By accessing this website, you acknowledge that Edmunds and its third party business partners may use cookies, pixels, and similar technologies to collect information about you and your interactions with the website as described in our
Privacy Statement, and you agree that your use of the website is subject to our
Visitor Agreement.
Comments
Any news on this?
Cheers!
Paul
There's a surprising variance in the maps of each engine, so using a permanent type of setting would eliminate the incremental operational gains realized by using the "learn and store" method. If they had a permanent burned in box of settings to run on, things would not be optimal, though I guess you could consider the factory defaults a "permanent" memory. As to who does what, there are a lot of flavors out there, but they can be grouped a bit. For instance, mfrs who use Bosch are probably using similar protocols vs those using Nippondenso, or Delco, et al.
Shlosser,
I'm starting to wonder if you're pulling our leg here. If you have a manual and you are truly driving it without a front drive shaft in place, you're going to toast the center viscous coupling eventually. If it were the automatic, you probably would have already fried the clutch pack they use instead of the coupling. That explains why you have a "clutch slipping" type of feeling - the VC is causing the slipping and while it's tough, it will eventally overheat.
IdahoDoug
Every time you drive, the map updates slightly with the new inputs. All of that information is stored in memory within the ECU module. But even when you turn off the ignition, some power is apparently routed to the ECU to keep the very latest information in these memory chips proper. This is known as 'standby state' or 'keep alive' mode. No activity is taking place - just the individual latches that represent each bit are being retained as either a '1' or '0' state. When you disconnect the battery, the remaining electricity in the system slowly dwindles (probably held by capacitors for some period of time), eventually shutting off the memory chips, and the stored map data is lost forever. This is known a volatile memory.
To me, this seems like a fragile way to keep the 'family jewels'. For not too great a cost (a few $$ per car), I would add some "flash" memory (non-volatile) as a system backup. Flash has been made popular by digital cameras and MP3 players. Write to it, and it retains the data forever. When you turn off the ignition, the ECU could transfer the current map to flash storage, then recall it when you start the engine the next time. Data would never be lost, until a 'reset' button were activated.
It is slower, more expensive, and allows fewer rewrites than system memory, so it is not suitable for instantaneous CPU operation, but great for this type of data retention application.
There are other, albeit, less elegant ways to keep data. Did you know that system data is kept alive in your PC by a standby battery? Probably a CR-2035 coin cell. There are also memory chips available with lithium cells carried in piggyback that instantly switch to retention mode. It doesn't take much power to keep modern memory in standby mode for months.
Steve
Speaking of brake pads, did you guys read the article featuring Danny Sullivan in this week's Autoweek? It's a must-see. He basically said he's replaced his tires 4 times and brakes 3 times in just 45k miles with his A6. The guy drives and understands you gotta pay to play. Cool article.
241k miles? Wow. You have GOT to get it up to a quarter million. :-)
Without the front right axle, won't all the power leak to that wheel?
I too wonder if the heat shields are necessary.
-juice
http://www.writerguy.com/primitive/skid.htm#rear
Mark
Personally, I drove a car for years without them, but admittedly it is not a good practice.
Steve
Would anyone care to conjecture how quickly the ECU advances timing once the knock sensor stops picking up pinging? In other words, you use cheap gas, the knock sensor does it thing and retards timing -- how soon before you're back to where you originally were (or better)?
Actually it's probably cost that's keeping cars from going to flash vs. DRAM. Burst-mode flash devices do have clock speeds up to 70MHz -- combine that with some clever data bus architecture and it should be enough to keep up with a CPU.
Ken
-mike
I have a 2002 5-speed Outback Wagon LTD. We had a blizzard in Colorado last week, got a lot of snow, so I had a chance to test my car in the severe whether conditions. The question that I have is about the AWD system. When I was driving through about 6-8in of snow, there was a strange smell inside the car, but when I stopped and got out of the car, I realized that it was coming from under the car. The thing is that there was a lot of wet, heavy snow and I could tell that every now and then one of the wheels was getting a lot of resistance from the snow. I never got stuck; however, when I felt that the car is about to get stuck I just pressed the gas pedal a little more and kept going. I know that there was no abuse of the car, there practically were no problems getting through. The smell was very strange, it wasn't the clutch or exhaust, that's for sure. My only guess is that it was coming from the coupling connecting front and rear wheels. I know that there is some kind of oil inside there. This is my first Subaru and first AWD car as well. Is it normal? Did it ever happen to anyone? Any suggestions? Thank you in advance.
