Throttle Position Sensor (TPS) Problems

[mr_wizard]

Originally I had found the TPS hanging off the side of the throttle body from the screw falling out, which was causing a majority of the cars horrible hesitation issue at 3300 RPM. It was hesitating so bad it would throw me back and forth in the seat trying to accelerate. Putting a screw back on the TPS didn't fix the problem, so I thought that wasn't it. Well after messing with everything else, I tried messing with that once more since you can sort of turn it like the distributor for adjustment, I turned it as far as it would go clockwise with the screw in and the car now run great up until about 5k RPM and sometimes even less depending on how fast I'm accelerating. I tried turning it the complete other way counter-clockwise and it gets way worse, so I know the problem lies within the TPS. Do I still have it installed wrong or do you think the TPS is f'd up? Is there a TPS installation procedure? Or any other suggestions? Thanks.

[onosqv]

yes, there is a procedure... it's somewhere if u search .

Should be around .4 volts closed, 4 volts open - the actual wire you have to probe is somewhere in the article (I used my safc to tell me the voltage, so I can't tell u which wire you need to check)...

[mr_wizard]

I did see that actually, I thought that was a "testing" procedure not installation though. I think if I know I have it installed correctly then the problem would be in the TPS. I dont have a volt meter either though haha. Thanks man!

EDIT: wait a tic, you mean turn the TPS according to the voltage readings?

[mr_wizard]

bump! suggestions?

[180fan]

you need a volt meter to do the tps testing. and yes you turn the tps to get the readings with the engine off but the electronics on.

[mr_wizard]

Ah ok. Thanks. I think what I'm going to do since I don't have a volt meter is just rev the motor as I'm turning it to find the sweet spot. It should stop hesitating when I find the right spot, in theory anyway.

[mr_wizard]

Hmmmm, ok now the motor isnt changing when I turn the tps. No matter how far I turn it clockwise or counter clockwise it acts the same. "Starts" to hesitate at 3500 RPM and then at 5k RPM it starts backfiring and going crazy (in neutral)... can't get over that mark... or atleast I don't want to try. Driving it you feel the effects alot more. To me, sounds like the TPS is bad since nothing is changing as I turn it. Idea's?

[onosqv]

Idea's?

you need a volt meter

Just shell out the 10 dollars for a voltimeter man. Once you get that, you can at least eliminate the tps problem and know for sure. once the tps is working rite and you still can't rev past 5k in neutral - it's most likely ur maf sensor or the maf connector, mine did that, replaced the maf & helped w/ that issue.

You can also use the voltimeter to test ur maf.

Voltimeters rule, that and an FSM are one of the top 3 things to have for do-it-yourselfers.

[onosqv]

And another thing, don't just mess around w/ stuff w/o a proper procedure, usually does more harm than good.

Just follow how you are suppose to do it:

zerothread?id=161700

Good luck, and report back when you've at least checked things correctly.

[mr_wizard]

Ok, what I did was warm up the car, turn it off, then starting from the furthest clockwise position turn it little by little while every time unplugging it for a few seconds, plugging it back up, then plugging it back in. It's essentially the same thing as if you were doing it with the volt meter, except it would be a little quicker that way. But anyway, I did not find the spot. No matter where I would turn it, it would act nearly the same. It did get a little better in the furthest counter-clockwise position but it still hesitates real bad under hard acceleration and higher RPM's. I made sure I unplugged for a few seconds and plugged back in before starting the car up to reset it like Hitman said, but no good. Looks like my TPS is bad.

Oh by the way, I replaced my MAFS trying to fix the problem, that did not fix it.

[180fan]

Bingo with the TPS. Pulling the plug on it isn't quite the same as calibration with a voltmeter. With a volt meter you can set a floor and ceiling for the voltages that pass through the tps. What you're doing is taking a stab in the dark. If you're going to switch out the tps anyway, it will still need calibration with a volt meter regardless.

[mr_wizard]

Yeah, I figured it would save me 10$ and a trip to autozone or whatever. If I just move it millimeter by millimeter, disconnecting the plug and reconnecting it from furthest point clockwise to counter-clockwise... it would be pretty much the same thing. And considering nothing changed, I think it's safe to say the TPS is bad. I guess it f'd up when it fell off and was barely hanging on without a bolt for 20 or so miles :-/

[mr_wizard]

Alright, I gave the multimeter a shot, and as I thought I would, I have no idea what I'm doing. I have different settings on this multimeter. There's like 3 sub settings for Ohms. One is just an Ohms symbol which I get no reading on when following hitman's diagnoses procedure, a "V", a "K" with an Ohms symbol after it, and an "M" with an Ohms symbol next to it. I used the M with the Ohms symbol because that's what it defaults to and what I got was completely backwards of what wrote up. With the throttle closed I get about 9.8 and with it all the way manually opened I get about 2.8. It should be the other way around right? Maybe I still have it on the wrong setting? I don't have instructions for the multimeter so I have no clue. OMG WHAT AM I DOING!?!?
Modified by mr_wizard at 4:27 PM 5/19/2006

[onosqv]

Just follow the instructions... try the K instead of the M.

