TPS- Throttle position sensor
 

So I followed the instructions for testing the TPS on the following site http://vbxmaxima.8m.com/tps.html

I began by connecting the positive lead on my multimeter to the number 1 pin and the negative lead to a ground in the engine bay while the ignition was in the on position. When I did this the multimeter showed 0v.

When I tested the ohms I got 670 at closed throttle and 3500 at WOT.

Does this mean the TPS is no good?
Also it seems that the screws for removing the TPS get stripped real easily. Does anyone have any tips for removing them?

you should have stopped after you saw no voltage. its busted, I have a spare if you would like to pm me to buy it. I can have it shipped in a day.
recheck it though. i would ground it directly to the battery, those multimeters are tricky****s. mine also read 0v when i grounded it to my block, but 12v on the battery.
i used mini vice grips to get my screws off. i replaced them.

either way you need to adjust the TPS anyway with that bad of a reading.

Resistance between terminals 2 and 3 of the TPS should be 500-4000 ohms, according to the FSM. Approximately. So it sounds like yours tests OK.

You could also check the voltage at ECM terminal 23, with the negative lead connected to ground or to ECM terminal 25. The voltage should be 350-650 millivolts at closed throttle, and 4 volts at WOT. It's important that it go up smoothly, without dropping back to zero in the middle of the range, for example.

Finally, if you have a scan tool you can watch the TPS % open and see if it looks right as you open the throttle.

Are you getting a P0120 code?

Oops, yes, sorry I didn't see that part. You should get a 5V reference voltage signal at terminal 1, with key on engine off.

No, I'm not getting any codes. However, when the car comes to a stop the idle holds at around 850rpm and then suddenly drops to 500-600. Every now and then the car will also stall when coming to a stop.
I Just did a tune up on the car but that didn't help. I also thoroughly cleaned the TB, IACV, MAF and EGR, but that didn't help either.

I will recheck it using the battery as the ground. I will pm you if I need a new one. Thanks for your help

I just rechecked the voltage and I am still getting 0v. Also, I rechecked the resistance with the car fully warmed up and I am now getting 770 ohms at closed throttle.

The Multimeter I am using is a EQUUS 3340 which is known to be pretty accurate and reliable.

sounds like an intermitent problem that the ECU isnt picking up on yet (wierd with the TPS). You should have a CEL for the issues your having, but it DOES look like your TPS is shot...

I have like 4 or 5 spares if you want, just PM me...

Your right, its pretty weird how the ECU isn't picking up on it. I think I will just go to autozone tomorrow and pick up a new Duralast TPS for $58. It comes with a 2 year warranty.

By the way, I drove the car tonight and when I came to a stop the idle starting surging up and down from 600 rpm to 900 rpm and back down. Could that also be a symptom of a faulty TPS?

Update: I just stripped both of the TPS screws. Looks like im going to have to remove the TB in order to take the TPS off.

I'm sorry,I don't want to hijack the thread....but,When you remove the old TPS and put the new one,are there any calibrations or setting should be done prior to putting a new TPS ? or it's just plug and play ?

Dude you gota read the thread...the whole thread is discussing the calibration and testing of the TPS.

If you check in the How-To section there is a write-up on how to calibrate the TPS. So, to answer your question....No, a tps isnt necessarity a "plug and play" install. Still easy none-the-less..

EDIT = This is the link in the How-To section that explains how to install and check a TPS

http://vbxmaxima.8m.com/tps.html

With the wierd readings your geting on your TPS i am assuming that its dead, but while your taking th TB off, go ahead and clean that as well as your IACV. Both of these things can cause wierd idling issues...You might want to go ahead and check to c if you have any vacuum leaks as well...

Might as well do the TB and the IACV since your there already and its easier to get to without the TB in the way :)

Thanks for the advice. I already thoroughly cleaned the TB, IACV, and EGR tube. I even cleaned and tested the MAF.
I got this weird surging last night when i came to a stop. Could that also be a symptom of a failing TPS?

Thats normal, in older carb cars that hang time was called the dashpot.

