E85Forum.com

Sinner · Joined: 04 Aug 2005 Posts: 33

The CEL came back on and I have an update on my blog.

http://thesins.blogspot.com/2006/02/anger-cel-update-and-bleg.html

The short version is that the CEL for lean fuel codes is now being blamed on the catalytic converter.

I also have a new ethanol-themed screed posted.

http://thesins.blogspot.com/2006/02/pride-alcohol.html

Revision · Joined: 14 Sep 2005 Posts: 194 Location: Carol Stream, IL

That doesn't sound right.

Usually rich/lean on the O2 sensor is done on the O2 sensor BEFORE the cat. The O2 sensor after the cat is just there to make sure the cat is doing its job and cleaning up the exhaust some, so it should be theoretically leaner if the cat is doing its job and burning off some unused fuel and breaking down hydrocarbons.

You should head over to your nearest Autozone and see if they can read your error code for your CEL and post it so we can see if it is being caused by the first O2 sensor or the second.

Chances are either the O2sensor is bad. Or you really are running lean meaning something isn't working. Either the CPU isn't compensating enough by richening the mixture or your fuel pressures are not high enough. Not much chance of clogged injectors since you are running E85.. Your fuel filter might be clogged which is another story.

Edit: We need more data.

Please do run over to Autozone or a small garage and see if you can get them to read the error code and give you the error codes. We can look them up here.

Also, you said have a 2004 Ford Taurus.
Does it say E85 capable on the gas cap somewhere?
How many miles on it?
Did you buy it used?
How many miles have you driven with E10?
What kind of oil are you running?
How often do you change your oil?

Corn Squeezins · Joined: 14 Dec 2005 Posts: 42 Location: Madison, WI

I agree w/ Revision and I have tested & replaced more than a few o2 sensors & cats for real problems. We need more info such as the true codes stored and any other notable tidbits such as he asked here. Then maybe we can help u out and get u back on a strict alcohol diet!!!

Sinner · Joined: 04 Aug 2005 Posts: 33

Revision · Joined: 14 Sep 2005 Posts: 194 Location: Carol Stream, IL

Hopefully when they flash the update, it'll fix the problem then.
I hope you are not paying for the cat.

Sinner · Joined: 04 Aug 2005 Posts: 33

Just got back from the dealer and I have the codes.

P0172
P0316

The bill for repairs came to $1047.68, all under warranty so I paid nothing.

It is interesting that the Ford Motor Company felt it worth over a thousand to push this back another few months.

Revision · Joined: 14 Sep 2005 Posts: 194 Location: Carol Stream, IL

P0172 System too Rich (Bank 1)
P0316 Engine Misfire Detected on Startup (First 1000 Revolutions)

System too Rich Bank1 is the first O2 sensor reading not enough oxygen or its gone bad. If it stays rich for too long, it could damage the cat.

And the Engine Misfire.. Is it cold where you are now?
I'm guessing you have the stock sparkplugs in there.

Sinner · Joined: 04 Aug 2005 Posts: 33

Yep, it's "fricken" cold here...

Yep, the stock plugs are in there.

So, you're saying that the cat got damaged and they replaced it but didn't actually do anything about the underlying problem, right?

Revision · Joined: 14 Sep 2005 Posts: 194 Location: Carol Stream, IL

The ECU is suppose to dump more fuel into the cylinders in colder weather, or else the sucker won't start. Same thing with gasoline. I had to run some high enrichment cold startup values when I was tuning my Tec3 engine management, if memory serves then for normal gas that enrichment in cold weather was something along the lines of 130% over normal. And E85 needs even more fuel compared to straight gas.

The rich reading is probably from all the cold weather and the ECU dumping fuel in. Same for the engine misfire.

One of the recommendations around here is that during cold weather to drop in an extra couple of gallons or so of regular fuel in with your E85 to help out with cold startup.

