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Discussion Starter · #1 ·
Been reading some threads over at the Sol forum on resetting your ECM. Over there, those guys claim that it's the cheapest (FREE) mod you can do to your car to increase mileage, smoother shifting, and in some cases performance. They say to disconnect the negative on the battery and to leave it unplugged for a half hour. Thought I read on this forum, of somebody doing a similar thing...but instead of disconnecting the battery terminal, they pulled the ECM fuse. Would this accomplish the same thing? Also...seems like all of the people that did this ECM reset over at the Sol forum, are driving 5-spds because many claim that it has improved the shifting...making it smoother. My question is...if I have an automatic, would resetting the ECM give me the same 'smoother shifting' benefits as those with the manual trans?
 

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nscrbug said:
Been reading some threads over at the Sol forum on resetting your ECM. Over there, those guys claim that it's the cheapest (FREE) mod you can do to your car to increase mileage, smoother shifting, and in some cases performance. They say to disconnect the negative on the battery and to leave it unplugged for a half hour. Thought I read on this forum, of somebody doing a similar thing...but instead of disconnecting the battery terminal, they pulled the ECM fuse. Would this accomplish the same thing? Also...seems like all of the people that did this ECM reset over at the Sol forum, are driving 5-spds because many claim that it has improved the shifting...making it smoother. My question is...if I have an automatic, would resetting the ECM give me the same 'smoother shifting' benefits as those with the manual trans?
I would like to know that also..
 

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Doesn't that make the computer have to relearn everything? How will that make it run better than it did before?
 

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Discussion Starter · #4 ·
HotSky said:
Doesn't that make the computer have to relearn everything? How will that make it run better than it did before?
Well, from what I understand it has a lot to do with the first tank of gas that was put into the car. Most dealers use regular grade fuel (87 octane) and so the ECM learns this and adjusts accordingly. But after that first tank is gone and the owner fills up with the a higher grade of gasoline (91 or higher), such as what is recommended in the owner's manual...the ECM is still using the settings from the 87 octane tank. Therefore, by resetting the ECM after the first tank of gas or after the break-in period...the ECM relearns with the higher grade of gasoline...thus giving better gas mileage and supposedly running better and shifting smoother. Again...this is just what I have read on the Solstice forum...but many there that have done this are believers that it works.
 

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Reflashing Retuning Your Ecm

nscrbug said:
Been reading some threads over at the Sol forum on resetting your ECM. Over there, those guys claim that it's the cheapest (FREE) mod you can do to your car to increase mileage, smoother shifting, and in some cases performance. They say to disconnect the negative on the battery and to leave it unplugged for a half hour. Thought I read on this forum, of somebody doing a similar thing...but instead of disconnecting the battery terminal, they pulled the ECM fuse. Would this accomplish the same thing? Also...seems like all of the people that did this ECM reset over at the Sol forum, are driving 5-spds because many claim that it has improved the shifting...making it smoother. My question is...if I have an automatic, would resetting the ECM give me the same 'smoother shifting' benefits as those with the manual trans?

You all should ck out the thread I started about the ECM REFLASH a while back...that should tell you pretty much what you need to know...

The disconnecting battery thing doesn't do ANYTHING! It doesn't re-set anything either...This isn't a free MOD...that's just looney talk!


You have a few options for the reflash/retune...anyone else know of any please post them.

1. You pull your ECM computer and send it to somone that can re-flash it for you such as VECTOR MOTORSPORTS.

2. You can re-flash it yourself if you have a lap top and know what you're doing. (software needed)

3. You can get a Retune/Reflash hand held computer use for only retuning (software needed..but not sure)

4. You can buy a JetChip for your ECM computer.

I'm sure there are others but IN NO WAY IS THIS MOD FREE....You are looking at anywhere from $200-400.00 for this Modification.

As for the whole 87 OCTANE OR 93 and HIGHER GAS....YES!

If you get your ECM reflashed you would only use 93+ octane fuel.

Remember, just ck out my Thread I think I did a month ago or so.

