My Cold Start Quirks

Posts specific to the 2.5 litre NA engine

My Cold Start Quirks

Postby Nottage969 » Wed May 18, 2011 11:07 am

Just a few little things i've noticed in the mornings on a cold start, was wondering if anybody could shed some light or had any similar problems.....

The obvious excessive cranking every now and then, but that's been spoken about to death and mine has subsided since running some injector cleaner through it with my last tank of fuel.

When taking off down the road i normally change around 2500rpm up until 4th gear where i slow on 50km/h..1st and 2nd gear changes are fine, but when i change to 4th from 3rd, the rpm doesn't drop. Obviously my foot is completely off the accelerator, but it just stays around 2500/3000rpm even with the clutch in...3 or 4 seconds later, it will drop down like a normal gear change. It only does this for about the first 2 minutes of driving, as soon as the temp gauge moves the slightest bit, it changes fine. I'm not particularly worried at this stage, just seems really odd and i was wondering if anybody had any ideas?...

If i go from 50km/h to a stop (every morning at the stop sign at the end of my street), i tend not to use the gears to slow myself down as i'm still half asleep and can't be bothered. I tend to go from 3rd to neutral, then release the clutch and roll to a stop. By the time i stop, my car loses rev's and starts revving a bit low, almost stalls, and then catches back up again. This happens more when it's cold, but every now and then once warm as well. Probably the easiest fix for that would be to drive like a normal person, and slow down with my gears..But you know! :P



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Re: My Cold Start Quirks

Postby mihai » Wed May 18, 2011 12:54 pm

Nottage969 wrote:When taking off down the road i normally change around 2500rpm up until 4th gear where i slow on 50km/h..1st and 2nd gear changes are fine, but when i change to 4th from 3rd, the rpm doesn't drop. Obviously my foot is completely off the accelerator, but it just stays around 2500/3000rpm even with the clutch in...3 or 4 seconds later, it will drop down like a normal gear change. It only does this for about the first 2 minutes of driving, as soon as the temp gauge moves the slightest bit, it changes fine. I'm not particularly worried at this stage, just seems really odd and i was wondering if anybody had any ideas?...


This is most likely the Subaru having a high idle when cold. I know in the mornings when I turn my car on, it will idle at a higher RPM than when the engine is warmed up. Not exactly sure what RPM mine idles at in this stage. By the sounds of it yours idle's at about 2500-3000rpm which seems a little high.

Nottage969 wrote:The obvious excessive cranking every now and then, but that's been spoken about to death and mine has subsided since running some injector cleaner through it with my last tank of fuel.


I used to have this some times, then I upgraded my battery to an Optima D34M. Mind you my stock battery was tiny (315CCA) and the Optima is now 850CCA so big improvement.
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Re: My Cold Start Quirks

Postby Robbks » Wed May 18, 2011 2:39 pm

Idle Air Control Valve

page 5 here
http://download387.mediafire.com/vcnpyl ... -+SOHC.pdf

same as 99 WRX

the IACV gets gummed up with blowby and carbon sh!t.
undo two small screws.
remove it (don't lose the O-ring)
clean all the gunk off it with carbie cleaner
clean out the housing
replace.

car will idle funny for a while as it re-learns correct idle motor positioning

win.

EDIT:
this was a regular thing to clean on the turbo'd motor
i.e every 500km's or so, even with a catch-can in teh intake system

and it also helps to explain the hard starting issues as teh car is unable to get teh correct amount of air into the motor that it requires for a clean start
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Re: My Cold Start Quirks

Postby Nottage969 » Thu May 19, 2011 7:23 pm

Robbks wrote:the IACV gets gummed up with blowby and carbon sh!t.
undo two small screws.
remove it (don't lose the O-ring)
clean all the gunk off it with carbie cleaner
clean out the housing
replace.

car will idle funny for a while as it re-learns correct idle motor positioning

win.


Legend. Did this today and didn't want to reply until i had done it. Piece of piss job to do, except my screws had clearly never been undone! :P I'll know for sure what the results are like tomorrow morning when i head to work, but she was definitely idling spot on all day today when i was driving after doing it. (Besides the initial time after starting, as you suggested).