Another trick some of the Subaru guys are using is to change the spark plugs to one range "hotter". Supposedly this increases the compression slightly as well. The hotter plug should also help with igniting the E85. A hotter plug on normal gas might ping. So if you have to switch to normal gas, then you may want to up the octane.

Here is a good explaination on spark plug ratings and how to tune the spark plug for your car.
http://www.off-road.com/dirtbike/tech/2002sparkplug/

In the end. I'm hoping (just like the dealership) that the reflash has fixed the issue. If it hasn't, try adding some additional regular gas to your fillup. Problem should go away when warmer weather hits. But if you want try the hotter plug, you need to understand that you need to monitor the discoloration of the plug.

Sinner · Joined: 04 Aug 2005 Posts: 33

I can understand that, thanks.

One question though, E85 is really E70 here during the winter. Isn't that the same as dumping a few gallons of E10 in the tank to help with the cold start problems?

I guess one more thing...

The last time I was at the dealer for CEL, they told me that I needed to stick wth E10 OR E85 and not switch. I understand that is complete BS, but they said it then and suggested it again this time.

specialgreen · Posted: Sun Feb 05, 2006 5:02 pm Post subject:

I have heard that if you unplug the car battery for a while, then the MPG may suffer until the car has learned a new long-term trim. Going back and forth between E-85 and E-10 could mean that your long-term trim is constantly changing. Picking one fuel (or one blend of fuel) could keep the long-term trim from changing much. But I don't know enough about long/short trim to really say.

Yes, E-70 is probably what you're getting this time of year, so that should help with starting. Going one plug range hotter is prabably OK; just check your plugs for any signs of pitting, cracking, etc.

Revision · Joined: 14 Sep 2005 Posts: 194 Location: Carol Stream, IL

SpecialGreen is correct.

There are two fuel trim levels in an OBDII car. Short term fuel trim and Long term fuel trim. Switching back and forth changes the Short term fuel trim and confuses the Long term fuel trim. Fueling is very important with E85 as it requires more of it to run properly. The other thing that changes is the ignition timing. E85 is a bit above 100 octane. The Taurus runs on 85 octane (right?). Switching back and forth will change the timing advance the computer will give. Timing changes differ from car to car, but a general rule is that if the computer senses knock/pinging it will retard timing and if over time it senses no knock, it will advance timing. The rate of advance tends to change over the long term and stay fairly static over the short term. Leaving it at one fuel will allow the computer to optimize fueling and timing for E85.

hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado

The learning rate for fuel trims and timing are actually not a significant issue. (at least in my experience)

Short term fuel trims change in nearly real time. If you put a data logger on an OBDII car you can see the fuel trims swing very rapidly with changes in mixture.

The long term fuel trim changes in a matter of minutes for typical fuel mixture changes. Even a serious fuel trim error is corrected in a about 15 minutes driving from what I have seen on my data logger.

Dyno operators have reported they can watch fuel trims and timing changes occur during single dyno runs of only a few minutes duration, and complete accomodation is reached in about 4 driving cycles.

Ignition timing is very quick. Most systems pulling timing on sensing detonation and then gradually add it back in. The major effect that slows down learning is if the driver does not use the full load range of the engine.

For example you put gasoline in and drive on 100% gasoline for a very long time. All your fuel trims and ignition timing tables will be stable and appropriate for gasoline. You then run the fuel tank dry and put in E85. If your driving style is very conservative the ECU will only learn the new fuel mixture and timing changes for the load cells you routinely reach in your normal driving style. If you suddenly change to a more agressive style (late to pick up the wife or late for work) and push the engine into load cells you have not seen since the fuel change, you could get detonation that would cause the ECU to pull timing to protect the engine. This will cause a drop in performance over that rpm and load range.

Larry

Sinner · Joined: 04 Aug 2005 Posts: 33

So the fact that I put on maybe 2 miles a day could be the cause of my woes?

hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado