jameswrx

iTrader: (4)

Bought this 02 sti wagon with a rocky idle, shakes the car at idle. Drives great, pulls hard, uses no oil or water or mixing of the 2, no smoke, power feels spot on, seems absolutely perfect running once the revs are up a bit and driving, just idle and up to maybe 1500rpm it's rocky, literally shakes the engine side to side and you can feel it through the car

Did a compression test..

Car wasn't that warm though, had been run this morning and put back in the garage and stood for 4 hours+

1 = 125psi
2 = 128psi
3 = 125psi
4 = 148psi

Not really the outcome I was expecting from a varying compression result!

I double checked it to make sure.

I've checked the net for info on V7 STI compression and when new they were 138-166psi and apparantly a drop of up to 40psi is to be expected when they are used, so it looks like the 125psi ones are pretty reasonable and to be expected. I've also found a vid of a low mileage v7 sti engine being tested on youtube and it was 125psi accross all 4.

Not sure about this one higher compression but was maybe thinking injector prob, ie sticking and coked that cylinder etc.

I've since run a tank of fuel with BG-44K added to it to see if I had an injector issue (ie dirty) but there's been zero change in the idle, not even a bit.


Plugged in my lappy and run ECUexplorer, few screen grabs


Car warm, engine off





Car idling




Car idling again but screen grab of rear o2 voltage fluctuation (normal?)




Engine held at 2200rpm




Car started to idle fast for some reason and ran really rocky/rough so did a screen grab at this point..




idling after a quick blast to check AVCS was advancing (2nd and 3rd gear) Only reached 24/25 degrees, thought they'd reach 30 odd?




Now I originally thought the problem was AVCS related (ie the difference between the 2 banks and the fact that the left won't go below 2-3 degrees) causing the rocking idle but i've been informed by somone that it won't effect the car in this way.

It's doing my head in now, and would be great if someone could see something glaringly wrong above. As I've got nothing to compare it to I can't really get my head round all the live data there.

Been hitting nasioc search and have seen info about some STI's getting dodgy injectors so may be that, could also potentially be cambelt, or maybe the AVCS difference would do it and the info I've received isn't right (although been told even with a 20deg differential between the 2 banks it idled normally)

Turbotits

iTrader: (2)

I take it youve done the obvious and cleaned the idle control valve>
Had mine sieze where it was so coked up. caused all sorts of idle problems.

cleaned it with carb cleaner and soaked overnight in wd40 and all has been good ever sinse

Midlife......

iTrader: (2)

My Bugeye WRX Idle problem was the ICVS ............... I can't actually remember how much it cost but it almost made my nose bleed !!!

Shaun

jameswrx

iTrader: (4)

Yes, done that.

I've also fitted new plugs, new coil packs.

It's an odd one really, not just a messing idle like I've had before with sticky iscv's but a real rocky old shake.

jameswrx

iTrader: (4)

Just to tidy this up..

Removed all the cambelt covers yesterday and lined it up only to find the rhs inlet cam was one tooth out (advance) as this is the avcs cam that's also not going to zero degrees then was quite pleased to see it.

Removed tensioner and lined pulleys up correctly.

The nasty rock is now gone!

Here's a before vid, notice the shake.

http://www.youtube.com/watch?v=4iT_A...eature=channel

after, with timing set right

http://www.youtube.com/watch?v=gWURX...eature=channel

Viz

This is interesting, a few questions;

1) what does the AVCS table in the rom say for your car?
2) since you sorted out the cambelt are the left & right AVCS now in sync?

I'd be interested in seeing a few more of your logs at idle & 2200rpm.

Cheers Viz

jameswrx

iTrader: (4)

I haven't checked with laptop yet, I'm hoping avcs is levelled. Will update when I've checked.

jameswrx

iTrader: (4)

Never did update further on how this went.. Can't believe how long it's been since this, just get so little time to play see days.

Car is now spot on when warm but I still have the same rock from cold starts. I was wondering if I'd sorted the previous prob and I had a cold start issue ie coolant sensor etc, changed coolant sensor and still the same.

I'm 99% sure (haha) it's still something to do with avcs. Not quite sure why it's only like it from cold but it's the same rock as before but since fitting the cambelt correctly it's perfect when it's been run for about 2 minutes, before I changed the belt it was like it all the time.

Ecuexplorer won't connect up to my car anymore for some reason so can't check what the avcs advance is like cold and hot. I'm presuming (the way it acts) that now the advance is circa 4deg when cold and goes back to 0 when it's warmed up, whereas before it'd be 3-4 deg all the time on n/s bank.

I did remove both ocv's a while back and cleaned them out, removed both oil line filters and it made a tiny bit of difference but I'm still not sure what it can be. I did consider the cam wheel mechanism physically sticking but then the warming up bit doesn't add up that it gets better every time.

I'm sure I remember reading somewhere that the avcs does something from cold starts for around 90 seconds but can't find where I read it.