Hi all. I’ve got a bit of an issue with my ‘20 plate 1.5 TSI ACT on 120k miles.  

 

When starting from cold the engine begins to misfire and throws up a few codes. One for  misfire across multiple cylinders P0300 and P0148 for fuel delivery issue. (If I turn it off immediately and restart it this does not occur again). Subsequent starts when the engine is at operating temperature are fine. 

The engine has also become a bit noisy over the past few months but still drives fine. A live data scan with Carista indicated a misfire in cylinder 2 but that went away quickly. 

 

I’m thinking that both are linked and there must be an issue with the high pressure fuel pump but I really can’t afford to fire the parts cannon at it any longer.

 

Anyone any ideas?

Plugs, coil packs usual 1st suspects. Beyond that, injectors, fuel pump, carbon build up.

 

Can you check fuel parameters, fuel rail pressure for one..  

I had a similar issue with my previous Octavia 1.5tsi, initially it was mainly at start up, gradually became worse over time, the AA did a code reader on it when it threw up an ecu light (the engine then sounded like a bag of hammers), random cylinder misfires. I had an extended warranty at the time with Skoda, so I then took it in for a diagnostic, they confirmed 3 of the 4 plugs were breaking down, even though they'd supposedly changed them less than two years ago, they replaced 3 under warranty & I paid for the fourth myself, as they were to tight to replace it under warranty. Anyway it solved the issue. Once the engine had warmed up & the AA breakdown fella had arrived the engine was running sweet again, but fortunately there was some historic codes stored. 

Edited 30 September, 20241 yr by Phoenixboy

Thanks for the input. Checking Google it seems to be highlighting carbon build up

on the inlet valves as the main culprit. I’ve purchased some arch oil snake oil and will see if that will make a difference. 

7 hours ago, gm73 said:

Thanks for the input. Checking Google it seems to be highlighting carbon build up

on the inlet valves as the main culprit. I’ve purchased some arch oil snake oil and will see if that will make a difference. 

With gdi engines the inlet valves are not washed with petrol, prior to combustion, hence carbon build up. Some gdi engines engines seem more susceptible to this than others. I know with the older mini, pug, bmw gdi engines those inlet valves were cleaned with a walnut shell blasting machine. I'd have thought if they were heavily carboned up it may of effected the performance of the engine, too. Although I'm no expert. 

Those 1.5tsi engines do seem to eat plugs, though. My last 1.5tsi ACT had two sets within two years. 

Stating the obvious have you had your battery load tested?

Edited 2 October, 20241 yr by Phoenixboy

On 02/10/2024 at 23:15, Phoenixboy said:

With gdi engines the inlet valves are not washed with petrol, prior to combustion, hence carbon build up. Some gdi engines engines seem more susceptible to this than others. I know with the older mini, pug, bmw gdi engines those inlet valves were cleaned with a walnut shell blasting machine. I'd have thought if they were heavily carboned up it may of effected the performance of the engine, too. Although I'm no expert. 

Those 1.5tsi engines do seem to eat plugs, though. My last 1.5tsi ACT had two sets within two years. 

Stating the obvious have you had your battery load tested?

Funny you should mention the battery. It’s started to act up. The car was laid up for longer than usual and yesterday when started it idled at 1000rpm most of the day as if it was compensating for low charge. Carista said it was at 68% capacity and only a long motorway run pushed it back to 82% and stopped the high idle. Got it checked at the garage and was told the testing equipment said to replace battery. Ordered a new one from Tayna for a good price and it arrives today at some point. Which opens another can of worms. It looks like you can code the battery to the car using Carista but I’m worried about any issues. 

7 hours ago, gm73 said:

Funny you should mention the battery. It’s started to act up. The car was laid up for longer than usual and yesterday when started it idled at 1000rpm most of the day as if it was compensating for low charge. Carista said it was at 68% capacity and only a long motorway run pushed it back to 82% and stopped the high idle. Got it checked at the garage and was told the testing equipment said to replace battery. Ordered a new one from Tayna for a good price and it arrives today at some point. Which opens another can of worms. It looks like you can code the battery to the car using Carista but I’m worried about any issues. 

When I had the EFB battery replaced my previous Octavia, the garage coded it in with cloned software, think I paid £150 all in with a 2 year guarantee. 

I've not as yet coded a Skoda battery in myself, so can't advise you on then, as I'm fairly new to vag. 

Hopefully the new battery may sort out your running issues, once you've coded it in. 

11 hours ago, Phoenixboy said:

When I had the EFB battery replaced my previous Octavia, the garage coded it in with cloned software, think I paid £150 all in with a 2 year guarantee. 

I've not as yet coded a Skoda battery in myself, so can't advise you on then, as I'm fairly new to vag. 

Hopefully the new battery may sort out your running issues, once you've coded it in. 

If the battery is the same type (EFB or AGM) and substantially the same Ah capacity then all you need to do is change one digit of the battery serial number in the BMS module.

On 08/10/2024 at 21:13, Phoenixboy said:

When I had the EFB battery replaced my previous Octavia, the garage coded it in with cloned software, think I paid £150 all in with a 2 year guarantee. 

I've not as yet coded a Skoda battery in myself, so can't advise you on then, as I'm fairly new to vag. 

Hopefully the new battery may sort out your running issues, once you've coded it in. 

New battery is installed. We’ll see what happens tomorrow as it’s going to be pretty cold first thing.  It began to misfire this morning as it was 2.5 degrees. I’d hoped the Archoil additive had helped but apparently not. 

Possibly the plugs, was with mine, but without an in-depth diagnostics, hard to tell. Last place I'd ever want to take my car out of warranty would be a skoda dealer. 

Just out of interest, does yours use any oil? Mine is on 68k now, useless around 1/4 of a litre of oil every 3 months or 2k covered. My last one didn't use, any. 

Edited 12 October, 20241 yr by Phoenixboy

On 12/10/2024 at 22:35, Phoenixboy said:

Possibly the plugs, was with mine, but without an in-depth diagnostics, hard to tell. Last place I'd ever want to take my car out of warranty would be a skoda dealer. 

Just out of interest, does yours use any oil? Mine is on 68k now, useless around 1/4 of a litre of oil every 3 months or 2k covered. My last one didn't use, any. 

No oil is being used although the oil sensor is on the blink. Just ignoring that as I check the oil manually every day anyway. 
 

The battery appears to have fixed the issue. No misfires this morning and it was 2 degrees.  

5 hours ago, gm73 said:

No oil is being used although the oil sensor is on the blink. Just ignoring that as I check the oil manually every day anyway. 
 

The battery appears to have fixed the issue. No misfires this morning and it was 2 degrees.  

Fantastic news. always best to have it load tested, even if you'd previously tested it with a multi meter. 

And the issue has returned this morning. Started the car and it long cranked and went straight into limp mode giving me a P0148 fault code which is a fuel delivery error. It’s done this before as well. Restarted the car and it was fine. It’s got a brand new battery as well. 
 

I’m wondering if it’s the oil causing the issues as I’ve switched to 5w30 on the last change. 

42 minutes ago, gm73 said:

And the issue has returned this morning. Started the car and it long cranked and went straight into limp mode giving me a P0148 fault code which is a fuel delivery error. It’s done this before as well. Restarted the car and it was fine. It’s got a brand new battery as well. 
 

I’m wondering if it’s the oil causing the issues as I’ve switched to 5w30 on the last change. 

Its not going to be the oil - although it should be ideally running on 0W30 LL FSIII VAG 504/507 spec oil.  

P0148 is generally a priority 2 fault code (high) and is usually to do with either fuel pressure, fuel regulation or according to Ross-Tech, this code is associated with Fuel Temperature Sensor A being faulty.  Can you get us a full VCDS/ODBEleven scan please?

