Tire pressure on an Infiniti 2003 M45?

[jEzTeR]

So this morning my Flat tire warning came on. I pulled over and checked all 4 tires and they were ok. So I drive to the next gas station and whip out the manual. One of my tires was reading 27psi for just a min but is now at 31psi. The order of the tires is not listed anyplace in the book. So I turned off the car and back on thinking that would reset the warning system, but it did not. My indicator light is still on and highlighted is the tire @ 31psi?

The tire that I think is giving me trouble has a stupid valve stem cap that does not match the others, so I'll work on getting that replaced today. Any other suggestions?

[maxnix]

Yeah, run at 35 psi minimum. Most run front slightly higher, like 38/35.

Z will post soon.

[jEzTeR]

The warning is set to come on at 27psi or less.

[szh]

Z will post soon.

You bet!

jEzTeR, the tire pressure system will reset after a number of miles of driving at the correct pressure ... I forget how long it takes, but I will look it up when I get a chance. In some cases, it needs a reset of the system (dealer tool).

There is no indication of which tire is showing on the screen, true. I consider this a bit odd really, but perhaps it was Infiniti thinking that the tires would be rotated and more people would be confused by the wrong tire being shown as being low. Regardless ... as long as you get back to the correct pressure, you should be fine after a bit of time. If not, the Infiniti dealer has a tool that can reset it for you (needs a Consult for a full reset as I recall, but I will look in the FSM when I get a chance).

Second, and more importantly, the minimum pressure you should run is about 35 to 36 psi - a bit more would be fine, as maxnix suggests - same on front and back. The load index of the tires on the M and Q need the extra support and extra load carrying capacity. My experience after 37k miles (two sets of tires so far and about to install the third) is that 36 psi is a good balanced number and you still get reasonably even wear across the tread.

I check tire pressure every two to four weeks and the pressure drops (this is normal) about 1 to 2 psi in that time. This still leaves it above the recommended value of 33psi (Infiniti manual) and room to not be concerned about things!

Z

[jEzTeR]

Thank you good man!

I'll get the psi to 36 on all 4 in the morning.

It did reset today after some driving.

[szh]

Thank you good man!

You are very welcome!

I'll get the psi to 36 on all 4 in the morning.

That will be good! Of course, this is cold pressure measurement ... without driving an inch ... in your garage if you use one ... before the sun hits it and "warms" it (according to Dennis/Q45tech! )

It did reset today after some driving.

Good!

Z

[TxGuy67]

Good advice! I'm going to bump up to 36 tomorrow.

[jEzTeR]

Well!

I couldn't get the cap(it was not the oem cap) off the valve stem, So I got a pair of plyers and turned it. Guess what it broke and the valve stem flew out and so there I am at the gas station by the air pump w 0psi.

So I jacked the car up and swaped the wheel/tire for the spare which is a full size oem wheel w/ the same size tire as all the other 4. It is not the same brand though.

Now the tire presure montering system is not reading any of the tires?

Do I need to be in a hurry to get the other one fixed?

How much is the part going to cost?

[TxGuy67]

Yikes! Sounds like you're going to have to visit your local "stealer". Usually the indicator would reset but since you put the spare on (it's not programmed) you'll have to have reset the system. As soon as I had the flat repaired and put back on (original wheel/tire) the system reset itself. Sorry have no idea what the part would cost.

[szh]

Well!

I couldn't get the cap(it was not the oem cap) off the valve stem, So I got a pair of plyers and turned it. Guess what it broke and the valve stem flew out and so there I am at the gas station by the air pump w 0psi.

So I jacked the car up and swaped the wheel/tire for the spare which is a full size oem wheel w/ the same size tire as all the other 4. It is not the same brand though.

Now the tire presure montering system is not reading any of the tires?

Do I need to be in a hurry to get the other one fixed?

How much is the part going to cost?

Ouch! When it rains, it pours!

I am not sure what the part costs ... might be worth a call to Joe Tsensky at http://www.everythinginfiniti.com. He has the best prices and is an Infiniti dealer.

If you keep the pressures at the correct values, and check it often, then I would not be in a hurry to replace the valve stem - I do not have the TPMS on my car and do just fine!

Do put the wheel back with a generic stem soon, so that you have the same brand of tire on each wheel at least.

Z

[jEzTeR]

Good!

Can I get 2 and have the Spare set?

It's in much better shape than the other 4 wheels as it looks to have never been out of the trunk.

I might go ahead and get a oil change and tire rotation done too even though I'm a bit early.

BTW: The OEM jack/spare/wrench set works well.

[maxnix]

Yikes!!! Something to be said for full sized spares and accurate air pressure guages, and their frequent use.