Avenger knows probably more about the whole Reflash/Retune...ask him

:thumbs:
 

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Discussion Starter · #7 ·
I'm not doubting anything that you are saying on this topic, cuz I will be the first to admit that I know NOTHING about it...however, if resetting the ECM, (not retuning or reflashing it), doesn't "do anything" as you stated...then why are so many Sol owners swearing by this procedure? :confused:

http://www.solsticeforum.com/forum/showthread.php?t=16466
 

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What else could be effected?

If you disconnect the battery won't you have to go through and re-program the stereo system? Would it have any effect on the On-Start? If the radio has an anti-theft program do you also need to re-set the stereo serial number in order for the radio to work? Is there anything else that may be effected? I don't know the answers to these questions but the full effect of the battery disconnect should be known before doing anything.
Jayne
 

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nscrbug said:
Well, from what I understand it has a lot to do with the first tank of gas that was put into the car. Most dealers use regular grade fuel (87 octane) and so the ECM learns this and adjusts accordingly. But after that first tank is gone and the owner fills up with the a higher grade of gasoline (91 or higher), such as what is recommended in the owner's manual...the ECM is still using the settings from the 87 octane tank. Therefore, by resetting the ECM after the first tank of gas or after the break-in period...the ECM relearns with the higher grade of gasoline...thus giving better gas mileage and supposedly running better and shifting smoother. Again...this is just what I have read on the Solstice forum...but many there that have done this are believers that it works.
But, many of the supporting tuners have stated that the ecm makes this adjustment by itself extremely quick, this is not a slow adjustment that takes place. The point the sol forum is trying to make, even though after reading the supporting tuners saying this really doesn't do much for the car, is that the engine is rough during the break-in. And you don't get great gas mileage from the start, and you take it a little easier on the engine during this period. Well, this is the period that the ecm adapts to the way the car is being driven, so why not reset and make the car re-learn when it is broken in and running smooth, also with the higher octane gas.

Believe what you want, this is still a debate over there, but to each his own. I am not experienced in this by far, so i don't really know which one to believe, but i tend to believe the professionals. :thumbs:
 

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If the car has a MAF, MAP, EFI, and Electronic Ignition all controlled by an ECM them I'm pretty sure it is going to have fuel trims. Your Fuel trims adjust the fueling mixture based upon what the ECM learns while you drive. These DO get reset if you unplug the ECM for an extended period of time. For Auto-trans cars, the way the transmission shifts is also learned and adjusted by the transmission management side of the computer. (I don't know if the Sky has seperate Engine and transmission computers...some cars do...some don't. I'm familiar with the Grand Prix and in that car both systems are in the PCM.) We routinely reset our fuel trims in the Grand Prix community whenever we make a change to the car and drive reasonably for the first 50 miles or so allowing the computer to map the various conditions properly. I wouldn't call this an "upgrade" though.
 

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Reseting your ECM does absolutely nothing for you unless your car has retarded the timing due to lower octane fuel. If you're still using lower octane fuel you'll just end up with the retarded timing again.
 

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brentil said:
Reseting your ECM does absolutely nothing for you unless your car has retarded the timing due to lower octane fuel. If you're still using lower octane fuel you'll just end up with the retarded timing again.
I am half making this up, but from what I read in this forum is this:

If you your car has lower octane fuel, the ECM has sensors that will detect a knock in the car and retard the timing to adjust for it. If you then put premium in the car it does not detect that it is premium and advance the timing. So by reseting the ECM and using premium it will not retard the timing to adjust and thus give you better performance.

Then again I am no car expert and may be just BackSideSmilie2.gif
 

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Rich, that is the way it works. Of course, the computer will also learn over time that you have premium fuel in the car since it will not longer be detecting knock and switch from the "bad fuel spark table" to the "good fuel spark table" (That's what they are called...I swear) eventually.

However the ECM will retard timing when it detects knock. This is called Knock Retard and is usually refered to as KR. Depending on the severity of the KR, you can see the ECM pull increadible amounts of timing (I've seen a car that would normally have about 16 degrees run at 2 degrees because of KR...that much KR and you're worrying about damaging your engine though.) The Sky's 2.4 should not see much if any KR though as it is normally asperated. It isn't until you start getting into Forced Induction applications that monitoring KR becomes extremely important.

