Technical Limp home mode or something else?

[varesecrazy]

How annoying.. :-(

As you said.. it was fine until they worked on it

Question being what didnt like being disturbed..??

The symptoms sound a little like the timing is incorrectly set

Member @puntodeltathema has some experience in a 500 with poor timing

The forums standard issue is with 'older tech' puntos

Similar engine..but no Stop:Start

 

[field500]

Did the problems start right after the timing belt replacement? Then what they should be looking into is the crankshaft pulley alignment. Did they align it with the small dimple so that it goes into the hole in the pulley? If not, it will cause this. Sometimes there is no dimple, it is cracked making it quite difficult to keep the alignment right. Phonic wheel relearn is not going to fix that.

It could be the crankshaft position sensor fault too, but it is not very likely if the problem started right after the belt change. If you had problems with the car even before the belt change, then you should get them have a look at the phonic wheel and its condition and the sensor itself.

Hi
Yes, timing belt, tensioner and water pump were done at 5 year service - fist time car was driven (3 weeks after work) the issue occured. Dealer had it back and spent a whole day checking belt, tensioner, timing etc - diagnostic pointed to misfire which they cleared by fitting a new Coil pack. 2 weeks later, first time driven out (other than on the way home from dealer), similar issue arose.
I made sure that i went over 70 today, as this was when the first instance happened - and it happened again. Not really sure why going over 70 would make this happen though - car revs up to redline etc albeit it would not go over 4k revs when stationery but seemed to be fine today
To be honest, the car is rarely driven over 60mph as my wifes commuter route does not permit it - and she does not drive it very often, so there is a chance the issue was present before the belt change. But it is a bit of a coincidence...........
Have contacted dealer and they will get it booked in...................

Thanks for the post though

 

[field500]

I have also read that any issue with the Engine Management will trip the Stop Start disconnect warning, so i think that may not be the cause..........

 

[varesecrazy]

I seem to recall somebody had a failing belt tensioner..
Its not 'fixed' as in the motors earliest use

But now 'floats' to keep better tension

A failing tensioner allows the timing to 'wander' this could fit your scenario and of course would have been disturbed to change the belt


Personal experience means the waterpump needs to be checked too

(I had a recently fitted waterpump run 'out of true' so badly it let the belt jump ... an effective auto tensioner may have prevented that )

 

[field500]

I seem to recall somebody had a failing belt tensioner..
Its not 'fixed' as in the motors earliest use

But now 'floats' to keep better tension

A failing tensioner allows the timing to 'wander' this could fit your scenario and of course would have been disturbed to change the belt


Personal experience means the waterpump needs to be checked too

(I had a recently fitted waterpump run 'out of true' so badly it let the belt jump ... an effective auto tensioner may have prevented that )

Hi - Belt, tensioner and pump were changed in Dec, and checked when issue occured. So I would hope that's not the issue really.
I would not expect the engine to Rev/start/tickover etc if the timing was out? I once changed a 1 litre FIRE engine timing belt and was one tooth out - car ran terribly.

As the issue seems to be triggered by high speed I am wondering if the Lambda Sensor (or similar) is playing up - the exhaust gas etc would be at a much higher temp at 70mph + ?

Thanks

 

[John202020]

Try driving at 50 in 3rd?







My wife just after we got the car found it will l do 70 in 3rd up the motorway by mistake


A faulty Lambda wouldn't stop the car driving " normally "

 

[varesecrazy]

Your error is potentially the Relationship of timing sensor Top vs Bottom 'floating'

And wandering enough at high rpm to trigger the error

3,000+ rpm for a minute of more..

Thats not hard to replicate at 40mph

To me.. the fact that turning off and on clears it means its not something 'overheating'... its a sensor input

 

[field500]

Your error is potentially the Relationship of timing sensor Top vs Bottom 'floating'

And wandering enough at high rpm to trigger the error

3,000+ rpm for a minute of more..

Thats not hard to replicate at 40mph

Thanks - will give it a try when I drive it over to the dealer - be great if I can replicate it so they can see. But they should see what's going on from the codes on the diagnostics?

That said, when I drove it back from dealer a few weeks back, I was giving it some stick - do not normally drive in a low gear/keep revs up - but wanted to make sure it was running okay - got home that day without any issue (so thought it was fixed)

Just dug the paper work out from a couple of weeks ago when they changed the coil pack - there were 4 stored errors - P01361-98, P01364-98, P0300-98 and P1036-23 - this first two were misfire cylinder 1/4 component/system over temp. The third code is a Misfire Random, component/system over temp and the last code is Downstream Lambda Probe - signal stuck low.

 

[koalar]

I don’t hang out much in this section

But I would be looking at the P1036

VVT solenoid

All the other error codes could be connected

Misfire
Unburnt fuel reaching the O2
Cam and crank not syncing

Not say it is but it’s where I would start

 

[koalar]

Classic symptoms of the timing belt being 1 tooth out?

