Technical Punto 1.2 8v 2003 gentle misfiring/ shaking HELP 😫😫

[Msyogi]

Guys! I’m losing my mind now…. I run out of ideas

Some time ago I bought Fiat Punto 1.2 8v 2003 pre lift, 56k miles on the clock.

So the issue I’ve got is, car getting micro misfiring ( at least that’s what I think) or shaking for literally second and repeating time to time, it’s also hard to describe…

What I done so far,
Basic service, oil, oil filter, air filter, new spark plugs, new leads, new coils, new thermostat, fresh coolant, just yesterday I replaced rocker cover gasket, also valve clearance been checked and everything up to specs, throttle body been taken off and cleaned up, no air leaks whatsoever. All sensors been checked, all ok. No errors on dashboard, also tried to connect with Delphi but no errors/faults. I’ve also done compression test all in specs. Battery been also charged looks ok, alternator working fine, fuel consumption is in about 43mpg urban+motorway. Idle is stable… don’t know what else I can check

The micro misfiring/shaking is only when the car is running on idle

Temperature is always stable… time to time I’m getting electric steering wheels error on the dashboard but that’s the known issue, restart engine always fix that issue.

There is no problem to start car when cold/hot
Heating it very strong, basically everything is working as should.
Forgot to mention do not have any information about previous service history, don’t know when the timing and water pump been done.
I’m just loosing my mind now…

Any ideas, helpful advice, any suggestions will be very much appreciated!!

The only thing I spot looks like previous owner did not replace the oil to often, he was the very old guy and looking through MOT history was only covering up to 3-4k miles every year…

 

[varesecrazy]

Have you replaced the main Earth cable?

Battery to gearbox... they can fail internally

And so cheap you may as well

 

[Msyogi]

Nah not yet, tbh not been even suspecting that…

Well maybe that’s the point, the old guy(previous owner) past away and no one used car for about 9 months, eventually family sell car to scrap yard due to avoid road tax etc., and I literally rescued it from behind shredded…

 

[varesecrazy]

There is 50+ things it COULD be..

You have checked the obvious stuff

Im just suggesting other cheap and easy things...

Have you ruled out the Crank Angle Sensor... famous for NOT leaving error codes..

I loved the old 188

 

[Msyogi]

There is 50+ things it COULD be..

You have checked the obvious stuff

Im just suggesting other cheap and easy things...

Have you ruled out the Crank Angle Sensor... famous for NOT leaving error codes..

I loved the old 188

Well the only thing I done to that sensor is plug it off, check the connection, check rust/moisture, clean sensor itself and put it back with no results.

Yea 188! I so simple and i really enjoy drive it run so smooth and engine is so simple BUT NOW MAKE ME MAD can’t figure it out what cousin my issue

 

[Cornish Ian]

Nah not yet, tbh not been even suspecting that…

Well maybe that’s the point, the old guy(previous owner) past away and no one used car for about 9 months, eventually family sell car to scrap yard due to avoid road tax etc., and I literally rescued it from behind shredded…

I was wondering how many miles you’ve done since it’s rescue. Now we are using this ethanol polluted petrol there is always a danger of condensation / water absorption especially if the tank was sat for a long time with a large air gap so it could breath in moisture. One of the 50+ perhaps.

 

[Msyogi]

I was wondering how many miles you’ve done since it’s rescue. Now we are using this ethanol polluted petrol there is always a danger of condensation / water absorption especially if the tank was sat for a long time with a large air gap so it could breath in moisture. One of the 50+ perhaps.

When I was doing rocker gasket I took off all injectors and clean them up in ultrasound bath, since first fuel refill I add injectors cleaning solution, and on the very last fuel refill I done she’ll v power 99 octane just to se if there will be any difference non of these stops the issue.

Hmm in total I’ve done about 800 miles so far.. maybe a bit less.

 

[bugsymike]

Don't know if it possible to check it or even change it on modern cars, but in the past if fuel/mixture was too weak it could cause what you describe on idle.
In theory when all ecu controlled it should be perfect lambda etc.
It may sound daft, but there is a cheap tuning mod that plugs into the Temp circuit on cars to trick them into thinking they are cold and chucks a little more fuel in to the engine. All it really is, is a resister which alters the signal to the ecu.
I don't know if a cheap or faulty lambda sensor could affect it.
If you have a mate at the Mot Station could he put his smoke tester up the exhaust, see what the reading is and see if it fluctuates when the engine plays up on tick over.

