RE: My PCM tuning with PCMforLess.com - Process and Results
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/15/2006 8:30:28 PM
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HummerGuy
Posts: 6584
Status: offline
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I think people with Automatics are going to see a bigger difference then with a stick, just because I don't have the new shifting tables and all that like you guys with the automatics do, but like I said, I can tell a difference. Because I don't have a CAI kit or exhaust, I probably won't notice it as much as you, but if it makes a difference for me with no mods, I'm sure it would make a difference for you. I'll see how it feels through this week with my daily driving.
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/15/2006 8:42:24 PM
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ChevyHighPerformance
Posts: 159
Joined: 7/5/2006
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quote:
ORIGINAL: HummerGuy
I'm very please with the results. I'm sure things will start working better and I'll notice more little things that I haven't so far. I have only been able to floor it off the line 2 or 3 times because A) my wife has been in the car the entire time and B) Every FREAKIN stop light or sign I have been up to I have been stuck behind slow people. BLAH.
As soon as I figure out if I'm getting better mileage, I'll let you guys know, but overall, I'm happy with it. I have no complaints. No security relearn or check engine lights came on. It started right away with absolutely no problems. I'm going to recomment Alvin to a couple of my Chevy vette owner friends and see if he can tune them. I think it was definitely worth it. I can't wait to really drive this thing this week to work and back and see what it can do.
The H3 will feel even stronger in a couple days. The PCM needs to learn things.
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/15/2006 9:40:01 PM
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HummerGuy
Posts: 6584
Status: offline
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OK I'm a bit confused being new at this. People on here say the PCM doesn't learn anything. It only adapts from the time you start the car to the time you stop, and then over again the next time. What exactly does the PCM learn? I'm just curious. I might just be missing something, but from my perspective, everybody seems to have their own theory as to whether or not the PCM actually learns and retains anything. Someone from GM said it doesn't, others say it does. Maybe I'm just stupid :) Please explain. Thank you!!!
< Message edited by HummerGuy -- 10/15/2006 9:41:46 PM >
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/15/2006 10:04:11 PM
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Ghostrider
Posts: 517
Joined: 9/18/2006
Status: offline
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I think and Im not totally positive but from what I have figured out, the PCM doesnt retain information like a data aquisition system would from a "black box" sense by logging MPH, RPM's, Temp, etc... but the engine basically has 2 operating modes, long term and short term. Short term is kind of like the 10% of your driving habits and is like when you pass a car or pull a trailer. The short term doesnt change much and can adapt the fuel trim quickly to what the system needs at that moment. Long term is more about how the engine runs under normal conditions and is what it reverts to once it decides its in for the long haul like on a highway. This long term is adaptive to your driving style though as its sort of a moving average of tuning the engine to how you use the pedal. If you take off from stoplights slow every time, it will probably give you a little more torque in the low end and die out sooner because it knows the engine rarely gets into its upper RPM's. However if you take off quick all the time, you will probably notice that your engine runs happily at higher RPM's. I did a little experiment with this and after a week of driving like a grandma leaving a stop light, I definately noticed that it was NOT happy to be at higher RPMs. But after a few days of leaving the line like a top fuel dragster, it accelerated smoother and quicker but my low end was a little shaky.
but these are all seat of my pants tests so who knows but in my attempt to understand long term fuel trim and short term fuel trim, that is what I concluded.
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/15/2006 10:05:28 PM
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Alvin@pcmforless.com
Posts: 25
Joined: 9/19/2006
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Glad you are enjoying it!
As soon as you start driving the truck like you normally do the gas mileage will start to increase. Most of our customers report about 2mpg better (if not more) on thier second or third tank of gas. There is a good bit of learning that has to go on and it does take a few hundred miles or so.
We did do some things to tweak the idle including spark changes and such. Thats probally where your noticing the smoother idle. We really give these tunes a thorough going over and change quite a few parameters
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/16/2006 8:46:53 AM
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HummerGuy
Posts: 6584
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quote:
ORIGINAL: Dennis
I am so glad everything turned out great for you Mike..especially the over revs on clutching....!
