Double checked on way home this afternoon. My TPS # with Ford Ranger in RUN position is 18. With SGII Fuel>Cutoff setting at 19 or higher, when Fuel Cutoff mode is entered, TPS is 18 and LP is OPEN (they are AND'ed) to satisfy the Boolean requirement you mention. GPH consumption is 0, MPG is maxed at 9999, and HPR is zero. I reset the SG value to 18, then 17, on the the way home, and SG does NOT exhibit Fuel cutout values. Stepped the # back up to 19 (or anything higher), and SG displays return to normal zero fuel consumption values. Proves that the SG setting must exceed the TPS RUN value in order to display the Fuel Cutoff values.

So the SGII-Xgauge setting for Fuel > Cutoff does do something, and must be > the actual TPS value in RUN position, Engine Off, but my question is "Why would you not want to display/know when you are really in Fuel Cutoff Mode"? I sent Ron at LL an email asking same, but I know he is probably a real busy guy, and may not have time to respond back.

 

You've got it figured out now, I think.
You need the cutoff value to be minimum throttle +1.

Exactlty 19 in the case of your Ranger, exactly 13 in the case of the Escape.

You do not want to forget and leave it at 19 if you put the SG in the Escape. If you do, your MPG averages will be in error... significantly high!

And to answer your question... you do want to know, but each car is different, thus Ron at Linear Logic cannot "pre-program" this value. Each owner needs to do exactly what you did to customize it for a particular vehicle.

It just occurs to me that leaving the default value of "24" may be causing some owners to get "false positives" and false higher than normal MPG averages. It would be slight, but enough to get a hybridder excited... only to be a disappointment at the pump. Care to comment Carl?

-John

 

Straight from the source, I did get a timely email response back from Ron at Linear Logic regarding my Fuel Cutoff question. In the interest of promulgating information that all of us inquisitive guys/gals seek, below is his response, copied and pasted verbatim. Thank you Ron. Now that's customer service

"The CUTOFF was a last minute addition to the ScanGaugeII. Some vehicles will report when they shut off fuel flow during coasting with the engine in gear. The same signal also indicates when the vehicle is enriching the fuel mixture during hard acceleration. If the throttle position is below the CUTOFF value when this signal is received, the ScanGaugeII assumes it means 0 fuel flow. Above this it means enriched flow. Normally you should not have to change this. If your TPS is above this level when you are coasting with your foot off the accelerator, you would need to raise it. If you set it to 0, this detection is turned off.

The value of 24 is good for most vehicles. The best setting would be to set it 3 above the value of the TPS with your foot off the throttle. This will better assure that it is not going to mistake hard acceleration for a coasting situation and vice-versa."

John - Switching my SGII from vehicle to vehicle is a pain, and does require resetting many of the settings, and destroys TANK and MPG data. I would like to dedicate a SG for each vehicle!

 

Thanks Ken.

I'm curious why Ron suggested setting it to +3 above minimum throttle.

+1 is the obvious choice to me, unless I am missing something.
I tried +1 last night, and it worked perfectly. (aka 13 ) The higher you go above the minium, the more chances you have for under-reporting fuel use.

My only beef is, I would NOT say 24 is the best setting for most vehicles.

+3 is "acceptible" but 24 is a long way from the ideal setting for a Ford Escape (13)... but not so far away from your Ranger (19).

-John

 

It sounds like from the quote there already is a fuel cutoff signal but its used for another purpose during hard acceleration.... therefore unless 24 appears to be hard acceleration on a particular vehicle it should work because the TPS would have to be higher than that AND the "fuel cutoff" signal active for it to register and say fuel is in use.

13 seems like the perfect option on the Escape because 12 appears to be what it is when shes off, but from the description, I think even 24 would work almost all the time because there is another signal "apparently" involved.

Or did I misread the quote. Is it possible the +3 is there because there is a certain amount of "play" in the TPS on some vehicles or under some conditions... say its 100F tomorrow... will that TPS still read 12 when the engine is off or will it read 13?

 

No, you didn't mis-read anything. Just Ron at LL over simplified his answer, not knowing how tech savy this group is over here.

If you set the cut-off value higher than the minimum, you will record zero fuel use during a cold engine warm-up period, when the engine in is open loop status due to temperature, not fuel cutoff.

I just tried it. With a cold engine, at idle, my engine was at TPS 16, and was "open loop" and was for sure burning gas. Having the cutoff value set to 13, this "open loop" was ingored. Had it been left at factory default of 24, the SG would have assumed fuel was cut-off during idle warm-up in my driveway.

It's that simple "Boolean" and command, best I can tell.

