2g TPS: No Volts

[Nayr747]

Ok, I got another p0120 code so I adjusted my tps by this method: http://www.dsmtuners.com/forums/showthread.php?t=170432&highlight=tps+adjustment
But where it sais this:

b.) Connect a digital voltmeter between the TPS terminal 2 (sensor output) and terminal 4 (sensor ground).

10. Turn the ignition switch ON (but do not start the engine).

11. Check the TPS out voltage. Standard value:400-1000mV


Should I put the probes on the actual tps pins or on the harness? I put it on the pins and there is no volts. The tps checks out other than that, but does this mean it need to be replaced?

 

[steve]

Did you adjust the TPS by where the IPS opens?

For checking the TPS voltage the harness needs to be connected to the TPS, or it won't get any voltage. The shop uses a breakout cable that fits between the harness and the TPS giving them access to the signals. If you have a SAFC you can monitor the output voltage using the sensor check.

Steve

 

[Nayr747]

Did you adjust the TPS by where the IPS opens?

Yeah, I put a piece of paper between the throttle stop, put the multimeter between pins 3 & 4, turned the tps all the way counter-clockwise, then turned it the other way until the multimeter changed from displaying numbers to dispaying a 1 on the far left which I assumed meant a change in "continuity."

I also put the probes on pins 2 & 4 and slowly moved the throttle as described in Chiltons. The numbers changed smoothly like it said it should.

Then I tested pins 1 & 2 and got 4.52 ohms (on the 20k setting, dont know if that's right). Chiltons sais 3500-6500 ohms.

But no I dont have an AFC so I guess I can't check the volts. I got the tps code about 6 months ago and did this whole thing back then. The code hasn't reappeared until this week. So I don't know what could be causing the codes. Someone said in another thread that there was a mitsu service bulletin saying it was just an error. So I dont know what to do. It seems like I'm getting some bucking when letting off the throttle in first. And my gas mileage and power seem low. And I pressure tested my intake so it's not that.


Thx for the help btw.

 

[RamenPride]

before I had an AFC I would jam two wires into the connector, re-connect it, and attatch the other ends of the wires to the leads on a multimeter

 

[steve]

Yeah, I put a piece of paper between the throttle stop, put the multimeter between pins 3 & 4, turned the tps all the way counter-clockwise, then turned it the other way until the multimeter changed from displaying numbers to dispaying a 1 on the far left which I assumed meant a change in "continuity."

Continuity (short) is what the ohmmeter displays when the two probes are touching. Usually that's 0. No continuity (open) is what the meter displays when the probes are flapping in the breeze and that may be what you described.

Did you fold the paper over so that it was 4 thickness? That's about 0.0177 in.

3. Insert a feeler gauge with a thickness of 0.45 mm (.0177 in.) between the fixed SAS and the throttle pulley.

This is key for adjusting a 2G TPS.

I also put the probes on pins 2 & 4 and slowly moved the throttle as described in Chiltons. The numbers changed smoothly like it said it should.

That's good not not 100% accurate. I've seen them work great cold and fail when hot.

Then I tested pins 1 & 2 and got 4.52 ohms (on the 20k setting, dont know if that's right). Chiltons sais 3500-6500 ohms.

But no I dont have an AFC so I guess I can't check the volts.

The acceptable range for the total TPS resistance is 3.5k to 6.5k ohms. On a 20k range reading 4.52 would be 4.52k ohms. That's also good.

You can try what RamenPride suggests. I've done the same in the past.

Steve

 

[Nayr747]

Ok, I'll try that. And yeah, I did fold it four times. That bottom bolt is sure a bi***. I had to disconnect so many things to get to it. Last time I had to pull the throttle body out.

That's good not not 100% accurate. I've seen them work great cold and fail when hot.

Should I warm the engine up and then test the throttle movement?

 

[steve]

Ok, I'll try that. And yeah, I did fold it four times. That bottom bolt is sure a bi***. I had to disconnect so many things to get to it. Last time I had to pull the throttle body out.
Should I warm the engine up and then test the throttle movement?