I'd like to give their tune a shot just like the one you got..and compare it to the tune I got earlier this year,..sounds to me like what Kelly was saying..Alvin's tune make it more driveable in the day to day city driving...Which is where it should be, snappier..Oh well I burnt that bridge ..so to speak
Alvin is a very nice guy. I think he might be able to find it in his heart to forgive you , or, maybe he'll just reprogram your PCM to make your engine self-destruct MUAH HA HA HA HA HA HA what.
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/16/2006 9:03:41 AM
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HummerGuy
Posts: 6584
Status: offline
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quote:
ORIGINAL: Alvin@pcmforless.com
Glad you are enjoying it!
As soon as you start driving the truck like you normally do the gas mileage will start to increase. Most of our customers report about 2mpg better (if not more) on thier second or third tank of gas. There is a good bit of learning that has to go on and it does take a few hundred miles or so.
We did do some things to tweak the idle including spark changes and such. Thats probally where your noticing the smoother idle. We really give these tunes a thorough going over and change quite a few parameters
Well, after driving to work under my normal conditions and driving the way I always do, here are the NEW things I have found:
1) I didn't drive no 200 miles yesterday like I thought (I don't know WHAT I was on...) but only about 70 miles.
2) I tell you, I found myself continuously braking the entire time to work, not because it was stop-and-go so much, but because the normal amount of pressure I would use to press on the accelerator made it accelerate much faster then it used to. I kept creeping up on everybody's rear end. I'm surprised my rotors weren't glowing by the time I got to work There really is more pickup. I know there has to be more going on then just a boost in HP. There seems to be quite a bit more torque.
2.5) On the way to work and back, I'm usually in 4th gear most of the time, just because of the way traffic is on my expressway. There is a noticable difference in pickup in 4th gear. I don't even want to shift it into 5th because me likey the power
3) The engine is much smoother accelerating at low RPMs then it used to. When I was anything under 1750 RPMs and floored it to accelerate at higher gears, the engine would virbrate. Now, there is no vibration at all, and even when I am a little under 1500 RPMs and cruising down the expressway, I hit the gas and no vibration. It seems like the engine is not struggling as much as it used to.
4) A HUGE difference in upper RPM vibration. When I would get past 4500 RPMs, the engine would really start to vibrate alot, like I was pushing it too hard. Now, it doesn't vibrate AT ALL. It's SO smooth getting past that 4500 RPM mark. I used to literally feel like my engine was going to just vibrate right out of the engine compartment. Now, it's as smooth at high RPMs as it is at low. I don't know HOW the heck you did that little fix, but it's pretty awsome! I'm not afraid of blowing up my engine anymore! Is there something you did to make it smoother at the higher RPMs?
Since nobody here seems to have a Manual H3, I can't say you guys would feel or see the same effects that I do, but for me, I'm really impressed. It's such a bargain for $149. I don't know what the long term effects will be obviously, but so far, it's really starting to show some hidden power.
I have to say, I'm still VERY impressed by how much power this little I-5 engine can make, especially now. You have to give the GM engineers alot of credit for being able to pull off the H3 with this engine. I just wish they would have come tuned this way. It probably would have given them more selling power. The boost is enough for me to finally be content with the amount of power I'm getting.
Alvin: Thanks! I don't know what else to say You made me a happy driver.
(Yes I sound like a commercial, and NO I didn't get any kickbacks )
< Message edited by HummerGuy -- 10/16/2006 9:08:06 AM >
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/16/2006 10:30:47 AM
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HummerGuy
Posts: 6584
Status: offline
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Was that timed on a track or just you watching the speedometer and your watch
That sounds like something I would do! It doesn't take me no 12 seconds to get to 60! Damn I DO have it good with this 5 speed!!
