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. . (01 Nov 2019)
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TPMS

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22 Oct 2019 07:02 #215026 by Bill Portland
TPMS was created by Bill Portland
The 1st coolish morning this morning (5°C) and within 100 yds of setting off the dashboard lit up with tyre pressure warnings. All tyres showing as 23 or 24psi on tpms. A short trip and the tyres were showing 24 or 25psi, warnings still lighting up the dash. I know that, when warm, the tyres are all where they should be - 26 or 27psi. Does this mean that every cool morning the dashboard's gonna be lit up for a few miles til the tyres get warm?

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22 Oct 2019 07:17 #215027 by GF68
Replied by GF68 on topic TPMS
On my other car with TPMS I always end up putting a little bit more air in, in the winter months. As I understand it pressure and temp are obviously linked, so if at this time of year lets say the average daytime temp is 14 degrees C, i go to the garage on an average temp day and top my tires up to the recommended pressure and it then seems to be fine for the season. When we get to the warmer months I go and do it again and it invariably involves a little bit of air being taken out, but it works fine.
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22 Oct 2019 08:07 - 22 Oct 2019 08:09 #215032 by facade
Replied by facade on topic TPMS
Mine did it a few weeks ago, since the tyres were blown up in the summer. I find the TPMS is good at telling which tyre is parked in the Sun.

Now it is going to be cold and dark all the time, they want topping up a bit.

Make sure the TPMS is set to "comfort".

Annoying isn't it? It keeps coming back and making the dash angry red- mine is angry red most of the time anyway with "Danger!-Danger! Crash imminent!" I'm glad it doesn't talk- or scream in fear :laugh:

It takes 10 minutes to go away, but comes on instantly too.


As an aside, my brother works for ATS, and he says company policy is not to blow up a tyre if it is more than 10% down, they are supposed to dismount it and check for internal damage. Considering you can loose 10% between yesterday afternoon in the sun and this morning with a cold snap, it seems a bit too 'Elf and Safety".

The pressure of an ideal gas is proportional to its Kelvin temperature, so the formula is


P2 = (T2 +273)/(T1+273) x P1

eg, 26 psi @ 25 degrees and now it is 2 degrees P2= 275/298 x 26 = 23.99 psi

This assumes you paid for the expensive dry nitrogen fill, it is probably miles worse with "ordinary" air all full of water vapour.

If it suddenly breaks, go back to the last thing that you did before it broke and start looking there :)
Last edit: 22 Oct 2019 08:09 by facade.
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22 Oct 2019 20:50 - 22 Oct 2019 21:07 #215056 by Scimike
Replied by Scimike on topic TPMS
What's the actual Suzuki recommend PSI for tyres on the G4?
Only asking as if it's 26 psi as per G3 then a trigger level of 24 psi or just below on the TPMS is awfully close to normal operating pressure. I googled and the web (it must be correct :laugh: ) suggested a typical 25% from recommend pressure is the normal trigger point. So at 26 PSI that's 19.5 psi, or at 32 psi it's 24 psi - that's an interesting coincidence.
So is 32 psi correct operating pressure or have Suzuki incorrectly set the trigger point as per the Swift etc?
Just over thinking it for fun.
Mike
Last edit: 22 Oct 2019 21:07 by Scimike.
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22 Oct 2019 21:31 #215058 by Bob1050
Replied by Bob1050 on topic TPMS
Strangely, I had a similar issue yesterday. Cold morning and expected first windscreen scraping of the winter. However, the school run was interrupted by lots of orange warnings about low tyre pressures. Suddenly all the tyre pressures were out of kilter by a few psig. Left car sitting for 3 hours to ensure tyres were stone cold. Checked pressures manually, 1.5 psig low on a couple, so re-inflated them, double checked pressures were to spec and reset the TPMS. Now no orange lights but according to TPMS I'm now running about at 1psig over spec! Good news is that all the orange warning lights have gone out.
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22 Oct 2019 21:59 #215060 by Fossie
Replied by Fossie on topic TPMS
So as a safety measure , or because modern man can't work a tyre pressure gauge,we now have a warning light...excellent .....BUTto make it not intrusive we now add more air than needed in winter reducing the tread area on the road when in the old days we reduced the pressures to expand the tread area....
PROGRESS,!