Fuel cut = Open loop and Low Throttle

But what is low throttle? Ron said in most cars this is less than 24.
Not so. Looks like every car is different, and the Escape is 13, and the Ranger is 19. Maybe Buicks are 24 and Toyotas are 28. But I don't know.

EDIT: Of course if Ron is using some other signal than the OPEN LOOP signal, I could be wrong. But since every car carries the OPEN LOOP signal, and not every car carries a fuel cut signal, this would be one way to do this.

 

John - thanks again for your comments and sharing your experiment and opinions on this. I think you illustrated another important point. Without knowledge, I'm sure most SGII-xgauge users will leave the setting at 24 (default), not knowing any different. I plead guilty. And there is simply no way Ron could choose a default number that would suffice for all vehicles! Your description emphasizes that cold weather starts will end up with Fuel cutoff being registered at the most inappropriate time, when cold engines love to consume fuel. This skews the Tank gallons used and/or remaining if the SG fuel cutoff value is set too high. I'm going to stick with 19 for awhile, because I have enough experience with Fuel Cutoff on my Ranger that I can predict with great accurace when it can/will occur.

So far, TPS always goes to 18 when the engine is warm enough to allow Fuel Cutoff, so a setting of 19 should work. I believe friends, we have this thing nailed, but then I've been wrong in my life

I learn something from these forums every day. Hybrid owners and SG users are probably some of the most inquisitive and savvy folks around. I offer my apologies for not contributing more with FEH issues, but my wife loves loves the FEH, drives it daily, so most of my inputs are based on my Ford Ranger!

 

Now, how long does the car run "open loop" when cold? Not long. Could be 20 seconds, could be 30 seconds. But the whole point of the "cutoff" feature is to make things as "perfect" as possible.

Previous SG versions did ok without it, because a few seconds here and there is no big deal to most folks.... but if you are reading this, you do not fall into the category of "most folks" now do you!


There is nothing wrong with LL setting the default to 24.
But when you know 13 is ideal for an Escape, why not set it?
I'm just not sure anyone knew the exact settings until this thread.
So Ken, you helped a lot!
And you are probably the first person on the planet to figure out the Ranger! Congratulations!

I personally, would have left it to zero, until someone actually wanted to evoke the feature... then the SG would behave just like the older ones, but no matter what... it's small potatoes, and probably adds up to a fraction of a MPG either way.
-John

 

Yep, we want to get it as perfect as possible. I'd say that cold startup OPEN loop is no more than 30 seconds, but what the heck. A few MPG reported incorrectly here and there might be close enough for some, but there are a few of us guys and gals that want the bar to be raised a little higher. Never perfect, but always trying.

I laughed when I read Ron's point about the SGII Fuel cutoff setting influencing "heavy throttle" as well as Fuel Cutoff MPG readings. I plead ignorant again..... "Heavy throttle or acceleration" is a language I don't understand anymore. Not in my vocabulary. Heavy acceleration would break that egg under my foot, wouldn't it? Ha!

 

Okay... I'm starting to think the 'cutoff' feature is more trouble than it is worth. There is merit to Ron at LL saying to put the cutoff a little above minimum.

Today I tried it at high speed ( 70 MPH ).
At this speed, I went open loop in L gear, which I'm 99% fuel was cut, and my TPS only went down to 16. Thus, at high speed, it will get ignored with my setting at 13.

So after that test, I set it back to the factory setting of 24.
I found a glitch. What do you make of this, Carl?

I was going up a steep grade at ~65 MPH. Then I pushed it hard, like you would need to do to pass a truck on the uphill grade. My tach went to 5000+ and was at WOT ( or close ) and went into open loop.

I was shocked to see the SG reading 0.0 Horsepower and 9999 MPG.
What the ?#$!
I quickly punched one button a few times to bring up TPS. TPS was 70.

Not to complain, but I found another "glitch".

Under fuel, we have Gas, Diesel A/B, LP, Hybrid. We also need ETHANOL.
I've been running tests this week with 30% ethanol. I've burned 2 tanks, about 24 gallons of 30% ethanol. Car runs well, just the SG does not come close at all to the right MPG. The Navi is dead-on accurate with 30% ethanol. For both tanks of ~ 12 gallons, the SG was off by more than 3 MPG on the high side. SG = 29.5 when navi = 26.0. Real at the pump was very close to 26.0 MPG. Next time, SG = 31.1 when navi = 27.1. Real at the pump was 27. I know those numbers look discouraging, but not really. Most of those miles were high speed highway miles, and it was very cold, in the teens and 20's outside. And I can buy E30 for $2.50/gal. ( Minnesota )

FWIW... I see a big drop going from gas to E10. There's not much additional drop with E30. E30 performs about the same as E10.

-John