I am not sure its octane either, I will find out over the summer. I have noticed the power is down and the trims LT stays around -3.1 and ST fluctuates between 0 and -10.

 

I found this to explain fuel trims for those that dont like to read. Obd-ii Fuel Trim

 

I like to read, but I'm enjoying that computerized voice better ;-)

Interestingly good information.

 

Im going to order an UltraGauge to see what is really going on and probably wont comment in this thread until I get some data.

Just a couple of things before I leave. Emissions are an issue where the engineers are not always able to tune for maximum power or efficiency. High peak combustion temperatures lead to NOx and spark advance can lead to higher HC and CO. The cat cleans most of it up, but not 100%.

Since my background is aviation, and we have leaded fuel, Lambda sensors wont work. Exhaust Gas Temperature sensors have to do, and mixture control is manual. Best power nor economy is at peak EGT (perfect A/F ratio). Max power is rich of peak and best economy is lean of peak. We go way rich for takeoff and climb and way lean ground idle and cruise (up to about 75% power).

Also, detonation is the correct term for "knock" that can do damage. Preigntion is a completely different event most often caused by glowing carbon deposits or a too-hot spark plug electrode, but is often confused.

 

Lambda sensors do work on leaded just not for as long as they would without it which is why you don't use one on an airplane. They physically perform just as they would on unleaded fuel though.

Before I started playing with toluene, xylene, ethanol, propane, water/meth injection etc. I used 100LL/AV Blue Gas from Palwaukee airport. But @ ~$8/gallon I found a better and cheaper way to achieve the effect I needed.

A new Bosch UEGO sensor only runs about $75 bucks now fortunately, and I have it mounted right up front on the downpipe about 6" from the turbine discharge (for the fastest response and most accurate sampling) and it only takes about 5 minutes to replace. EGTs are a nice sanity check though. But you can pull the plugs and figure it out from there as well.

There are plenty of leaded race fuels as well like C16/Q16 and those work just fine with a lambda sensor just usually not for more than 10k miles depending on the tune and duty it sees.

High combustion temperatures are usually the result of lean burning, and NOx emissions on unleaded pump gas usually are not a problem until you start approaching 15.0-15.4:1AFRs where peak fuel economy occurs on pure gasoline.

As noted earlier by Lyon, if your fuel is consistent and your driving is consistent, fuel trims will not change much unless there are extenuating circumstances. Like atmospheric conditions, heatsoaking, or a hot spot in the intake tract that makes you more prone to pre-det.

Fuel Trims should remain more or less the same between grades in most cases, unless you are switching from Regular 87 with 10% ethanol to Premium 93 with no ethanol. Where you will lean out for two reasons and see a dramatic shift in STs and LTs. From both the lack of ethanol and that you no longer need to add fuel to slow the reaction with the more stable 93.

EGTs are different then combustion temps, you can create high EGTs through rich burning as well as too lean because the combustion continues out into the exhaust manifold.

This is one of the principals anti-lag systems are based on. There are many factors that contribute to EGTs, the mixture is one of the main ones though obviously.

And the Cat only cleans up emissions when they are hot enough, which is why OEMs try to tune for stoich or lambda 1.0v for as much of the map as they can get away with safely..

 

Reading all of this thread and giving it some thought has me missing the simplicity of my old 84 Harley Wide Glide.... It had what looked like a plumbing fixture for a carburetor called a S&S Super B with an adjustable main jet and taking plug readings were quickly done.... If black smoke wasn't visible in the rear view mirrors when accelerating lightly under 35 MPH it was time to reach under the fuel bowl and back off a couple of turns on the adjustment needle or it would start burning oil and ping like hell.... It ran well set on the lean side at 65MPH and yielded 65MPG doing it but going faster meant opening up the jet adjustment just like when going slow.... The old Shovel Heads ran best with black smoke coming out of the pipes which would have presented a problem if the top end couldn't be removed, the heads decoked and reassembled and running in an evening while enjoying a six pack or two of Heineken, which was something easily accomplished by any hard corps Harley rider of the time.

 

All gasolines,racing fuels, alcohols have a burn rate which all the fuel burns completely. Pump gas is around 14.7, and 10 percent ethanol is 14.2 air fuel ratio. Regular gas used to be 89 octane and then you have unleaded. I feel the ecu maps are set up for 91 r/m octane and can run 87 until knock retard lowers your mpg and premium sends it the other way making it more efficient.

