With the onset of cold weather I have had my first hint of a problem with my STi V.

7 months old - 10,000 miles

Cold mornings it starts fine then after five seconds chokes and dies. Restarts with much misfiring, only one or two cylinders catching. Once it gets a little warmth it is fine.

Also, on ordinary days, it feels as if there might be a slight misfire until fully warmed.

Always run on SUL, AFR fitted richening mixture by about 0.6% as insurance against alleged problems with STis. Also it is fitted with HKS plugs which are slightly hotter than standard.

Any thoughts?

David

PS Frosty mornings are great for increasing charge density

 

Have you tried it with the afr at standard ie no extra enrichment, could be overdoing it on a cold morning.

Bob

 

Thanks - good thought - I'll try that

David

 

Is there any trace of black smoke during the startup? It might be case of over rich or lean. I'm not sure if there's a cold start injector but sensors play a part in telling the ECU what to do.

 

Update - AFR now set to neutral, and although it hasn't been as cold in the morning the car still isn't right.

It will start and it is as if it is thinking about what to do - resets the revs to about 600rpm as if the car is already warm. As it is dead cold, the revs the just die.

Best way is to restart it a couple of times, buy which time it realises it is cold and holds up the revs until it is warm.

If I use the throttle to do this, much misfiring for two/three minutes!

Any thoughts?

Cheers,

David

 

Try checking (getting checked) the engine temperature sensor/s and check the manifold sensor pipes are all soundly attached (and clipped).

Moray

 

My car has behaved like this a couple of times. In my case it was a dirty air filter causing the engine to run slightly rich. when the engine was turned off - the ECU sensors got a rich fuel reading and remembered this when the engine was started up the next morning the revs would drop to around 500 and the engine would often stall. On restart the engine would fire-up OK (this wasn't in the winter).

I was told by the garage that 'blipping' the throttle when switching off the engine was the biggest cause of this problem.

Simon

 

Why don't you try changing back to original spark plugs?
Sounds like the plugs you installed are fouled up.

 

Update again

Set AFR to zero, some serious driving to clear out the system, reset the ECU, etc.

And today, when it was very cold and damp and foggy this morning, the car started fine.

Moral, don't run it rich in the winter!

Thanks for all your comments,

David

 

A further update...

...the car is still having a problem - with the additional bonus of the Check Engine light staying on sometimes for up to 10 seconds.

The symptoms are the same, no additional adverse effects or noises, car still pulling like a train - even more so now the Super Drager and Induction kit have been reinstalled.

Any clues - I have seen many comments about temperature sensors, AFMs, etc failing - could this be related?

Firefox - any clues - you seem to be the man!

Cheers

David

PS I have read that if you install an induction kit you need to move the air temperature sensor - is this true of STi Vs and if so where is it now and where should I move it too - and could this be the source of the problem?

 

Dave,

Have you tried that thing we talked about with Penni @ Donnington where you turn the ignition on - wait a few seconds until it stops 'whirring' then start the engine?

Mine doesn't start very often if i just put the key in and try to start the engine straight away.
Just a thought...


Dave

 

Dave,

I have promised never to mention our secret again

However, I did try the key thing, but it makes no difference.

The best way to start is to let the engine die, restart - need up to three goes and then it stays running.

Odd - as it seems to run quite well when it does finally get going

David (Rannoch - goes it would make a great RAC Stage)