Nissan 370Z Tech Forums banner
1 - 20 of 45 Posts

·
Registered
Joined
·
100 Posts
Discussion Starter · #1 ·
Hi everyone

I've done LOTS of research on this. Even including TPS systems on other cars.

A question I have is, How does the TPS sensor function when installed as shown in the Tech Guide on this website? see: http://www.350z-tech.com/zwiki/Tutorial:TP...ermarket_Wheels

Doesn't the TPS sensor need to see a difference between the inside and outside air to be able to create a reading? I am thinking this is why TPS sensors which involve the valve-stem as part of their design (as ours does) must be mounted AS the valve stem. Right?

If this is not the case please correct my thinking. In addition, please let me know exactly how the TPS sensor's valve stem is connected on an aftermarket wheel when not actually mounting to the wheel's valve-stem directly (as is done in the tech article).

Seems like there should be a final picture on that article. Should there be a hose connecting the sensor to the valve stem on the wheel?

Thx
-Smoky
 

·
Premium Member
Joined
·
665 Posts
Aloha,
The install as shown should work. The sensor does not use outside atmospheric pressure as a reference. If it did, you'd get pressure changes from elevation and temp differences. Therefore the sensor doesn't require a hook up to the wheel's tire stem.
 

·
Registered
Joined
·
100 Posts
Discussion Starter · #4 ·
Aloha,
The install as shown should work. The sensor does not use outside atmospheric pressure as a reference. If it did, you'd get pressure changes from elevation and temp differences. Therefore the sensor doesn't require a hook up to the wheel's tire stem.
I had meant for the title to say "is the article incomplete", rather than stating so. From you're saying Paul (and from ToyKilla's response), then the install as shown in the pic is the end of it.

So then, getting back to another thread I have which kind of died off... all other things aside, could I mount all four TPS sensors inside the spare, at 90 deg angles to each other (for programming), and use that to "fool" the TPS receiver into thinking that my aftermarket wheels had them installed?

That is exactly how I'd like to do it (for a number reasons...too many to go into here). Could it be possible? Or am I missing something about how they have to be installed or configured that prevent all four from being in the same wheel?

Thx!
-Smoky
 

·
Premium Member
Joined
·
665 Posts
Aloha,
In theory it should work. However, the TPS wouldn't work anyway since the spare wouldn't be turning. The Z needs to be moving at approx. 20mph for the sensors to "activate". Simply removing the sensors will effectively "disable" the system, if that's your goal. It doesn't have any input to the ECU. It's just a monitor/warning feature. The low pressure icon shouldn't go on and you'll get bars across the display on the TP display.

BTW, since there is no data/info on the type of signal the sensor is sending, the physical distance between the front sensors to the spare might be too great. No, it's not bluetooth. Just for giggles I tried to pick it up via my PDA, no luck.

A Hui Hou

PaulO
 

·
Registered
Joined
·
100 Posts
Discussion Starter · #6 ·
Interesting idea with the bluetooth. lol I wouldn't have thought to try that. I think it just a plain old RF frequency.

I'd love to believe that simply removing the sensors will disable the system. However during my research on this subject I have found a mixed report of 350z owners throughout all years (except 06). This suggests to me that in the absence of sensors the TPS warning only goes off on longer drives, and not in-town drives. This is (I think) why some folks report that removing the sensors disables the system entirely.

What is your experience? Have you gone for long distance/highway speed drives without the sensors installed to verify that no warning will come up? If so I'd love to hear it.

And Paul just curious...have you ever posted on sa750.com? There's a guy there with the same "PaulO" signature, so I just wondered.

Thx
-Smoky
 

·
Premium Member
Joined
·
665 Posts
Aloha Smoky,
Sorry, not me on the other site.

As far as the sensors, no I've never removed the sensors. Took about a year and 4175miles before I got the low pressure warning, that happened yesterday. I guess if you want to find out if the system will in fact be disabled on your Z, you could jack her up and run her up to speed with the rear wheels removed.

Getting a bit tech here, but the sensor probably has a centrifugal switch which requires the proper speed to turn on and send a signal to the receivers. It does have to be oriented in a certain position (there is a top and bottom). As far as RF, probably right, I'm guessing FM. Most widely used method for low cost data transfer.

Anyways, I'm betting on no sender, no signal. No signal, no warning and hashlines on display. BTW, as soon as I hit about 20-25mph, the low tire signal went out and the tire pressure display gave a reading 15-20 seconds after that.

A Hui Hou

PaulO
 

·
Registered
Joined
·
100 Posts
Discussion Starter · #8 ·
Interesting. I'm going to have a talk with the service guy. They may know, or may even know how to actually disable the system (doubtful, but you never know...it may not even be possible to turn "off").

I don't actually have the car yet. It's delivered but they are installing stuff on it. I have the wheels and tires here at the house. Mounted and balanced, and I don't want to risk the paint to test if a custom sensor install will work out. I don't even really want the system. I'm happy with checking the pressures myself.

So we'll see. I hope you're right and the computer is smart enough to recognize no sensors = don't bother. Then again, I would have to think that some of the reports I've heard might mean that to avoid lawsuits there has to be some kind of error check in place in case the batteries die, so the driver is "alerted" beyond the usual ---.

Thx
-Smoky
 

·
Premium Member
Joined
·
6,474 Posts
Aloha,
In theory it should work. However, the TPS wouldn't work anyway since the spare wouldn't be turning. The Z needs to be moving at approx. 20mph for the sensors to "activate".

FYI

The sensors will "activate" if they sense a difference of air.

