Technical I am going crazy with a P0300

[Flat Earth]

What spark plugs are you using?

NGK ZKR7A-10, before and after replacement. I've been using them since I bought it.

 

[koalar]

I not sure I understand what’s going on

If you unplug a injector or coil you don’t get a misfire code

If you loose connection to either you get a different error code

It just doesn’t all fit into place.

Timing causes cylinder 1 and 4 misfire but not only while it’s hot

VVT is run by oil so could be affected by heat but should come up with a mismatch error with cam as well

ECU has been located there for 12 years without any heat issue

Strange but at least it’s fixed

I be tempted to put the original ECU back in. Clear all the adaptive memory and relearn everything and see if the problem reoccurs. It’s possible there is a dry joint in the ECU that’s effected by heat. But it would be the first we have seen on here.

 

[Txuchin]

It seems that only the injectors remain to be changed
You can buy them in China for less than euro100.
You can also swap 1 and 4 to 2 and 3

Parece que solo quedan los inyectores por cambiar
Puedes comprarlos en China por menos de 100 euros.
También puedes intercambiar 1 y 4 al 2 y 3:

 

[koalar]

It seems that only the injectors remain to be changed
You can buy them in China for less than euro100.
You can also swap 1 and 4 to 2 and 3

Parece que solo quedan los inyectores por cambiar
Puedes comprarlos en China por menos de 100 euros.
También puedes intercambiar 1 y 4 al 2 y 3:

That’s what I would do
Swap and see if the fault follows the injector while it was giving the error

However the original no longer has the misfire code since changing the ECU although the car isn’t 100%

 

[Flat Earth]

This is going to be funny. Today was really hot again, so I took her for a ride and misfires were so obvious that I stopped the car. Checked DTC but none reported, no EML or limp mode either. I changed the ECU back to the original one and P0300 came back immediately.

Just for test purposes, I swapped ECUs one more time and unplugged oxygen sensor to see if DTC would come up. It didn't. So I'm thinking the refurbished ECU is not reporting any errors. I'm going to ask for a replacement. The improvement that I felt the other day may be related to a lower ambient temperature and not the "new" ECU unit.

You are right, I need to test my injectors but I don't have the tools. I visited 3 garages today but no one would take my car (they say they are overwhelmed with work). Either I wait until September or I start buying tools

One more thing. I was reading the manual today and I realised that tappets need to be checked and adjusted every 60.000km. I don't think the previous owner did it (I bought it with 73.000km) and I'm now close to 120.000km so I'm thinking it may be related. However, there is no "tappy sound" (I don't have the faintest idea how to translate that, but I'm referring to this metallic sound engines do when tappets wear down).

I will keep you posted. A few weeks later, this car is still driving me crazy.

Thank you all!

 

[koalar]

Sorry to hear you are still having problems

P0300 isn’t very helpful

If you can hear a regular misfire from the exhaust at idle

You can unplug an injector or spark lead one at a time.

The ones that make little or no difference are the cylinders that aren’t firing properly

Tappers do rattle as the car ages. I have had two car that have done close to 200k miles without reshimming

 

[koalar]

It’s a bit of a long shot

Fiat recommend checking this earth lead, unbolt and clean

It’s bolted to the front right of the cam cover on my right hand drive car

 

[koalar]

The picture above is the return earth for the coil pack

Might be worth doing a compression test before spending any more on more parts

It will tell you quite a lot about the state of the engine

If it’s low on compression it can send you round and round in circles

 

[DaveMcT]

Don't forget the earth wire to engine ECU. It has it's own M6 stud and goes to the body shell in the corner above the ABS unit.

 

[Flat Earth]

Thanks again for your help. I checked the earth leads but they all seemed fine. Finally, I found the time and the tools to remove the injectors.



Notice the stains in the 4th injector. No idea what they are, maybe rust?

I swapped 1 and 4 with 2 and 3, respectively, and I flooded the common rail with injector cleaning fluid. I pushed ignition until all the fluid was out and I also cleaned the o-rings with the same fluid.

P0300 is gone for good, I've been unable to reproduce it. Emission tests are also ok now. There are still misfires from time to time so I'm thinking of replacing them entirely. Any thoughts regarding the quality of Chinese ones? I've been reluctant to use non-original parts but these are expensive AF.

 

[Txuchin]

I put these injectors:

Boquilla de inyector de combustible, accesorio para Fiat Palio Panda Punto Seicento Siena Lancia 032906031A,71719101,71724088,IWP116,0280158169,IWP095, 6 unidades - AliExpress 34

Smarter Shopping, Better Living! Aliexpress.com

es.aliexpress.com

They work exactly the same as the originals. You will have to find the ones that work for your engine.

 

[koalar]

I very much doubt the injectors are the problem

Cheap China are normally rubbish and even dangerous

Seeing how few we have fail here on UK fuel I would be quite happy to pull a set out of a running car at the breakers

 

[Flat Earth]

I put these injectors:

Boquilla de inyector de combustible, accesorio para Fiat Palio Panda Punto Seicento Siena Lancia 032906031A,71719101,71724088,IWP116,0280158169,IWP095, 6 unidades - AliExpress 34

Smarter Shopping, Better Living! Aliexpress.com

es.aliexpress.com

They work exactly the same as the originals. You will have to find the ones that work for your engine.

