first time used forum so bear with me lol i have a type r v3 has slight idle issue were it goen between 900 and 1100 not bad realy small idle issue but when i take my airbox of and fit my hks filter idle clears perfect all vacums perfect no air leaks recent strip down on top end every hose replaced and gasket replaced and all cleaned properly but still issue presists

 

Have you checked your MAF sensor?

 

What panel filter have you got in there? What condition is it in?
Clean ICV
Was the car mapped with the HKS on?

 

hi guys thanks for getting back intouch i have cleaned iacv and all sensors have had alook at maf and looks mint no eml light or power loss stuttering etc car hasnt bein mapped just i had a hks filter lying around so thot i would try does run good with hks no issues i havent got a maf handy to try engine is mint and no issues leaks etc i was thinking possibly maf aswell just thought might of saw more signs

 

Putting the HKS on would increase airflow,perhaps the car is running a little too rich on idle with the airbox on?
It's the o2 sensor that controls idle and light cruise so maybe a sign of that failing? Sometime cleaning them up can have a positive affect.

 

thanks again for getting back sure I could source a o2 sensor to try drives perfect on light cruise just the idle issue sein few videos of other people with idle issues isn't near as bad its slight up and down between 9 and 11 drives a1 and only does it when cars at temp

 

As with most thing on these cars,could be a number of things causing it,coolant temp sensor being another one.

 

I wouldn't go changing parts ***** nilly tho and start chasing a problem that isn't there.
That's why I love the fact we can just plug our cars into a laptop,monitor and log all the data,this can help diagnose any problems,as well as getting you head under the bonnet to see if you can eyeball and hear anything that might be causing you problems.

 

mine a 1997 v3 sti no obd port old school count the lights id have to have a scope to see what sensors are doin no onboard diagnostic

 

Mine is a v3 sti too,I have the luxury of ESL tho so can read all the data and DIY map
There is a way of bench testing the sensors with a voltmeter,have a search there is some good info on how to's on here.

 

Have you tried moving the iscv to stabilise the idel? Also, cleaning the maf element with brake cleaner may help.

 

tried cleaning never moved it was afraid to make it worse but could mark before move

 

ill get the volt metre out tommorow give it a check thanks again shame didnt have esl or some better way to read data unprivledged lol

 

Try an ecu reset.

 

update idle issues clears back to normal when brake pedal pressed has new hoses oneway valve refitted was same as before just wondering if any more ideas

 

Try disconnecting the electrical wires from the brake pedal switch, or better still, temporarily removing the switch from under the pedal, and then check whether pressing the brake still has the same effect. If it does, that would confirm the problem is intake air-flow/air-volume related (applying the brake diverts some of the intake vacuum in the manifold to the servo). If it doesn't, with the brake-switch still unmounted from under the pedal, try pressing the switch and see if that stops the erratic idle. If it does, it would mean it was the ECU altering fueling/timing when you pressed the fully-assembled pedal that was making the difference before.

 

tryd disconnecting plug from pedal still no difference had a check engine light come on knock sensor code 22 checked knock sensor bad crack down it have ordered one would this cause slight idle issue im having

 

What do you mean, still no difference? You were the one who said pressing the brake pedal was making a difference. So are you saying that with the switch disconnected, pressing the brake pedal doesn't make any difference any more? Also, you do realize that everything in my last post was meant to try and help you find the problem, not as an actual way to fix it, right?

You certainly shouldn't be driving the car with a damaged knock sensor no matter what, so fix that first and then see if you still have the idle problem.

 

hi soz was bit vague on last response do understand what your sayin i removed electrical connection goin to pedal and revs still settle when pressing brake which would properly be as you said air related issue i dont drive the car much atall i have a few cars. i wouldnt expecially with knock sensor problem ordered new one so is on way have checked all vacuum lines and all perfect no leaks just wondering if could be linked with knock sensor problem

 

OK,based on that and what you say in your first post about the HKS filter, it's looking like it's just running a little too rich, as per earlier poster's comment. A bad knock sensor would definitely not cause this, although a faulty MAF could. Another thing you have to remember though is that the fuel mapping is to an extent 'learned', so if the car's been running for a long time with some condition (whatever that might be) that either makes the ECU believe it's getting more air than it really is, or which was really feeding more air into the intake than is getting in there now, the ECU will gradually adjust the map richer over time. If that extra air supply then suddenly disappears for whatever reason, or the ECU was getting false readings all along, you'll end up with an ECU that over-fuels slightly. Solution - reset the ECU, and that should fix the problem, for a while at least. Easiest way ro reset ECU is to just disconnect the battery for an hour, or if you use the search on here there's also a way to do it using the diagnostics plugs.
Just out of curiosity, when was the car last MOTed. and what were the emissions results like?

 

april not sure never motd i have disconnected battery for a while and cleared ecu faults but same scenario again was thinking on trying maf just thot may have had more symptoms than currently am gtn but if ye think posibly worth trying maf will give it ago

 

new knock sensor fitted just like you said didnt affect idle issue have had battery of and tryd reset still same im just wondering if could test with multi metre first dont have a scope or readable ecu to no exactly what goin on im nearly sure its maf with changing filter and problem clears and also brake pedal affects idle earlier thread above says posible o2 sensor aswell

 

Hi there have you made sure for 100% for any air leaks etc and if you've lost any coolant while changing pipes etc there could be an airlock in there maybe or level of coolant? Always check simple things first before any complications good luck hope you get it sorted mate