Hi all!

i have an 2001 s2000 AP1. The car has nearly 200,000km on it and loads of service history. Anyway on first start in the morning after been sitting there all through the night after it fires up and idles at about the normal cold start rpm (about 2,200) it drops right back down below 900rpm and shoots straight back upto its cold idle rpm, but it does this really fast and really rough! The car runs fine when its warm or even hot

But if i tap the trottle a slight bit it settles itself and everything is fine!

Ive also noticed recentley that if you accelerate hard at really low revs (under 1000rpm) when cold it chuckles extremely bad at 2000rpm.
ive changed spark plugs and no difference.

Any info be great thanks!

 

Map whack and zip tie also clean map sensor and sensor hole

also clean the IACV and throttle body

also disconnect the battery for 2-4 mins
to reset the ecu

after reset of ecu let the car idle for 5 mins then rev up to 3k for 10 -15 secs to cycle the cooling fans

make sure engine is warm when doing this

 

Ok cool il try that tomorrow, have a close inspection and see if i can see anything.

Also i hear alot about the Throttle Position Sensor seems a common fault with these cars. Not to say it is.

Il do a voltage check on the sensor tomorrow aswell while im checking the basics.

Il let you guys know tomorrow how i get on anyway

 

so did it fix your problems

 

Sorry for late reply hard to get a chance to look at it with work

ive checked the tps with a multimeter and found that its at about 0.4 volts when closed and 4.50 volt at full throttle. Im not sure if thats ok those readings.
I also checked the map sensor and couldnt really see anything.
Also checked the IVAC i believe its called on the side of the intake manifold and was spotless! Barely any oil or dirt!
Checked what looked to be a temp sensor towards the rear of the intake manifold and seen only small oil on the sensor. 'Maybe its a intake air temp sensor?
Changed spark plugs aswell and still the same.

this morning was frosty and my car started and then cut out! Then when it did start it done what it always done with the hunting/flutuation revs

 

Cleanliness is not the issue for the IACV valve. It becomes 'sticky' at the extremes of open and closed rotations. You need to follow the DIY on this forum to take it off and spin it until it rotates freely.

 

Ok thank you.. i thought i was looking for a build up of carbon or something obvious on that line.. il look at the DIY section and see what that says.. il update as soon as i know more

 

Ive checked the IVAC and cleaned as best i could, used brake cleaner and cotton buds. Repeated 3-4times with a good clean. Even tho there was no dirt or any carbon.
Im getting a lone of a "SNAP ON ETHOS" diagnostic kit today and im hoping that will give me some sort of clue or atleast some sort of past fault maybe stored in the ECU.
Has anyone ever used this kit before, also i will be checking the car cold in the morning when the car is stone cold! Can anyone tell me what i should focus on because ive only one chance of doing this because the car idles fine after 5-10 seconds and im afraid i might miss something during those few seconds of that bad idle i need to resolve...

 

*UPDATE*

Ive had it really bad frost first this morning and went to start the car and it cut out straight away when it fired up, started it again and cut out again! I then started it again and idled really bad and while i let it tick over bad it started to billow out smoke from the exhaust and then when the idle started to settle back to normal the smoke cleared. Would it be possible that its maybe an o2 sensor because it ONLY does this when the car is cold.

i was thinking it maybe could be obviously something that is related to the likes of a temp sensor?

 

LOL, check engine compression...