The ECM will switch to the "Bad fuel spark table" if you have consistant KR. It will remain on this table and continue to pull timing in the form of KR until whatever is causing the KR is resolved. Once the ECM is not seeing KR, it will take some time for it to switch back to the "Good fuel spark table". Some will reset the ECM in order to bypass this "wait" period and thus the "performance gain" is immediate but it would have happened eventually...just not as noticably. As Brentil mentioned, reseting your ECM really does nothing if nothing has been changed between before the reset and after (such as switching fuel grades).

When I get my Sky I'm going to see if my Powertuner will hook up to it. It should work as a scanner on ANY GM car. I'll see if the car sees any KR on regular 87. If it doesn't, then the ONLY thing the car would need to relearn between 87 and 91 octane (don't have 93) would be cylindar pressure and the advanced or retarded timing that goes along with it. Even that is a minor thing and will not provide you with TONS of power.
 

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Robotech said:
Rich, that is the way it works. Of course, the computer will also learn over time that you have premium fuel in the car since it will not longer be detecting knock and switch from the "bad fuel spark table" to the "good fuel spark table" (That's what they are called...I swear) eventually.

However the ECM will retard timing when it detects knock. This is called Knock Retard and is usually refered to as KR. Depending on the severity of the KR, you can see the ECM pull increadible amounts of timing (I've seen a car that would normally have about 16 degrees run at 2 degrees because of KR...that much KR and you're worrying about damaging your engine though.) The Sky's 2.4 should not see much if any KR though as it is normally asperated. It isn't until you start getting into Forced Induction applications that monitoring KR becomes extremely important.

The ECM will switch to the "Bad fuel spark table" if you have consistant KR. It will remain on this table and continue to pull timing in the form of KR until whatever is causing the KR is resolved. Once the ECM is not seeing KR, it will take some time for it to switch back to the "Good fuel spark table". Some will reset the ECM in order to bypass this "wait" period and thus the "performance gain" is immediate but it would have happened eventually...just not as noticably. As Brentil mentioned, reseting your ECM really does nothing if nothing has been changed between before the reset and after (such as switching fuel grades).

When I get my Sky I'm going to see if my Powertuner will hook up to it. It should work as a scanner on ANY GM car. I'll see if the car sees any KR on regular 87. If it doesn't, then the ONLY thing the car would need to relearn between 87 and 91 octane (don't have 93) would be cylindar pressure and the advanced or retarded timing that goes along with it. Even that is a minor thing and will not provide you with TONS of power.
Good explanation. I have been wondering how the ECM could respond to a better grade of fuel if all it did was adjust timing when knock is detected. Thanks!
 

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ggccg said:
Good explanation. I have been wondering how the ECM could respond to a better grade of fuel if all it did was adjust timing when knock is detected. Thanks!
What we've seen with the Grand Prixs is that when you switch to a better grade fuel (We must run premium all the time and will switch to 100 or 104 octane race fuel at the track sometimes) is that when you switch to a race gas your mixture seems to look rich to the O2 sensor (for those of you with Sky's already look just above your cat and you'll see your front O2 sensor...this is the O2 I'm talking about here). For instance, with the Grand Prix an O2 reading of about 890-920 (depending on if there is an intercooler installed on the car) is about right. Below 890 you're lean and above 920 your rich. I've seen my car, which runs about 890 at 1200' altitude on 91 octane have O2s at 960 with 104 octane at 2700 feet. Now, the thinner air at 2700 feet has something to do with it too but not that much. So the higher octane is causing a higher O2 reading.

Also, cylinder pressure increases. With greater cylinder pressure the PCM wants to run more timing. So the richer your mixture, the more timing you get. I may see 15 degrees with O2s of 890 but then see 19 with O2s in the 960 range!

I imagine switching from 87 octane to 91 or 93 would have similar yet not as drastic effects.