The bottom one is a PITA. I just leave it semi-tight (hard to turn the TPS) and tighten the top one to lock it down.
I hope you didn't fold it four times, two times is four thicknesses.

If your still getting TPS codes after you go through and check the IPS and reset the ECU I'd check the voltage change as you open and close the throttle when it's hot.

Steve

 

[Nayr747]

Damn! Yeah I did fold it four times. I thought it seemed thicker than my feeler gauge. I don't want to go through that all over again though so I'll just see what happens.

So I reconnected everything and started it up. It idled around 2,600. for a couple minutes until I decided to just start driving it and hope that gets it down. Now it idles around 700 like normal and the car feels better than it did before this whole thing.

I got those wires jammed in there too (took the back of the connector off and got the wire boots out with a flathead). It read 0.4 at the 200v setting (still confused as to all the different settings). So I'm hoping that's 0.4 volts like it's supposed to be.

If your still getting TPS codes after you go through and check the IPS and reset the ECU I'd check the voltage change as you open and close the throttle when it's hot.

So just with the car off, just fully closed to anywhere in the open range? What should the voltage be when open? You're not talking about the ohms changing smoothly thing are you?

 

[steve]

I got those wires jammed in there too (took the back of the connector off and got the wire boots out with a flathead). It read 0.4 at the 200v setting (still confused as to all the different settings). So I'm hoping that's 0.4 volts like it's supposed to be.

You need to set the meter to the lowest range/scale to what your measuring. So it you choices were 2v, 20v, 200v, 2000v you would want to use the 20v scale.

So just with the car off, just fully closed to anywhere in the open range? What should the voltage be when open? You're not talking about the ohms changing smoothly thing are you?

Ohms or voltage, they are directly related and if one changes smoothly then the other will too.

The TPS output voltage at WOT will be whatever it is. You can't adjust it, you can only make sure that the mechanical operation of the throttle is working correctly. If the TPS happens to move all the way to it's end when the throttle plate is open 100%, then the voltage would be 5v. Usually you don't want the chance that a variable resistor might hit it's mechanical limit before the object it's attached to does so you wouldn't design the circuit to depend on the voltage. You would use limit switches, like how the IPS is used.

Steve

 

[Nayr747]

You need to set the meter to the lowest range/scale to what your measuring. So it you choices were 2v, 20v, 200v, 2000v you would want to use the 20v scale.

Well my choices were 200m, 2000m, 20, 200, 1000 (w/black box around it?). I'm just confused because I put the leads on a 1.5 volt battery and set it to 200 and it reads 1.5, but when I turn it to 20 it reads 1.61 ??? And when I turn it to 2000m it reads 1606. So I just thought that if I put it at 200 it would read straight volts. There are also two "V" boxes on the mutimeter. The one that I was using has a horizontal line with three dots under it, the other one has a wavy horizontal line beside it. Very confusing.

 

[steve]

The lower ranges (20 vs 200) have more precision/accuracy and that's why you use them for measuring lower voltages.
The V with straight lines is for DC voltages and the wavy lines for AC voltages

Steve

 

[Nayr747]

Ok, I have been out of town for a couple days but I'm still planning on testing the throttle when hot.

Hey but RRE does say to fold the paper four times. "[Fold a piece of paper in half 4 times if you don't have the feeler -Ed.] " http://www.roadraceengineering.com/2gtbswap.htm
Is that just a typo? I will email them if it is so they can fix it.

 

[Nayr747]

Well I finally got around to testing between 2 & 4 when hot. Just as you said it couldn't take the heat I guess. The numbers jumped around; in most of the range the numbers just went up by like 0.02 increments skipping some numbers (0.50-0.52-0.55) but in one place in particular it went up to 0.90s then dropped back to 0.80s.

I guess it's time to find a used tps. I think it will be hit or miss though since I suspect no one tests them when hot. Worst thing is now I have to completly REMOVE the bottom bolt. I have no idea how I'm going to do that.

 

[Nayr747]

Steve, do you think it's worth it to spend $30 or so on a used tps? If it's not affecting performance or dependability of the motor then I don't really want to spend the money. And the one I buy may have the same problem. Then there's installing the thing...