Yes, I have the reference and the part from aliexpress. However, I found this video where they compare them to Bosch originals and the variability is significant. Not quite sure what to do (btw, thanks for your video replacing the injectors, it's been very helpful to me

I very much doubt the injectors are the problem

Cheap China are normally rubbish and even dangerous

Seeing how few we have fail here on UK fuel I would be quite happy to pull a set out of a running car at the breakers

I was in doubt too, but no other part replacement has shown any real improvement. The injector cleaning did. 250-mile drive with no power loss or noticeable misfires. I honestly don't know, quite noob at mechanics

Thanks for the recommendation and help

 

[koalar]

personally run fiats still on there original injectors @

200,000 x 2
150,000 x 1
90,000 x 1

That’s miles not kilometres

They may not be perfect but run fine on UK cheapest petrol
I have never heard of a petrol injector failing

Diesel yes but rare

In your country the petrol maybe different.

Not sure of cost in your country but here in the UK it’s about £15 per injector to have them tested

I suspect some local garage would test them. For a bit of beer money. If they weren’t busy

 

[Flat Earth]

personally run fiats still on there original injectors @

200,000 x 2
150,000 x 1
90,000 x 1

That’s miles not kilometres

They may not be perfect but run fine on UK cheapest petrol
I have never heard of a petrol injector failing

Diesel yes but rare

In your country the petrol maybe different.

Not sure of cost in your country but here in the UK it’s about £15 per injector to have them tested

I suspect some local garage would test them. For a bit of beer money. If they weren’t busy

I think they just don't want to diagnose her. It takes time and small, straightforward repairs and/or maintenance yield more benefits than struggling against a single car... maybe if I personally remove the injectors and ask them for a test they wouldn't hesitate.

For that little money it is worth it to test them before replacing, specially if the use of chinese parts is discouraged.

Thank you!

 

[koalar]

Have you looked at the VVT solenoid

The fine mesh grill can get clogged worth checking anyway as it’s only one bolt, easy to get to and a visual inspection

Flow would alter as the oil changes viscosity

It’s this mesh here and always on the side at the bottom that gets blocked

 

[Elliott 4]

Hello everyone!

I have a Fiat Panda 1.2 69HP "born" in 2013 that is throwing P0300, P0301 and P0304 errors. I've replaced sparks, spark plugs, coils, oxygen sensor and MAP sensor, with no luck. The problem persist and it's more accute in hot temperatures. Long fuel trim -55%.

Any ideas? I have no idea regarding how to test the ECU, and since the long fuel trim is really high I'm starting to think that it might be some leaking inyector.

Thanks!

Hi, did you ever get to the bottom of this? The reason I’m asking is because I’m having the same problem with my fiat panda, 1.2 2012. Although the temperature outside and RPM etc makes no difference. It can happen a short or long distance from home. I’ve had two new coil packs and leads, but the intermittent fault persists.

It’s been to an electrical garage but they can’t get to the bottom of it either.

New timing belt this year.

I’ve attached the fault codes and engine misfire sound.

Hello everyone!

I have a Fiat Panda 1.2 69HP "born" in 2013 that is throwing P0300, P0301 and P0304 errors. I've replaced sparks, spark plugs, coils, oxygen sensor and MAP sensor, with no luck. The problem persist and it's more accute in hot temperatures. Long fuel trim -55%.

Any ideas? I have no idea regarding how to test the ECU, and since the long fuel trim is really high I'm starting to think that it might be some leaking inyector.

Thanks!

 

[Flat Earth]

Have you looked at the VVT solenoid

The fine mesh grill can get clogged worth checking anyway as it’s only one bolt, easy to get to and a visual inspection

Flow would alter as the oil changes viscosity

It’s this mesh here and always on the side at the bottom that gets blocked

View attachment 410914

No, but I will definitely do it, thank you. These recent months have been a nightmare in work, I'm sorry for not replying sooner. Unfortunately, the fault came back a few weeks ago, same cylinders (1&4). When I removed the injectors to clean them, I swapped them intentionally to the other two cylinders (2&3). But the error is still in the original cylinders, therefore I don't think they're faulty anymore.

I should have time by Christmas, so I will try to have the VVT valve checked. I'm about to buy a new car; the only reason I have one is the possibility of going wherever I want whenever I need, but if it is unreliable it does not worth the money. In any case, I intend to keep my Panda until I find out what is causing this mess. It has become a challenge of some sort

Hi, did you ever get to the bottom of this? The reason I’m asking is because I’m having the same problem with my fiat panda, 1.2 2012. Although the temperature outside and RPM etc makes no difference. It can happen a short or long distance from home. I’ve had two new coil packs and leads, but the intermittent fault persists.

It’s been to an electrical garage but they can’t get to the bottom of it either.

New timing belt this year.

I’ve attached the fault codes and engine misfire sound.

I'm sorry, but I never did. Your car sounds exactly like mine, although my faulty cylinders are one and four. I will keep you posted if I do.

 

[Elliott 4]

No, but I will definitely do it, thank you. These recent months have been a nightmare in work, I'm sorry for not replying sooner. Unfortunately, the fault came back a few weeks ago, same cylinders (1&4). When I removed the injectors to clean them, I swapped them intentionally to the other two cylinders (2&3). But the error is still in the original cylinders, therefore I don't think they're faulty anymore.

I should have time by Christmas, so I will try to have the VVT valve checked. I'm about to buy a new car; the only reason I have one is the possibility of going wherever I want whenever I need, but if it is unreliable it does not worth the money. In any case, I intend to keep my Panda until I find out what is causing this mess. It has become a challenge of some sort



I'm sorry, but I never did. Your car sounds exactly like mine, although my faulty cylinders are one and four. I will keep you posted if I do.

Sorry, I’ve only just seen your reply. Thank you very much