Chad05TL

Well i thought i was done but i just read something interesting and it has a little bit to do with csmeance comments but you have to read between the lines a bit.

Several points:

The article i read was just 1 person replying to another about a cold start issue. They replied and said that if the engine temperature sensor is not accurate, then it may not idle correctly until the engine warms up. Such as if the engine was overnight cold, and the ecm didnt know it, then it might idle rough until it warmed up to match the readout from the sensor. That is just a possibility.. i'm not saying they are correct with the TL.

The other thing to note is that the old fashion chokes were used to reduce the air supply so the fuel mixture would be rich during startup. It might be possible that the TL is too lean during start up because maybe it doesnt know the correct temperature. Maybe it doesnt know it is cold-cold. So I agree with turbonut that it would be rediculous for Acura to engineer a rough idle.. so it should not come from the factory that way..

Also, I do not know if the TL has a smog pump, but my 97 camaro had one that injected plain air into the exhaust at start up to boost the exhaust temperature so the cats would warm faster and burn off the rich fuel mixture at startup.. all cars should burn rich at cold start but they dont stay that way after it warms up. Remember though, a smog pump only injects air into thet exhaust.. it has nothing to do with how the engine runs. So, my point is, if Acura left off the air pump or smog pump, whatever it is called, then I can see why they might run the engine lean at cold start to keep from gasing out the cats and my lungs. So this could make it idle rough. I'm not sure if the rough idle is due to being lean or being rich at start up.
So i think this is related to csmeance's comments.. somehow..

And I already replaced my motor mounts. Didnt make squat didly difference.

Also, cats are designed to burn off fuel vapor from the exhaust that is not captured through egr. Thats why they need the cats hot, and fast. But if raw fuel goes into the exhaust, that would be a serious acura malfunction. Maybe dragsters might be able to do that if you go extreme, but this is Acura oem design. Not dragstrip. I doubt its relatively possible to get a TL to dump raw fuel into the exhaust unless there is a malfunction.

So anyway, if the TL has a smog/air pump, then I see no reason for acura to try to lean out the fuel mixture so that the exhaust does not fumigate the outside air. So basically it should be rich on the intake in this case.

But if the TL does not have a smog/air pump then I can see why they have this rough idle when cold . And if they figured out how to get around the smog pump then I would like to know how..

Regardless if it has a smog pump or not, all engines should be rich on the cold start. If acura left off the smog pump then it gets real tricky to keep the engine running smooth at start up and not have a real rich exhaust.

Btw, my grandpa used to have a 1966 chevy van, inline 6, doors on the sides and rear.. that old van had a MANUAL choke. And sometimes he forgot to turn off the choke after the engine warmed up, and it began to idle rough. Then he would release the choke and it ran fine. Now this is a littlet bit reverse as to what the TL suffers from since it is rough at cold start, not after it warms.. but I suspect that..a rough idle can exist whether the fuel mixture is too lean OR too rich at any given temperature..

Somewhere in there is our answer. We just have to figure out if it is too lean or too rich and Why.... sensor not reading right?

Turbonut

iTrader: (1)

No air pump, and I've said this before. When warm, run the idle up to 1200 and the engine certainly isn't smooth and there's no problem.

I believe the V-6 is a 60 degree engine and should be of the smoothest design, but it is still is a V-6 with inherent vibrations that the manufacturer tries to eliminate. Have they eliminated all vibtations, probably not.

Chad05TL

when my engine is warm is it very smooth at idle. At 1200, its even smoother. So, your comparison is not a good one IMO


I know you are trying to say it is normal.. but if I did this, it would prove you wrong.

Chad05TL

however, right here you said there was no intentional misfire manufactured.. So are you saying it is normal, or not normal?

Turbonut

iTrader: (1)

There is NO misfire.
As far as the 1200 rpm when warm, I haven't tried it in our TL recently, in fact haven't been in our TL in a year, but in the past the TL and MDX had the same consistency at 1200, far from a smooth running V8.

Let's wrap this up. IMHO there is no problem with the 1200 cold idle although not smooth, and the cars have the same idle when new, nothing dirty, clogged, etc.

Chad05TL

I think I see what you are saying. No misfire as in the electrical system is firing ok. And no malfunction in the electrical system. I do agree! But the rough idle is likely a fuel or emissions type thing or intake type problem.