Correct

Not revving past 4K is normal for a belt that is one tooth advanced

However the engine light should be on from start up and it would be impossible to do a phonic relearn

The cam pulley has probably been undone so maybe a fraction out.

But the VVT error needs sorting first

 

[koalar]

I like to check I am reading this thread correctly

In summery

The car was running fine

Had a cam bet change

Didn’t run fine

Went back

Had a coil pack

Still doesn’t tune fine

Is this correct ?

 

[varesecrazy]

I like to check I am reading this thread correctly

In summery

The car was running fine

Had a cam bet change

Didn’t run fine

Went back

Had a coil pack

Still doesn’t tune fine

Is this correct ?

@field500

It says new parts were fitted..

Was this by a FIAT dealers workshop?

 

[field500]

Correct

Not revving past 4K is normal for a belt that is one tooth advanced

However the engine light should be on from start up and it would be impossible to do a phonic relearn

The cam pulley has probably been undone so maybe a fraction out.

But the VVT error needs sorting first

Hi, thanks for the suggestions. The VVT thing sounds interesting - excuse what may be an obvious question, but is the VVT solenoid the same as a cam variator? And if so, as its a solenoid, i guess its an electrical part? That was mentioned when they had it in, before the duff coil was suggested as the problem. They checked all the belt and timing when i took it back, and as its a well regarded main dealer, i would hope they checked it correctly. When they swapped the coil for one they have for testing, tried it out and no codes reappeared, they popped a new one on and i had the car back. But of course, issue reappeared.........

They will get back to me on Monday with a time they can fit me in - as soon as I know the answer I will post an update..............

 

[koalar]

Hi, thanks for the suggestions. The VVT thing sounds interesting - excuse what may be an obvious question, but is the VVT solenoid the same as a cam variator?

VVT variable valve timing

Variator is a type of special camshaft pulley used to adjust the VVT

The VVT solenoid is an electric valve used to adjust oil flow to the Variator which varies the valve timing

They can get blocked after the cam cover been disturbed. I be tempted to pull it out and inspect the gauze

It’s only one bolt, unfortunately it’s a torx

And if so, as its a solenoid, i guess its an electrical part?

Yes

That was mentioned when they had it in, before the duff coil was suggested as the problem. They checked all the belt and timing when i took it back, and as its a well regarded main dealer, i would hope they checked it correctly. When they swapped the coil for one they have for testing, tried it out and no codes reappeared, they popped a new one on and i had the car back. But of course, issue reappeared.........

They will get back to me on Monday with a time they can fit me in - as soon as I know the answer I will post an update..............

Looks like the coil pack was a red herring

 

[field500]

VVT variable valve timing



Variator is a type of special camshaft pulley used to adjust the VVT



The VVT solenoid is an electric valve used to adjust oil flow to the Variator which varies the valve timing



They can get blocked after the cam cover been disturbed. I be tempted to pull it out and inspect the gauze



It’s only one bolt, unfortunately it’s a torx



Yes



Looks like the coil pack was a red herring

 

[field500]

Many thanks for the update. Yeah. Seems coil pack was not the issue. I will mention the VVT solenoid when they get back to me, and if it is something that can be disturbed when changing the belt and tensioner, it could be the issue. I would have hoped the dealer would have thought the same, and you would imagine they have come across most things that can go wrong etc.

Been going there for over 20 years, so know all the guys who work there. Car was purchased new from them too.

Thanks again and I will update when I know more.

 

[TQ1]

I’d hope you’re not paying their labour & the parts for them to just randomly change parts which a “diagnosis” machine tells them to when plugged in.

Any monkey can do that. The actual skill is troubleshooting.

Either they give you the coil pack FOC or refit the original. Unless of course it’s been damaged by the timing being incorrect & the car throwing a wobbler, in which case you should be having the replacement FOC….

Motor industry the only one where being incompetent is more rewarding than competent.

Don’t know what the problem is. Just change things until it’s fixed and bill the customer for it.

 

[jrkitching]

I'm astounded by how many posts we see from folks who've had problems after what should have been routine cambelt changes, sometimes even when the work has been carried out by franchised dealers.

Just how hard can it be, and why are so many of them going wrong?

 

[koalar]

Just how hard can it be, and why are so many of them going wrong?

It’s better if the cars running 100% before a belt change otherwise you don’t know if it’s cause or effect.

A timing mark on the camshaft pulley and a timing mark on crank pulley lined up with the two lines on the belt is hard to mess up but still it happens

Now add ECU, coil pack, VVVT solenoid, cam sensor
wrong and/or incomplete instructions and poor quality tools and it’s starts to be a bit of a lottery


Not that should effect a garage that do it week in week out

 

[eeeno]

After reading thru all the posts here, it begins to sound like that the garage has made a mistake with the belt change. I think you should mention that to the garage if they're trying to give you a hefty bill. Fiats aren't that exotic and even a DIY guy can change the belt without this error. Btw, did they do "phonic wheel relearn" as described in the elearn material?