Technical Series 4 Turismo banging underneath

[Goudrons]

Last couple of days my 595 Turismo has started banging about underneath.

It feels like it's on the rear axle but it's hard to tell for sure and seems more prominent when I turn.

Any input on the steering while driving and it's bang bang bang from underneath, it's not just the banging, there's a certain feel to the cars handling as well, like along with the bang bang bang, there's a bump bump bump.

It does do it on the straight as well, if I hit a manhole cover or bump, but it's not all the time.

It's not the exhaust, I checked that and all seems ok and still attached to the mounts at the rear and middle (can't see any at the front yet)

It feels/sounds suspension/wheel/rotational.

Nothing is in the boot either.

I did a quick check of the rear springs and they appear ok too, not really checked the shocks on the rear yet though.

I'm a bit worried, it does feel and sound really bad, not just an annoying knock but a full blown banging.

 

[varesecrazy]

Last couple of days my 595 Turismo has started banging about underneath.

It feels like it's on the rear axle but it's hard to tell for sure and seems more prominent when I turn.

Any input on the steering while driving and it's bang bang bang from underneath, it's not just the banging, there's a certain feel to the cars handling as well, like along with the bang bang bang, there's a bump bump bump.

It does do it on the straight as well, if I hit a manhole cover or bump, but it's not all the time.


It feels/sounds suspension/wheel/rotational.

Nothing is in the boot either

I'm a bit worried, it does feel and sound really bad, not just an annoying knock but a full blown banging.

Hi. Does sound a bit odd.

1st.. go round all the wheel bolts with a wheel brace to;

1. Check the bolts are tight

2. See if the wheel..on its hub.. can 'float'in the wheel arch

Itll give an opportunity to rule out loose trim panels rubbibg tyres too.

Maybe find an empty car park.. and do some

FullLock circles.. should be virtually silent.. 1st gear.. clutch out

Then cluth in.. coasting

Worth getting checked sooner..rather than later.


Had any work done lately..??

Charlie

 

[Goudrons]

Thanks for replying.
I have been out and checked the wheel nuts and in doing so think I found the issue.

It was hard to spot in the dark as the tyre profile is so low anyway, but it appears I have a flat or way under inflated tyre on the nearside rear.

I haven't yet seen anything stuck in it, but I am surprised the TPMS didn't alert me??

It must have been like this a least a day and a half and I flick through to the tyre screen on the dash in the mornings and check.

There's nothing on that or the little orange tyre warning light.

When I get a minute, I'll see what the actual pressure is.

 

[varesecrazy]

Amazing what spending a minute close to
'The mechanicals'can tell you.

Charlie

 

[Goudrons]

Well, I had the boy run the pump up to me at work.

Totally flat, not a breath of air in it and no bloody TPMS light??
Also the tyre looked like it was a little soft rather than totally flat, I guess that's what 40 profile look like when they are flat.

Pumped it up and I can hear is hissing away, I can't see/feel anything but there's got to something in it.

 

[jimboy]

Amazing what spending a minute close to
'The mechanicals'can tell you.

Charlie

Aye! 'tis an eye opener indeed when you actually take a look at the situation & see whats what....

 

[Goudrons]

Right, I have a problem.
I have tyres with such a low profile that they look the same flat as they do fully inflated and a TPMS that doesn't appear to work.


Does anyone know how the TPMS works?
Should there be sensors on the valves inside the tyre?

Had my tyre repaired and there was no sensor on the valve and I'm starting to think because I chose a different wheel as an option, the sensors didn't get fitted with them.


The car's dash just shows all tyres are ok and there was no orange warning light.

 

[Thaidai]

If you look at 4th post down it explains how it works

https://www.fiatforum.com/abarth-500/463282-tyre-pressure-sensors.html?463282=#post4362163

Not sure why it didn't work, maybe because it was a slow puncture and not an instant release of air??

 

[Goudrons]

Thanks for that.
I suspected it was an indirect system (cheap) and I guess the system couldn't determine the flat due to the large wheel and low profile tyre, I couldn't and I was inches away from it!

After the faff getting it to the tyre shop, I think I'll fork out for a spare.
Perhaps a standard 500/Panda 14" wheel will fit in the well?

 

[Funky Spike]

FWIW my TPMS picked up on a slow puncture, it alerted me when it got to about half of what it should be.
The system is a bit flaky though, whn I swap between summer 17's and winter 16's it always goes off but usually a day or two after I've done the swap!