But first, you have to adjust it w/ the correct voltage (V):

Adjustment:

If Throttle Sensor is replaced or removed, it is necessary to install in proper position, by following the procedures shown below:

1. Install Throttle Sensor body in the Throttle Chamber. Do not tighten bolts. Leave bolts loose.2. Connect Throttle Sensor harness connector.3. Start engine and warm up sufficiently.4. Measure output voltage of Throttle Sensor using voltmeter.5. Adjust by rotating Throttle Sensor body so that the output voltage is 0.45 - 0.55 volts.6. Tighten mounting bolts.7. Disconnect Throttle Sensor harness for a few seconds and then reconnect it.

Then once that is good, change over to K Ohms & see if it is correct...

Trouble Diagnoses:1. Disconnect Throttle Sensor harness connector.2. Make sure that resistance between terminal #1 and #2 changes when opening the Throttle Valve manually.Looking at the "pins" of the connector w/ the locking tab of the connector pointing up, terminals #1 is the one on the LEFT. #2 is in the MIDDLE and #3 is on the RIGHT.

The results of the test should be:

Accelerator Pedal Condition Resistance in k OhmsCompletely released Approx. 2Partially released 2 -10Completely depressed Approx. 10If test shows "No Good", replace Throttle Sensor.

I'm trying to help you man, I really am, but you're gonna have to figure it out on your own if those instructions weren't clear enough. I don't see how it can be more clear.

Like you said, if the TPS is busted, you won't be able to get those values (test shows "no good"), but at least you'll know how to do it when you have the replacement...

[mr_wizard]

Just follow the instructions... try the K instead of the M.

But first, you have to adjust it w/ the correct voltage (V):

Then once that is good, change over to K Ohms & see if it is correct...

I'm trying to help you man, I really am, but you're gonna have to figure it out on your own if those instructions weren't clear enough. I don't see how it can be more clear.

Like you said, if the TPS is busted, you won't be able to get those values (test shows "no good"), but at least you'll know how to do it when you have the replacement...

There's holes in the instructions where he sort of expects you to know alot of this stuff. I have no clue on how to use a multimeter. So this "4. Measure output voltage of Throttle Sensor using voltmeter." does not make any sense. Where do I put the positive and negative pins? It does not say. After I warm up the car, do I leave it on? It doesn't say that either. Because if you were to leave it off, where would you get output voltage from? And if you had the car on, you have to disconnect the plug to measure anything. So where would you get the voltage then?

[onosqv]

Ok, first things first.

We are only going to use the voltimeter (volt) part. If I don't explain how to use a voltimeter well enough, please search through google - as that's how I learned, so I know you can do the same.

When adjusting the voltage, the car should not be running - but put in the ON position.

you need a volt meter to do the tps testing. and yes you turn the tps to get the readings with the engine off but the electronics on.

Like 180fan said ^^^^^

Now that it is on, you can do your testing.

To know which wire is positive and negative, please go here: http://www.zeroyon.com/ and d/l the fsm for your car... In there, you will see any and all wiring diagrams. It's the FSM, use it, love it, it's your friend.

I would tell you which wires are positive and negative, but I don't remember off the top of my head, and I think you would learn a lot more once you figure out how to do this on your own - the FSM actually outlines how to test your TPS also...

The voltage should read .4 when closed... Your battery, if you just put the negative prong on the chassis or neg terminal and positive prong on the positive terminal, should be about 12 - that is the scale you want... The voltimeter gives you different scales for different applications... you want the lowest volt reading usually listed as 0-20 or something.

Once you do all that, the instructions should be clear.

I understand you are getting frustrated... but if you can't figure some of the simpler things on your own, how do you expect to fix your own car in the future when something more serious happens? People can't spoon feed you all the information all the time...

I hope you d/l the FSM and look through it, it should help you a lot.

[mr_wizard]

Ok, first things first.

We are only going to use the voltimeter (volt) part. If I don't explain how to use a voltimeter well enough, please search through google - as that's how I learned, so I know you can do the same.

When adjusting the voltage, the car should not be running - but put in the ON position.

Like 180fan said ^^^^^

I missed the part about it only being in the "ON" position. Doh.

OkNow that it is on, you can do your testing.

To know which wire is positive and negative, please go here: http://www.zeroyon.com/ and d/l the fsm for your car... In there, you will see any and all wiring diagrams. It's the FSM, use it, love it, it's your friend.

I would tell you which wires are positive and negative, but I don't remember off the top of my head, and I think you would learn a lot more once you figure out how to do this on your own - the FSM actually outlines how to test your TPS also...

I use the FSM religously, but I must have a different version because the only information I have about a TPS is a description of what it does. I looked through this thing SEVERAL times, I know I do not have anything on that.