The OBDI and II operate very similar meaning they use sensor to figure the fuel trims. The OBDII is more efficient and uses new technology to ensure a properly running engine. The fuel trims holds the key to how a engine is running and is the first step in diagnosing the problem. Some of the new OBD2 tech includes a 3 way EGR, knock sensors,wide band o2s and MAF,MAP with coil on plugs to name a few. The fuel trims use all the sensor including knock retard to adjust trims. When knock is present you will use more fuel because of the extra oxygen in the exhaust.

Here is some more info on ecu/fuel trims Ford EFI System Tuning - Inside The Black Box Part 1 - Muscle Mustangs & Fast Fords

http://www.stealth316.com/misc/obdii_fuel_trim.pdf

 

My mpg was 34.3 today at fill up. I filled up with mid grade to see where my fuel trims go. Its still pulling fuel and my LT is -5.5 right now and the short trims are all over the place +and- 10. The timing is near 0 compared to premium 6-8 and the Cat temps are lower too.


I heard Honda can have knock retard even with out knock here is a link http://www.pencomputing.com/rsx/rsx_knocking.html . I understand it a K series motor but I can bet its similar to all the motors. This would explain some of the mpg differences and why I am see lower timing running a mix of premium and mid grade.

 

My fit definitely retards for Knock in realtime. It has saved my ass countless times. There appears to even be a fuel/spark cut based on knock. You can see the pit marks on my ground strap on my plugs where the engine has been pinging off of it. This engine is incredibly resilient to knock.

Remember that the l15a7 ecu has more in common with the r18 ecu than anything else, use that as a reference. It is safe to think of the l15a7 as little more than a narrow version of the r18. Honestly the whole configuration of the l15a7 more in common with the r18 than the outgoing original l15. Hell we even use the same injectors as the r18.

 

I'm not trying to be an ass by saying this but I can honestly say the same thing about my old 79 Lincoln.... Your car probably makes considerably more power than it had though... There are a lot of older cars that pulled timing at the first sign of knock but you could hear it briefly where as the newer cars you hear nothing and need a gauge or a sensitive butt dyno to know it has happened.

 

Did the Lincoln have fuel injection? That was around the time of the switch to fuel injection. It took them 10 years or so to perfect that technology and still getting better.

 

That big old dog had the 400M 2V engine and a something like a 1.9 to 1 rear end ratio.... Fords made in 79 were all equipped with tall gearing and terrible acceleration.. My former father in law had a 79 Galaxy and it pinged like a bitch... My brother in law had a small Cadillac from the early eighties that had FWD and port injection... KC is a Cadillac man (Alfa Romeo too) and probably knows which car I am thinking of... The Lincoln pulled timing so much that when I move back down from the High Plains pulling a 4000 lb travel trailer I had to keep it in second gear except when going down hill... It was fine in 3rd gear at 70MPH but the speed limit in 1995 was 55MPH.

 

I did some research and the 302 had fuel injection. When a car down shifts to accelerate most of the time its the timing, it cant retard so it down shifts. I am noticing running midgrade that this is what happens. I used to accelerate form 55 to 65 with out the trans down shifting with premium.

My fuel trims are stay steady -3.1 LT and ST, on the way home it got colder and went to -2.3 LT,ST. I am feeling the timing retard, even when the temps are cold. Its starting to make sense to me and continuing to read more on the subject. Sorry KC back to fuel trims.

 

Coyote, you bring up a sad day in automotive development:Looking back to those years, Detroit really had its head up its ass. Everyone was confused - old school thoughts ruled an old school industry and the world was changing. Jimmy Carter had the idea to put solar collectors on the White House and ended up being laughed out of town... unemployment and gas lines. We were so naive we would actually line up for gas, like it would run out or something.
Who knew what a solar collector was or really cared where the gas came from - none of us really had any idea. We were still in our parents WWII patriotic fear years.

I can remember setting timing advance by feel and buttdyno backyard intuition. I also remember seeing all I was familiar with get replaced with 'smart' boxes that really didn't work and no one understood what they were supposed to do anyway.

Not too long back someone mentioned dwell meters and old strobe timing light and I went down and dug mine out. I wish I had my old collection of JCWhitney's.

A standard in my kit used to be a smooth palm sized stone that I would use to hone the points. Still have that stone kicking around in my tool chest. Fun explaining to the son-in-law how I used it in a ritual lucas prayer. Usually in the rain on the side of somewhere.
--------------------------------------------
Today I'm still trying to understand. Check me if I'm wrong, bear with me if I'm slow...

Fuel trim is something I can see and almost understand.
It is the injector duration factor based on a 'factory mapped' base line.

