mcmaklin

Hello I need someone wise who is able to help.
I have Nissan MaximaQX 2001, it is Japaneese version but I think a lot is similar to Amercian.
There is a throttle position sensor (which is brand new now) and it has 2 connectors - upper is brown and another white, down.
I had problems with pumping engine speed (on N or P in A/T whenever I pressed acceleration pedal to between 1-2 (here the video http://www.youtube.com/watch?v=r67kF1YqB_Q engine started pumping up and down by it self. There were also some problems while changing gear from 2-3 (automatic transition) - sometimes it was gliding from upper engine speed.

I have disconnected the second connector and everything works perfect.

I read in the manual:
"When the throttle valve is in the closed position, the closed throttle position switch sends a voltage signal to the ECM. The ECM only uses this signal to open or close the EVAP canister purge volume control solenoid valve when the throttle position sensor is malfunctioning

I don't understand much of this, what will happen to my car if I drive without this plug connected. There are no problems and my car drives much better. Please help me finding the solution. Thanks

mcmaklin

Uhhh, noone is able to help?

sticky

so your stepping on the gas when its going up and by itself,and when you unplug the bottom conect it works right

mcmaklin

Correct, and while connected gearbox works more rectangle-like I feel sometimes something strange, and gliding between 2nd and 3rd gear (A/T). The only thing I noticed when disconnected there is no way to enter my car into diagnostic mode (that the LED codes show errors of A/T). Thanks you are my last chance. NothIng bad happens while disconnected- just opposite- car works better!

mcmaklin

Like on the movie I am stepping gas trying to keep it between 1,5-2 and it pumps up and down by itself.

mahanddeem

MAF problem maybe ? mass airflow meter

mcmaklin

Why MAF problem if it dissapeares when disconnecting this lower connector??

sticky

did you adjust your new tps,someone said throttle plate had to be closed all the way

mcmaklin

What does it mean Throttle plate must be closed? How to do it?

sticky

so are you getting a transmission code

mcmaklin

Dear Sticky are you reading what I Am asking or you are going to have 15 posts?

sticky

yes im reading,im going through the same thing i unplugged the bottom plug to the tps and mine will rev up fine but i still cant drive car stays between 1500 and 1800 rpm only shifts in to 2nd gear ok back up what did you before this started, i changed my iacv,tps when mine started,your throttle plate needs to be closed,take off air box where you can see in the throttle body and make sure it has no gap, let me know how yours started. thank you

mcmaklin

Maybe there is a small difference between US and European car. Mine works very well without this bottom connector. What exactly means" throttle plate needs to be closed? Sorry I am not native English speaker. When, in what conditions my throttle place needs to be closed? Can you describe it from the beginning what to do? Thank you.
OK I know what is throttle plate already but don't understand an exact procedure. When you ask me to close the throttle plate. Can you please describe it step by step what to do?
Thanks a lot

NAVY00MAXIMA

Knock sensor in electronic motor mount is bad.

replace the electronic mount.

mcmaklin

Navy: How do you know it is that sensor? Does this bottom connector has to do something with it?

NAVY00MAXIMA

I know what a knock sensor does. It senses detonation through vibrations and decreases timing or modifies TPS to keep from detonating. Your mounts sensors are just bad. Knock sensors do go out. It modifies the TPS which you are unplugging...

http://en.wikipedia.org/wiki/Automat...rmance_Control

Check out that link - Instead of controlling the wastegate it changes TPS/timing to get it right. But still a similar process. Your sensors are just downright OUT like a blown light bulb.

I do suggest starting with the cheapest first. the knock sensor.
http://shop.ebay.com/i.html?_nkw=200....c0.m270.l1313

sticky

when did your problem begin,did you replace anything before it happened,or was you driving it

mcmaklin

Thanks NAVY00MAXIMA it can help me a lot.
Sorry for asking here but in Europe this car is very rare and in fact noone knows much about it, even in Nissan.

So to resume this:

1.You think disconnecting the bottom plug causes that ECU ignores information about knock sensor? And therefore my car works without problems?

2.When I connect the bottom plug I notice:

-automatic transition does small strange things sometimes - it enters into 3rd gear sometimes with slide down from upper engine rotation.

-when on P or N while I am stepping on access pedal trying to keep engine speed between 1,5-2 engine speed pumps up and down by itself like on the video:
http://www.youtube.com/watch?v=r67kF1YqB_Q

Strange that "knock sensor" error doesn't show up.

Can I destroy something in my car driving without this connector? I never here any sound that I could hear as "detonation"


Do you know the good link (sometimes there are different part numberts) or if the sensor from American Maxima will fit to MaximaQX Japan, 2001, 3.0, A/T?
I think I would order it from America if possible.

And one more is it easy to change this sensor or you have do unmount most of the car?

thanks!




Sticky: the "pumping up and down" problem I have for 2 years, but I noticed something strange with A/T after replacing IACV and TPS. I want to add everything has been reset as in the manual

sticky

ok mac you need to ohm the tps mine is brand new and it is testing bad do like it shows in the manual,and also make sure its the right one,and make sure when you put it on it is not moving the throttle plate open,that bottom plug is the wide open,im going down to get a new one,if it idles good test the bottom one with ohm it should be zero then when you open throttle it will start reading

mcmaklin

And what about the knock sensor?

sticky

i replaced a knock sensor in my nissan truck only because i had a fault code and it was using too much gas

mcmaklin

Can someone make a photo of a Knock Sensor connector in A33? Maybe I will try to disconnect it and reconnect the TPS bottom connector? And see if it helps

sticky

have you fixed your car yet

NAVY00MAXIMA

Have you fixed yours? What was your problem?

sticky

throttle body

yungwun98

I am having the exact same problem. Did you ever fix it? If so what did you do to fix it?

CMax03

iTrader: (3)

Sounds like you got a bad TPS or MAF sensor..... Maybe the package was mishandled along it's journey!!!!! Those items connected to the motor mount are electronic controlled orfices to control engine transmitted vibration....it's not the knock sensor.....

CMax03

iTrader: (3)

Mcmaklin is your car throttle cable controlled or electronic throttle?

getflushed

nice of this guy to come back and state the fix for his car...... if you watch that video by mcmilken... mine does the exact same thing!!!!!! it doesnt die but jumps around at that throttle position, when cold in park... when cold and im in any gear...... once warm it kinda goes away but i can still feel it under load..... im getting a tps tomorrow(168.00) i really really hope its the problem... i know older post but! .... as close as ive been to see a simularity.... i also have hard starting and sloppy hanging 2nd to third shift.... i think its sloppy only because its shifting at the wrong spot.... and yes i have tried adjusting my tps... right now its at .60 closed.... ive tried differences from .48 to .75!!! the higher the better .... meaning it shifts later than sooner which gives it firmer shifts..../............