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23 Oct 2019 11:16 #215070 by facade
Replied by facade on topic TPMS

Scimike wrote: What's the actual Suzuki recommend PSI for tyres on the G4?
Only asking as if it's 26 psi as per G3 then a trigger level of 24 psi or just below on the TPMS is awfully close to normal operating pressure. I googled and the web (it must be correct :laugh: ) suggested a typical 25% from recommend pressure is the normal trigger point. So at 26 PSI that's 19.5 psi, or at 32 psi it's 24 psi - that's an interesting coincidence.
So is 32 psi correct operating pressure or have Suzuki incorrectly set the trigger point as per the Swift etc?
Just over thinking it for fun.
Mike


It is 26 psi for the Gen4 with a light load
I think it triggers at 23.00, I had 4 23s but only the NSF, which catches the sun on the drive flashed, logically the NSF would be the warmest, and in the cold darkness therefore it will drop to the lowest, the other 3 must have been 23 and a big enough bit not to trigger it.

90% of 26 is 23.4, so 23.00 is more than the 10% difference that should have the ATS fitter taking them off the rims!

25 % would be better I agree, but I just want the warning to stay off- I normally check the pressures with a swift kick, and get the gauge out only if I'm going hundreds of miles on the motorway (but I'm a Bad Driver :whistle: )

If it suddenly breaks, go back to the last thing that you did before it broke and start looking there :)
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23 Oct 2019 21:58 #215093 by Bob1050
Replied by Bob1050 on topic TPMS
According to the tyre pressure sticker on the car - Gen 4 is 26 psig all round for lightly loaded or increase the rears to 29 psig if 4 up with luggage. Interesting that my warning lights came on at only 1.5 psig under the recommended 26 psig. The comments about a tyre dealer removing tyres if more than 10% under-inflated sounds like a job creation wheeze to create an additional income stream.
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24 Oct 2019 06:47 - 24 Oct 2019 06:47 #215099 by Bill Portland
Replied by Bill Portland on topic TPMS
It does seem that the differential between "normal pressure" and "low pressure" is too small (much like the differential between headlights on and headlights off is too small). I wonder if its adjustable in the software somewhere?
Last edit: 24 Oct 2019 06:47 by Bill Portland.

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24 Oct 2019 06:51 #215100 by GF68
Replied by GF68 on topic TPMS
Alas Fossie, that is not the way it works. If the tyre is at 26psi in the summer at 24C and we add more air in the winter to make the tyre 26PSI at14C, the amount of tyre in contact with the road will be the same in both summer and winter.

For the reason that facade explained above.

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24 Oct 2019 07:10 - 24 Oct 2019 07:11 #215103 by Scimike
Replied by Scimike on topic TPMS
To me it does appear to be a bit trigger happy. What you actually have is a cold weather warning device, sort of tyre pressure based ice warning :laugh:
I negative is that some could possibly over inflate tyres just to avoid getting temperature based warnings. I know my Jimny gets more lively (bouncy) if the pressure goes much above 26. I would think the device just sends back a representation of the tyre pressure, so the trigger level must be in Software????
Possibly something Suzuki could adjust?
Who knows, it's easier just to put 32 psi in the tyres like ATS.
Last edit: 24 Oct 2019 07:11 by Scimike.

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02 Nov 2019 11:19 #215302 by stiffsteve204me
Replied by stiffsteve204me on topic TPMS

Bill Portland wrote: The 1st coolish morning this morning (5°C) and within 100 yds of setting off the dashboard lit up with tyre pressure warnings. All tyres showing as 23 or 24psi on tpms. A short trip and the tyres were showing 24 or 25psi, warnings still lighting up the dash. I know that, when warm, the tyres are all where they should be - 26 or 27psi. Does this mean that every cool morning the dashboard's gonna be lit up for a few miles til the tyres get warm?



Had this happen on Wednesday morning. All showing 23psi., but the warning was for NSF only. Pressure readings increased to 25psi all round, but warning did not clear, even after stopping and restarting.
The car was parked for several hours, and when started, the low pressure warning still showed. After driving a few miles, it cleared.

It will be a pain if this is the norm on a cold morning.



Steve.

“He that strikes the venison first shall be the lord o' the feast.” — Shakespeare, King Lear.

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