You'll find the computer pulls from a number of different data sources and refers to a ton of different data sources to calculate timing. In my Grand Prix I actually have a Timing knob in the car. I can increase my timing by up to 7 degrees if I want. This is done by reprogramming the Air Temperature Spark table and fooling the Intake Air Temperature reading into believing the air is a certain temp. (Not the same as the E-bay $20 resistors that claim to do this...same principle, but if you haven't edited the Intake Air Temperature Spark table in the ECM it does NOTHING.)

I'd really be interested in seeing the parameters in the Sky's ECM and comparing them to the GP to see how they differ.
 

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does this have any relevance----

about 2 months ago, I changed out my battery in my saturn SL and put on new brakes. The battery was disconnect for a few hours.
when finished, I took the SL on some back roads and got on it a bit ( I went to test the brakes, but got bored)

I'd say I was riding it hard for about 20 minutes.

I came home, parked. When I went to leave sometime later I started the car and the RPMS shot up to about 3k. I figured the ECM was still in some sort of "learn" mode or something so I took off, drving normally.

The thing would not stop idling so high... I almost couldn't even shift cause when I push in the clutch it would shoot to 3 - 3.5k If I held in the clutch for a moment (about 30 secs) then they would begin to drop into a range where I could get it into the next gear.

Still figuring it was the ECM, I stopped, unplugged battery for 30 mins... and drove off again... this time at a normal pace while the ECM re-learned.

Everything was fine! I'm not an expert on ECM's but this makes me feel like there was more going on with the reset than just octane rating.

whatcha think?
 

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That's a new one and may be something specific to that car.

In the Grand Prix's PCM (again, because I can see the info and I have a general familiarity with it) there are two settings. One is for the desired RPM with the car in park. The other is for the desired RPM setting for when the car is in gear. They work pretty well and are fairly accurate.

It almost sounds like your PCM was commanding a 3,500 RPM idle! I don't know why it would do that but obviously it had to be PCM related with the way it didn't do it when you reset it again. Very odd though.
 

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Robotech said:
That's a new one and may be something specific to that car.

In the Grand Prix's PCM (again, because I can see the info and I have a general familiarity with it) there are two settings. One is for the desired RPM with the car in park. The other is for the desired RPM setting for when the car is in gear. They work pretty well and are fairly accurate.

It almost sounds like your PCM was commanding a 3,500 RPM idle! I don't know why it would do that but obviously it had to be PCM related with the way it didn't do it when you reset it again. Very odd though.

ya, everyone I mention it to, scratches their head on that one. Its a '97 with 170k miles... and I'll be trading it in next week for a SKY if all goes as planned!!!
 

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Revive the dead thread!!! ITS ALIVE!!!! ITS ALIVE!!!!!

Sorry to revive a dead thread. I am coming from a 93 MR2 to my new sky RL. I am learning all I can about this car so I don't ask questions that have been answered in other posts. The knowledge base is so small for these cars since they are so new, its hard to find answers. So here goes...

As for the ECM reset. If you install aftermarket parts, the ECM "learns down" the part to factory HP levels by i guess retarding timing? I have heard this happens after about 300 miles. Now will an ecm reset make the car have to learn down the add on again? And if so, you can, in theory, put add ons on the car, and do an ecm reset every 1-2 tanks of gas and still get the performance.

Jeb
 

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You Can Say That Again..LOL

What you state makes sense and is probably so and doable. However, my understanding is if you have a Redline Turbo Sky, AND get the GM latest upgrade tune, the learn down is disabled. Another words, it does NOT unlearn the upgrades, ie cat back, down pipes, etc.. I'm sure that the "tuner" will pop in and give you more "technical" information. But yea IMO, your statement is true, altho a PITA if you have to disconnect batt all the time, or I suppose with a tuning device it is possible to "reset" the ECM.. Lets see what other state..:cheers: Also, many pro tuners have been hacking into the ECM now for a bit and have manage to "control" these learn downs on our kappas. Of course you have to pay for these "tunes" unless you have the equipment, time and knowledge to DIY.. Good Luck!

PS: I own a plain old 2.4L, and still oem tune, donno of any tune that "blocks" per se any learn down, I would have to do what you stated to get it back to "virgin" if you will...
 
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