Thats not normal, but I don't think it has anythiing to do with your TPS or the throttle body.

The 5V referance signal comes from the ECU, make sure your probing the TPS while it's plugged in. You can also just probe the connector to check for the 5Volts.

Thank you for your advice.
The grey connector was plugged in when I probed the number 1 pin. The instructions in VBXmaxima site says to disconnect the brown connector and probe the number 1 pin with the key at the on position? Thats exactly what I did.

I just went down to autozone and ordered a new TPS. They said it should be in by 3:30pm.

I also did some research and found this list of symptoms for a faulty TPS.:

1 Bucking and jerking of the car
2 Idle surging
3 Sudden stalling of the car engine
4 Hesitation while the driver of the car is trying to accelerate
5 Sudden surge in car's speed while driving on the highway
My car has symptoms 2,3, and 4.

You have to probe the pin 1 position on the harness connector side (the female side), with the connector unplugged. Stick the read probe into the hole that pin 1 goes into, and put the black probe on a ground (negative battery terminal, engine block, etc.). With the key on, you should read 5V.

Or alternatively, leave the connector plugged in and backprobe the wire to pin 1. Pin 1 on the TPS won't have any voltage when the connector is unplugged.

Thanks for everything guys. I just back probed pin 1 and I am getting 5v. I also checked the resistance by back probing pins 2 and 3 with the car fully warmed up. I got 820-830 ohms at closed throttle and 1300-1400 ohms at wot. So i guess it does need to be replaced after all.

Those phillips headed bolts are easily stripped. After I stripped one of the two I had to use 6" slip joint pliers to loosen it. I got the other one off using a flat headed mini screwdriver. I then replaced them with hex headed bolts so I can easily loosen them now with a rachet wrench.

First try using a flat mini screwdriver. If they're already too far stripped for those then try 6" slip joint pliers.

HELP
 

So I replaced the tps and adjusted it to 530 ohms at closed throttle and 3900 ohms at WOT. Now my idle is at 1700rpm. I even tried adjusting the IACV but that didn't help. What should I do?:confused:

With an rpm that high you probabaly have a vacuum leak. If you're a smoker then blow smoke around the UIM from the drivers side while the car is idling. If not then just listen for vacuum leaks.

Check to make sure that the calibration is still on point with your multimeter..It might have changed when you re installed the TB.

A good way to check for vacuum leaks is carb cleaner...spray it where u think there could be a air leak and listen to the idle..if it changes as you spray, thats your leak...

My favorite way is using a stethescope like from a halloween costume or something, and take off the part that you use to put up to your chest so its just an open tube. Put it on your head and start poking around with the tube listening for a SSSSsssss that doesnt sound normal...this works best IMO...or a thick hose works too...just hold it up to your ear...

TPS
 

Thanks for all the replies. I finally got it all worked out. What I did was reset the ecm by disconnecting the battery over night. Next I reconnected the battery and turned the key to the on position. Then I depressed and released the accelerator pedal 5 times so the ecm could relearn the throttle positions.

When I turned the car back on it started Idling a little low when it was warmed up which was probably due to me closing the IACV screw last night. So I readjusted the IACV and the car runs beautifully. I took it on a 10 mile test drive and the car is now running very strong. The Idle is steady at 650rpm and I have a much better throttle response.:)

@njmaxseltd

I read the how-to link several times but it says to test the #1 pin with the + then ground the - to verify the 5v. but you say test with tps plugged in. Are saying with both connectors plugged in or just the one closer to you. Because I don't know how I would probe with both connectors plugged in, there aren't any bare wires exposed?

Also my multi-meter is autoranging and it was all over the place when I tested with pin one.

Thanks for any help.

Use a t-pin or even a sewing needle. Then just probe the pin or needle.

