idle question: 967842782450

[Kamatari]

So i know idle questions seem to get asked quite a bit so forgive me

starting my car from cold see\'s my idle sitting at about 2000rpm and stays there for atleast 20mins at the least. i\'ve found that at times when ive parked up and come back to the car say 10mins later it settles at about 1000rpm.

Now when it idles high i don\'t really have to use the accelerator as it practically drives itself... so im thinking that this might be something sticking open

To add to my idle problem, 90% of the time if it drops to 1000rpm, it is a pulsing idle between 1000-1500, i\'ve gone about setting the tps and ive adjusted the idle air screw but this hasn\'t done anything, from this i\'m believing it might be an vacuum leak?

FINALLY, the car idles quite rich, now from what i\'ve read there is a variable resistor (which ive found) that is also meant to be adjusted for the idle as well as leaning it out (or richening) the only problem is ive read it needs some special tool to adjust it? does anyone have any ideas about this?

Thanks for any help guys!

[m1tch]

Hi there,

the first rev up might be the accelerated warmup system, it basically revs the engine when cold to warm the engine up, to disable this drop the clutch and put it in first, the revs should drop (but of course don\'t put the clutch up!)

The hunting throttle rpms might be the TPS (throttle position sensor) or maybe an air leak.

[Kamatari]

thanks for the reply! it could be something to do with the accelerated warm up although it doesnt go away for atleast 20mins which i belive is wrong

[m1tch]

Yeah, it shouldn\'t keep revving like that, have you check the throttle cables aren\'t caught or tight, or indeed the cruise control cable/pulley/motor

[Kamatari]

hadn\'t thought of the cruise control cable, ill have a look into it

has anyone got any ideas on what this tool is to adjust the idle resistor? or what i can use instead of it?

[m1tch]

The TPS adjustor is quite specific, but it might be worth having a look at the BAC valve on the side of the engine, its on the inlet manifold, drivers side, looks like a tube with some water lines going into it. There is a screw that controls the idle and drops the idle when the engine is warm (hence it has a coolent line in it)

Perhaps try that, or indeed check for any vac leaks that might cause issues.

The cruise control motor is also on the driver side, its a small box with a black lid with a cable coming out of it, check its not that tight when the engine is off etc.

Here are some details on FC3S pro which also has guides on how to fix stuff

http://fc3spro.com/TECH/PROBLEMS/P1/ENGINE/IDLE/idle.htm

[Kamatari]

with the bac valve, mine is a non turbo so i believe my screw is on the top of the engine....if i am turning the right thing then it seems to be doing nothing

[Prof]

That\'s the right screw for an N/A
 
Maybe your throttle plates are sticking open - it could also be a sign that the wax thermo device on the back of the throttle body isn\'t warming up properly or isn\'t closing the throttle as it warms, leaving you with a more open throttle ?
 
Without taking stuff off the top of the engine it\'s hard to say.
 
Make sure you\'re water level is good, as air locks can give these sorts of problems too.

[Kamatari]

Still need to sort this out, it seems to have good and bad days where it may idle properly for a drive and then come next drive it\'ll do its idle bounce and then a drive after that idle high... reading more things there was a mention about the o2 sensor... Now with the o2 sensor i could get a replacement but i\'m looking to get a wideband O2 sensor as i have picked up an s-afc neo, could anyone see anything wrong with me using the wideband as a replacement for the normal o2 sensor?

[Prof]

Still need to sort this out, it seems to have good and bad days where it may idle properly for a drive and then come next drive it\'ll do its idle bounce and then a drive after that idle high... reading more things there was a mention about the o2 sensor... Now with the o2 sensor i could get a replacement but i\'m looking to get a wideband O2 sensor as i have picked up an s-afc neo, could anyone see anything wrong with me using the wideband as a replacement for the normal o2 sensor?

Basically the stock ecu will not know what to do with the signal from a wideband.  Some widebands output a 0-1v wideband emulation signal - that can be used, but it\'s not a very good alternative to the actual sensor and results vary.  That being said - the lambda has nothing to do with the idle issue - it\'s only used between about 1500-3000 rpm\'s on cruse and light load

[m1tch]

Have you checked for splits in the hose or a small leak on the intercooler pipework?