Obdii "live data" ???

Recently lost some fuel mileage, not sure why?

Gone from 28 mpg's to 25 mpg's

Maybe just the colder weather?

No CEL, 3130 Scanner, Green Light, No codes...

Lots of "LIVE DATA" though,,, What does it all mean ???

I imagine these parameters must fall within a particular range ?

Not much good if I can't interpret the data.

The definitions are all out there...

STFT = Short Term Fuel Trim

B1 = Bank 1

S1 = Sensor 1

IAT, ECT, O2, MAF, MAP, HDORWM... And so on...

Again...Lots of "LIVE DATA",,, What does it all mean ???

Where can I find info to help me understand this data ?

Also pushin' 110,000 mi

I've read around where the Oxygen sensors should be replaced @ anywhere from 60 -100,000 mi ???

A factory repair manual would have the acceptable ranges for all the data you're seeing. I don't know of a free website that offers that information.

Thanks Richdude,

Figured that!

With as much info that is available for free, not everything is free !!!

Guess I'll save up the Buck50 for the FSM. Be good to have.

Whats your take on replacing the O2 Sensors ???

I've read where even thought they function within specs, they do become dirty, so there would be benefit from replacement ???

Thanks Again...:loser::loser::loser::loser::loser::loser: :loser::loser:

Oxygen sensor replacement is a dicey issue. I believe that the factory replacement interval is rediculously low mileage. Oxygen sensors will last a lot longer in a car with mostly highway miles versus one used for short trips. A sudden drop in mileage like you're experiencing with no CEL may be caused by a carboned up O2, but it will normally show up as short and long term fuel trim readings being off.

90% Highway, 10% 'Roundtown

My drive to work is 110 miles round trip daily 5 days a week, mileage does add up quickly.

Car runs / drives "GREAT" otherwise.

Thanks Again For Your Input

Fuel mileage usually goes down in the winter time since the Big Oil folks make a winter blend that is Lighter in nature. This helps the gas to atomize/vaporize easier on cold winter days. Being lighter usually means a drop in mileage.

HOPE THIS HELPS

My winter mileage drops from about 30MPG down to around 26MPG.

Now you'all got me thinkin', maybe it is the "Fuel Blend", Up until recently I would use Shell Gasoline almost exclusively, only because it was convenient on my drive to work route, but a while back they opened a new stretch of highway that takes me out a different way, So lately I've been mixing it up with Shell, BP, Murphy's USA and Exxon, Maybe I'll go back to one blend and see if my mileage comes back... before I make any other changes

Post the short and long term fuel trim values and we can explain it to you or it might indicate why your fuel economy has dropped.

When a 02 sensor gets really bad or lazy it normally sets a code DTC(s) in the form of lean to rich or rich to lean.

Try staying with one brand of gasoline and do not blend them. What grade or octane are you using?

I'll take it for a ride later and post the STFT / LTFT later on this afternoon, but from memory they fluctuate anywhere from + - 7 or so, I don't recall anything higher or lower than that but I haven't had the scanner very long and I will need to give it back to its owner soon, So I'm going invest in my own in the near future, definitely a good tool to have handy.

02 S1 : bounces around between 0v and .950v
02 S2 : stays around + - .600v or so

Bought it with 28,000 and I've always used "87"

02 S1 : bounces around between 0v and .950v


Bought it with 28,000 and I've always used "87"

OK so this is a base model with the NA SIII 3800 engine. The pre CAT 02 sensor appears to be working properly or not dead based on your data. Typical readings will be in a range of 0-999 mV (millivolts) and it should fluctuate.

6 frames of live data I captured earlier, Nothing stands out as obvious to me, the software that comes with the 3130 is kind of lame though can't do anything with it, graphing is sort of lame too, but anyway,Anyting jump out at you ???

I appreciate your input... Thanks Again !


http://i461.photobucket.com/albums/qq339/dc1263/110000a-1.jpg

Hey DC1263 do you have Microsoft office? I've got a wonderful list all data and definitions and "generic" parameters for most GM cars and trucks

He could use open office which is freeware and a Microsoft office compatible.

Troy,

Yes, I do have MS Office, anything you could send my way would be greatly appreciated, It would be real nice if I could dump this data into an excel spreadsheet, but as I said earlier, the scanner software is really kind of lame, I think they could have done better with it, anyway, I could load it all in manually though, no big deal, sometimes it's easier to visualize whats happening when this kind of data graphed rather than trying to follow a bunch of fluctuating numbers

Thanks, you guys are a great help !!!

From what I can see the short and long term fuel trims look normal or nothing out of the ordinary. The ideal figure to achieve is 0 % but that will never happen. Ideal fuel trim = zero. Greater than zero indicates the PCM is adding fuel to compensate for the lean condition. If fuel trim is less than zero the PCM is reducing the amount of fuel to compensate for a rich condition.

The fuel trims are considered abnormal when you see the following on the scan tool.

LT fuel trim is greater than (+) (-) 17%. ST fuel trim greater than (+) (-) 2%.


