2.0 TDI BKP start up smoke/missing when warm

[bkpbod]

Hi,
First post and relative newbie Passat owner so sorry in advance for long post! Have got a 2006 Passat 140 tdi (BKP) with just under 150k on it, had since last year but been having some issues with the engine I just can't get to the bottom of. Basically has always put out a fair bit of smoke on start up for first 5 - 10 secs when cold and always starts immediately (almost too fast) either winter or summer, glow plug light never stays on more than 2 seconds. When starts it also runs pretty rough first 5 seconds. More recently it also feels like its misfiring when warm and cruising on light throttle and has now put on the emissions light (constant).

Car is a non DPF with the C head, had the injector recall at 90k, so far i've;

- replaced tandem pump with new one as fuel filter was pretty black, pulled it since and looks ok now.
- cleaned egr valve (wasn't too bad)
- put in a new genuine vw injector wiring harness. This seemed to stop the misfiring for awhile but now back.

On a budget so I don't have VCDS but scanned it with a foxwell VAG scanner and came up with;

- 01648 glow plug module control circuit sporadic 006 - short to plus
-01649 cyl 1 glow plug circuit - sporadic 006 - short to plus
-01651 cyl 3 glow plug circuit - sporadic 006 - short to plus
-04711 cyl 3 pump/injector valve-N242. Value above upper control limit - sporadic 006 -short to plus

After cleaning the EGR and replacing the harness I cleared the codes but the emissions light came back on shortly after, the code 04711 also appeared. Have got a new set of correct type Bosch glowplugs ready to fit and a good s/h relay but i'd be grateful for any help as not sure if theres something else it could be, ie would the faulty glowplugs/relay cause the smoke/instant starting (overfueling?) and maybe be related to the injector 3 code, with inj 3 causing the missing? Read on other posts of incorrect glowplugs being fitted so don't know if that's part of the problem. Maybe unrelated but the car has always had a high pitched noise from the turbo and more recently seen lots of black smoke out the back when accelerating. Isn't using any coolant, using some oil but not a huge amount, Mpg also down lately compared to before.

Cheers for any help and sorry for the ramble
Pete

[niall campbell]

17675/P1267/004711 - Ross-Tech Wiki

Sounds like you need to replace injector number 3, as you have replaced the wiring loom ............................. maybe look for frayed wires

The glowplugs only last so long , so I wouldn't worry about them causing the smoke too much ........................... it should help though................... but my guesstimation is the injector not spraying correctly due to wiring problem or putting too much diesel into the cylinder

Oil should go from Max to Min every 10,000 miles ................................. my A6 uses oil between 10K & 20K with long life .................... I now only use normal oil & change every 10 K with filter. I am happier with that, as I was worried I was losing oil rather than using it



P.S I am sure someone in here had a similar problem recently and it was solved by using a screwdriver to crimp the wire on correctly .................. If I find it I will post it on here..............but don't damage the wires !!!!

[bkpbod]

thanks, will check the wiring and look out for an injector. My oil consumption is definitely on the up so reckon i'm probably going to need to do the turbo soon after reading others posts, has been sounding a bit like a siren especially when cold!

[DMitch16]

If you have the twin balance shaft unit mounted under the crank (in the sump) make sure your oil pump drive key and shaft are not worn to the point it might fail any minute. Mine first went at 151k. Tank lift pumps also wear out becoming weak as they get older making the tandem pump work harder (if the car will start). Mine failed after / during a cam, valve stem and injector seal renewal job at 195K. Failures of these are common on older cars. Injector seals often start leaking at higher mileages and are one of the common reasons for bad running or fuel economy. Turbos are normally quiet or emit a high pitch whistle but if your oil pressure has suffered due to a worn pump drive key it could mean the oil drive is about to fail as turbos start to sound angry just before this happens.

[bkpbod]

thanks, hadn't thought about the oil pump! Any idea what the easiest way is to get to it? Have got oil seals and bolts on order to do all four injectors when i'm there, not done it before so going to take a day off to do it. My turbo noise seems to have stayed the same since bought the car last, sort of like a high pitch whistle but quite loud especially when cold, get some funny looks from pedestrians! When I cleaned the EGR the boost pipe looked pretty clean, don't know if this would be mucky if my turbo was on the way out or if there would be other symptoms to look for? Definitely lots of black smoke lately on even moderate acceleleration that wasn't there before though maybe the soon to be replaced injector 3 isn't helping.
cheers for the help

[bkpbod]

Thought i'd provide a quick update, I decided to pull the rocker cover on my day off today, lo and behold glow plug no.3 connector had somehow become completely disconnected and the routing for the two wires to injector no.3 connector were almost folded back on themselves! As it was me who put the new harness in a few months back guess I've only got myself to blame... Carefully straightened out the wires and fitted the new NGK glow plugs, the old ones looked pretty knackered;, with the tips of 1 & 3 pretty much gone and 2 looking like a different type.

IMG_0591.jpg IMG_0589.jpgIMG_0590.jpg

Reckon when I fitted the new harness i didn't push the glow plug connector in hard enough and/or the angle of the wire acted a bit like a spring to bring it back off the glow plug. Did an oil change and cleared the codes, going to see what comes back. Had a really good look for the glow plug relay to fit a spare, as a code for that had previously come up but couldn't find the thing anywhere. Looked under the Fuse box to rhs of the battery as read its supposed to slide out from under there but couldn't see anything like that. Also looked round the bulkhead and at the relays below and to the right of the steering wheel but still no joy?

[Crasher]

It is under the engine bay central electrics unit and you have to take the whole thing to bits to get at it.

[bkpbod]

thats great thanks, will have another go. I removed the cover, loosened off the single central screw and started to gently pull up the top bit holding the fuses, it moved upwards a fair bit but the connecting cables appeared to be stopping it coming completely off. I'll try disconnecting the battery and removing all the connecting leads, hopefully it'll come off then!

[Crasher]

You have to dismantle the BUS bar at the front, remember to keep the fuses in order.

[bkpbod]

Thanks, will do. Have been using the car for awhile and no relay code has reappeared since fitting the new plugs, will see if comes back in colder weather. Only problem I have that is persisting is a 'misfire' when cruising that seems to come and go at random. Sometimes its fine and other times feels like its misfiring with mpg also down then. Scanned half expecting to see the previous N242 code for injector 3 but no fault codes at all, bit stumped. Did try some Diesel rhino additive when filled up but no difference.