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black smoke on start up and first hard throttle


mellonman
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been having this for a while now was thinking valve stem seals but just wanted to check as its black smoke not the blue as normal

 

the car was used everyday for years but now have a work van and the car just sits there all week now.

what happens is on the first start up it will have some black smoke and then when i pull off up the road all i see is a load of black smoke behind me if i give it some or if i drive around for a while and then give it some stick, but after that first hard throttle it no longer smokes

leave it for 5 hours no smoke leave it for a day very little smoke.

 

i was thinking this could be a rich state causing this as black smoke is what that normally means, but what is throwing me off is that surely it would not get worse over the days sitting

 

it surely would do it every cold start up if rich

 

is there anything else it could be

 

rich

valve stem seals

Edited by mellonman (see edit history)
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its starts up fine

 

i must point out i do have 650cc injectors and a aem fic

 

it must be over fueling then as its black smoke. my afr's look to be normal though?

 

plugs was changed about 2000 miles ago

air filter looks clean

 

maybe a sticky injector but they have only done about 10k if that.

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Too much fuel.

 

Mine gives out a bit of black smoke if you rev it when the engine is warm. It also gives a bit of blue smoke on start up so I think the seals may need doing.

 

A lot of people have commented saying "mm, the smell of unburnt petrol" so maybe I have the same problem..

Edited by Josh (see edit history)
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Mine gives out a bit of black smoke if you rev it when the engine is warm. It also gives a bit of blue smoke of start up so I think the seals may need doing.

 

A lot of people have commented saying "mm, the smell of unburnt petrol" so maybe I have the same problem..

 

have you checked your o2 sensor josh? do you get bad mpg these are things to check

blue smoke would look like stem seals matey

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have you checked your o2 sensor josh? do you get bad mpg these are things to check

blue smoke would look like stem seals matey

 

Cue Scotty and the "46mpg" crap :D

 

I'm going to check the o2 sensor at the weekend and see what's what.

 

Fuel consumption seems fine, but next time I fill up I'll set the trip computer to 0 and record how many miles I get and what kind of driving I do.

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Too much fuel.

 

if it was too much fuel wouldnt it do it all the time?

 

it does only seem to do it more when fast idle is still active( where you have to be stationary for a while once warm and wait for revs to drop)

 

with my fast idle im getting afrs around 12-13 for the fist couple of minutes is that wrong?

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Your looking around 13.2 for a cold start, 14.7 is optimum when its hot.

 

12-13's wouldn't give black smoke though. Are you sure its black and not blue? It does sound to me like valve stem seals, as what your saying is correct in that, if it was fuel, it would do it every cold start (if left for a few hours).

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Your looking around 13.2 for a cold start, 14.7 is optimum when its hot.

 

12-13's wouldn't give black smoke though. Are you sure its black and not blue? It does sound to me like valve stem seals, as what your saying is correct in that, if it was fuel, it would do it every cold start (if left for a few hours).

 

im sure its black, i got the misses to start the car and rev it so i could be sure

 

thats the part thats getting me why dont it do it every cold start. strange

 

well as it looks like a fuel thing and i have bigger injectors and a not so good piggy back i will have to live with it.

 

thing is the o2 would be trying to keep the afr stoik and shows that on the guage so maybe not fuel what else could do it i might try and do a vid in a couple of days when it should be bad

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i wish it had a cold start table lol

 

its a aem fic 8

 

i have to dump fuel in the thing at 0-400 rpm it to start once hot and let cool for a hour or so

 

might that be the problem?

i would of thought it would of burnt off the excess fuel almost straight away?

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So you mapped it? lol. Send me your map over and i'll take a look for you. I've done a few FIC6's, don't see why you would need the 8 in a supra? :S PM'd you my email address.

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i didnt map it fully have had 2 club respected people on it

 

but i did have to map some close loop stuff to stop boncing afrs

 

Can they not sort the over fuelling then?

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