CHUGGING ENGINE IN THE MORNING

[Leonfrdiesel184]

Hi there everyone I have noticed on some cold mornings my car starts absolutely fine but now and again the engine chuggs for a brief second as if fuel is not getting through. After I rev the engine for a bit it stops it completely. Like I say only seems to do it when the temp drops. Any ideas. No warning lights on engine at all and starts first time every time my car has just done 63k and is 2018 model could the fuel filter need changing ? cheers thanks

 

[SteveGSXR600K1]

My 184FR does exactly the same thing, and it's doing my tit not know why it does it! It's done it a few times over the years.
Starts up on a freezing cold morning perfectly, de-ice the car for a few mins, then it starts misfiring/chugging/lumpy. Switch it off/on and it's back to being fine. I'm assuming it's a sensor somewhere, but I've Googled everything I can think of to see if anyone else has had the same issue, and nothing.
I put OBDeleven on it the other day and nothing recorded.
Do you use your car daily?

 

[black_sheep]

Not too sure if this is part of the cold start cycle - as you are probably aware, diesel has a tendency to 'wax' when very cold - similar to slush.

Glow-plugs typically heat for 5-7 seconds pre-heat, a couple of seconds during start, 120-180 seconds once engine is running. Perhaps, glowplugs are switching off before enough heat is in the engine for smooth combustion.

Switching engine off, restarting, will restart the glow plug cycle, hence smooth running.

 

[SteveGSXR600K1]

I had the waxing on a C-Max TDi. Ford said the fuel filter would wax up and stop the flow of diesel through the pressure rail. Whenever I put my foot down, it would go into limp mode. They recommended changing the fuel filter annually.

Wondering if the 184 is waxing up as I'm only using it 1-2 times a week. May not be such a problem if I was using it daily.

Sent from my SM-G781B using Tapatalk

 

[Leonfrdiesel184]

My 184FR does exactly the same thing, and it's doing my tit not know why it does it! It's done it a few times over the years.
Starts up on a freezing cold morning perfectly, de-ice the car for a few mins, then it starts misfiring/chugging/lumpy. Switch it off/on and it's back to being fine. I'm assuming it's a sensor somewhere, but I've Googled everything I can think of to see if anyone else has had the same issue, and nothing.
I put OBDeleven on it the other day and nothing recorded.
Do you use your car daily?

Hi mate thanks for the reply I do alot of miles everyday in mine so little use shouldn't be the problem but at least it sounds like it's nothing to worry about if your car has been fine last few years mate.

 

[Leonfrdiesel184]

Not too sure if this is part of the cold start cycle - as you are probably aware, diesel has a tendency to 'wax' when very cold - similar to slush.

Glow-plugs typically heat for 5-7 seconds pre-heat, a couple of seconds during start, 120-180 seconds once engine is running. Perhaps, glowplugs are switching off before enough heat is in the engine for smooth combustion.

Switching engine off, restarting, will restart the glow plug cycle, hence smooth running.

Hi mate do you think changing the fuel filter would make any difference to this at all ? Thanks mate

 

[Leonfrdiesel184]

Not too sure if this is part of the cold start cycle - as you are probably aware, diesel has a tendency to 'wax' when very cold - similar to slush.

Glow-plugs typically heat for 5-7 seconds pre-heat, a couple of seconds during start, 120-180 seconds once engine is running. Perhaps, glowplugs are switching off before enough heat is in the engine for smooth combustion.

Switching engine off, restarting, will restart the glow plug cycle, hence smooth running.

Is it anything to worry about mate ?

 

[black_sheep]

In your initial post, you stated that you rev the engine it stops. I assume you mean the 'chugging stops' rather than the engine stops/stalls?

If this is the case, then it is probably be ok

With VCDS it is possible to raise the low idle engine speed slightly to cure a rough low idle.

In terms of the fuel filter, it should have been replaced at 90,000 km (56,250 mi). If not replaced, then it is due.

 

[Leonfrdiesel184]

In your initial post, you stated that you rev the engine it stops. I assume you mean the 'chugging stops' rather than the engine stops/stalls?