Even though some may have had this problem when new I don't think everyone has.. so that means it is fixable.

Stay tuned. We can open another thread later. Haha

I hate cars

Chad Chad Chad. There's no answer in there. That's a bunch of made up crap. I'm not trying to be harsh but there's not a single bit of truth in there.

The choke is there on carbureted cars to create more of a vacuum in the Venturi area to richen the mixture. It's not there to restrict airflow. It's there to increase fuel flow relative to airflow.

In a fuel injected car the ECU just increases injector pulsewidth to richen the mixture. The throttlebody does a pretty good job of restricting airflow to you know, throttle the engine so it's not at full throttle all the time.

The coolant and intake air temperature sensors check one another after sitting overnight. Upon first startup after sitting overnight both sensors should read the same obviously. If one is way off, the ECU knows one is off.

Smog pumps are old technology. Even my GN from '84 had no smog pump. Most port injected (or DI) cars have no smog pump. It's there to introduce air to help burn off unburned hydrocarbons, to help catalyst efficiency. If you've ever watched the 02 sensor of just about any car made in the last 15 years you'll see it crosscounts lean-rich-lean-rich, several times a second. Guess why it does this? You got it, to provide additional air to aid in catalyst efficiency without a smog pump. The smog pump is only used when cold in the upstream pre cat location to lean it out and increase exhaust temp to light the cats off quicker. We don't need that anymore because the TLs design is far superior. The cats are bolted to the heads, the 02s are preheated, the cats and 02s light off incredibly quick, quicker than they did in the old days with the cat 10' from the heads and the smog pump injecting air. A smog pump is best used for supercharging a small lawn mower engine or for crank case scavenging on your car.

The TL goes into closed loop extremely quickly after a cold start. The 02 is providing feedback control in under 15 seconds. The TL doesn't run rich (comparitavely) during a cold start, it's in closed loop already.

No car is going to run bad because it doesn't have a smog pump. Emissions aren't measured when cold. It is not required to pass smog when cold. There are certain requirements to meet the various ULEV, ULEV2, PZEV, etc., that require an engine to be warmed up and in closed loop with emissions equipment fully functional and in compliance within a certain time limit but smog tests are done fully hot. So running a car super lean when cold because it does t have an air pump is ridiculous. It crosscounts instead.

There are many advantages to not having to run super lean on cold start, emissions, longer engine life, longer oil life, and a very small mpg increase.

About dumping raw fuel into the exhaust. You say it can't happen yet it happens every time there's a misfire. Every car dumps raw fuel into the exhaust on a misfire. The fuel enters the cylinder but there's no ignition. You have a cylinder full of air and raw fuel. Guess where that unburned fuel goes on the exhaust stroke?

One more thing, any engine will run smoother at 1200 rpm vs idle. It's the same reason why a V10 idles smoother than a V8. You still haven't tried to quantify your rough idle. Anyone who bought one of these cars new will tell you they aren't the smoothest idling cars. Now you get on here and say all of the original owners don't know what they're talking about but somehow you do with these half baked smog pump and chokes and other ideas that makes no sense.

When you see me and Turbonut agreeing, it's pretty safe to say it's true. The only thing I disagree with is the cold start misfire. I do believe there are a low number of intentional ignition misfires to introduce raw fuel into the cats which decreases warmup and light off time. We'll probably never agree on that but that's ok.

So again, try to describe how bad the rough idle is and stop asking a question only to tell everyone they're wrong including the original owners and you're right.

What I predict is this.... You will never come on here (truthfully) and say you fixed the rough idle problem because there is no problem. It would be helpful to know if it's better or worse in gear.

For what it's worth, while I call my idle rough, it's rough for a properly running semi-luxury car. It's not rough compared to most 4 cylinders and cheaper cars but it's far from BMW inline 6 smooth or Mercedes V12 smooth or even the typical cheap Ford V6 used in most of their low end cars. My GN idles smoother but if you watch the engine it does a dance sitting at idle that's not felt inside the car. Part of the problem is engine vibration is harder to isolate in a FWD car and it's 60 degree V6. The 60 degree V6 needs compliant mounts because it's inherently unbalanced while an inline 6 needs just a little isolation because its nearly perfectly balanced by nature. Being FWD, the TL has to use less compliant mounts to avoid wheelhop. This, combined with the V6 makes for a seemingly rough idle while the same engine in a RWD a car could be better isolated and considered smooth.

