TPS will not go to 0%. Is this ok?

[EagleTalonTim]

Hey peoples! I was messing around with my logger and noticed that my TPS never went below 9.7% and would not go above 98.1%. I posted part of my log in another post and someone told me that my TPS should be at 0% when at idle so I turned the key on, put the logger under the hood so I could see the readings while I adjusted the TPS. The lowest I could get it to go was 2.7% with the cable loose and the IPS adjusted all the way out. Here is the catch.... If the TPS read below 6%, my CEL would come on and it would throw the error for the TPS. I tried adjusting the IPS to ensure that it read that the throttle was closed and it still did not work. I left the TPS reading at 7.4%. I moved the throttle all the way open by hand and the reading was 97.3%.

Now, for some reason, I get 1 to 2 counts of knock while driving as soon as I accelerate. It used to not do that when the TPS was at 9.7% at idle. What should I do to fix this or is it really a problem?

I also noticed while driving normal down the highway, my logger randomly sees up to 40 counts of knock with no adjustments in the throttle. My talon is still running on the stock fuel system, 13b turbo, and hacked MAF can. I always run 93 octane from BP or Exxon. What would cause this?

 

[Avionixx]

My TPS is normally around 10-11% at idle according to MMCD. As long as it reads 100% at WOT and your idle speed is where you want it to be, you should be OK.

 

[cmptrphreak]

If I'm not mistaken the tps should read at 10% at idle . I don't think its supposed to be at 0% . It should goto 100% at WOT .

The tps is a rotating resistor. It senses the throttle valve angle. When the throttle rotates , The output voltage on the tps changes. The ecu sees the voltage and notices at what angle the throttle is open. The ecu then computes the voltage and judges the engine acceleration state and accordingly corrects fuel injection amount during acceleration.

It should be adjusted accordingly to factory settings. Correct me if I made a mistake.

 

[TurboAnything]

the 1Gs have a closed throttle switch. I think its for idle and when you let off the gas in gear it pulls fuel to save gas.

 

[steve]

If I'm not mistaken the TPS should read at 10% at idle. I don't think its supposed to be at 0%.

Correct. On a 1G the Datalogger reports raw values not scaled values like on a 2G.

The Factory adjustment spec for the TPS voltage is 0.48V to 0.52V which happens to be about 10% of a 5V max output voltage from the sensor. If you have a SAFC you can read the sensor voltage or just adjust the TPS for a 10% reading on the datalogger.

The TPS doesn't have to ever generate a 100%. It typical for it to be in the high 90's at WOT. The actual voltages depends on the mechanical linkage, how far the throttle cable opens the butterfly. Ther are specification of the amount of slack in the throttle cable at idle but you can have additional slack in the pulleys for the cruise control if it's not adjusted correctly.

 

[EagleTalonTim]

what would cause the excessive knock at normal driving? I have seen 40 counts of knock just cruising down the highway.

 

[steve]

For starters how old is your knock sensor?

 

[EagleTalonTim]

not sure. i bought the motor from a JDM distributor. that was about 3 months ago or less.

 

[steve]

not sure. i bought the motor from a JDM distributor. that was about 3 months ago or less.

Then the first thing to do is check it and replace it. What all did you replace on the engine before installing it?

 

[EagleTalonTim]

nothing at all. just dropped it in and changed the oil. Been running ever since

 

[always_broken]

My tps reads 0% at idle...

2g

 

[steve]

My tps reads 0% at idle...

2g

That's nice.

 

[Spoolin4Ever]

I'm pretty sure as long as it changes smoothly when you adjust it, and it is set at the proper voltage, you are fine regardless of what it says...that's how it ended up when i replaced mine and it has been working good. Most will not be exact 0% and 100%.

I'm curious about when your timing components, waterpump and crank pulley were last replaced. Might be worth a few hundred bucks to do that stuff..?

 

[EagleTalonTim]

i replaced the timing components about 2,000 miles ago. Why would I have to replace the crank pulley though? Never had to do that on any of the 4 1g's that I have owned.

 

[always_broken]

That's nice.

And my car is black.

 

[corsair231]

If your tps voltage is low (7.4% vs 10%) the ecu will see the throttle blade angle as not as open as it really is. This could get it out of the range of adjustment of the mas and maybe not putting enough fuel in, causing it to run lean. That could be causing your knock.