Spike

 

[varesecrazy]

Thanks for that.
After the faff getting it to the tyre shop, I think I'll fork out for a spare.
Perhaps a standard 500/Panda 14" wheel will fit in the well?

I suspect whatever fits in a 1.2's well is ideal..

Even a 175/65/14 old punto wheel..as they are @£10 nowadays

 

[simon_16vpunto]

I’ve got a normal 14” 500 wheel and jack in the boot of my turismo.
It won’t fit on the front because of the brakes but will go on the rear.

 

[varesecrazy]

I’ve got a normal 14” 500 wheel and jack in the boot of my turismo.
It won’t fit on the front because of the brakes but will go on the rear.

Big brakes eh..

You can put a REAR 17 on the front.. and then mount the steelie at the rear.

Personally I wince when I see 'space savers' on the front of anything..

Charlie

 

[Thaidai]

FWIW my TPMS picked up on a slow puncture, it alerted me when it got to about half of what it should be.
The system is a bit flaky though, whn I swap between summer 17's and winter 16's it always goes off but usually a day or two after I've done the swap!

Spike

Mine alerted me a couple of days after having my front tyres replaced...

 

[Goudrons]

Even a 175/65/14 old punto wheel..as they are @£10 nowadays

That's what I was thinking, something like a 14" wheel off the Panda Pop, that's got to be better than a skinny space saver.
I once drove back from Yorkshire, late one Sunday night on one of those and it was awful, the tyre wasn't much better! (sorry, couldn't help it)

I could pull one off our lad's Panda to check it fits the wheel well.

I believe the standard Panda/500 jack fits under the side skirts ok, so I can fit one of those plastic tool holders in the centre rather than have everything rolling around the boot.

The only thing that needs swapping over is the towing eye, the Abarth's is a lot longer than the Panda/500.

I was aware of the brake issue at the front, I'm thinking the standard 14" might actually fit, the Turismo doesn't have the massive Brembo's like the Comp, though they look bigger than a standard 500, but it shouldn't be a hardship swapping a good rear to the front if I'm stranded.


Going back to the flat and the TPMS, spoke with a mate last night and they have a Comp and had exactly the same problem.

Got a rear puncture and no warning, the tyre flapped and banged about yet looked inflated, they actually took it back to the dealers as they were stumped for what was wrong.
The dealer seemed to think that because there's little weight on the rear and the suspension so stiff, the system has trouble picking up a problem and the tyre looked inflated as the other one on the other end of the axle was taking the weight parked up.

They'd already stripped out the back seats, so ended up strapping a full size wheel in a fancy leather Abarth cover in the back.
Not ideal for me, my windows will be smashed and the wheel gone in minutes around here!

 

[RichardH13]

It works by sensing differences in wheel speed by reading the ABS sensors.

It worked when I had a slow puncture.

I suspect there could be an ABS issue, get them to check the ABS system.

Never heard of this problem before, the only ones I've seen with Tyre Pressure Measuring System (TPMS) is to do with the so called live systems that read the pressure from sensors in the valve. That seems to be a very flaky system.

But that can't be the problem, because the 500/595 has an ABS based system

 

[varesecrazy]

Great info there. Thanks Richard.

Given all inputs need a TOLERANCE..
And how little sidewall is in play..

Combined with CENTRIFUGAL FORCE 'reinflating' at decent road speeds.

Its got very little chance of being superreliable..

Example:
The difference between 7mm of tread and 1.6 mm of tread .

could be seen by the ABS as greater than say .

7mm @35psi vs 7mm @05 psi

 

[Goudrons]

An indirect system like this would also need a decent run in the straight ahead to detect a flat as the wheels on the same axle will naturally rotate at different speeds around corners.
I doubt I do any straight ahead in central London!

Like I wrote originally, the banging was mainly on cornering and over the odd bump, straight ahead you couldn't feel or sense any problem.
I know what a flat feels to drive on, which is why this puzzled me to start with.

I reckon the suspension is so stiff it's been "carrying" the flat rear wheel until a corner, which is why the system hasn't detected it, it won't on a corner and on the straight it's just been skimming the road as the suspension has held it up.

I wouldn't volunteer to try it, but I think you could probably remove a rear altogether and still drive it straight, like the old Citroen DS.

I guess this sums up the system.
https://www.thisismoney.co.uk/money...pressure-monitors-putting-drivers-danger.html

 

[Mercky]

So is the tyre knackered?

 

[jrkitching]

So is the tyre knackered?

Personally I'd be more worried about the wheel being knackered.