I changed my o2 sensor around 40k miles ago. it should be ok still?
how to lower hydrocarbons for emissions test ?
- Thread starter jaker04
- Start date
Yes e85 is a higher blend of ethanol. The problem you’re being told is excessive hydrocarbons. Your car isn’t burning off all the fuel which indicates that it’s running too rich. Ethanol will burn cleaner.
The greatest risk of ethanol in a non flex fuel system is corrosion. magnesium, aluminum, or rubber it that comes in contact can theoretically be damaged. This isn’t gonna happen on a one and done occasion. With modern vehicles it probably wouldn’t happen at all as modern vehicles are required to be made resistant to ethanol. I know of a guy that used e85 ina non flex fuel vehicle for 80k and his vehicle has over 300k now.(not advocating for this) Another risk is it could cause it to run too lean. You could run a 50/50 mix of e85 and e87 to try and pass if pure e85 worries you.
My advice is just to get you past a smog test not as a solution to your underlying issue.
Some of the cheap Chinese knockoff oxygen sensors don't last long. Most decent quality ones will last a lot more than 40,000 MI.
Yea, I’d rather splice on a Bosch universal than use a Walker or SKP sensor. Ideally, stick to a Denso or NTK sensor. Soon to the same company since Denso is brokering a sale of their spark plugs and O2/AF sensor business to NGK’s parent company.
I've already Redline fuel system cleaner with a full tank of gas and used up all the gas. I added in CRC guaranteed to pass last week and I am almost done with this tank of gas too. Will a clean injector lower HC?
Clean injector will inject fuel that burns better so yes less unburned fuel at the cat input
When you said it "felt hot" do you mean it felt hot to the touch? It should be hot enough to fry skin instantly... As in between 500f and 1200f.
Dry black soot is an indication of running rich. If the soot is oily and wet to the touch, it’s from burning oil. But it’s normal to have some black soot at the tip of the exhaust, especially on these Hondas.
A picture of it would be nice to see if it seems excessive or not.
While hydrocarbons are unburned fuel it does not necessarily mean it's running rich. There are other factors that can cause unburned fuel to enter the exhaust.
Take an infrared thermometer to the exhaust. A little soot is normal but not to the point of visible smoke or seeing chunks fly from the exhaust.
That looks a bit on the wet side, so there is most likely oil, but it doesn’t look excessive to me. My old 95 Accord was about the same if I remember correctly. It burned oil, the level would be about half way on the dipstick in 3k mile OCIs. Passed emissions without issue.
How much oil does yours burn?
I think your issue is more fuel related though, unless your oil consumption is though the roof, which doesn’t seem to be the case.
You mentioned it wasn’t getting up to the operating temperature, that could cause a rich condition or even running in open loop in these old vehicles. I would change the thermostat if that’s the case.
What do you mean by open loop?
The computer does not regulate the fuel mixture for lowest emissions while the engine is warming up. The normal feedback loop through the oxygen sensor is "opened," and a preset intentionally rich mixture is used instead. That is designed to reduce rough running and stalling which will happen running a cold engine lean.
Once near normal engine temperature is reached, the "loop is closed" and oxygen sensor readings are taken and used to control the fuel to a leaner region where emissions of HC and CO are lessened.
Once near normal engine temperature is reached, the "loop is closed" and oxygen sensor readings are taken and used to control the fuel to a leaner region where emissions of HC and CO are lessened.
In simple terms, it means the ECU is ignoring the input from the oxygen and maf sensors and runs in the enriched mode, sort of like using a choke in the carburetor days. But that is bad for emissions.
Once the vehicle reaches certain operating temperature, the ECU switches to the “closed loop” mode where it reads the input from the oxygen and maf sensors and adjust the fuel/air mixture accordingly.