If this is the case, then it is probably be ok

With VCDS it is possible to raise the low idle engine speed slightly to cure a rough low idle.

In terms of the fuel filter, it should have been replaced at 90,000 km (56,250 mi). If not replaced, then it is due.

Thanks again mate no the engine doesn't stall just the chugging goes away once I give it a few revs. I will get the fuel filter changed it seems an easy thing to do looking online should I have some spare diesel in a can to top the filter back up afterwards ? What is vcds mate ? Lol

 

[black_sheep]

VCDS is a diagnostic tool, equivalent to the dealer tool. It can read/write to the vehicle control modules and can be used to conduct some maintenance functions.

The workshop manuals are here:

General maintenance - Leon Mk3 Official Seat Workshop Manuals Link

Hi All! I obtained these a few months ago, and they've been a great use so far. Here's a link to all of the Seat Workshop manuals for the Leon Mk3 3dr/5dr. https://drive.google.com/drive/folders/1M4ofxxMgsFjE7hNWg6l4KuifelmdMUu0?usp=sharing...

www.seatcupra.net

Instructions are in the documents titled 'maintenance' and 4 Cyl Diesel Engine (or something similar).

 

[SteveGSXR600K1]

Not too sure if this is part of the cold start cycle - as you are probably aware, diesel has a tendency to 'wax' when very cold - similar to slush.

Glow-plugs typically heat for 5-7 seconds pre-heat, a couple of seconds during start, 120-180 seconds once engine is running. Perhaps, glowplugs are switching off before enough heat is in the engine for smooth combustion.

Switching engine off, restarting, will restart the glow plug cycle, hence smooth running.

I wonder if it's got any thing to do with the automatic glow period control unit - J179

 

[black_sheep]

I wonder if it's got any thing to do with the automatic glow period control unit - J179

View attachment 35289

The issue is that it is operating as intended. Whilst the glow plug controller could be changed to operate for longer on the start cycle, this would reduce the life of the glow plugs. The car isn't stalling, and there are plenty of other sensors measuring pressures, temperatures, engine speed, vibration etc that ensure it is functioning within the design parameters. For example, no of cold starts is one of the factors that will reduce the distance/time on a car subject to variable servicing regime.

As above, unless the amber glow plug in flashing on the dash, and no DTC fault codes, the car is ok.

 

[RUM4MO]

Diesel, in UK, changes to a winter formulae in maybe early October, same for petrol, so waxing should not be happening unless it is still Summer Diesel that is in the tank.

 

[SteveGSXR600K1]

As above, unless the amber glow plug in flashing on the dash, and no DTC fault codes, the car is ok.

Tomorrow morning is going to be a bit more milder than it has been, but if it does play up, I'll record it and see if revving it makes it go away. When it plays up the revs are up and down between 750-950, car shakes/rocks, engine sounds like someone's tapping it with a hammer. Definitely not ok.

 

[black_sheep]

Diesel, in UK, changes to a winter formulae in maybe early October, same for petrol, so waxing should not be happening unless it is still Summer Diesel that is in the tank.

EN590 CFPP (cold filter plugging point) is -15 deg C (winter grade), but the fuel starts to cloud (wax) from -5 deg C (but there is no specification for this). Also, a lot of fleet/plant operators are having issues with newer bio-fuels mixes waxing at higher temps than is the norm.

 

[Leonfrdiesel184]

Tomorrow morning is going to be a bit more milder than it has been, but if it does play up, I'll record it and see if revving it makes it go away. When it plays up the revs are up and down between 750-950, car shakes/rocks, engine sounds like someone's tapping it with a hammer. Definitely not ok.

Hi mate how did you get on ?

 

[SteveGSXR600K1]

Hi mate how did you get on ?

It didn't do it! Only weird thing it did was, once it was started, if I raised the revs to somewhere between 1500-2000, it was all over the place. Let it back down to idle and it was fine again. Think I need to get an independent VAG mechanic to have a look.

 

[Leonfrdiesel184]

Good luck with it mate if you could update when you can that would be great