e85

[Shock24Z]

Originally Posted by AleroB888

How/when are you getting a reading of 50 degrees of timing?

X2 I want pictures of this as well as the 20* of KR. These numbers should not be seen from a stock pcm.

[Pete]

Originally Posted by torq455

did anyone suggest adding about 30% more fuel when running E85? there's a guy with a turbo 3400 doing it after much research and it's running great!

It's not possible to add 30% more fuel with stock injectors.
But yes, that is the idea. Ethanol seems to run over a wide latitude of mixtures.
Leaner than you would expect under light loading, and also richer than you would expect. I have heard numbers as high as 40% more on the rich side and it continues to make more power. For me, it's more about economy.

There are a few companys selling 'kits' to make your car flex, but I don't see how it can work properly, there just is not enough fueling available in the stock setup.

[Pete]

Just to comment on the Knock issue.
I have no knock retard what-so-ever on E85.

Also I have seen 50 degrees of advance under light load at highway speeds.
Usually going down a slight grade. Around 47-48 degrees is common.

I am getting around 20mpg combined city highway.
(still waiting on the HPTuner stuff)

What I have noticed the most about running E85 is the smoothness of the engine.
Also it takes less throttle to maintain speed, and there is less of a tendency to lose ground going upgrade at a given throttle position.

[peppermill]

Originally Posted by Shock24Z

X2 I want pictures of this as well as the 20* of KR. These numbers should not be seen from a stock pcm.

I'll see if I can shoot video with my phone.

[peppermill]

The ethanol has arrived. 300 gallons of E100. It smells different than E85. Less sharpie smell, and more "burn your nose hairs" smell.

Not sure how I'm going to blend it yet, but most likely it'll be in to vehicles that have gas tanks that are at least 1/4 full with regular gasoline. The thing that has me concerned is that it may take a while for the fuel to blend around, at least a few minutes, and I really don't want to take the varnish off the fuel pump or injector wires.

Maybe I'm looking too much in to it.

[Pete]

My HPTuner was shipped.....
Oh happy day.

[peppermill]

Originally Posted by Shock24Z

X2 I want pictures of this as well as the 20* of KR. These numbers should not be seen from a stock pcm.

You want pictures because you think I'm just making this stuff up? Or that I'm fibbing and stretching the truth when I say "About 50"? Do I not seem credible that I'm dumping E85 in to a totally stock V6 Grand AM and driving on it successfully? Does it just blow your mind?


Sorry about the quality, I was trying not to go off the road, sheild the light from the gage, handle the gage, handle the phone, watch the video on the phone.... and not go off the road. The AC's on high, I'm doing 69MPH with the cruise on turning 2K revs. At one point, I tickled the rumble strips along the shoulder.

Knock Retard is on top, ignition advance is on bottom.
I think I saw 53 and change at one point but I don't think the vid picked it up.

[SpyhunteR]

can't see **** in that video....

I can tell ya one thing.. The stock PCM does not have anything to tell the car to be pushing 50+ degrees of advance, unless if the car was tweaked by someone with DHP or HPTuners.

[peppermill]

Originally Posted by SpyhunteR

can't see **** in that video....

I can tell ya one thing.. The stock PCM does not have anything to tell the car to be pushing 50+ degrees of advance, unless if the car was tweaked by someone with DHP or HPTuners.

It's a single owner car. It was purchased with 2 miles on the odometer. So either the tuner fairy snuck in and flashed the PCM on some magical night, or you don't know nearly as much about these cars as you think you do.

I guess Pete's car was also victimized by the tuner fairy? That little fairy gets around!

You have no idea what exact algorithms are running behind the scenes in the PCM. None of us do. It's closed source. We can't know. All we can do is guess, and change some tables. That's what frustrated me about my LT1 Edit tuning. It's also why serious builders start with an after market computer.

[AleroB888]

Originally Posted by peppermill

You want pictures because you think I'm just making this stuff up? Or that I'm fibbing and stretching the truth when I say "About 50"? ]

No, because I'm not getting readings that high with my own scans. I had to search a long time to find a peak of 47 degrees in my stock '03. But my cars certainly don't routinely push nearly that much timing.

There could be some kind of issues with the measuring devices being used, mine being HP tuners.

[peppermill]

Originally Posted by AleroB888

No, because I'm not getting readings that high with my own scans. I had to search a long time to find a peak of 47 degrees in my stock '03. But my cars certainly don't routinely push nearly that much timing.


There could be some kind of issues with the measuring devices being used, mine being HP tuners.

Would a scan gage reading the OBDII give the same numbers as HP Tuners reading the ODBII? Isn't timing.......timing?

I think if you ran 100+ octane in daily driving for a couple of hundred miles of cruise, maybe you'd also see timing above 50. I know if I were writing PCM code, I'd create a very very long term trim for maximum timing and base it on knock events. I'd want to see some knock, some of the time, under heavy load (and quickly adjust to it with knock retard). It used to be in the days of carburetors that engines were EXPECTED to knock slightly (enough to hear) under moderate to heavy load (but not WOT). So if I were writing PCM code, and if my code didn't ever see knock, I'd very very slowly increase timing up to some number based on a number that would start to yield negative engine torque. What is that number? Is it absolute? It it were possible to actually measure the engine torque, finding that number would be fairly easy. If torque decreases after increasing timing, you've gone too far.

