Saturn Sky Forum banner

1 - 20 of 44 Posts

·
Premium Member
Joined
·
1,640 Posts
Discussion Starter #1
My dad has a 2007 Sky NA and was wondering if it would be possible to add Tire Pressure Monitoring System - the question really being could you take factory parts from later models and somehow make them work. I am thinking that there may be wiring harness parts, fuse, computer programming, and a receiver module that would all be needed - and possibly even something in the radio head unit.

Might be easier to get a complete aftermarket kit and add that then it would be to retrofit the 2008/2009 TPMS components into a 2007 - depending on how many parts and or changes would be involved.
 

·
First 2000 Sr. Member
Joined
·
5,953 Posts
It would be easier to get a tire guage and check tire pressure at least once a week than spend all that money to retrofit........Skip.....:):D:)
 

·
Premium Member
Joined
·
1,640 Posts
Discussion Starter #4
i hear ya

It would be easier to get a tire guage and check tire pressure at least once a week than spend all that money to retrofit........Skip.....:):D:)
Even those caps that are calibrated to show low pressure might work.

Dad had both his knees replaced this year so the use of pressure gauge is not so easy.

He thought all you needed was the sensors in the tires. but I have to think that other changes were made to accommodate the sensors.

Retrofitting a power seat would be easier - since aside form input power it is a self-contained system.

I think the main reason he asked was that his Civic tire pressure light came on and you cannot tell from looking at them which if any are low - when I checked em and filled em - one was maybe close to 2 psi low - one was maybe 1 psi low and two were less than 1 psi low.

My Accord also had its warning light come on - but I was getting no less than 28 on the hand held gauge - but then the spec is 30. Have to drive it yet to see if the light goes off.

My Sky shows an actual number for each wheel - and it was 27 for three of them and 26 for the other - handheld gauge though was more like 28 for each - so I took em to 30 - seems that it does not update until you either drive - or some preset time goes by - since the readout still shows 27 and 26 - but did not drive it yet. Generally when I drive it the psi goes up about 2 point per tire - sometimes with one side getting there just before the other.
 

·
Registered
Joined
·
95 Posts
It might not be that difficult.

Now that all the components are on a data bus a lot of the time it's as simple as interfacing with the body computer and telling it that the option exists.

I'm running a factory navigation system in my 2002 Trailblazer that came out of a 2005 Escalade. It was plug and play (no harness mods), but to get it to work all I had to do was use my Tech II scanner and tell the body computer it was a 2003 Trailblazer (nav wasn't an option in 2002) and turn the option on, it powered right up after telling the body computer it was there.

My Seville STS also didn't come with factory nav, yet I was able to transplant one in there (that one did require harness work), and tell the body computer that the navigation was installed. Came right up afterward.

I did the same for both vehicles with an XM receiver.

Both vehicles utilize the nav system just as if they came from the factrory.

The 2006 (and some 2005s I believe), are all on the new CAN bus. I don't know enough about them yet to know if they were as, 'friendly' as the Class II bus it replaced. It might be worth looking into though.

Since TPM wasn't an option in 2007, you'd have to modify the harness but it's really just adding a bus communication wire and not a bunch of wires most likely. You never know though, maybe the harness was already set up for it and TPM just didn't make it in for that year. If you can find out where th TPM receiver should be it might be worth looking to see if there is an open plug off of the harness for it.
 

·
First 2000 Sr. Member
Joined
·
5,953 Posts
My knees snap crackle and pop like RICE KRISPIES. Have for years. No knee replacement and yes very hard to get down and check tire pressures. But I still do it once a week on my POS truck. Besides iffen you had knee replacement then it should be easier to squat down and guage the tire pressure.....just my opinion....Old man Skip. :):D:)
 

·
Registered
Joined
·
2,987 Posts
TPMS always seems bogus to me anyway.

If I make the tpms all match... Hand held tire gauge is off ...

I just pump them up to 30 PSI with my hand held mechanical tire gauge and leave the TPMS alone...

Temperature also greatly affects tire pressure, so remember that you should almost always have to fill your tires when the first cold temps come around.
 

·
Registered
Joined
·
5,831 Posts
My TPMS on DIC matches my tire gauge exactly (i.e., less than 1 psi difference), and has done so since I bought the car.

psi will fluctuate about 1 psi per ten degree temp change.
Another rule of thumb is about 1 psi lost per month.

Low pressure in tires is a widespread problem (if you live in seasoned regions) when transitioning from Summer to Fall to Winter. The temp will drop several tens of degrees, resulting in tire pressure dropping several psi.

You can minimize checking often by simply noting what the outside temp is when you check and fill. If you fill 'em at 60 degrees, then you can bet you're at least 3 psi low at 30 degrees. If it's been a month since last check, then the 3 psi low becomes 4 psi low.

If you know the temp will drop, then account for it. I brought my GS-2s to 31 psi (two psi above recommended cold spec) a couple of weeks ago on a 50ish day, knowing we would have some 30 and 40 days ahead. On 40ish days, the DIC shows 30psi. On 30ish days, it shows 29. I should be good into December, when I'll bring it up again to account for the temp drops. If you have a heated garage, then you need to account for the outside temp when filling in warm environment (i.e., 60 degree garage with 20 degrees outside means you should fill it 4 psi higher than spec)

I do the same to my other two cars, without DIC. Use the rules of thumb, track the weather temp, and you can pretty much PREDICT what the pressure is in the tires a month later. In general, fill 'em a little bit high into Winter, and they will stay around spec longer.

The main reasons to check weekly is to find a leak before it finds you. This is perhaps the main benefit of TPMS. Not day to day management, but damage notification. TPMS saved me when I had nail in tire. Even a weekly check wouldn't have helped in that case.
 