 

On 11/11/2024 at 09:50, varaderoguy said:

Its not going to be the oil - although it should be ideally running on 0W30 LL FSIII VAG 504/507 spec oil.  

P0148 is generally a priority 2 fault code (high) and is usually to do with either fuel pressure, fuel regulation or according to Ross-Tech, this code is associated with Fuel Temperature Sensor A being faulty.  Can you get us a full VCDS/ODBEleven scan please?

 

Recommended oil for this car is 0w20 VAG spec 508/509. 
 

It must be a fuel delivery issue as a blip of the throttle seems to resolve the misfire. But since it occurs only when the car is cold perhaps the fuel temp sensor is incorrectly reading. 
 

It can’t be carbon build up as it doesn’t do it at any other time.  

Hello all.

 

I have the same issue with my 2019 - Octavia MK3 - 1.5 TSI ACT.

I guess the fuel problems are due to the high pressure pump, more exactly with the piston on the bottom of the pump that can be changed separately. 

 

As of my knowledge they must be changed at every 40k to 60k Km.

 

I had the Cyl 2 Misfire and misfire at first 1000 rotations for a while  but now, since the cold has come, i throws random misfire, cyl 1, cyl2 and cyl3.

 

The sparkplugs have less then 10k KM, all 4 new from Bosch.

 

Dose anyone figure this out ?

1 hour ago, Sailas2006 said:

Hello all.

 

I have the same issue with my 2019 - Octavia MK3 - 1.5 TSI ACT.

I guess the fuel problems are due to the high pressure pump, more exactly with the piston on the bottom of the pump that can be changed separately. 

 

As of my knowledge they must be changed at every 40k to 60k Km.

 

I had the Cyl 2 Misfire and misfire at first 1000 rotations for a while  but now, since the cold has come, i throws random misfire, cyl 1, cyl2 and cyl3.

 

The sparkplugs have less then 10k KM, all 4 new from Bosch.

 

Dose anyone figure this out ?

This engine seems to eat plugs, I had two sets fitted on my previous 68 plate 1.5tsi act engine. First set started to fail under 10k, codes were random misfires and single cylinder misfires. My engine started to randomly run rough on tickover and then gradually became worse from a cold start over time, until eventually the engine ran on 3 cylinders from a cold start. Once the plugs were changed again the engine was back to A1 again. 

My current 19 plate 1.5tsi (different car now), had its plugs changed 10 months ago, up to now I've experienced no engine issues whist running or during tick over, its now covered 70k. Always ran smoothly within any conditions. 

Any update?

Hello. I have the same problem. Have you fixed the problem? My car is Octavia 3 1.5 tsi 200k km. I have change the spark plugs, the coils pak and no effect. I have misfires only on Cylinder 2 and 3...My battery is from 12.2021...

Edited 21 July, 202521 Jul by bgd1106

Two things come to mind: At such high mileage, the inlet manifold might be completely blocked from carbon deposits. The injector port may also be gummed up. Seen this a lot on higher mileage VAG cars. Other thing to check - make sure you have good compression on all cylinders too.Try running several tanks of super unleaded (such as Shell V-Power) to try cleaning EGR/Inlet/Valves.

Edited 24 July, 202524 Jul by varaderoguy

Should I also put an additive in the tank specifically for cleaning the valves?

1 hour ago, bgd1106 said:

Should I also put an additive in the tank specifically for cleaning the valves?

It's direct injection, surely, so won't go near any intake valves if it's in the fuel.

Won't have an EGR valve either.

So it won't help anything at all

52 minutes ago, bgd1106 said:

So it won't help anything at all

Correct. On the 1.4/1.5 EA211 there are only direct injectors but the 1.8/2.0 EA888 does have an extra indirect injector so on them an additive MIGHT help.

1 hour ago, Breezy_Pete said:

It's direct injection, surely, so won't go near any intake valves if it's in the fuel.

Won't have an EGR valve either.

Is EGR only applicable to diesels then?