I don't believe that GM uses only TPS for fuel... - Tuning Forum

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I don't believe that GM uses only TPS for fuel...
Friday, September 08, 2006 3:09 AM
Alright, I'm in Iraq, and I wish I could see this for myself. But a lot of info is being passed off saying that 1bar J tunes use only TPS for fuel, the MAP is for spark. Screen shots to support this?

Just curious. I mean, how can one guy not have any luck with HPT, and some else can shave off .8 in 15-20 mins?

Proof please.

O noes!

Re: I don't believe that GM uses only TPS for fuel
Friday, September 08, 2006 5:32 AM
Its called Alpha-N, and yes, J's use it. I don't have screen shots, but you'll just have to take my word for it. The VE tables (tables that identify how much air is going into the engine so the engine can calculate how much fuel to give), are TPS vs RPM vs VE.

And for your second point, its skill. If you don't know what you are adjusting, you can make your car slower with HPT pretty easily.





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Re: I don't believe that GM uses only TPS for fuel
Friday, September 08, 2006 4:26 PM
Okay, so what's the IAT input for? And the MAP input? I mean, since they monitor the incoming air charge, wouldn't it make sense to use those readings to adjust fuel, too? Although I guess that explains why my car ran fine when I forgot to plug the IAT sensor back into the harness when I did my intake...



Re: I don't believe that GM uses only TPS for fuel
Friday, September 08, 2006 6:10 PM
ln2johnny wrote:Okay, so what's the IAT input for? And the MAP input? I mean, since they monitor the incoming air charge, wouldn't it make sense to use those readings to adjust fuel, too? Although I guess that explains why my car ran fine when I forgot to plug the IAT sensor back into the harness when I did my intake...


incoming air charge? what does that mean?

MAP input is used to control spark mostly... IAT (Intake Air Temp) is so that the ecu know the temp of the air going in... i've seen tables that retard timing based on the intake air temps



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|
Re: I don't believe that GM uses only TPS for fuel
Friday, September 08, 2006 6:13 PM
IAT = Spark adjustment based on intake air temp
MAP = Spark based table uses this. There is the Injector Pulsewidth vs MAP multiplier, but its set to 1 from the factory.

Its pretty simple, Alpha-N only looks at TPS and RPM when using the VE table to calculate fuel.





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Re: I don't believe that GM uses only TPS for fuel
Friday, September 08, 2006 6:16 PM
Acer wrote: incoming air charge? what does that mean?

MAP input is used to control spark mostly... IAT (Intake Air Temp) is so that the ecu know the temp of the air going in... i've seen tables that retard timing based on the intake air temps


Okay, that kind of sort of answers my question, but

Acer wrote: incoming air charge? what does that mean?


You're joking, right? People say it all the time. Even the so-called experts of the great Org say it. Typically referring to the incoming air? You know, the stuff that fuel needs to burn?





Re: I don't believe that GM uses only TPS for fuel
Friday, September 08, 2006 6:36 PM
I find it hard to beleive that the MAP sensor has nothing to do with fuel metering. The car would either run lean at sea level or rich at elevation. And if you go from one extreme to another it'd think the O2 sensor was bad and CEL.




--------------------------------------------------
'96 Cavalier Good ol' Pushrod 2.2
-24X,000 miles on factory build
-Some oil loss between changes, me thinks it be rings.
Re: I don't believe that GM uses only TPS for fuel
Friday, September 08, 2006 6:41 PM
David Jones wrote:I find it hard to beleive that the MAP sensor has nothing to do with fuel metering. The car would either run lean at sea level or rich at elevation. And if you go from one extreme to another it'd think the O2 sensor was bad and CEL.


What does it have to do with the O2 sensor?

Alpha-N tuning (hey look its so popular it has a name) is pretty common in OEM vehicles. I don't know how else to put it guys, GM uses it, it works, its worked for years. I'm sure that the ECU takes a barometric reading before cranking for fuel adjustments, but its a static constant that doesn't have an editable parameter in the ECU. I will have to ask Chris to verify.





4cyltuner.com - Information Source For 4 Cylinder Tuners
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Re: I don't believe that GM uses only TPS for fuel
Friday, September 08, 2006 10:14 PM
ln2johnny wrote:You're joking, right? People say it all the time. Even the so-called experts of the great Org say it. Typically referring to the incoming air? You know, the stuff that fuel needs to burn?


uhhh, obviously i put together what you were trying to say... i was able to help a little. your welcome. and... i have just never heard of that terminology so its automatically stupid. and so are you.


lol, jk... thanks for the sarcasim though, i appreciate it!!



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|
Re: I don't believe that GM uses only TPS for fuel
Friday, September 08, 2006 11:13 PM
Oooohhhh I get it Alpha-n lol ok sorry that's the old way of tuning(tps vs rpm) i'm only really familiar with load based fuel injection systems which definately would use the MAP sensor. I've never even had to deal with the efi part of my car for the most part. That isn't an editable perameter your right. They just make it where the O2 sensor can modify the fuel map more so it runs stoich. I'm a toyota guy and they have used load based since the mid/late 80's.




--------------------------------------------------
'96 Cavalier Good ol' Pushrod 2.2
-24X,000 miles on factory build
-Some oil loss between changes, me thinks it be rings.
Re: I don't believe that GM uses only TPS for fuel
Saturday, September 09, 2006 5:00 AM
Acer wrote:
ln2johnny wrote:You're joking, right? People say it all the time. Even the so-called experts of the great Org say it. Typically referring to the incoming air? You know, the stuff that fuel needs to burn?


uhhh, obviously i put together what you were trying to say... i was able to help a little. your welcome. and... i have just never heard of that terminology so its automatically stupid. and so are you.


lol, jk... thanks for the sarcasim though, i appreciate it!!


If I wasn't a sarcastic little s-o-b, people would begin to think i didn't like them.




Re: I don't believe that GM uses only TPS for fuel
Saturday, September 09, 2006 7:37 AM
ln2johnny wrote:
Acer wrote:
ln2johnny wrote:You're joking, right? People say it all the time. Even the so-called experts of the great Org say it. Typically referring to the incoming air? You know, the stuff that fuel needs to burn?


uhhh, obviously i put together what you were trying to say... i was able to help a little. your welcome. and... i have just never heard of that terminology so its automatically stupid. and so are you.


lol, jk... thanks for the sarcasim though, i appreciate it!!


If I wasn't a sarcastic little s-o-b, people would begin to think i didn't like them.






|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|
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