I wouldn't worry about the AWD system, and you did the right thing by gassing it when you were getting stuck, that lets the AWD system work
-mike
As modern electronics become a bigger part of the 'behind the scenes' driving experience, I wish we had someone from Subaru on these boards that could answer these questions.
For instance, you mentioned DRAM. I thought about that also, but have a feeling that SRAM might be better suited. DRAM is less stable over temperature, and requires constant powered refresh operation - the simple cell design has no data retention capabilities (beyond a few milliseconds). Great for your PC, but maybe not for automobiles. I realize probably nobody else cares, but inquiring minds like mine want to know!!
Steve
While memory requirement of embedded systems have grown like everything else, keeping up with expectations of functionality and requirements of latest operating systems, I believe SRAM to still be the memory of choice for its simplicity of implementation. It also has the lowest power requirements, and its static nature allows processor speeds to be reduced to a crawl where possible to save still more power. Its also very easy to add backup battery or supercap for retention of parameters.
On the ECU reset question, I come off the fence in favor of the idea that a simple reset to known baseline can be accomplished fairly easily - such as mechanic removing the battery cable. While the systems learn the particulars of the specific vehicle during operation, I would think the baseline parameters to be pretty well optimized to begin with for the vehicle design so that a reset to a known state would not be detrimental to the system.
As for gas mileage and emissions, does anyone know if the EPA tests specify control of operating parameters such as these? Certainly they would not allow parameter optimization to the point where emissions do not meet requirements, but would they further specify qualification tests at the baseline settings? Perhaps doug can offer some more insight here.
Steve
I too favor an easy, do-it-yourself reset. What I wanted to avoid was accidental resets (disconnected battery when doing some other routine service, dead battery, etc.). A micro-reset button with a more non-volatile memory would still give you active control.
Steve
Greg
OTOH, if it takes a tank of gas to rebuild, the saved memory would be more of an advantage to the consumer (less time running on defaults, etc).
The comment about emissions is an intriguing one. I'd think that the factory defaults would be conservative power wise, which means generally it would be more emission oriented. Would indicate that someone having trouble passing an inspection should reset their ECU. Hmm. Interesting now that vehicles with advanced electronics are indeed getting old enough that this might be an issue one day.
I have a suggestion for keeping your map during battery replacement. I often disconnect batteries on my vehicles for various puttering and tinkering and years ago bought a cheap little device that saves the ECU memory as well as station presets, alarm system issues, etc. It holds a transistor battery and the other end plugs into the cigarette lighter. It energizes things enough to prevent the loss of various memory stuff. Cost a few bucks and I've seen them advertised since then at a few places.
Shlosser,
You are truly a daring dude. I'm impressed your Sube didn't really miss a beat driving it like that. I drove mine around in FWD only mode, but that is part of the AWD system's designed in capability. Nice job getting to that many miles. Do you do anything special maintenance wise? Run a lot of highway miles? How have things held up on the vehicle?
I have a vehicle I will now keep forever (93 LandCruiser) and dream of putting a half million miles on it. It is truly a landmark design and has been remarkably durable despite fairly rough use. It doesn't get driven enough though and only has 120K after 10 years, so it will be awhile at that rate - 30 years from now! Let's see - I'll be 72 then. Hmm, probably driving a Town Car and wearing Sansabelt slacks and a toupee....heh.
IdahoDoug
-juice
What would be cool is if there were some what one could back up and restore different ECU states. Imagine a little compact flash slot in the dashboard that would let you do that.