It is effected by the way you drive and, not by the 'grade' of fuel but, the oxygenation of the fuel. [10%ethanol]
It's primary determiner is the primary O2 sensor, however, other factors effect it.

It's almost time to move on to timing... but that's another thread I think, but here's a teaser.

So, in one of those verbose fuel threads not long ago I was at the point of somehow understanding that my 2010 FIT could 'take advantage' of premium grade fuel.

Timing curves would be adjusted... hmm.
This is interesting news to me for some of the reasons I've just seem posted in this thread.

Most stock set-ups will retard timing if a lower than designed for octane is used - how you say knock sensor.
Never knew of one that would advance, so, in my mind, the stock 'factory mapped' timing tables in my FIT are thought to be established for a higher than minimum octane...

Am I getting close?

I will continue to do the trim/grade thing. Curiosity has got me...

 

Looking back at WW2 and how the USA was able to create and manufacture machines, aircraft, weapons, uniforms, food and many very good and very bad other things and at the war's end the guy that set up and ran the system was sent to teach the Japanese what he knew... I can not think of the mans name but he had been with GM but was unwanted by them since they were more interested in building up wealth for their executives and cars that were as poorly built as the buying public would tolerate.... It was a British army officer that supervised VW after the war and it became the company that built the highest quality most sensible in the world until they obtained Auto-Union and gradually lowered their standards... I guess it is time for me to get flamed but I am a very observant person that has seen a lot of bad things and have become very analytic about things... The Big 3 had a chance and they chose to be dinosaurs while the rest of the world moved ahead... The people of the US shook in their boots during the Cold War while the military industrial complex exploited the fear and taxed the hell out of them and had them willingly send their boy children of to shoot up little 3rd world nations just like what is going on now... I strongly believe if we had chosen people like James Earl Carter instead of talking heads that are groomed by international banking interest and corporations, all of what is considered new technology would have happened 2 decades earlier and we all would have been aware of how the new stuff works because it wouldn't be new to us... Germany has been exploiting solar technology for quite some time and eliminating the construction and soon the need for nuclear powered electric plants and we are still burning coal and people are pissed because they don't want to give up Edison's light bulb and use the type designed by Tesla.... Germany has much less annual sunlight than us and is succeeding and the great talking head had the solar collectors removed from the White House when He and Nancy moved in... There were numerous small companies building solar panels in 79 that were out of business by by 81 and the US was only toying with building cars that had electronic fuel injection... I know I drifted off topic... It was KC's fault

 

I should really stick to these threads.

 

You get to thinking out loud like I sometimes do too much, weird people begin popping up asking questions, things go bump in the night that can't be explained and you see people that no one knows over and over in places far apart just blankly staring at you.... Seriously, it happens.

 

Like Jim Morrison said, people are strange when you're a stranger.
You guys are a trip. But damn near always right.

I do voice whats on my mind, maybe too often.

Some people just like appeals to populism and pre-conceived notions, but that only hurts the community so I speak up (whether or not I should is up for debate) and inevitably catch some flak..

I'll try and post something useful here in a bit.

Today has been a long one, meetings with professors from 8:15-12:00 and then on the grind for a couple more hours. I really want a new job.

Maybe I should open a GD/GE specific tuning garage... Street car/Standing Mile/Circuit what have you. Now I just need some start up capital, a couple solid tech guys, lifts, some machinery and definitely some little sweetheart to do my PR.

And here I ramble on again..

 

Those guys you're talking about Coyote were part of the victors, and to them went the spoils, at least that's what the allies had in mind.
Thing is, both Japan and Germany took things to heart and got it done.
Think about it, there's got to be a reason each country is as secure as it is today.

No one's crying the blues over it and no one should. The USA needs to wake up and get with it. We can not afford this free-for-all we've been running any more. ALL the good social plans have long been corrupted and capitalized by special interests. More lawmakers are interested in putting their name on something than effectively accomplishing anything let alone protecting the original intent of the accomplishment. At the same time we keep thinking we're going to 'create' a health care plan.

Take cell phone's. In Germany the government determines where the cell towers are to go in order to provide coverage for the country. The providers then pay to mount their equipment.

My brother-in-law's father is a pensioner in Germany and now not able to care for himself. So the B-I-L goes over back in December to make arrangements for home care and all that for his Dad. Do you know that he was reimbursed his in-country costs for doing what he did by the German Government? That's a health care system.

Those staring eyes are those that know. Helpless as they go - understanding as to where they've been.

Thanks for the interlude Coyote - anymore of that sweet heat?

 

I'm a little bit afraid to pull the cork.... What the hell, I'll do it now and report back with my evaluation.