I can't see why this wouldn't have helped. Thanks heaps mate! I'll edit with my results at work tomorrow morning :)
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Re: My Cold Start Quirks

Postby Robbks » Fri May 20, 2011 9:01 am

good to see it's helped something.

on eof those things that are never touched, and Subaru would have just thown it out and replaced with a new one at something like $500
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Re: My Cold Start Quirks

Postby swingn » Fri May 20, 2011 11:16 am

Personally I hate driving around when the car is on choke (Especially if you have an auto) thus why I let it warm up for a few minutes :)
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Re: My Cold Start Quirks

Postby Nottage969 » Fri May 20, 2011 11:33 am

swingn wrote:Personally I hate driving around when the car is on choke (Especially if you have an auto) thus why I let it warm up for a few minutes :)


If i have the time, i always do to. However most mornings i am running late enough to work as it is! I don't have very good self-motivation to get my butt to work!... :twisted:




Drove it this morning and it helped the idling/stalling issue at the stop lights. The changing from 3rd to 4th was improved, but it still revved high and wouldn't drop below 2grand for about the first 3 seconds. If anything it's made the start-up worse (ie. it started rough again this morning, and hasn't done for a while), but it's really not a major deal. Overall, i'm not dropping rev's and nearly stalling at the lights anymore, so it's helped at least something! And was piss easy to do, so thanks! 8)
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Re: My Cold Start Quirks

Postby Robbks » Fri May 20, 2011 12:34 pm

could have an issue with the colant temp sensor.
throws in too much fuel and causes it to run rich, ECu opens teh IACV more to get teh fuel mix in check
more fuel + more air = more revs.

also check adjustment on your throttle and cruise cables
and clean the throttle body
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Re: My Cold Start Quirks

Postby black_2.5 » Sun May 22, 2011 9:44 am

Modern cars are meant to idle higher when they are cold. Gone are the days when we needed to manually adjust a choke, so now its just an automatic thing.
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Re: My Cold Start Quirks

Postby Nottage969 » Sun May 22, 2011 11:54 am

Got some more feedback...

"Problem" (if that's what you want to call it, it's not really a huuuge deal :P), has returned back to how it was. Low idling is better at stop sign and lights and stuff now in general, although last night driving home it did drop a bit low a few times at the lights. However, high idle when changing from 3rd to 4th is still exactly the same in the mornings. Cranking in the morning got worse straight after cleaning the Idle Control Valve, but has returned to normal now (pretty much starts like a dream again). So overal just back to square one.

None of the quirks are a huge deal, especially as they are predominantly only when the car is cold, just thought if it was an easy-fix that somebody knew about, i'd give it a shot.


Thanks for the input guys, much appreciated!!! :)
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Re: My Cold Start Quirks

Postby Robbks » Mon May 23, 2011 11:40 am

other things to look at now.

coolant temp sensor
air/ vacuum leaks
dirty/ leaky injectors/ seals
o2 sensor (issue once it's warm)
poorly adjusted TPS and throttle cables
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Re: My Cold Start Quirks

Postby Nottage969 » Mon May 23, 2011 1:13 pm

Robbks wrote:other things to look at now.

coolant temp sensor
air/ vacuum leaks
dirty/ leaky injectors/ seals
o2 sensor (issue once it's warm)
poorly adjusted TPS and throttle cables


Thanks mate, you've been a great help.

I have a mechanic that i'll take it to soon since it's just about due for the good ol' Timing Belt change (better to get in early and be safe rather than sorry! :P). So i'll mention the symptoms and see what he comes up with. I have no doubt it'll be a similar diagnosis. My mate also recommended Coolant Temp Sensor, which i hope is what it is, as that would probably be the cheapest to fix! :P


Thanks again! :D
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Re: My Cold Start Quirks

Postby Robbks » Mon May 23, 2011 2:24 pm

coolant temp is easy and cheap to replace.
-loosen alternator tensioner
-remove alternator
-undo sensor
-fit new one
-re-install alternator and belt
-drink beer

don;t even need to drain the coolant.
just pklug the hole with your finger as soon as you get the old sensor out
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Re: My Cold Start Quirks

Postby Nottage969 » Mon May 23, 2011 5:38 pm

Robbks wrote:coolant temp is easy and cheap to replace.
-loosen alternator tensioner
-remove alternator
-undo sensor
-fit new one
-re-install alternator and belt
-drink beer

don;t even need to drain the coolant.
just pklug the hole with your finger as soon as you get the old sensor out


Hmmmmmmmmmmmmmm. Since i'm not exactly scared of playing around under my hood, i might just give that a shot! Can only try!... :P
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