MK4 1.8Tdci lumpy start / white smoke.

[b9y]

Hey guys.

 

So I had an issue recently where the injector leak off pipes needed replacing, and it was ***** fuel (turns out, was just an O ring but the garage couldn't get it individually, and apparently the whole system needed changing....sigh...anyway). I got it back from the garage 2 days ago, but now it's not starting well when left overnight. It needs a bit of throttle to give it some oomph, without it, it'll just stall. When it does get going eventually after a few tries...big white plume of smoke out of the back.

 

Any idea what this could be? Even with the leak, it was still starting for a while....then it got worse and didn't. 

 

Thanks!

[FatHead1979]

On 9/19/2020 at 10:42 AM, b9y said:

Hey guys.

 

So I had an issue recently where the injector leak off pipes needed replacing, and it was ***** fuel (turns out, was just an O ring but the garage couldn't get it individually, and apparently the whole system needed changing....sigh...anyway). I got it back from the garage 2 days ago, but now it's not starting well when left overnight. It needs a bit of throttle to give it some oomph, without it, it'll just stall. When it does get going eventually after a few tries...big white plume of smoke out of the back.

 

Any idea what this could be? Even with the leak, it was still starting for a while....then it got worse and didn't. 

 

Thanks!

Any idea if they disturbed the fuel filter, there have been many garages over the years that have reinstalled the fuel filter incorrectly on this engine.  The filter comes with a large rubber seal which goes UNDER the top circular plastic bit of the filter, it's often fitted on top of the filter but this doesn't create a perfect seal and causes problems with starting and low rev performance/idling etc.

 

The white smoke will be unburnt diesel which could be down to faulty glow plugs but if it wasn't doing this before I'd be more likely to suspect that some part of the fuel system has a tiny leak and is allowing a small amount of air in.

[b9y]

I spoke to the garage, they told me the mechanic had spotted issues with the injectors..so I'm taking it back there. The garage said it could be all 4 injectors but they won't know until it's been checked, could that be the case? Seems a bit weird how all 4 could be faulty because the engine does run ok ish once it's started. I'll ask about the fuel filter thing.

 

Basically it judders between 1-2k rpm, and then stops when pulling off, and judders from about 50mph onwards. Throttle is a little shakey in 5/6th gear. It sometimes will stutter just for a split second  when my foot is on the throttle and gently accelerating.

 

I think I've noticed that it's harder to start parked uphill, if that helps? But yea, apparently it's the injectors!

[FatHead1979]

On 9/24/2020 at 2:05 PM, b9y said:

I spoke to the garage, they told me the mechanic had spotted issues with the injectors..so I'm taking it back there. The garage said it could be all 4 injectors but they won't know until it's been checked, could that be the case? Seems a bit weird how all 4 could be faulty because the engine does run ok ish once it's started. I'll ask about the fuel filter thing.

 

Basically it judders between 1-2k rpm, and then stops when pulling off, and judders from about 50mph onwards. Throttle is a little shakey in 5/6th gear. It sometimes will stutter just for a split second  when my foot is on the throttle and gently accelerating.

 

I think I've noticed that it's harder to start parked uphill, if that helps? But yea, apparently it's the injectors!

Interesting.  Most of the symptoms could be either an injector fault OR a small amount of air getting into the system, unfortunately it's not always easy to tell which is actually the root cause.  Don't forget to let us know how you get on.

[b9y]

They replaced all 4 injectors. Said they were all a bit shot to *****....although the car did actually run reasonably well so I'm not sure why they did all 4. Sigh. But anyway, it hasn't solved the issue and now it's running even worse in lower speeds...jumpy / jerky etc. Won't start well either. They reckon it's a pinpoint airhole somewhere, but where, who knows. I feel like the car is just gonna go to scrap and I've paid £2400 + £1700 so far to get it fixed. Damn. 

I had to take it back early to move house but they're gonna do a full diagnostic. Leave it at an angle each night and see if starts. On a flat it'll die after a few hours of being sat, then fire up...then after that it's usually fine for a few hours until it's cold again. 

 

Very weird. Not sure what to do. 

[Bungz]

Sounds like they haven't a clue, the 1.8 tdci is not a hard engine to work on.

Wouldn't entertain giving them any money on the basis they have made the car worse, I presume it ran fine with the leak off problem....

 

1700 for a set of injectors is also very top end, new they are only 150 or less and are not hard to change

[Texasso]

Hi. Had similar problem to you one in my wife Focus 1.8 tdci . Apparently when changing fuel filter I have put seal incorrectly and there was problem to start engine but what's funny it went wrong after 1 month . Check fuel filter  seal first is my advice if that won't help check fuel supplying hoses for damages  ,especially next to timming belt cover . White smoke comes when engine doesn't get enough fuel delivered.

Edited December 9, 2020 by Texasso
Adding answer