[CakeDaddy]

I'll mention up front that I have stagged 20's on my 03 M, but that shouldn't make a difference when it comes to psi, correct? My psi is at 31-33 all around. I notice when my car sits for a week or so in the garage it take atleast 10 miles of drive to get the psi back to its normal reading. It would start off at 29 then gradually go up. I have no faith in that TPS system, so I still monitor mine the old fashion way; with a tire gauge.

Jetzer,

I can tell you from experience that the front left(driver side front) is the bottom reading from the display in our cars.

31 psi33 psi33 psi27 psi <----- front left

[szh]

Actually, in most cases, I would still strongly recommend going up to 35 to 36 psi - even with 20" or 22" tires. The closer the actual load index of the tire is to the low end of what you need for the M (like 94 or 95), the more I would be careful to stay higher pressures.

Remember that load index is "officially" measured at 36psi, and derating is applied below that.

A simple tread wear measurement tool (and, yes, you can go crazy here! ) should be a required item, along with a good to excellent tire pressure gauge, in everybody's tool kit. With low large wheels, and low aspect ratio tires, it does not take much air to change the pressure by 1 psi!

With 20" tires, the aspect ratio is also usually lower, so you have less leeway to be off - just the act of measuring the tire pressure can reduce it by 0.5 psi, as you put on and take off the gauge! Measure the tread depth across the tread and, over time, you will get a feel for tread wear. This can be used to adjust the tire pressure up or down, but don't go too low in an effort to equalize the tread depth across the tread - live with the consequences of having to change tires more often instead!

Z

[szh]

I notice when my car sits for a week or so in the garage it take atleast 10 miles of drive to get the psi back to its normal reading. It would start off at 29 then gradually go up.

Definitely normal - the air heats up and the pressure increases.

I have no faith in that TPS system, so I still monitor mine the old fashion way; with a tire gauge.

Good! Just do all measurements with cold tires, ideally when the sun has not had a chance to heat the tire either - inside the garage before you drive.

If you read 29psi in the morning before you start driving, that is too low - you need to get it higher than that for sure.

Z

[jEzTeR]

Jetzer,

I can tell you from experience that the front left(driver side front) is the bottom reading from the display in our cars.

31 psi33 psi33 psi27 psi <----- front left

I think mine is different.

38 psi <----front left0 psi <----(spare)front right41 psi - rear right 38 psi - rear left

[CakeDaddy]

I think mine is different.

38 psi <----front left0 psi <----(spare)front right41 psi - rear right 38 psi - rear left

thanks fellasI appreciate all the good info and I’ll increase my psi another 3 lbs.

Jezter,

If your numbers are correct, I'm really bothered by this. I’m positive that my driver front is bottom reading. ;( I have no faith in that system.

Oh, and Szhosain mention something about a tool kit. Now I may get kicked out of NicoClub for this question, but where is this "toolkit" located?

[jEzTeR]

I have a first aid kit in my rear center armrest. There are some places in the trunk that I just found, but havn't looked into all of them yet.

[jEzTeR]

Yeah I am going to get a good gauge tomorow. The one I have is a old cheep O and I'm not trusting it either.

[szh]

Oh, and Szhosain mention something about a tool kit. Now I may get kicked out of NicoClub for this question, but where is this "toolkit" located?

Oh, sorry for the confusion! I meant that you should have a good to excellent tire pressure gauge and tread depth tool "in your tool kit" generically - i.e., your set of tools in your car, in your garage, in your workshop ... wherever!

Infiniti does not actually provide these in the vehicle per se.

Z

[maxnix]

Yeah I am going to get a good gauge tomorow. The one I have is a old cheep O and I'm not trusting it either.

http://www.longacreracing.com/...tid=8

[szh]

http://www.longacreracing.com/...tid=8

Yeah! Good stuff, but not inexpensive. I have asked about their high-end digital stuff before ...

I ended up with an Accutire digital from Radio Shack (on sale for $14.99) and it serves my needs just fine!

Z

[maxnix]

I ended up with an Accutire digital from Radio Shack (on sale for $14.99) and it serves my needs just fine!

Z

Personally, I am suspicious of cheap digital sensors. I would always calibrate across the operable vehicle tire pressure range against a known good analog gauge.

[szh]

Personally, I am suspicious of cheap digital sensors. I would always calibrate across the operable vehicle tire pressure range against a known good analog gauge.

Yes, I agree. However, this one is not cheap - was just on sale when i got (of course, even MSRP is well below the Longacree high-end model!). It is an Accutire and they have had good reviews before (on Consumer Reports and other places for example).

I compared it to a good analog one time and it seems to be very accurate (but it is another reason that I always err on keeping the tires at the high end of tire pressure readings anyway).

Ultimately, I will also pick up a good analog one too probably - just that for the moment, things seem to be okay with the digital one I have.

Z