forgedmarco

iTrader: (10)

If it works that's what counts. There must be a permanent fix that has the same effect?

JohnD

iTrader: (5)

Don't know if you've considered a possible dribbling injector after switching off? It was this thought that originally led me to my stick on the throttle thing! By venting the manifold/head, the fuel would have a better chance of evaporating instead of fouling the plug(s) on the next start. The only thing that made me doubt the injector theory was that the problem continued after an injector change!
Worth considering?

JohnD

romford-boy

I've just seen the updates on this thread.

I think we have the same issue! As you know I also have had the STi remapped, pretty much got the same set up as you. I get the puff of smoke that you do, but I'm pretty sure that is not an issue as once the car is warm it is perfect and doesn't miss a beat, unless the map is leaving the car with too much fuel in the engine - I think our maps run slitghly rich for all those extra pops and bangs.

https://www.scoobynet.com/general-te...art-ideas.html

Inviroman

iTrader: (2)

Today started the car for the first time in just over a week, same issue cranking before fire up, but when it did noticed small cloud of blue smoke?
Checked the car running and on lift off no smoke and all the breathers ok no smoke etc.
It looks now as the issue is mechanical but no issues when driving or smoke.
Ideas?

JohnD

iTrader: (5)

If the car has a few miles on it then an initial puff of smoke when starting after a week of inactivity is not at all unusual, especially if the oil was fully warmed the last time it was used.
It seems there are quite a few people with the same or similar symptoms and the stick on the throttle trick seems to work for some, but of course, it's not the proper answer!

JohnD

Inviroman

iTrader: (2)

John,
will have to give in a try the "stick on the thottle trick"
Just been out with pal following me and there is no smoke at all from the car on and off boost (cheers Lee)
Car has 66k in regards to miles

gazzawrx

iTrader: (11)

It could also be the normal forged engine puff of smoke on start up, bear in mind sti newages got forged pistons as standard so maybe thats a possible culprit?

Welloilbeefhooked

iTrader: (3)

Check and clean the contacts on the engine earth lead that connects to the block near the starter.

Turbotits

iTrader: (2)

id ask one of you to check the voltage at ecu during cranking. it maybe the starter is sapping all the power initially and shuting some other electrics down

JohnD

iTrader: (5)

Thinking exactly that I actually replaced the battery and the problem was still there!
That battery is now 6 years old has been close to letting me down on occasions after a week of inactivity and struggled to turn the engine, but it still fired up fine (after having used my 'stick trick')

JohnD

JohnD

iTrader: (5)

Give it a go! - you might be pleasantly surprised!

JohnD

Inviroman

iTrader: (2)

Well after no use of the car for a couple of weeks, first the battery was flat so charged up for 24 hrs and on start up the same issue of cranking for while before spluttered into life with cloud of blue smoke.
Would like to get the to root cause of this as it seems that depending on the cycle the enigine is at when switched off may be the issue.
On some starts fires up first time and others the issue with long cranking then the blue smoke.
Starting to think that either engine/turbo inspection my be required to find the issue.

Inviroman

iTrader: (2)

Again today car struggled to start and the blue smoke was back, seem that there is oil in the combustion chamber when car is left for a while which when attempting to start this is noticeable as there is spark.

merlin24

iTrader: (1)

To the OP.
Have you had the fuel pressure checked ?
Easy enough to fit an inline fuel pressure gauge between the filter and inlet manifold and you can see if the fuel pressure is dropping away overnight or struggling to build when priming.

Mick

forgedmarco

iTrader: (10)

I know sensors came back as ok but did you try changing coolant temp sensor to see if that works?

forgedmarco

iTrader: (10)

Also tried mine again last night primed the pump four times before cranking and it fired right up.

CutMasterT

iTrader: (2)

Inviroman - did you ever get to the bottom of this? Mine has an almost identical issue, so just wandering if you ever found the root cause?

jameswrx

iTrader: (4)

If the stick on the throttle is working for people, I might suggest you've got a leaking injector. The open throttle allowing the fuel to evaporate more easily.

A fiend had a bugeye that would display these symptoms and that's all I could trace it to. After being left it'd struggle to start, ie crank for a long time and run like it was flooded and take a while to pick up and run clean. If you turned it off and restarted straight away it'd Fire clean, if you left it over a certain amount of time it'd do the poor starting thing. All I could visualise was the injector leaking. Restart it before X amount of time and not enough fuel would drip in, leave it over X amount of time and enough fuel would drip to cause a problem starting, residual fuel pressure in line eventually drops away and once it's been stood long enough to evap it's fire fine. Hence why the stick on the pedal physically opening the throttle body allowing leaked fuel to evaporate may work, otherwise what other benefit would the throttle stick be?

CutMasterT

iTrader: (2)

Gonna give that a go and see if it helps.


But would the above cause the car to fire up 'too' easily - i.e soon as it cranks it fires up and limps on, instead of a few cranks and then firing up - which seems to be intermittent too

JohnD

iTrader: (5)

That's the conclusion I came to when I first started doing it however, the problem continued even after an injector change! Of course, there is the possibility that there was a leaker in both sets but not likely?

328isport

iTrader: (6)

Just to add.. I also have this issue, on my 93 WRX! shows it's a problem that happens across a wide range of years..

Mine is the usual cold start only, spluttering for a few seconds (sometimes longer sometimes shorter) before picking up to the correct 1500rpm. Like what James WRX described with his friends bugeye, usually I start it, let it run rough for literally a second and then shut it down and restart, generally its much better on the second start.

