Last post on Jan 19, 2012 at 12:42 AM
You are in the Toyota Tacoma
What is this discussion about?
Toyota Tacoma, Toyota, Engine, Truck
#9 of 18 Re: 2009 Tacoma running rich [09taco]
Jul 18, 2011 (6:20 pm)
Carbon is a normal byproduct of combustion. The "soot" you are refering to is pure carbon that is left over after the combustion of the hydrocarbons has occured in the combustion chamber. Other byproducts of the automotive engine include H20, C02, N0x, CO, et all. Because complete combustion is impossible - you will always have soemthing left over. A quick internet search of any model will reveal that a lot of people take notice of this condtion regardless of make or model. It is 100% normal - dont sweat it. If your engine light is off you really have nothing to worry about.
Yes I am a Toyota MDT.
#10 of 18 Re: 2009 Tacoma running rich [roosterjon]
Jul 22, 2011 (4:54 pm)
I disagree with you, your answer sounds like a typical dealer service "brushoff". The problem that 09 taco is describing is not 100% normal, or even 10% normal, based on casual observation of other vehicles that I see.
I don't see "sooting" on my Tacoma, or my Avalon, either. I think the post about an exhaust gas analyzer would be a good place to start, because there is something definitely wrong, and it is not being indicated by the "check engine" light for whatever reason.
#11 of 18 Re: 2009 Tacoma running rich [wwest]
Jul 22, 2011 (4:57 pm)
wwest, I am ashamed of you. You normally give a much more technical response to the problems that folks have.
#12 of 18 Hows a grand sound?
Jul 23, 2011 (9:30 am)
With no MIL light on...... I will bet $1000.00 that your 09 Tacoma is operating 100% normal and you just can't accept that you are wrong. I deal with guys like you all day long. I will gladly put it on my 5 gas for no charge. I will even invite the engineer of your choice to come and be a witness. Does that sound like a brush off ?
#13 of 18 Re: Hows a grand sound? [roosterjon]
Jul 23, 2011 (2:06 pm)
Gas burners do not soot up the sides of a car if all is well, just saying.
Key in on the words "gas mileage is down", and "black exhaust smoke". I think that might indicate some sort of fuel problem. At least it did in all my years of engineering automobile fuel systems.
I have no doubt that you "deal" with folks that have legitimate problems every day.
#14 of 18 Re: 2009 Tacoma running rich [popsavalon]
Jul 24, 2011 (9:02 am)
Okay, is the Op's Tacoma burning oil and that's the source of the soot..?
#15 of 18 Re: 2009 Tacoma running rich [09taco]
Jul 24, 2011 (9:19 am)
Given the level of A/F ratio checking, forward oxygen and post-catalyst oxygen sensor, it's hard to believe that the idle or cruise A/F mixture could be rich. But during acceleration or the engine under load, uphill or towing, the engine runs intentionally rich and therefore switches to the MAF/IAT module sensors to control an enriched, ~12:1 A/F mixture.
The mixture is now being control via PRE-PROCESSING, ONLY, based on intake airflow rate/volume and the temperature of the intake airflow....
NO downstream A/F mixture "cross-checking" as happens during idle or cruise.
I would switch in, as a test, a new MAF/IAT module sensor set.
Second possibility would be a too sensitive knock/ping sensor. Your engine is not really likely to knock/ping in idle or cruise when the cylinders are nowhere near to getting a FULL A/F mixture charge, but WOT or nearby...?
If knock/ping occurs, even the slightest level (not aurally detectable), during acceleration or with the engine under a serious load level, the mixture will automatically be enriched, up to a certain level, to abate the knock/ping. The same method used to allow a modern day high compression engine to run on regular fuel.
#16 of 18 Re: 2009 Tacoma running rich [popsavalon]
Jul 24, 2011 (9:20 am)
#17 of 18 Re: 2009 Tacoma running rich [wwest]
Jul 24, 2011 (1:46 pm)
Yes, now we have got something to go on!
#18 of 18 Re: 2009 Tacoma running rich [09taco]
Jan 19, 2012 (12:42 am)
Mine is a 2009 Tacoma Regular cab, mt, 4wd, 2.7 motor. I too have the black exhaust. 3 dealers showed no interest, but Penske Toyota took me in and linked to the engine. All showed fine. Forward to January 2012, I'm at 40k miles, average 22 mpg and no drivability issues. I feel the oil is a bit dirty, but not excessive. Unrelated, my 2004 Tacoma xcab, auto, 4wd, 3.4 motor has a perfectly clean exhaust. So far, the exhaust soot is a cosmetic issue only.