Tire pressure issue

[SADVIPER]

So suddenly the sensors read a drop and I inflated all tires to 206 KPA. I drove fine and parked for a couple of hours then when I wanted to drive again the fronts were down to 180 kp! The weird thing is two tires had same pressure but one was showing as a red and one as a green!
I think the sensors are not well.. any ideas? I'll try manual reading to see if there is really a drop.

[swexlin]

Did you check the pressure with a manual gauge. The pressures sensors in our cars can be a bit foopy at times, but sounds like yours are malfunctioning. If your pressure checks out OK with a gauge, then I would get it looked at by a Viper tech. After the car sits, the tires will cool off, and the pressure will drop, this is normal.

[AZTVR]

Tire pressure from hot track performance pressure to cool morning pressure can range between 36 psi to 28 psi depending on the tire (248kPa to 193 kPa). You can even get a 2 psi ( 14 kPa ) change when the tire goes from sitting in a cool mode (not run much yet) in the shade to full sun. So, make sure that your two readings that are being compared are done under the same environmental and operating conditions and with the same instruments.

[swexlin]

Tire pressure from hot track performance pressure to cool morning pressure can range between 36 psi to 28 psi depending on the tire (248kPa to 193 kPa). You can even get a 2 psi ( 14 kPa ) change when the tire goes from sitting in a cool mode (not run much yet) in the shade to full sun. So, make sure that your two readings that are being compared are done under the same environmental and operating conditions and with the same instruments.

Yes. My cold out the garage pressures this morning were 29/30, and by the time I was done driving, 33-34. These Corsas are very temp sensitive.

[SADVIPER]

I checked with a manual gauge and seems the readings are more or less accurate but the thing is I've inflated all tires 3 different times in the past week! Is this normal to get lower pressures even if I drive the car?

[ViperSmith]

are outside temps changing a lot in your area?

[swexlin]

Temps are changing here in the Northeast, but you shouldn't be adding pressure to the tires normally unless temps are dropping quickly. Yesterday morning and this morning, I took the car out the garage, outside temp mid 50s, starting pressures were 29/30. By the time I finished my drive, pressures were 32-33. As we get colder (here come the warnings about Corsas in the cold, LOL) mine will start 27-28 (or even lower) then heat up to 29-30. By that time, I'll add a few pounds, so they don't flat spot over the winter in my garage.

Of course, the other things are:

1. Are they mounted properly? I had about 1 lb per week loss in a Contisport on my Dart (when none of the others were loosing). Nothing in the tire, turns our there was in imperfection in the rim that wasn't sealing right. My guy did a little sanding (or something) and all fixed.

2. These Corsas pick up everything. It is entirely possible you have something in the tire allowing a leak (has happened to me). Check them carefully.

Just a couple things to keep in mind.

[SADVIPER]

The temps are not changing here been hot all summer long. I did not replace them or touch them so I don't know about the mounting issue and I'm a bit nervous about dismantling them and checking them with a snoop solution.. I guess it's a good idea to apply it in place and look for bubbles! I hope there is no leak.
Thanks guys.