Hi

My car Fiesta mk8 2018 plate zetec

Cold weather so checked my tyre info screen and tyres were around 28psi

So off I go top up to the required 30psi front 29psi back

Get in the car reset the tyre values and back read 29 psi so great, but front read 32psi

Got out double checked and yes 30psi, inside car says 32psi

So drove it round block parked it up and left it awhile, just checked it both fronts now read 30psi

Not sure what's occurring here? Backs were still reading 29

Confused 😕

Perfectly normal, often takes a couple of minutes of driving for the computer to catch up with actual values. A good reminder not to use the monitor as a pressure guage, it's there to give an indication only of actual values and notify you of any sudden loss of pressure. Having said that, I've found mine is spot on compared with my pressure guage once the computer has "caught up".

Exactly as you said later it displayed the correct pressure inputted

Thanks just couldn't figure it out

 

11 hours ago, Waggy said:

Perfectly normal, often takes a couple of minutes of driving for the computer to catch up with actual values. A good reminder not to use the monitor as a pressure guage, it's there to give an indication only of actual values and notify you of any sudden loss of pressure. Having said that, I've found mine is spot on compared with my pressure guage once the computer has "caught up".

Thanks for the info Colin.   I was wondering about that.

I'm still unsure on the TPMS readings I am getting from mine.

I posted a while back on a vague feel to the handling I was experiencing and that I'd finally traced it to a faulty tyre pressure gauge I had been using.

I bought a new gauge which claims to be certified to a particular standard . According to that, my Fronts which are supposed to be at 33 psi were at 28 psi and the rears which are supposed to be at 26psi were at 21psi. So, 5 psi under inflated.

I pumped them up to 33/26 as shown by the new gauge and the car definitely feels better handling wise but my TPMS readings were showing 39 front and 34 rear which would make them 6psi over inflated.

Realising they might need to be reset I went through the menus and performed the reset and then drove to work which is about 35 miles. The TMPS reading from the car still shows 39/34. Strangely my old guage which I'd suspected of being faulty now seems to agree broadly with the TPMS readings.

I then took it to the local petrol station and their gauge says 37/32 which is 2psi less than the TMPS readings.

I then bought another gauge which also claims to be accurate to within +/- 1 Psi and that is showing 34/29.

I'm now confused 3 gauges all showing different values and none the same as the reset TPMS readings.

My vague handling has also not entirely disappeared as I thought, I suspect it is a combination of incorrect tyre pressures and something not right either alignment wise, or worn dampers/play in some linkage.

Considering I've only done about 18,000 miles from new and never hit any potholes or kerbs and only driven up and down the motorway for 90% of those miles I'd be surprised if anything was worn. Obviously it could just be a faulty component that has failed prematurely.

Problem at the moment is getting anyone to look at it and provide me with a courtesy car so I can get to work. Seems Covid restrictions have put a stop to that.

I've jacked it up and checked for any obvious play in any linkages etc.. and it doesn't seem like anything is about to fall off. I've also swapped the tyres round but something is definitely not right somewhere.  

A lot to take in from above, but two suggestions on tyre pressures to start with. It's not straightforward using a pressure guage. Get a decent one by all means, but you have to know how to use it, there's definitely a knack. Practice taking several readings on the same tyre. They should all be the same, otherwise you're not doing it right. What I do is make sure the guage is square on to the valve, then push on fully, quickly and firmly. It takes practice, but if you push it slowly like a girl (did I say that?), you'll end up with all sorts of readings. The tyre pressures stated in the manual should be when the tyre is cold, ie normal outside temperature. It's normal for the pressures to increase while driving, perhaps 2 psi in winter, anything up to 4 psi in summer, so take this into account as well. My TPMS system is spot on within 1 psi of my pressure guage, but there is a bit of a time lag to respond after changing pressure, so the car needs to be driven a bit before you can rely on it.

And finally, don't trust any guage on a garage forecourt!