Sorry for going OT. ;-)
Ken
Cool idea. I sometimes get a little squimish about doing things when you have the potential to accidently weld a wrench with up to 500 amps available, but don't want to have to go thru the reset process. Where did you get it? Is there some circuitry to step the 9v battery up to 12v?
What is your procedure for using it? Can you use this 'backfeed' approach on the Subaru, as the cigarette lighter is off without the key turned to 'on'. I would think that if you turned the key to the on position, the "power up" state (fuel pump primed, ECU active, ignition and coil on, dash lights self test, etc.) would suck that little battery dry in seconds.
On the ECU topics - do you have any good connections thru your training business to get some answers? Again, I would love to know what you could find out.
Steve
http://www.mototuneusa.com/break_in_secrets.htm
So I would like to put it to the experts here on the Subie board... is this guy onto something or is he selling snake oil. Doug? Juice? Anyone?
-james
Yeah, right. Snake oil.
I don't believe a just broken-in (per manual) pistion would as bad as that photo, either. Not even on a Honda with 100k miles!
Synthetic oil manufacturers will deny several claims made on that page.
Miata.net has long claimed timing advance yields more power, with lots of dyno charts to back it up. Lots. That's not a myth, as that page claims.
Then you get to the beer and bikini-clad models and, well, I've seen enough...
-juice
Also are we comparing apples and oranges? these are race bikes and run higher RPMs than car engines.
--jay
I think I got mine at MG Mitten a couple decades ago, but I think I've seen them in Griot's and a couple other automotive mail order places.
To use it, I simply plug the thing into the cig lighter and go to work. I don't turn the key on or anything and believe it simply provides some current in the system. Never thought about it, but it is kinda curious how it works. I've also always wondered how those "jump your car through the cig lighter" things worked.
As for pursuing the ECU stuff specific to Sube, it would be a piece of work to have the training guys find me an automotive EE in charge of this stuff. Ironically, he's probably Japanese as this is core engineering stuff done centrally there by all Japanese brands. It would be interesting to know - maybe we could hit someone with it on the Thursday chat thing??
IdahoDoug
Greg
BTW, I have enjoyed the discussion Steve and Doug. Keep it going!
-Brian
I had the clutch shudder as well on my 2000 OBW. After mentioning it to my service tech, he just said "we'll replace it." HAven't had it since.
Mark
-juice
Greg
-Brian
A while back I mentioned a problem with cupping on all 4 tires (Dunlop SP Sport A2's). Well, the mystery deepens as I just had the alignment rechecked and there is nothing out of spec with the alignment that might be causing the increased wear.
As it stands, these [new] tires are ruined and there doesn't appear to be any logical reason. They've been rotated every 6-7K, pressure checked every week or so, and not driven hard...bizarre. With only 15K miles on them, they are probably due for replacement in the next couple thousand miles at most. I'm hesitant to put expensive tires on again, given this car's propensity to eat tires.
The tire guys at BigO (who rechecked the alignment yesterday)think it's just a mismatch between tread design, suspension design, and driving patterns. Apparently there are times a certain tread just doesn't get along with a car and this might be one of those times. I drive about 2000 miles a month on I-80 from Reno to Sac and another 500 miles a month to and from work in town, and that may be a contributor.
Next time it may be some bargain basement Kumho's or Sumitomo's for $60/each...
Brian
Greg
IdahoDoug
Steve
Regarding "block feathering" -- this is how I would describe the appearance of my tires. The individual blocks are unevenly worn, but the tread depth across the entire looks pretty even...they sound like 33" all terrain tires.
I cross rotated them a few weeks ago and it did change the pitch of the noise under 50mph, but not the decible level. More than the noise, I'm concerned about the fact that these tires are on track to be uniformily bald at around 20K miles...that's REALLY fast wear for a non-high-performance all season tire.
Incidentally, we got a few inches (3-6") of snow last night and I discovered that the Sport A2's were downright dangerous with half of the tread gone. It was all I could do to get the car moving on a slight incline, and the back end refused to stay behind the front end going uphill. Even when nearly bald, my OEM Firestones were more stable in snow and ice.