Maybe that's the hangup...... is there a maximum absolute timing number in the PCM somewhere? Is it hard? Or does everyone just think that it's hard? Is it adjustable by some watchdog code perhaps? All I know for sure is that I don't know. And without seeing the source code, no one else can be either.

If I were writing the PCM software, I'd also purposely make knock occasionally just as a knock sensor check. Probably every X number of starts during cruise, right after fuel vapor system purge or something.

[Malaclypse]

If I remember correctly, the PCM will advance timing quite a lot during closed throttle coasting for emissions reasons. I think seeing around 45 - 50 degrees of timing while coasting could be considered normal.

I believe I picked that up from my instructor years ago..

Originally Posted by peppermill

If I were writing the PCM software, I'd also purposely make knock occasionally just as a knock sensor check. Probably every X number of starts during cruise, right after fuel vapor system purge or something.

That's actually the case with all of the emissions self-checks within the PCM.

For EGR, the PCM commands the EGR valve open from 0% during closed throttle coasting and measures the change in manifold pressure using the map.

For Knock sensors, the PCM does just what you suggested. It generates slight knock.

[peppermill]

Originally Posted by Malaclypse

If I remember correctly, the PCM will advance timing quite a lot during closed throttle coasting for emissions reasons. I think seeing around 45 - 50 degrees of timing while coasting could be considered normal.

In my case, I think I'm seeing the timing actually decrease 5-10 degrees during coast. The max timing happens during slight hills, at about 20% throttle, cruise control on.

I'll have to watch throttle % vs timing to see exactly what that relationship is, and report back.

[peppermill]

I'm not going to sugar coat what I'm doing. There is a major problem to pouring E85 in to a non Flex Fuel Vehicle. One that will probably require some tuning to take care of, assuming the start timing can be changed independently of the optimum operating timing.

The drawback to running E85 in a non Flex Fuel vehicle is that the engine doesn't like to start at less than 60 degrees F. Is it due to too much fuel, not enough fuel, poor volatility, or a PCM using too much ignition timing at start up?

The Scan Gage shows Ignition Timing in the top display, and Injector Pulse Width (in milliseconds) in the bottom display.

During cranking, muffled backfires can be heard. Eventually, after enough start attempts, the PCM removes all the extra timing and the engine starts. After a minute, the timing is added back, and the fuel flow decreases as timing increases, clearly showing the effect of timing on fuel consumption.

[peppermill]

Sorry for the poor video quality. This shows Knock Retard on the top, and injector pulse width on the bottom. The beginning of the video is 40MPH, on a slight down grade, then climbing a long hill while accelerating to just over 100MPH at between 50% and 75% throttle achieve the maximum level of engine loading without power enrichment (no power enrich needed to help create knock). The RPMs are between 2500 and 4500 during the entire event, with the exception of one short excursion to 5200 during a down shift.

I may have been able to reach 20 degrees of knock retard, but as I watched my pulse widths, and realized how close I was to running out of injector, I just didn't have it in me to go to wide open throttle and risk the engine damage that may have come with severe leaning.

I could feel the decrease in power as the timing was being pulled away by the PCM, but never heard any audible knock. Other than the horrible numbers on the scan gage, there was no sign of impending doom.

[peppermill]

After yesterday's video, I wanted to try something different. This morning, the engine is at 51 degrees, as per the coolant sensor, after sitting overnight. Normally cold soak starts with E85 are hard, and it takes 2-3 attempts with a cold soaked engine. So today, I tried some starting fluid. The engine did start right away, then bogged down, and I heard the idle air controller open up and make a long sucking sound as the engine was nearly ready to stall. Then something happened; the timing went away, and it ran fine.

The only way to reproduce a cold soak start on E85 is to let it sit overnight. Even parking it 10 hours during the day time doesn't let it get cold enough. It always starts right up... unless it sits overnight.

[peppermill]

After yesterday's video, I wanted to try something different. This morning, the engine is at 51 degrees, as per the coolant sensor, after sitting overnight. Normally cold soak starts with E85 are hard, and it takes 2-3 attempts with a cold soaked engine. So today, I tried some starting fluid. The engine did start right away, then bogged down, and I heard the idle air controller open up and make a long sucking sound as the engine was nearly ready to stall. Then something happened; the timing went away, and it ran fine.

The only way to reproduce a cold soak start on E85 is to let it sit overnight. Even parking it 10 hours during the day time doesn't let it get cold enough. It always starts right up... unless it sits overnight.

[SpyhunteR]

wow.. i'm done with this thread, holy hell.

[Malaclypse]

.... Yeah. Have fun when it explodes.

[Pete]

Originally Posted by peppermill

After yesterday's video, I wanted to try something different. This morning, the engine is at 51 degrees, as per the coolant sensor, after sitting overnight. Normally cold soak starts with E85 are hard, and it takes 2-3 attempts with a cold soaked engine. So today, I tried some starting fluid. The engine did start right away, then bogged down, and I heard the idle air controller open up and make a long sucking sound as the engine was nearly ready to stall. Then something happened; the timing went away, and it ran fine.

The only way to reproduce a cold soak start on E85 is to let it sit overnight. Even parking it 10 hours during the day time doesn't let it get cold enough. It always starts right up... unless it sits overnight.

Mine starts up just like it did on gas.
You really need to do the injector mod.
It was a pain because I don't have much of garage these days so I had to do it in the driveway, but it was well worth the effort.

-Pete