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/16/2006 6:46:12 PM
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ChevyHighPerformance
Posts: 159
Joined: 7/5/2006
Status: offline
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quote:
ORIGINAL: HummerGuy
OK I'm a bit confused being new at this. People on here say the PCM doesn't learn anything. It only adapts from the time you start the car to the time you stop, and then over again the next time. What exactly does the PCM learn? I'm just curious. I might just be missing something, but from my perspective, everybody seems to have their own theory as to whether or not the PCM actually learns and retains anything. Someone from GM said it doesn't, others say it does. Maybe I'm just stupid :) Please explain. Thank you!!!
The PCM learns three major engine items: fuel, spark, and idle. You can picture that the PCM is pre-programmed with fuel and spark info. As you drive the PCM looks at the oxygen sensor before the cat. converter and adjusts the air/fuel ratio to be 14.7:1. Learning is required because of tolerances in fuel pressure, MAF sensor, etc. The data the PCM learns about the fuel is stored in Trim cells (as in fuel trim not the other kind). So the PCM fine tunes the inital starting points. The data is retained until you reset it (using HPTuners, Tech 2, etc.) or when you disconnect power to the PCM.
Spark timing is similarily learned. The PCM starts with an upper and lower spark table (high octane and low octance). As you drive the knock sensor is monitored and timing is adjusted and ends up somewhere between the upper and lower table. This learning is reset under the same conditions with the fuel but also when you add significantly more gas.
Idle is learned as a function of engine temperature and gets reset the same way the fuel trims do. This learing is fuel, spark, and more importantly throttle position need to for the programmed idle RPMs.
There is other learning that the PCM does besides the big three that I mentioned.
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/16/2006 11:48:13 PM
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HummerGuy
Posts: 6584
Status: offline
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When you say it learns the spark, what exactly does it learn? Does it learn how much voltage the spark plugs should get for the best combustion, or do you mean the timing of the spark? If you put something like Iridium spark plugs, or those Bosch Platinum +4's, how do things like that affect the PCM? Does it adapt to things like that, or does it always just use the first initial xxx miles of data for the rest of it's battery life?
Also, do those goofy 9 Volt battery adapters you buy at the store REALLY help keep your PCM's memory when you disconnect the computer? I can't see how that could work considering it's sending power opposite of what it's supposed to. Someone actually told me to use those things before thinking the computer's memory would be retianed when switching batteries. I'm a sucker though don't forget
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/17/2006 6:36:41 PM
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CerberusSVT
Posts: 371
Joined: 7/30/2006
From: Pittsburgh, PA
Status: offline
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quote:
ORIGINAL: lotus4s
I hope my buddies from the lotus forum don't see those 0-60 times.....
lol, its ok the guy from the SVT forum (me) caught you though!
I've stayed out of this thread because I don't really feel like I have much to contribute, but I do want to say that from the sounds of things I'm going to want to get a tune!
_____________________________
Bo
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Black 06 H3
SMA Brushguard
Black Grill
Black factory rims
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/17/2006 11:08:56 PM
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lotus4s
Posts: 48
Joined: 8/21/2006
Status: offline
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quote:
ORIGINAL: CerberusSVT
quote:
ORIGINAL: lotus4s
I hope my buddies from the lotus forum don't see those 0-60 times.....
lol, its ok the guy from the SVT forum (me) caught you though!
I've stayed out of this thread because I don't really feel like I have much to contribute, but I do want to say that from the sounds of things I'm going to want to get a tune!
 
_____________________________
06 H3 Superior Blue, lux/adventure, sunroof, oem ucp & rock rails, 35" Cooper STT's, DOI winch bumper, gobi stealth rack and PIAA 1500xt's, dvd
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RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/18/2006 2:08:36 AM
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Alvin@pcmforless.com
Posts: 25
Joined: 9/19/2006
Status: offline
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quote:
ORIGINAL: CerberusSVT
I've stayed out of this thread because I don't really feel like I have much to contribute, but I do want to say that from the sounds of things I'm going to want to get a tune!
Let me know if you have any questions or anything like that. I really feel like we have a great product for these Hummers. Our tune has got to be the absoulute best bang for the buck performance wise or mileage wise. They have been slow to take off but I sorta knew that was going to be the case as hummers are kinda on the rare side. I'm really eager to get a bunch of people to try the tuning.
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