The voltage should read .4 when closed... Your battery, if you just put the negative prong on the chassis or neg terminal and positive prong on the positive terminal, should be about 12 - that is the scale you want... The voltimeter gives you different scales for different applications... you want the lowest volt reading usually listed as 0-20 or something.

Once you do all that, the instructions should be clear.

I asked around about this in detail, I think the part I'm missing here is you have to actually peel back the insulation on the TPS wiring in order to get a reading. My battery is fine, I've measured that, but I'm not going to risk f'ing up my TPS wiring trying to measure voltage like this.

I understand you are getting frustrated... but if you can't figure some of the simpler things on your own, how do you expect to fix your own car in the future when something more serious happens? People can't spoon feed you all the information all the time...

I hope you d/l the FSM and look through it, it should help you a lot.

I recently just frankensteined an OBD II motor into my S13 with several mods and little help from anyone on here when I blew my motor. It was just me and my FSM. Spoon fed? I think not. I'm just not afraid to ask questions when I don't know what the **** I'm doing.

Look, I appreciate your help, but all this **** that I have to do just to see if my TPS is working, and I still may not be doing it correctly, I should just buy one I know works from a junkyard or something for some pocket change. This is the reason I didn't want to do it in the first place. Thanks again for your help.

[onosqv]

Good for you, buy one.

The main point of this again is:

If you're going to switch out the tps anyway, it will still need calibration with a volt meter regardless.

And do you have the real FSM (there's 2 versions floating on the internet, the real scanned version and the version that someone typed up similar to chiltons)??? Cuz if you look through it religiously like you say, there is a specific section detailing how to adjust and check the TPS... I know, I just used that section last month...

The version on zeroyon.com that I pointed you to has the tps info for sure, 100%.

I don't personally mind when ppl ask a lot of questions... but in your case, it's getting borderline frustrating for me... maybe it's because it took you 4 days & 7 of your posts before you even got a multimeter... and then once you got it (today), you complain that the instructions are too hard, you don't know how to use a multimeter, and haven't even bothered searching google, or other sites to see how you are suppose to use it... maybe it's just me...

You're afraid of messing up your TPS measuring the voltage the way most everyone else does it? You don't even think your TPS is working and are about to throw it out for a replacement... so what's the harm?? If you search through the nico pages, there's a thread saying an easier way to do it is to get a pin and stick it in there... then take the reading off that pin... now you don't have to peel back the insulation.

If you can check the voltage on your battery, you can check the voltage on your tps... it's not hard. And as I said, 100% sure, the wire (positive, neg, etc) of the tps is in the FSM. If you don't believe me, I will go home and look through it myself and let you know which page it is on...

[mr_wizard]

Out of curiousity, I wanted to try and read what I was getting with the multimeter. Alot of you keep insisting that the only real way to do it is with a multimeter. I thought I explained clearly what I was doing. There wasn't much room for the TPS to be moved anyway, so I thought what the hell, since I don't know how to use a multimeter I'll just move it little by little and I'm bound to hit that sweet spot the multimeter would show me quicker. So I moved it little by little unplugging and re-plugging and starting etc... and I never hit it. I must have moved it 20 or so times within the couple inches it allows you to move. Unless the TPS has to be at the correct spot EXACTLY then I doubt I missed it. But because you all still insist I should use one, that's why I did so late in the game.

I'm sorry it was frustrating for you, no need to check your manual... hitmans write up should be the same as what would be in there. It looks as if I have the scanned copy, but I can click certain things and it brings me right to that spot in the book. Not sure though. But my car has been running like *** for the passed couple weeks, and after all the money, blood (got a scar to prove it), sweat and time I've put into this car and for it to f up like this after everything I've tried is slightly frsutrating for me. Then when others are getting frustrated by my questions it's just not worth it. I'll just buy a new TPS that I know is working and configure it then. Thanks.

[mr_wizard]

I got a friend to help me out with testing the TPS. Long story short, the TPS tested fine and I had it in the right spot. And I'm still getting the same problem grr...

[mr_wizard]

Well I had the ECU pulled out and I went to read the FAQ on 240sx.org.... I kept thinking in the back of my head "I know this isn't the problem but what else could it be?" So I was looking and I glanced at "checking grounds" I went ahead and read through it and the symptoms of bad grounding sounded a hellava lot like mine. So I went and measured the ohms like it said and they were reading kinda all over the place. So I made sure all my grounding wires were tight and secured well and went to start the car up and it ran awesome! So the whole time it was just bad grounding. Pfft, who woulda thought something that small and simple could cause the motor to lose so much power?

[180fan]

bad grounds can do this and cause alot of other crazy problems.

[sultennok]

How do i measure TPS signal if i got a 6 wire TPS instead of a 3 wire "normal" TPS... Mine got 6 wires.. and i cant find out how to measure this. all guides are for 3 wires?

Please help.. And BTW.. i got the multimeter/Voltmeter.

[Deadrodent]

where are the "ground" wires located?