Consistent running issues / gremlins from cold and misfire
 

Hi all, i have posted a few times in the last couple of months about running issues i have been having with my uk t2000 my00 PPP package otherwise standard to try and get to the bottom of it to no prevail as of yet...

It starts fine everytime and idles ok but once you start to drive from cold for the first 5 mins of driving it will drive really lumpy with vertually no power at all at the bottom of the rev range... Say up to 2500 rpm. After that it revs smooth. And once upto temperature runs perfectly fine too. And like i say only from stone cold, if it's hot and u switch off/switch on it will still drive fine. Its slowly getting worse and was only efecting things when cold and still drove perfect when warm, but i have now noticed a very slight hesitation on WOT higher up the revs and the ocasional misfire/jerk going through the revs.

I have changed the following one by one, with a couple of days between each item with various ecu reset attempts also to try and iron out the problem...

Maf
Lambda
Coolant temp sensor
Knock sensor
Boost solenoid
All vac hoses replaced/checked etc (car comes on boost and holds boost fine, no high idle or lumpy to indicate air leak)
Intake hose replaced with silicone item not long ago before problems started and new intake manifold gaskets with that fitted
I had a bailey bov but changed to original
Fuel filter

So what do you guys think?

Sometimes i have fitted one of the above and all has seemed fine for a couple of days so i get chuffed :D but then shot down again when it returns :( really gutted cos i am reluctant to drive it hard and havent been able to have a good blast in it for a long time.

Really could do with some input here, cheers guys.:notworthy

failed or failing 02 sensor will cause these symptoms, had mine 8 years and everytime this has happened it was the 02, its runs rough when cold but when it warms up runs normal, 02 cel code only comes on when doing about 75mph uphill on part throttle, get the 02 checked look up 02 testing on you tube, you need a blowtorch and a voltmeter

Could try cleaning out your idle control valve.

^^^^this and don't forget to buy a gasket as the old one will be no good once you remove icv.
When was the fuel pump replaced? They don't last forever.
Also as already said O2 sensor which controls idle and closed loop can cause these problems when faulty.

Thanks for replies guys, ok a couple of things to do here then. The ICV i actually removed to change out the knock sensor as it was in the way to get my ratchet down there, i replaced with the old galsket as it still looked perfect but i will get one ordered, and when removed clean it before re fitting it.... How do you guys best clean them just lash it with carb cleaner?

The fuel pump ive thought about also, or fuel starvation so i changed the fuel filter and things havent changed. Wouldnt a pump problem be more aparent higher in the rev range or just more consistently bad all the time and not just when cold at low rpm? How would i check that?.... Main fuel line in with ignition on with pressure tester in fuel line?

I think ill check these couple of things before thinking about another lambda.

Ive got a coil, leads and plugs on the way to fit to rule these out over the weekend, although these were changed less than a year ago lol but hey ho.

Cheers guys.

Check and clean if necessary the throttle body as they get gummed up over the years. Worth a try

Ok been reading a few threads about the icv and when the seal goes they can cause water to get in the inlet, and i do get white smoke on start up and i spose the symptoms i get are as if some water coukd be in the intake. So ive ordered a icv seal and throttle body gasket so im going to give that a good overhaus over the weekend along with changing the plugs and leads and see how i get on!

the classic and newage icv are different so make sure you've ordered the correct one �:thumb:

On the V5 impreza turbo the ICV has an "o" ring not a gasket.

Yep thats the one ive got on the way from advanced automotives along with the throttle body gasket. Next day delivery so should be here tomorrow fingers crossed. Will get some carb cleaner and strip it down, clean the whole thing and rebuild it with the new gaskets see how that fairs. Im feeling optimistic though... Again lol. :) ill leave the battery unplugged overnight the night before i do it to clear the ecu aswell.

Ok quick update, i ave stripped and overhauled the throttle body, cleaned idle valve, new seal, new gasket on throttle body itself. Exactly the same running conditions. Its worth mentioning ive tried 2 maf and 2 lambda sensors and symptoms are exactly the same with any of them fitted so i doubt there all dying.

Ive been very vigilant to how it drives this morning, there is an inconsistancy with power also sometimes it picks up great and goes like stink and so,etimes it feels vey underpowered coming on boost or as if its losing a bit of power and it comes back. The boost gauge is consistent though and doesnt fluctuate and alsaws pulls a strong 15-16psi so heres what i am starting to think now lol...

Possible ht/ignition breakdown maybe coil pack.
Also can ecu's go bad? I have an old stock t2000 ecu i may plug in and see if it makes any difference just to rule another thing out. What do you guys think now. ,any thanks for your input again, the way its going everything undr the bonnet will end up being replaced trying to fix this lol. Cheers

Heya aaron, I have a 2002 wrx that has some similar symptoms to what you've just described in your last post. Slightly necro-ing a thread but curious if you did indeed find you a solution/the root cause of your problem? :wonder:

Cheers,
CBR

I would start with the basics first before you throw any more parts at it tbh,
Spark plugs out and do a compression test to make sure the internal health of the engine is ok.
Renew spark plugs.
Check the coil pack resistance's and plug lead resistance and condition.

If all the above is ok then do you have any fault codes stored in the ECU ?

Mick

Heya Mick, a compression test was just done about 1000km ago and it was 145-147 across the 4 cylinders so pretty healthy. There are currently no new engine codes. Yes I'm saying new as their were some engine codes before I reflashed the ECU after cleaning the MAF. No check engine light or anything though. I had taken a memory snapshot with my cobb accessport but am unsure how to view the file XP. To date I've put about 3 tanks of gas through the car though so I feel like that should be enough km to retrigger any new valid codes.

I agree my next plan of attack is checking out the plugs + coils, one other side note that has me slightly concerned is that when i first went to buy the car it had a dead battery, now it's cold as heck out here and the car had sat for 2 months without being driven and hadn't been started for 3 weeks. (it had been started, idled and had 1 short test drive but not enough to charge the battery). So the battery is possibly suspect but, I've been driving it every few days and it starts just fine and even today, it metered out at 12.3 volts which at -28 is pretty good so..... I'm going to leave it for now and see.

Cheers,
CBR

Hi CBR,
Did you finally solve the problem? I have exactly that problem with my 03 sti and I have to run it at idle for 5min when starting from cold because the car will stall on me.

I had similar symptoms on my UK Turbo 2000 MY'99..
Turned out to be coilpack and leads.
I think it's an age/mileage thing
Changed them for genuine Subaru items (after first trying cheap imitations) and problem disappeared.

Hey Greggar, I ended up having it re-compression tested and it ran a 130ish on 1 piston. This difference between cylinders in greater than factory spec (which is around 8psi diff max if I recall correct). I ended up engine swapping for a fresh JDM EJ205 and flogged this one. I hope your solution will be less costly than mine was.

Cheers,
CBR

PS it may also be your O2 sensors as they have a finite lifespan of around 80 000 miles. They are often responsible for idle issues.

:thumb: