Technical Panda 100hp woes

[wakey]

Hello All

It's my first post and like many I found the forum by searching for info related to a problem I have. I hope someone would be kind enough to help.

Car - 100hp. 50k miles owned from new and serviced every year on the dot.

Problem - Acceleration dies randomly, take foot off gas pedal and back on and its ok. Seems more prominent when cold.

Things replaced recently - new battery and Alternator, crank position sensor and oil pressure sensor (had yellow triangle warning) and brake pedal switch.

I'm thinking the likely culprit is the Throttle position sensor?

I've tried the reset procedure for the Throttle body and for the pedal box but to no avail.

Questions -

1 - Are these available separately from motor-factor stores as fiat will only sell a complete throttle body.

2- Are the TPS unique to the 100hp? I'm led to beleive they are the same as the one on the 1.4 grande punto?

3- Does anyone know where sell them?

Sorry for the long post. We love the car and have never had any problems until now

Many thanks in advance

 

[A3jeroen]

I'd have the codes read before replacing anything. Could be accelerator pedal (electronics) as well. Or a (ground)problem at the coils or injectors.

gr J

 

[wakey]

Thanks for the reply

I've read the codes and no faults found - that said it's a generic code reader.

RE the coils - its not a misfire of a hiccup, its a cut in power. Its like Ive taken my foot off the pedal and the car decelerates even though my foot is on the accelerator.

If I do take my foot off the pedal when it happens and press it again it accelerates normally. Like its lost the signal to accelerate.

Thats why I was either thinking of the potentiometer on the pedal or the one on the throttle body.

 

[Yellow Peril]

+1 on getting the codes read. Maybe a blocked fuel filter?

 

[wakey]

Just an update on the thread and hopefully someone can help me

I have replaced the throttle body - no change.

If I perform a throttle pedal reset - it drives great but as soon as I stop the car and restart, the problem is back

This lead me to believe that it might be the ECU not retaining the data. I have had the ECU tested and its come back fine.

So, my conclusions are that it's either the potentiometer on the pedal - therefore needing replacing or it's the wiring from the pedal plug to the ECU.

If it was the wiring, then surely it would be creating problems even after a pedal reset?

Fiat want £130 to fit a new pedal which I'm tempted to go for, but in the back of my mind i worry it might be something else.

I've got a code reader that allows data logging and when the fault occurs, the absolute throttle position changes without any change to the position of the accelerator pedal - this makes me think it might be a worn potentiometer on the pedal that is losing its resistance value and giving varying data to the ECU and therefore changing the throttle position and causing the hesitation

Can anyone offer any further thoughts?

Many thanks in advance and any help greatly appreciated.

 

[varesecrazy]

Just an update on the thread and hopefully someone can help me

Can anyone offer any further thoughts?

Many thanks in advance and any help greatly appreciated.

look at the over revving thread in the Multipla section..,
maybe the same issue

 

[wakey]

Thanks for the suggestion

Ive had a look but cant see how they are related - the multipla is a diesel with suspected Hgf and mine in a 1.4 petrol with an erratic throttle response

 

[Daveb100hp]

I'd recommend getting it diagnosed professionally. It could be a number of things and sometimes a combination of things. I had a similar thing happen to one of my old cars so I took it to a rolling road and had a professional diagnostic done. It cost me 60 quid but they found the fault straight away and saved me a fortune in the long run. Also May be worth going to see an auto electrician

 

[wakey]

An important thing I've realised is this:

If I perform a throttle and pedal reset, it runs perfectly.

As soon as I turn off the engine and restart, the fault reappears. It's as if the car is not retaining the new data settings following powering down.

All this started after a flat battery, I restarted it using a charger but I set it on the boost start setting ie high voltage and current. I have since been told this method car cause spikes and maybe corrupt software and or sensors.

So, if the car runs perfectly when parameters are reset - for ages without a problem, this would surely rule out a faulty sensor, loose wire or similar.

I have had the ECU tested and it came back OK, but they download the software, test the ECU functions and then reload the software.

They found no faults with the ECU operation and function.

Could it be that the software held in the ECU has been corrupted?

If this is the case, is there a way to re-flash the ECU with a factory software and therefore remove and corrupted files?

 

[Amboman]

This is a simple and cheap fix. It is the earth strap. Same problem with mine, also a friends 100hp, earth strap both times.

 

[wakey]

can you enlighten me? Which earth strap? The one from the ECU that bots onto the casing or another earth point somewhere else?

Ive been through the mill with this little car (owned from new) and love it to bits so if you could give a bit more detail I'd be eternally grateful

 

[Amboman]

The earth strap in question runs from under the battery tray to the gearbox, bit of a sod to get to, but take the battery out and it's much easier.
My car required a new strap as it was really starting to fall apart. Same symptoms as yours.
What happens is as you drive, the engine is always moving in relation to the body, meaning that the strap moves too. With a damaged strap the resistance will change with this movement. As the throttle pedal is a variable resistor, it messes with the signal to produce the symptoms you are having.
My friend's 100hp started doing the same. His strap was not damaged, but the securing bolts were not tight at either end. The strap was removed, cleaned and refixed. Problem solved.
I'd be certain that this remedy will provide a cure for your car.
Good luck!

 

[wakey]

Well, well - I must admit to being a bit skeptical but today I removed the battery and battery tray and low and behold was a mouldy green copper strap.

The body connection point where it mates with the battery negative was good but the connection to the 'box was very corroded.

I stripped it all down, cleaned the strap with contact cleaner and a small wire brush, ground the spade end back to clean copper, replaced the steel nut with an M8 copper nut and built it back up.

It runs better than I can ever remember, super smooth acceleration, starts immediately and feels a lot more spritely.

Thank you very much for this help - Pandy has now been saved from going off to WBAC as I was that fed up with all the things I'd changed.

It's like a new engine is in the car!

Thanks again, really appreciated

 

[Gavv8]

The 100hp really does seem to be very sensitive to weak electrics and greatly benefits from a good battery and good connections, maybe its because its CANBUS?

 

[Amboman]

You're welcome. Always satisfying finding a fix that costs nothing but some time.

 

[varesecrazy]

Thanks for the suggestion

Ive had a look but cant see how they are related - the multipla is a diesel with suspected Hgf and mine in a 1.4 petrol with an erratic throttle response

I'm not convinced you read this..

https://www.fiatforum.com/multipla/274961-engine-revving-out-controll-2.html

it's a throttle / accelerator pedal related electrical issue.

 

[varesecrazy]

You're welcome. Always satisfying finding a fix that costs nothing but some time.

Thanks Amboman, :worship:

the earth cable is indeed THE most common simple issue on FIAT vehicles nowadays.., ( well possibly #2 to neglect)

some cables break down internally too

Charlie

 

[wakey]

I'm not convinced you read this..

https://www.fiatforum.com/multipla/274961-engine-revving-out-controll-2.html

it's a throttle / accelerator pedal related electrical issue.

No, you are right - I just skimmed through it. Sorry

Just just picked up on all the things I'd already tried - I had pulled all plugs and cleaned them and check all wiring connections.

Thanks for the suggestion though

 

[wakey]

Just one other thing I forgot to mention when resolving this problem....

In order to get to the earth strap I firstly removed the battery, plastic battery tray and the metal holder for both the aforementioned. This gives easy access.

The one thing I noticed though, the metal battery tray first houses a plastic insert and on the bottom of the insert is a rubber drain tube that threads through the metal tray. Guess where the drain tube locates.....yep right above the terminal on the gearbox - the one that was very corroded on mine.

I'd suggest other owners visit their earth strap and once cleaned up cover it with spray white lube or grease - this should put a halt to what seems to be the inevitable.

Hope that helps someone in the future

Once again, thanks to all who contributed to this thread. She's running like the day we first bought her

 

[rmachermad]

Thanks @Amboman, :worship:

the earth cable is indeed THE most common simple issue on FIAT vehicles nowadays.., ( well possibly #2 to neglect)

some cables break down internally too

Charlie

Found out recently that the earth cable on my 1.2 needs to be replaced. So, not just 100's have that problem.
Need to find the part number but eper isn't working properly.

With all the problems my Dad had on his Stilo, I wish I had known this was common. I would have checked that...