 1500 whilst coasting, and will keep a steady 9mph.

With AC on it idles higher when coasting, 2k but when you come to a stop, it idles for 2k for 2 secs then drops and very nearly stalls. At a stand still, if you[ rev the car with AC on, it struggles to bring the idle back up to 900, shudders for a good 4-8 seconds.

No idea if this helps !

 

Update bump!

I reset the Ecu, and followed the instructions for relearning the idle. Now I am back to square one!

This now happens:

Idle Issues 1

Idle Issues 2

Weirdly even though clearly the RPM is damn low, its not always indicating it is.

So to recap...

New Idle Control Valve thingy, new map sensor, TPS check and is ok, all the vacuum stuff is ok.. and still this?!

The fact it now stalls too (did on the first 10 mins of the drive home) feels like resetting was one step back

Ant

 

Have you cleaned the throttle body? The PCV leaves an oil coating that is best cleaned up every 20K miles or so.

 

Sorry for the late reply, took the car to a friends garage and he cleaned out the Throttle body, checked all the wiring to the sensors, checked valve clearances and then we did the idle relearn.

Same issue when its warm, revving/coming to a stop, soon as 0 mph is shown it dips to 500~ rpm. After a few seconds it will now bring it up to 650-800. but its kind of goes up and down, on the down it shudders the car.

On a cold start, or a semi cold start. Coming to a stop it will bog then stall. If i save it with a blip of throttle a couple of times it will steady out at around 600rpm.

I am at a lose now, there is not much left to do!

It had a great deal of new parts on it last year due to the previous owner not taking care of the car. This also includes injectors.


A note though, i am playing around with Torque on my Nexus tablet and notices the car at a standstill has 9% throttle. Is that normal?

Any ideas would be hugely appreciated.

Ant

 

 

Hi Ant

I have a 2003 S2K that had the same issues. I checked the TPS settings but my code reader read percentage and the data I got from Honda was in degrees and my conversion rate, i.e. 360 degrees = 100% did not equate. loosening the TPS screws and moving the TPMS in its full adjustment made no difference. I cleaned the Idle Air Control Valve (IAVC) which made no difference. I then replaced the IACV. Still the same.

I then gave up and took the vehicle to a Honda dealer, they said try replacing the IACV even though it was new. They plugged in their diagnostic machine and all data was OK.

In desperation I saw an advert for a low mileage throttle body complete with MAP and TPS sensors from a 2006 model (it actually must have been 2005 as the 2006 is fly-by-wire)which I fitted. At the same time I took the rocker cover off and did the tappets. When I put the car back together it was like a new car. It has never stalled or idled roughly since. If I have a grip is the idle is too high when cold (about 2,500RPM) for a minute or so.

My car has only done 22,000 miles so you would not expect anything to be worn at those miles.

Good luck with it..........

 

If I had to guess, I would say the TPS is not in the correct location. I believe the TPS should be at .33 (volts I believe) at 0% throttle and close to 5 at 100% throttle. Not sure how to check this with a stock ECU, but I would start by looking at the TPS.

 

After checking the TPS, make sure you don't have a intake manifold leak past the MAP sensor. Check all vacuum tubing and around the gasket. Try using propane or carb cleaner around the manifold....if you get an increase in rpm then you have a leak.

 

Check your throttle cable isn't too tight, make sure the throttle is against the stop.

 

Hi again,

I have been quite ill but back on form now, and ready with an update!

I have had the throttle body cleaned buy a local performance car shop, and they guy went over the car. Everything seems to be ok, as long as nothing electrical is on...

This includes putting the roof down, windows up or down, even just the blower on (no AC) and the idle dips very low and shudders the whole car. As soon as you turn it all off it idles nicely again.

Also, when the car is cold, it will idle at around 2.1k rpm, this seems a little high.. at 2 bars of heat (AP1 Dash) it will idle around 1.5k. Weirdly when you are driving and come to a stop, it will almost stall, then bring itself back up to 1.2-1.5k rpm.

If i am leaving work at the traffic is bad, even with the engine warmed up, until i get up to speed the car just doesn't idle ok. Soon as i go up to 70mph and down it is alright again.

Also to note, you can seem a slight dim on the dash when you hold the windows down, or putting the roof down.

Any ideas would be great, am getting so tired of these issues i am tempted to sell the damn thing

Thanks

Ant