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My first scan... wth is going on?

PonchoDvr4Lfe

PonchoDvr4Lfe

New member
So changed out the basic parts on my Prix back last year this time (i.e. CAI, 180* T-stat, 3.6 pulley, colder plugs, plog, cat-back, no d/p though.) I was down in Columbus visiting a friend so decided to let Intense do a quick std. tune on it. Never did anything else with it.

Bought a hp tuner for my camaro and decided to check the Prix. Well, never checked with my tuner because of my friend being an idiot and left it in his vette all night with no top on in a rainstorm because he was making a booty call. Needless to say I am out a laptop and tuner now.

Anyways, borrowed a friends laptop with proscan on it. Just to cure my curious mind. And I noticed that my LTFT is outrageously running around -12 to -24. My front o2 sensor shows mostly around .6 but wll drop down around .05 sometimes so it think that is taking a dump. Why would my fuel be so outrageous?!?!:confused:
 


I wouldnt think it would be that far off with just a few modds like that, when your talking about the o2 sensor what do you mean by .6 .05?
 
chrisb said:
...when your talking about the o2 sensor what do you mean by .6 .05?
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The voltage from the sensor indicating how it's running. A good mix hangs around .45v anything higher your rich, anything less and your lean.

I really cannot think of why my LTFT is off that far though. Having a leaking LIM gasket wouldn't cause that would it? I know getting coolant on a o2 sensor will jack it up. I tried to get the gasket changed asap. But I am more stumped about the fuel mapping. Any ideas please?!

I am ordering a new HP Tuner to replace my drippy one. Until then, I don't know whether to believe this scanner software or not.
 
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Thats what i thought you were talking about but i guess im used to mv since thats what my hptuners is set up to display. Not really sure on any ideas to be honest.
 
My fueling was way off too. Both stock and with the Overkill pcm. Took PRJ about an hour of street tuning to get that straightened out.
 


Sounds like the proscan isn't really cooperating with the gtp's pcm. Negative LTFT's means its pulling fuel and therefore it wouldn't be a lim leak. With a leak you will usually see the car adding fuel and trims +16. I don't think i've seen a fuel trim get up to 24 or if its possible...
 
I really don't know what to think about it. Has anyone ever had problems with their OBD2 port not communicating properly? Maybe I don't have the timeout and baud rate set-up right or something of that nature.

I am ordering another HP Tuner next Thursday and should be here Friday. Just waiting for a client to pay up so my wife doesn't see the money disappearing.:th_winking:
 
Your LTFT's should not go over +-16 unless your EVAP is purging. Mine gets to -22 sometimes after I fill the tank, but goes away pretty quick.
 
your LTFTs physically cant go over +-16.4. that is the max/min it can even read.

also, its good to have your LTFT running either at 0 WOT or just barely adding a little fuel (+1, 2, 3). its never good that the car is pulling fuel at WOT (-1,2,3, etc).
 
Bio248 said:
your LTFTs physically cant go over +-16.4. that is the max/min it can even read.

also, its good to have your LTFT running either at 0 WOT or just barely adding a little fuel (+1, 2, 3). its never good that the car is pulling fuel at WOT (-1,2,3, etc).
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I really haven't got into tuning yet at all as I only had my 1st tuner for 1 week before my buddy supersoaked it. But why is it that it will only read +-16 on LTFT? I know that if you are getting a +16 you def getting a vac leak somewhere.

I want to buy a book on tuning and saw the one the new one written by Greg is what everyone is talking about over on the hp board. Good idea or do you guys recommend something else?

where else would be a good place on here to get some quick facts about tuning?
 


mine went -28 on both long and short term fuel trims everytime i put gas in it...check for a leak in the tank..gas cap...tubing going from each
 
PonchoDvr4Lfe said:
I really haven't got into tuning yet at all as I only had my 1st tuner for 1 week before my buddy supersoaked it. But why is it that it will only read +-16 on LTFT? I know that if you are getting a +16 you def getting a vac leak somewhere.

I want to buy a book on tuning and saw the one the new one written by Greg is what everyone is talking about over on the hp board. Good idea or do you guys recommend something else?

where else would be a good place on here to get some quick facts about tuning?
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goto hp tuners and read EVERY siticky before you even dream of touching your tuning. EVERY STICKY...EVERY STICKY...EVERY STICKY am i clear yet on the reading every sticky part yet? if you decide to start messing around in your cars pcm without the proper knowledge have a spare motor and a cherry picker handy as youll need it
 
DOUGLASMELTER said:
goto hp tuners and read EVERY siticky before you even dream of touching your tuning. EVERY STICKY...EVERY STICKY...EVERY STICKY am i clear yet on the reading every sticky part yet? if you decide to start messing around in your cars pcm without the proper knowledge have a spare motor and a cherry picker handy as youll need it
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QFT! I read everything I could get my eyes on while I was waiting for my tuner to arrive in the mail. Even with that, I still had a few issues getting started properly. Read until your eyes hurt, close your eyes for a minute, then keep reading...
 
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