Brian
Greg
-juice
FYI - in choosing your next tire, look for a tire that has tread block designs that are longer in the direction of rotation over one that is not. If your vehicle/driving style/terrain tends to create uneven wear, this type of tread design will resist it better. Anecdotally, the Michelin X1 is such a tire and I've been extremely impressed with them in the snow. This, despite the use of specific snow tires for winter use. In other words, the X1s were impressive even when compared to these winter tires. They're pricey, but are designed for looooong wear. No comments about the French aspect ;-)
IdahoDoug
Re: The Michelin X1's -- those were considered last time and I just might do them next time around. Costco has them for around $100/each IIRC. As far as being from a French company, well, that scores bonus points with me given the current situation...
Brian
As for the French not helping the "coalition", French products have been of vital importance to the British effort. Storm Shadow cruise missiles have been the primary long range stand off weapon for RAF Tornados GR4s and that is from an Anglo French firm -MBDA -developed from the French Apache/Scalp missile. Similarly RAF Tornado F3 air defence is in the hands of Asraam, the worlds best short range IR missile in active service,again from MBDA.
French tactical reconaissance remains the primary source of manned recce in Afghanistan, as it was in the Balkans, and air strike sorties by Armee De L'Air Mirage 2000Ds are being generated at a higher rate, per capita, than any other coalition air force operating in Afghanistan.
Now that thats off my chest, did anyone see that letter in the papers about some guy who slanged off another guy for buying that darn French made Saab! Same flaming ignorant idiot will probably be slanging off Hyundai and Kia when the North Koreans attack the south!
it's suddenly "anti-american" to hold a different view from the masses or to question authority.
B
So my parents have been driving around with the CEL coming on and going off but they've actually reported higher fuel mileage than usual...strange!
thanks!
keith
-juice
Steve
<< Re-Mapped ECU Learning Trick 10-20hp in 5 seconds
Just a little trick that has been shown to accelerate the factory ECU's ignition timing learning process.
Background: There is something called "Ignition Advance Multiplier". It represents, by some complicated algorithm, the average learned positive knock correction applied to the ignition maps. It's represented in 1/8th degrees increments. 1 being the lowest and 16 being the highest (1/8 to 2 degrees in absolute terms).
The "happier" (knock free) the car is, the higher the number will be. Conversely, the lower it is, the more knock prone it is. This number, after ECU reset ore ECU swap defaults to 8 and usually creeps up to 16 (if well mapped) through normal driving. Depending on driving characteristics, this can happen within a few hours or a few weeks. Well, here's a way to make it happen in about 5 seconds ....
First: With the car fully warmed up, reset the ECU. This can be done by killing power the ECU or by simply pulling off the neg. battery terminal and pressing the brake pedal for a couple of seconds.
Second: Drive to a nice open road without traffic. Don't go on boost until you get there. Put the car into gear (3rd gear works the best) bring the revs up to 2600rpm. Push the go pedal down slightly so boost stays right around 2-4psi. You will need to MAINTAIN 2500rpm and 2-5psi for approx 5 seconds. You can do this by left-foot braking gently as to prevent acceleration. During these few seconds, the advance multiplier (which you can't see so you'll have to trust me) will go from 8, to 12 and then to 16. Works like a charm. And on our reflashed ECU, is worth an immediate 10-20 horsepower
In an attempt to save a lot of dyno time between reflashes (when the advance multiplier resets itself), I do this little trick after every reflash. In a typical dyno session, it's not unusual to reflash the same car up to 5 times. On the dyno, all I need to do is tell the dyno to hold revs to 2600rpm. Then I just lay on the throttle until I see a few psi of boost... Bingo!
Warning: This little trick artificially speeds up the learning process. This is only a good thing if the re-mapped ECU is mapped properly. If there are trouble-spots where knock is present, this trick will make it even more present. So be careful!
Cheers,
shiv
www.vishnutuning.com >>
He lost me there. What does pressing the brake pedal do when theres no power, since batt is disconnected?
-Dave