·
Registered
Joined
·
771 Posts
Sort of a blessing & burden.

I do love how it reads each tire separately. :cool:

However, being somewhat anal, I hate it when they don’t match!
:banghead:
 

·
Registered
Joined
·
363 Posts
Sort of a blessing & burden.

I do love how it reads each tire separately. :cool:

However, being somewhat anal, I hate it when they don’t match!
:banghead:
Agreed and agreed!

My buddy has an '05 Audi S4 convertible with just an idiot light for the TPMS. Early on in his ownership he had the light on for weeks. Couldn't figure out why it was reading "low" when all of his tires were checking out within spec. Turns out, the TPMS on his car also took the spare tire into account, which was in fact what was reporting itself as being low; though there was no way to know it!

The color-changing caps would get my vote. Your dad can just eyeball 'em and get to the driving. The potential of wiring in a system just for the convenience of reading the tire pressure on the DIC? Sounds like a lot of work for little return, but to each his own. :thumbs:
 

·
Registered
Joined
·
771 Posts
Ah ha! Good ole American engineering trumps the Germans again. That would never happen in a SKY.
U 2 Funny!:agree:
 

·
Registered
Joined
·
771 Posts
Not to hijack, (but in hopes to supplement)...... being anal once again......

What is the magic PSI number to be aiming for? 29 (cold)?:dunno:
(air that is, not nitrogen)

I’ve only got 10K miles and the tires look quite even as for wear – however it seems you can never really tell till you’re almost out of tread.

Granted it depends on the driver’s habits and the twisties and such... but what are the folks that have gone through a set of tires finding out?
 

·
Registered
Joined
·
95 Posts
Not to hijack, (but in hopes to supplement)...... being anal once again......

What is the magic PSI number to be aiming for? 29 (cold)?:dunno:
(air that is, not nitrogen)

I’ve only got 10K miles and the tires look quite even as for wear – however it seems you can never really tell till you’re almost out of tread.

Granted it depends on the driver’s habits and the twisties and such... but what are the folks that have gone through a set of tires finding out?
I'm wondering the same thing myself. I've seen a few references to below 30psi and am a bit puzzled. Is this for comfort? All my vehicles run between 33 and 36 psi in the tires, below 30 seems too low to me. How about tire wear on the outer tread with lower pressures?
 

·
Registered
Joined
·
2,987 Posts
Not to hijack, (but in hopes to supplement)...... being anal once again......

What is the magic PSI number to be aiming for? 29 (cold)?:dunno:
(air that is, not nitrogen)

I’ve only got 10K miles and the tires look quite even as for wear – however it seems you can never really tell till you’re almost out of tread.

Granted it depends on the driver’s habits and the twisties and such... but what are the folks that have gone through a set of tires finding out?

All depends on what you are doing, what tires you have, temp and road conditions....

If im hitting the twisties... I put about 30psi up front and 28-29 in the rears. Get more give and grip in the tires. (more control)

Summer MPG 32-34 PSI all the way around

Cold temps 30PSI all the way around

Colder road/tire temps = less traction.
Higher psi = less traction (tires balloon up)


From my experience 30PSI is a good number to aim for.

And I also hate it when the TPMS dont match :banghead:
 

·
Registered
Joined
·
5,831 Posts
I'm wondering the same thing myself. I've seen a few references to below 30psi and am a bit puzzled. Is this for comfort? All my vehicles run between 33 and 36 psi in the tires, below 30 seems too low to me. How about tire wear on the outer tread with lower pressures?
It's based on a lot of factors. Vehicle weight. Tire size. Profile.

If the SKY weighed more, the recommended cold pressure would likely be in the 30s on the same tire.

Here's a hypothetical example based on weight and contact patch. Let's say from a design standpoint the engineers want a 25 square inch contact patch on each tire and that the vehicle weight is evenly distributed. To keep things simple, we'll assume uniform patch as well. To get tire psi, you simply divide the weight by the patch size:

For a 3000 lb car (750 lbs per tire), it would be 750/25 = 30 psi.

For a 3600 lb car (900 lbs per tire), it would be 900/25 = 36 psi.

Again, there are a lot more factors than weight, but this illustrates how the weight can factor into the recommendation.
 

·
Registered
Joined
·
95 Posts
All depends on what you are doing, what tires you have, temp and road conditions....

If im hitting the twisties... I put about 30psi up front and 28-29 in the rears. Get more give and grip in the tires. (more control)

Summer MPG 32-34 PSI all the way around

Cold temps 30PSI all the way around

Colder road/tire temps = less traction.
Higher psi = less traction (tires balloon up)


From my experience 30PSI is a good number to aim for.

And I also hate it when the TPMS dont match :banghead:
I guess we must have some really stiff sidewalls. I thought at that low of pressure you'd start rolling the sidewalls over in agressive cornering. I know my Corvette recommends 33-36psi in the tires.

Ok, I guess we should get back on the subject of installing the TPMS. :thumbs:
 

·
Registered
Joined
·
140 Posts
Battery life

Curious what the expected battery life of TPMS is. Are they user replaceable or do you have to buy new units? If new units, what's the cost?
 

·
Registered
Joined
·
2,322 Posts
Curious what the expected battery life of TPMS is. Are they user replaceable or do you have to buy new units? If new units, what's the cost?
5 years.

Get new ones if you try this.
 

·
Registered
Joined
·
140 Posts
Stupid me wasn't clear in my previous post :( Is the battery replaceable, or is it a sealed unit and you have to buy a whole new unit?
 
1 - 20 of 44 Posts
Top