Plus, we can't forget our cars started life as a Honda Accord where NVH reduction was not at the top of the list and a little extra sound deadening doesn't just make up for it. My new BMW with its turbo 4 has just about zero vibration into the interior and a 4 cylinder naturally idles rougher than a 6. Plus, over bumps and imperfections, the BMW is in a different league. Not a single hint of a rattle. The chassis is so rock solid compared to the TL but it was engineered from the beginning to be a semi luxury car and being RWD the mounts can be more compliant.

The TL is what it is. The idle is a little rough by nature but they were all that way when new so unless you want to make some custom mounts, you're wasting your time with this.

I hate cars

I fully agree with your summary. The misfire not so much but we can agree to disagree. I can't remember, are you an original owner too?

Turbonut

iTrader: (1)

No, 32K miles.

Chad05TL

IHC IHC IHC... no one died and left you in charge.. And I speak nothing but the simple truth.

I only saw a few random comments and you seriously need a reading comprehension class. I did not say a smog pump makes a car run smoother.. I said it is after the engine.. Get some spectacles. The smog pump is only used for burning fuel vapor from a rich mixture at start up by aiding the warmup of the CATS. So its all exhaust.. So, stop trying to warp what I say.

Ain't addressing anything else because I am not going to educate you.

The subject was "several points..." And that means all these truths are separate. There were several comments about all this fuel stuff in the post.. So get the big picture.

tihomirbg

iTrader: (1)

I was due for an oil change so I pour 8oz Seafoam in the crankcase, went to Autozone to buy oil and filter, came back, changed it, started the car and the check engine light was on. Drove to Autozone to get then read the code- came back P0175 Fuel system too rich bank 2.
Is this bank 2 front or rear and it's the air-fuel sensor, not the O2 sensor, correct?

vietxquangstah

iTrader: (7)

bank 2 is the front near the radiator and the fans.

air-fuel sensor and 02 sensor are essentially the same thing just different name.

Don't even think about replacing the o2 sensor. That code isn't saying the o2 sensor is at fault. The o2 sensor is picking up the rich condition and telling the computer that the vehicle is running rich which sets off the check engine light.

Now if you replace that o2 sensor for a new o2 sensor than your going to have the same problem. The NEW o2 sensor is going to also notice the vehicle is running rich for bank 2 and tell the computer and you guessed it.... trigger the check engine light.

summary: replacing a o2 sensor is not going to fix a p0175 code. Figure out the root cause of the rich condition. It's not the o2 sensor.

tihomirbg

iTrader: (1)

acording to this website P0175 Acura Fuel System Too Rich Bank 2 OBDII Engine Light Trouble Code | Engine-Codes.com it could be all of these
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Faulty Mass Air Flow (MAF) sensor
I don't even know where to start from

vietxquangstah

iTrader: (7)

thanks for correcting me.

I'll try to help you out. our TL doesn't use a maf so you can rule that out.

If fuel pressure was too low than I would assume it would affect both banks.

If it's misfiring it usually throws a code for that. If it's bad enough you can even feel it from the drivers seat.

If fuel injector was not working properly than that would also cause a misfire code.

I guess it all comes down to a exhaust leak or o2 sensor.

Turn your engine on and open the hood and see if you can smell exhaust fumes coming from under the hood. If so, you got a exhaust leak. It's going to be a leak before the o2 sensors and not after. So maybe a cracked catalytic converter?

tihomirbg

iTrader: (1)

The check engine light hasn't come on today at all- going to work and coming back home. This is good and it's not good at the same time. Since the light came on- there was something that triggered it and I think it's exhaust leak.

Jackass

Lost this thread until now. I don't think mine has a rough cold start idle....however my wife has asked me several times about it over the years so apparently it does. Mine is a 6-speed so it doesn't really transmit into the cabin much.

tihomirbg

iTrader: (1)

I got a notice in the mail that the TL was due for an emission test- check engine light hasn't come on since last Sat. So, yesterday I had sometime after work and went to see if if will pass emission- it did PASS. It's good till Nov 2016