 

[Msyogi]

Morning guys just a small update, straight after night shift. Just make two pics of earthing points, as been mentioned above. The question is are they bad enough to causing issue I’ve got? What’s you thinking guys? Definitely one on the gearbox is in way worse condition than the other one, that’s for sure…

 

[bugsymike]

Wow! Certainly a salty area you live in.

 

[Msyogi]

Wow! Certainly a salty area you live in.

Coventry

 

[Msyogi]

Small update: took it off MAP sensors today to give it a good clean, clean up all earthing connections, clean battery terminals, checked all cables but still nothing…. Just feed up of this…

 

[varesecrazy]

The cable rots..corrodes ..inside

If the outside it that bad.. the inside is probably wrecked

The Copper strands just Green Sludge

 

[Cornish Ian]

Small update: took it off MAP sensors today to give it a good clean, clean up all earthing connections, clean battery terminals, checked all cables but still nothing…. Just feed up of this…

I think I would have the emissions checked as Bugsymike suggested.
Perhaps a lambda sensor is dirty or partially failed and screwing up your emissions.

 

[Msyogi]

Small update:

Just swapped lambdas today and still no difference
I also checked coils charging times not ok, I’m actually slowly starting considering that something wrong with engine maybe valve burned

 

[The Panda Nut]

That earth looks diabolical! I wouldnt trust it a micron let alone and inch. It may work as the vital connecting surfaces may be clean but I would attent to that. I though mine looked poor. It was just a little green deposts on the copper which I did today. The surfaces of the lead and the washer under that nut and the nut were rusty tho so cleaned them carefully. Do the jump lead thing from battery to a good earth and see if it makes any differrence, I used two jump leads onto two differetn earths. My earth wirebrushed nicely so I left it as was. I do give it a good soaking with oil regularly and spray copper grease. Seems to have worked as its still the original lead 11 years on.

Dont rule out the battery either. I have just done two cars that went down two days apart. The difference is notable and it runs much better with a new one. So much so Im actually a bit shocked how much better it is. Its pretty clear that the battery has more affects on this engine than I have ever expereinced before. Previously I found I had an inlet manifold swimming in mayo and that made the car run pretty badly. Error codes at higher revs and some of what you are describing. New coil and leads made a little difference but no cure. Just mopping out the manifold did make a HUGE difference. On the Panda the MAF is in the bottom of the manifold so it was probably affected badly by this. I just removed the airbox and throttle body and the issue was pretty clear. Cleaned out with clean cottong rage and paper towels. Its at least quick simple and cost free to do but dont drop the throttle botls or tools down the back of the engine. I did and they ahve never been seen since!

 

[Msyogi]

Small update just done combustion leak test and results ok (I think lol) it’s saying if there is any leaks on head gasket that fluid should turn yellow… it’s from eBay called dr head gasket
Also received usb obd/usb cable dedicated for Fiat so I can do test via mes all clean

 

[iABDOzz]

I had Punto mk2a 2000 for years it's perfect, the only problem I had is this misfire on idle and I live with it normally it has no effect on car performance at all, I understand it's annoying, but the car is 20 years old with 130k km on it changed the engine once caused by wrong cheap oil stupid guy changed for me and the engine started making noises and leaking oil, after the new engine used a Liqui Moly 5w40 every 8000km and overall covers most of my needs, new car's has problems more than that so Iam thankful, I noticed that if I rolled my windows up or down the misfiring increase so I'm suspecting something with the car electrical parts, if you find a solution share it please.

 

[porta]

As a everyone else has stated the obvious, check that the cambelt/pulleys are in the right position
my old 1600 sporting punto had jumped one tooth on camshaft pulley, it was lumpy on tick-over, seemed to run fine underload but ran better when it was sorted, I just didn’t realise it! Have to say my 16v 1242 sporting was more enjoyable round corners.

 

[Cornish Ian]

As a everyone else has stated the obvious, check that the cambelt/pulleys are in the right position
my old 1600 sporting punto had jumped one tooth on camshaft pulley, it was lumpy on tick-over, seemed to run fine underload but ran better when it was sorted, I just didn’t realise it! Have to say my 16v 1242 sporting was more enjoyable round corners.

Small update just done combustion leak test and results ok (I think lol) it’s saying if there is any leaks on head gasket that fluid should turn yellow… it’s from eBay called dr head gasket
Also received usb obd/usb cable dedicated for Fiat so I can do test via mes all clean
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If all else fails ( earth leads etc) an “Italian tune“ might remove any carbon that may have accumulated, if the previous owner didn‘t drive it much, didn’t change filters or just drove very steady then perhaps worth an additive also. Perhaps you should also look at changing the cam belt before you do the “tune“ though. While your in there you could check the timing marks as Porta suggests.