BTW - The best reference to use for DTCs and the explanation of why or how they set is the GM Factory Service Manual. The problem with generic and extended code listings is not all DTCs are applicable to certain year model Grand Prixs and the respective engines. Also, they do not have the proper corrective action to take or any detailed diagnostics procedures.


Note: One of the STFT values is off but that could be the scan tool but it is not that bad. The specs are using a GM Tech 2 scan tool.

Thanks for the insight into fuel trim, now i can understand the data, after using the 3130 i was thinking about buying one for myself, but after seeing the software that comes with it maybe i'll will think again... Maybe another brand.


Elmscan bluetooth @ $199.99 ??? Any opinion ??? Don't have a laptop.

You're welcome.

I have no experience with that brand scanner but it appears to be full function which is better than just a code reader. I use Autotap on a 10 year old Compaq laptop and have a DHP Powertuner for the laptop. Tblake - Tim uses another brand software and interface on a laptop so lets see what he has to say.

Yep Guys, I've got digimoto with mobydic. It seems to do alright, same concept as autotap. I got it for christmas. Only thing I wish is that it could scan for Knock Retard, Myabe with the next software upgrade. Other than that it does the job, scan/erase DTC's, real time sensor charts, dyno runs (not sure how accurate).

www.digimoto.com

Only thing I wish is that it could scan for Knock Retard, Myabe with the next software upgrade.

Thats why I went with Autotap. And the virtual gauge display is neat and comes in handy. :grinyes:

If only I had known digi didnt go KR.... Oh well.

My FAV or home use is Alex peppers. OBD II / CAN, Bi directional controls, Trans, abs, body, cluster data and DTC's. Lots of enhanced data oh my, LOL And yes you can us open office 3.0 to open M$ office stuff.

Hey DC1263 do you have Microsoft office? I've got a wonderful list all data and definitions and "generic" parameters for most GM cars and trucks

Troy : YES, I have MS Office, and I would greatly appreciate if you could pass along this information to me.

Had some severe weather blow through here last night had to everything shut down, 10 tornadoes reported here in Eastern NC, Not Fun!!! Another round of weather is supposed to roll through later on today, I'm gonna hold her down best I can.

Thanks Again You guys a a great help


http://i461.photobucket.com/albums/qq339/dc1263/032709.jpg

"The First Step For Successful Troubleshooting Is Eliminating The User As The Source Of The Problem"

^^^I like that, how true it is!!!^^^

I bought a snap-on red brick off e-bay, and have about $400 total into it including all the adapters, cartridges, personality keys, etc... and I like it. I need to upgrade my cartridge so I have newer Vin Specific info (my current ones only go to 01 but works for generic OBD-II up to the CAN protocol), but other than that I'm very happy with it.

Sent you a PM DC1263

"The First Step For Successful Troubleshooting Is Eliminating The User As The Source Of The Problem"

^^^I like that, how true it is!!!^^^

I bought a snap-on red brick off e-bay, and have about $400 total into it including all the adapters, cartridges, personality keys, etc... and I like it. I need to upgrade my cartridge so I have newer Vin Specific info (my current ones only go to 01 but works for generic OBD-II up to the CAN protocol), but other than that I'm very happy with it.

Rich, how much did the snapon brick run you one ebay?

Snap On "Red Brick" a.k.a. MT-2500.

Troy : PM reply sent

mine is actually the MTG2500, which can show color graphs and such. It cost me about $250, and came with the case, manuals, and a set of cartridges for 81-99 Domestics/Generic OBD-II, and a few adapters for OBD1 and the OBD-II adapter w-a few keys. I also bought separately the thru 01 cartridge set and troubleshooting CDs, a cable to interface with my PC, a cigarette lighter power cord, data extension cable, a few more OBD-I adapters and a few more OBD-II personality keys which ended up at about $400 total for everything. I'm constantly watching e-bay for the new programmable/updateable cartridges so I can better diagnose 02 and newer cars.

The other option out there is HP Tuners and DHP Powertuner especially if you desire to mod and do your own programming. Plenty of bin files floating around on the Net you can use to get started. Plus they have the capability to do good ole odb-ii diagnostics. The ones being discussed are OK but do not have the capability to change any parameters and write to the EEPROM in the PCM module. Around $400. Just another option to consider.

mine is actually the MTG2500, which can show color graphs and such. It cost me about $250, and came with the case, manuals, and a set of cartridges for 81-99 Domestics/Generic OBD-II, and a few adapters for OBD1 and the OBD-II adapter w-a few keys. I also bought separately the thru 01 cartridge set and troubleshooting CDs, a cable to interface with my PC, a cigarette lighter power cord, data extension cable, a few more OBD-I adapters and a few more OBD-II personality keys which ended up at about $400 total for everything. I'm constantly watching e-bay for the new programmable/updateable cartridges so I can better diagnose 02 and newer cars.

Rich, if you come across another "brick" deal on ebay like yours, would you let me know? 250.00-400.00 for the scan tool, and misc cartridges and keys seems like a steal (doesnt it?). What do the snapon mt-2500's usually go for?

Thanks!