IE: adding air when stationary will result in values. Even from a cold start.
 

·
Registered
Joined
·
3,881 Posts
the post is complete, however, you can use them as valve stems pending on tire size, the lower the profile the less likely you can use them as a stem as the sensor would protrud torwards the outside surface of the tire which may render it damaged over road conditions.

I also dont think that it the TPS is due to rotation as I can sit at idle and the sensors can sync after 60-70 seconds - I forget where I read it also but there is a 1 minute, 3 minute and 5 minute sync cycle

edit -- I recently added TSW's to my car, they don't have sensors yet - there are no alarms and no readings - if the sensors were due to rotation, the alarms would be going off like crazy as they would not sync and they would sense 4 flats! i do miss the sensors and have order new ones for these wheels.
 

·
Registered
Joined
·
100 Posts
Discussion Starter · #12 ·
If this is the case, and the sensors do not need to see rotation, then is the idea of mounting them in the spare to fool the receiver still plausible?

I would have to think range is not an issue as each sensor can be recalibrated to be on each wheel. Since the spare is closer than the furthest wheels, then the range should be sufficient even for the fronts. (It feeds off the keyless entry receiver anyway, right? so the range should be beyond the car's dimensions).

If the sensor can be mounted anywhere in the tire, and only needs to be in a pressurized environment, and does not need motion to be initialized, and initializes on it's own cycle, then I wonder if it could work.

Would be cool, wouldn't it? I know a lot of folks like their TPS sensors. So this may not be a widely useful trick. But I bet a lot of aftermarket wheel owners would feel better to know there is another solution should the sensor not be adaptable to their wheel.

lol.. I'll probably end up finding out the dealer can go under the hood and pull a fuse or flip a jumper switch and turn the whole thing off. :rolf2: Not likely...but hey I can wish things were that easy. :)

Cheers,
-Smoky
 

·
Registered
Joined
·
3,881 Posts

·
Registered
Joined
·
100 Posts
Discussion Starter · #14 ·
I've looked and looked through this Shrader article and can't find anything mentioning that rotation is required for operation. In fact, they point out that accurate readings are possible at a standstill.

But the literature also says that the sensors auto program themselves and we all know that is not the case.

Thx for the link though! At least now if my service advisor hasn't got a clue then I have the link for the manufacturer and can ask them.

Cheers,
-Smoky
 

·
Premium Member
Joined
·
6,474 Posts
I've looked and looked through this Shrader article and can't find anything mentioning that rotation is required for operation. In fact, they point out that accurate readings are possible at a standstill.

+1. Appreciate the link as well.


But the literature also says that the sensors auto program themselves and we all know that is not the case.

How is that not the case?
 

·
Premium Member
Joined
·
665 Posts
Aloha,
This is from the 2005 User Manual regarding the TPS:

Section 2-10:

Tire pressure indicator (PSI)
The tire pressure indicator shows tire pressure
(0 - 51 psi) of all wheels (except the spare tire)
by sending a signal from a sensor that is installed
in each wheel. Press the trip computer setting
switchB to change the display to F (front) or R
(rear).
The tire pressure sensor will activate only when
the vehicle is driven at speeds above 20 MPH
(32 km/h). If the tire pressure signal cannot be
received correctly, the display shows (----).
The tire pressure indicator mode includes a low
tire pressure warning feature. If the vehicle is
being driven with low tire pressure*, the tire
pressure indicator mode is automatically selected
and the PSI indicator will blink in order to
attract the driver’s attention. Press the trip computer
mode switchA if you wish to return to the
mode that was selected before the warning
occurred. The PSI indicator will continue blinking
until the tire pressure of each tire is properly
adjusted.

Don't know about other brands of sensors, so this only applies to the Z (probably other Nissans as well).

A Hui Hou

PaulO
 

·
Registered
Joined
·
100 Posts
Discussion Starter · #17 ·
How is that not the case?
Because the sensors have to be programmed. You can buy the programmers at Tire Rack, etc. They are probably meant to automatically sync with the receiver, but I think more often than not they need a nudge from the programmer.

-Smoky
 

·
Registered
Joined
·
100 Posts
Discussion Starter · #18 ·
Thx for the info PaulO. I'd seen that in the online owner's manuals. I wasn't sure if the 20mph was simply a reading of the speed sensor before the system initialized.

So I spoke with my dealer today. It is all being confirmed for me, but they are 99% sure that:

1. The sensors require rotation to operate (PaulO is correct)

2. The TPS system can be disabled!!! Apparently the dealer can disable the TPS system through programming (perhaps through the OBD port..not sure).

So, good news! Now I don't have to worry about the sensors at all.

If this info changes I'll report back. Otherwise, looks like case closed and I'm a happy camper!

Thx everyone for your input!

-Smoky
 

·
Premium Member
Joined
·
6,474 Posts
1. The sensors require rotation to operate (PaulO is correct)
FWIW:
From what I see, this isn't 100% true.

If you provide air to the tire, the display will read without movement. I've experienced this multiple times. As I check my pressure before almost every drive. And I don't have to get it rolling to get a response.
 

·
Premium Member
Joined
·
6,474 Posts
Because the sensors have to be programmed. You can buy the programmers at Tire Rack, etc. They are probably meant to automatically sync with the receiver, but I think more often than not they need a nudge from the programmer.

-Smoky
If you remove the sensors from the wheel(s)... and months later you reinstall them. They will automatically re-sync. I have witnessed this also first hand.

I'm not sure if this is exactly what you meant, but I wanted to offer the info.
 
1 - 20 of 45 Posts
Top