You still got that intake for sale

I have the same problem after running sea foam thru car. Engine wont rev past 1800 rpm unless I disconnect the TPS (which is new x 2); then it idles high (1100 rpm in neutral; 1800 in gear) but runs normally. Any ideas? Thx :-)

i have a similar problem too. i got an 00vi, when i originally installed it idle was fine but about a week later the idle just randomly crept up to 1100rpm and i haven't been able to get it back to normal ever since. I did not touch anything on the car since i got it done when this happened.

Since i used used gaskets i thought must be a vacuum leak so i replaced my lower and upper intake manifold gaskets but before i did that i checked my tps... i got 5V and 0.79K ohms (0.5-0.8 is normal) closed throttle and 3.97K WOT (about 4k is normal)... so i went on to replace my gaskets. when i did that the problem was still there :confused: but it was somehow better.

beforei changed the gaskets it would always idle at 1100. after the change, on cold starts, the car does its fast idle and comes back down to 1000 but 5 mins later it goes back up to 1100. during warm starts i can get an idle at 600 but its a bit rough and then 30 secs later it'll go back to 1100. sometimes at stoplights the idle will drop to 600 (slightly rough) and within 20 secs it'll creep back up to 1100. I also have a laggy throttle response when i dab the throttle at idle. it lags for about half a second and then rpms rise (my short ram intake connections are tight)... this only happens at idle.

i also replaced my iacv but that didn't do anything, and neither does adjusting the idle with the idle adjust screw on the iacv. My old tps only had one connector (1995 5 spd max) and this tps on the 5th gen TB had two (from a max with an auto tranny). I'm not sure if this matters, it worked fine with it before. My fuel mileage also went down, i get 450-500km a tank and i'm not getting a CEL... yet... WTF? lol

So what i don't get is that i get the readings within the limits for the tps but i get a lot of the symptoms of a faulty tps. could this be a rogue tps? shadyonedeath recommended i reset my tps and he gave me a link http://lyberty.com/car/Maxima_A32_do...NTB99-053b.pdf but i have an a33/5th gen TB :confused:

So what was the main problem?? Was it just the faulty TPS or a combo of things?

I'm in the middle of my testing of these issues. So I too would like to know what the outcome was. I have 5 volts in pin 1. Problem I'm having is when checking the continuity I have my multimeter set to 20k ohms then touch pins 2 and 3 I'll have .32 reading. When wot I have .32 reading why? I checked 5 and 6 pins like the updated tps test says and I have same readings as pins 2 and 3. Used feeler gauges and I still don't understand the purpose or maybe I don't understand the outcome but using them is like not using them there's no difference still .32. I'm stumped. No one will prolly reply to this since no one has replied to Bonzie2k's as of yet, but I will keep hope alive.

When I put my maxima 97 in reverse, the engine begins to accelerate and decelerate. What could cause this? .. It may be the TPS?

It would do the same thing in drive and while idling. I can't say for sure that what you have are signs of the beginning stages of a TPS failing or something else altogether. I wish I knew more sorry. Check vaccuum lines, Intake Air Control Valve and tranny fluid just to strike those off the list. The last thing you need is your brain overloaded thinking of all the other things it could be. Process of elimination is crucial when troubleshooting these little beasts. Good luck!

Its like I put in the other thread. Sorry if I came off Elitist, I am by far not a guru on this forum. I learn new things every day. But what I was saying is that the Orgers on here with a lot of knowledge are gonna ask for more info on this in order to help you out.

Lots of things to rule out and they will need to see if you checked. Check easy things first, like the MAF, unplug it run the car observe the behavior, clean it with the process found on the stickies etc. Check your coils.

Genious!!!!!
 

You absolutely nailed this one! For a year I've been replacing different parts(IACV, Coil packs, spark plugs,3 different TPS,knock sensor, sheesh) trying to get this TPS to work correctly. The factory Tps from Nissan was still revving too high. I did exactly what you said to do and VOILA!!! Thank you so much for this post. You've helped me more than most :) Much appreciated.

You need to download the FSM (see my signature) If you had it, you would have know how to set the TPS. Enjoy. :D

What?!

Read, research, fact-check? You have got to be joking.

If it can’t be found and explained on Tik-Tok, it ain’t real.