Black smoke on startup

MitchEG · 12-12-2005, 05:35 PM

Hey there

whats the deal with a puff of black smoke out of my exhaust when i start it? I noticed it yesterday on the cruise after hard driving and put it down to that...but this morning i had another look and it did it again...It seems to do it after idling the car for a while shutting down and then starting it soon after.

So i know tha black smoke means unburned fuel, is there a way to stop it? or is something in need or fixing (Injectors?), or is it a BJ thing cos they run rich alot of the time... i have seen chicaboo's and twiggys do the same thing, but mine is far less modded so i diddnt expect it. any other BJ owners noticed this?

thanks

dfvadr · 12-12-2005, 08:11 PM

yep its fuel so it could be a leaky injector , now new injectors are about 55 dollars each at repco or u can reco them for about 35

what ur saying id say what is happening is while its sitting the fuel leaks through an thats why it is so everdent on start up

MitchEG · 12-12-2005, 08:18 PM

hmmk, thanks, well i found a bit of info before on how to test the injectors to see which one/s are losing pressure or leaking but it wasnt for a mazda. I might leave this one till my next service cos it doesn't seem like too big a deal for now, my fuel economy hasnt shot up or anything so i can live with it for a while. Do u think the idling followed by hot start is related? ive never noticed it on cold start.

dfvadr · 12-12-2005, 08:47 PM

no i suspect thats because when ur driving its still ok but wen it sits around it drips into the cylinder an maybe even at idle there is still alittle to much fuel getting through , but when ur driving the amount of fuel to engine revs is ok

twilightprotege · 13-12-2005, 11:53 AM

could be the o2 sensor (you can have mine if you can help me find appropriate bolts to block the o2 holes)

MitchEG · 13-12-2005, 10:01 PM

hmmk, O2 sensor, i'll keep it in mind. Thats the sensor near the headers right?

edit: oh wait, thats the exhaust temp thing, i dunno where it is

Cosmo Dude · 13-12-2005, 10:14 PM

The O2 sensor is the thing in the exhaust manifold with a wire.
It isn't used on startup.

Is the smoke black or blue?
Does the engine start quickly or does it chug to life?

MitchEG · 13-12-2005, 10:30 PM

definetly black/brown sooty looking. No probs with the running of the engine, it puffs out for an instant and is gone and only on a hot start it seems.

12-12-2005, 05:35 PM	#1
MitchEG AstinaGT Regular Join Date: Mar 2005 Location: Brisbane, South Car: Cibicu Posts: 324	Black smoke on startup Hey there whats the deal with a puff of black smoke out of my exhaust when i start it? I noticed it yesterday on the cruise after hard driving and put it down to that...but this morning i had another look and it did it again...It seems to do it after idling the car for a while shutting down and then starting it soon after. So i know tha black smoke means unburned fuel, is there a way to stop it? or is something in need or fixing (Injectors?), or is it a BJ thing cos they run rich alot of the time... i have seen chicaboo's and twiggys do the same thing, but mine is far less modded so i diddnt expect it. any other BJ owners noticed this? thanks

12-12-2005, 08:11 PM	#2
dfvadr Senior Member Join Date: Feb 2003 Location: Queensland Car: ss , sp20 , 94ba Posts: 1,708 View Photos By: dfvadr	yep its fuel so it could be a leaky injector , now new injectors are about 55 dollars each at repco or u can reco them for about 35 what ur saying id say what is happening is while its sitting the fuel leaks through an thats why it is so everdent on start up __________________ 2001 SP20 Mazda Astina Turbo - t28b/b turbo teflon coated forge pistons 20thou o/size , billet rods , whole motor fully balanced - custom body kit - 18"ame's - custom interior - kenwood head unit , pioneer speakers driven by 800 watt amp , kicker subs driven by 1000 watt amps each sub [135.2db at supernats], two 1th caps 4 tv screens dvd player - xbox - airbag suspension with gas strut towers - custom plates an airbrushing on bonnet

12-12-2005, 08:47 PM	#4
dfvadr Senior Member Join Date: Feb 2003 Location: Queensland Car: ss , sp20 , 94ba Posts: 1,708 View Photos By: dfvadr	no i suspect thats because when ur driving its still ok but wen it sits around it drips into the cylinder an maybe even at idle there is still alittle to much fuel getting through , but when ur driving the amount of fuel to engine revs is ok __________________ 2001 SP20 Mazda Astina Turbo - t28b/b turbo teflon coated forge pistons 20thou o/size , billet rods , whole motor fully balanced - custom body kit - 18"ame's - custom interior - kenwood head unit , pioneer speakers driven by 800 watt amp , kicker subs driven by 1000 watt amps each sub [135.2db at supernats], two 1th caps 4 tv screens dvd player - xbox - airbag suspension with gas strut towers - custom plates an airbrushing on bonnet

13-12-2005, 10:01 PM	#6
MitchEG AstinaGT Regular Join Date: Mar 2005 Location: Brisbane, South Car: Cibicu Posts: 324	hmmk, O2 sensor, i'll keep it in mind. Thats the sensor near the headers right? edit: oh wait, thats the exhaust temp thing, i dunno where it is Last edited by MitchEG; 13-12-2005 at 10:10 PM.

13-12-2005, 10:14 PM	#7
Cosmo Dude コスモ Join Date: Dec 2002 Location: Location: Vic Car: Mazda '95 Astina I4, '86 B2K and '10 3 MZR-CD Posts: 7,888 View Photos By: Cosmo Dude	The O2 sensor is the thing in the exhaust manifold with a wire. It isn't used on startup. Is the smoke black or blue? Does the engine start quickly or does it chug to life? __________________ My 'stina Hatch

12-12-2005, 08:18 PM	#3
MitchEG AstinaGT Regular Join Date: Mar 2005 Location: Brisbane, South Car: Cibicu Posts: 324	hmmk, thanks, well i found a bit of info before on how to test the injectors to see which one/s are losing pressure or leaking but it wasnt for a mazda. I might leave this one till my next service cos it doesn't seem like too big a deal for now, my fuel economy hasnt shot up or anything so i can live with it for a while. Do u think the idling followed by hot start is related? ive never noticed it on cold start.

13-12-2005, 11:53 AM	#5
twilightprotege Driving a faster car now! Join Date: Oct 2003 Location: Work, always at bloody work... Car: Lotus ....... . Posts: 5,217 View Photos By: twilightprotege	could be the o2 sensor (you can have mine if you can help me find appropriate bolts to block the o2 holes)

13-12-2005, 10:30 PM	#8
MitchEG AstinaGT Regular Join Date: Mar 2005 Location: Brisbane, South Car: Cibicu Posts: 324	definetly black/brown sooty looking. No probs with the running of the engine, it puffs out for an instant and is gone and only on a hot start it seems.

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