What else beside telling when its timt to go WOT. Does the TPS?
Arent the fuel maps based on vaccume?

THanks

 

Hmmmm let me take a shot at this one... with my limited knowledge I'll hit as much as I can.

Fuel injection suffers from the same fate as a carb when you pop open the TB butterflys the system needs to enrich the mixture so you don't get a hesitation. The TPS supplys part of that information to the ECM using a circuit that looks at change in TPS over time.

The next function is the Decellerate fuel mixture. With your foot off the gas the TPS sends the reference signal to the ECM so it knows when to use a modification of the fuel tables during decel. This helps increase fuel mileage in coast.

The TCC is controlled by the ECM which depends on the throttle 'percentage' and VSS to control when the TCC gets activated.
In cruise the ECM uses the TPS voltage to understand when to disengage the TCC so you can accelerate without an abnormally high load on the engine.
Again it looks at throttle opening over time to know whether you are gently pressing the gas or nailing it. TPS supplies this info.

Edit: Power Enrichment is based on Percentage of TPS voltage.
I don't think mine uses KPa for that at all. There is a table with those values in it. So it DOES control the PE. (Mine is a MAP system BTW)

I'm sure there are a couple more places and reasons it gets used but that's about all I can think of right now.

The ECM must know the "throttle angle" to accurately control fuel delivery.
The TPS supplies this data in the form of a DC voltage.


[Modified by VetNutJim, 3:42 PM 6/10/2003]

 

hmm ok thanks.

So a higher TPS vs a low TPS value in same Kpa range can change the fuel in that area, if you have moved the TPS.

What I mean is if you have tuned your car at one point, when the ratio between the TPS and the acctual postition on the TB blades is set. And then you change the TPS vs the position of the TB blades ( due to a new minimal idel set, due to a more agresive cam etc), the fuel will be diffrent.
WHy?

Beacuse lets say you pump up the IDLE to 950 rpm in the chip. You make a new minimal idel set to match the new setting and to keep the IAC counts low ( around 30 ).
Then the TPS also increase. And ( if you have a adj TPS, pre 90 cars ) then you back the TPS position to keep it at 0.54 V at the new base idle.
Then you change the hole geometry of the TB blades VS TPS volt. Your TB blades will be more open at a lower TPS volt from idel to WOT, then your first setting.

Your toughts on that?

 

anyone coments? This really bygging me.. :/

 

On my '85 the tps (throttle position sensor) is just that. After you set your idle speed, you set the tps sensor so that the computer knows what your idle speed is. The change in resistence in the sensor changes the voltage drop across the sensor telling the computer how much you have accelerated, so it can make the required adjustments ie: fuel and timing.
Does that make sense? :)

 

well my 1995 vette would not downshift from 3rd to 2nd going say 50 or so, The tps sensor was bad, it can be seen on a scanner- mine was showing 0-59% and the new showed 0-99% Downshifts perfect now, also the shifts were mushy and now they are firm.

Eric

 

As long as it starts and runs :iagree:

 

so u can set ur idle to say....400rpm and then set the tps to .55 or what ever have u and it will react fine with that idle and the computer won't go nutz!?
:confused: do u understand my question? :flag

 

the scanner shows blade angle and tps volts, I knew it was bad as the blade angle was only going to 59% and the new goes to 99%. :party:

 

yep

 

I haven't had to play with a MAP car yet. What table is concerning you?

I think you're understanding TPS function, but what TPS vs. fuel table is bugging you?