A4 2.5TDi struggles to start cold weather

[kev A4 B6]

Hi wondered if anyone could help. I own a a4 b6 2.5tdi quattro 180
Its slow/struggles to start from cold in cold weather but then runs sweet and will start perfect everytime after when warm Also get quite a bit of dark smoke when struggles
Cheers kev

[Crasher]

Quite possibly faulty glow plugs. First of all you need a fault code read to check for issues such as a faulty coolant temperature sender and also a valve timing check would be a good idea as would checking a setting known as the Commencement Of Injection (COI) which is done using a diagnostic computer. If all appears well, I would remove the glow plugs and test them BUT even if they are working fit new ones as old ones tend to snap and a broken glow plug will really ruin your day, well year actually.

[kev A4 B6]

Quite possibly faulty glow plugs. First of all you need a fault code read to check for issues such as a faulty coolant temperature sender and also a valve timing check would be a good idea as would checking a setting known as the Commencement Of Injection (COI) which is done using a diagnostic computer. If all appears well, I would remove the glow plugs and test them BUT even if they are working fit new ones as old ones tend to snap and a broken glow plug will really ruin your day, well year actually.

Thats good advice cheers I will change plugs first then see how that works Any reconmendations to which plugs to use?

[c7trp]

Had similar problem with my 2.5 last winter.

Local indy specialist removed and tested them, and 3 were duff.

I found mine started better if you let the heater lamp go out, then ignition off and back on again for another heat cycle.

HTH

[Crasher]

Yes, letting the glow plugs run another cycle is a good way to help you get going and to decide if that is the issue. I like Beru glow plugs, either (assuming it is an AKE engine) the original VAG 059 963 319 H which are reasonably priced at around £20 each or from a Beru retailer under the Beru part number 309630319059H.

[pebblypuss]

Got a similar problem with a struggle to start on cold but with tons of white smoke. I'd always associated black smoke with diesel not burning fully. Mine's been to dealers already and I was quite prepared to pay for glow plugs but they insisted it wasn't them and changed the fuel filter and seals (which needed doing on schedule anyway). This didn't make a jolt of difference so now it's booked in week after next for a cold start on diagnostics. Needless to say it barely requires turning over when even slightly warm.

Having read a few other threads on other forums it's quite possible that the fuel timing is out. I used to have a 1985 golf 1.6 diesel (long before TDi) and that had a manual advance on the injector pump and was used in the same way that the choke is on petrols. Not using it when cold meant it'd never start easily so I'm coming round to this way of thinking.

I'll keep you all posted of what fixes mine, if indeed it gets fixed. BTW it's the BDG engine.

Mark.

[toff]

Hi,

My 1.9 TDI has also been struggling to start in this very cold weather. I hooked-up a battery charger only to find that the battery was almost full with a healthy voltage reading.

A neighbor told me to turn the ignition, wait until the glow-plug symbol extinguishes, repeat that process 2 times then try to start the car (pretty much what Crasher is suggesting). It's still a lumpy start, but doing this has undoubtedly got the car going whereas I would have been stuck before!

Whats involved in replacing the glow plugs? Does lots of other stuff have to be removed first, like the fuel injectors?

Al.

[Crasher]

They are very easy to get at and change (10-mm deep reach socket) BUT there is always the possibility of them snapping, it happened to us once a few years ago on a 2001 A4 AVF for no reason. I got it out with an extractor but it was touch and go and I was sweating. I always do them with the engine very hot to help release them and I pray (nearly literally) that they will not snap but always pre warn the customer that if they do, it is not my responsibility. For this reason I never re-fit old glow plugs, it is just not worth the misery a snap one will cause for the sake of £50.

[toff]

Thanks for the info Crasher.

The aforementioned neighbor has a 53 plate Golf 150 TDI.. he had to have a rebuild because the end of one of the glow-plugs fell off into the combustion chamber!! Have you heard of that happening before?

So, I will extract the glow-plugs after returning home from a long motorway journey (good hint). I take it a gentle, smooth push with an extra-long breaker bar would be better than a short-sharp nudge with a normal socket wrench?

Is it worth spraying each one with releasing agent or could that cause problems if it drips in the combustion chamber?

My A4 has covered 137k and unless it's part of a service, I doubt they've been changed! eek!

Al.

PS: I always worry about bits of dirt getting into the engine whilst doing work like this - is compressed air the best thing to clear debris before undertaking such work?

[scooby_d0o]

i have the same prob on my 2.5tdi quattro, although i put it down to the pump timing being a hint off, or the leak offs on the injectors (a couple leak slightly which would mean air is able to enter the system allowing fuel to run back) but back to the glow plugs - VERY prone to snapping! i had to completly rebuild my engine after it and a puddle had a falling out (2 pistons, 2 conrods) anyway as engine was in pieces i decided to replace all 6 glow plugs - 1 of the new plugs snapped (i tourqued to required Nm setting (from etas)) and one broke off - took me the whole day to get it out - basically drilled it out starting with a small drill bit and getting bigger, until i was left with only the threads and could turn the remainder of the glow plug out. My engine had tapered threads which mean the plugs can only be used once - also means they get good and stuck when installing them. BE CAREFUL