Conversely sometimes it will start absolutely fine, as mines a daily driver I've had plenty of time to monitor patterns etc, funnily enough mine was vastly improved in sub-zero temperatures over the winter, in fact it went weeks of first starts! Before dropping back to starting rough the majority of the time as the weather picked up. If anyone has a theory on why this might be I'd be interested to hear it!

I tried Johns stick trick but it did'nt work for me, I had a few decent starts but then a few full on rubbish spluttering ones, though should anyone else want to try this the Subaru jack acts as a perfect stick for pinning the throttle pedal :-)

My feeling is that it is fuel related, if I drive off straight away after starting I'll usually pick up a slight misfire in the first minute or so of driving, which is consistent with the sound on start up that it's not firing on all cylinders, I'd expect the likes of a cam or crank sensor to fail completely rather than only affecting cold starts, though as my car is coming on for 22 years old I do intend to replace these sensors anyway.

Just to advise what I've done so far, all of which made no difference;

new genuine coolant temp sensor
different MAF's
different ECU's
New plugs (correctly gapped)
New fuel filter
For ref my car has a HRC fuel pump
Checked connectors to IACV etc and cleaned with electrical contact spray.

I've just got back a set of injectors which I've had ultrasonically cleaned and will be fitted along with new seals and a new stock fuel pressure regulator as the next step.

If this doesn't work I'll do the cam/crank sensors next, and then failing that look at the throttle position sensor and a grounding kit.

CutMasterT

iTrader: (2)

I also tried the stick overnight trick, and although it made it fire up it spluttered on before climbing to 1500 or just below.

With mine its like the hotter the engine is the easier it is to start and the idle is perfect. But as soon as you leave it to cool that's when the idling and starting problems happen. When the engine is cool but not stone cold it will always fire up but it comes on at low revs, and seems to start literally as soon as it cranks rather than a few cranks and then firing. But its intermittent and won't always do it.

So far I've fitted new coil packs, new genuine lambda, new walboro and cleaned crank sensor but nothing has helped.

Next thing for me to try is coolant temp sensor, but from my understanding a failing one would normally cause the cooling fans to come on when starting the car, which mine don't

328isport

iTrader: (6)

Alex, you may as well stick a new coolant temp sensor in as at least it covers a potential issue in the future if nothing else, plus not too expensive from ICP. I didn't have anything actually playing up when I did mine either but did it given that it's supposedly known to cause poor starting issues.

That said wasn't yours absolutely fine before you had your most recent run of mods done? Were your injectors changed as part of the upgrade?

CutMasterT

iTrader: (2)

Yer man got one from icp ready to fit and as you say at least it eliminates that.

Yer I had some deatchworks 740 injectors fitted with the other work I had done but it did have a problem before I had this work done with the old injectors in so not entirely convinced its injector related - but certainly not impossible I guess. Thing is tho wouldn't the issue be more permanent if it was injector related? But with the old injectors in the problem wasn't cold starts, it was once the car is warm/cooled down (not stone cold) when trying to start it would fire up lumpy and literally as soon as it cranks. But the problem seems to have manifested its way to cold starts after having had the twin scroll done

I've ordered a brand new crank sensor from icp too just to rule out that.
I'm sure its something simple but its just annoying and when you know its not right it just bugs me lol

jameswrx

iTrader: (4)

If anyone with poor cold starting cold has shaking idle that you can feel through the car until it warms up, I'd be getting a leak down test done. I've had a couple of Imprezas over the years with exhaust valve seat issues that only show up when cold. Bought both times when the sellers had them warmed up for me! Start and run smooth when hot.

If you have a real noticeable shake when cold starting, it's a big pointer towards the valve seat compression issue.

CutMasterT

iTrader: (2)

Would that a a permanent problem if this is the case? Because mine is intermittent.

Also what sort of a job are we talking to sort something like that out? Cheers

328isport

iTrader: (6)

Alex interesting to hear yours started as a warmish start problem and has now become cold start! will be interested to hear how you get on with the new sensors.

I have something for you to try.. and anyone else who has this problem currently, as I've had 6 spot on cold starts in a row now by doing this which is unusual!

So ignition on, prime fuel pump, DON'T start car, instead switch the ignition off, then back on again and prime the pump for a second time, now start..

I'd be interested to hear how people get on with the above..

t4and greys

Check the pcv valve isn't sticky
And also check the fuel pipes under the seat base as they have a habit of going rusty and getting pinholed were they pass through car under seat base causing all sorts of weird issues !!

Smoke on startup could be sticky injectors leaking slightly under pressure ??

328isport

iTrader: (6)

Oh dear.. unfortunately looks like I may have more to add to this, despite a week or so of good starts, today my car started rougher than ever and didn't clear, upon giving the throttle a squeeze the car shuddered and wasn't firing clean at all, I decided to try and make it the 10 miles back to home which I didn't think I was going to make a few miles in as the car was very jerky and hesitant, though thankfully not cutting out, anyway about 5 miles in it started improve and shortly after was running and idling fine..

I started it again a few hours ago from cold and was greeted with the same poor running as earlier in the day.. I have recently fitted a sports cat and changed the plugs so I do need to double check it's not something to do with either job, but it sounds very similar to what James described earlier in this thread, if it's the valve seat issue then I expect I'm looking at a full rebuild..

CutMasterT

iTrader: (2)

I tried the priming the fuel pump thing, but didn't work.

Exactly same thing with mine this week - been stood for days, then when to start it, and I had to have foot on accelerator to get it to fire up. Fired up rough as fck too, within a few min of idling its fine. Thing is its so intermittent, sometimes I'll fire it up after standing for days/weeks and its perfect..

I've still got to clean the IACV and replace gasket, and also have a new PCV to fit - will see if that helps.

After that its going to API, cant be bothered randomly replacing bits in the hope it fixes something.