Strange Rough Start issue....

[dtrvler]

Working on an 05 BHW.
Rough start after sitting overnight.
Blows a little blue/brown smoke upon rough start which clears right up. I'm thinking an injector is dribbling fuel into the cylinder as it sitz overnight. Cyl 1, 2 are out or range upon rough start. Cyl #1 is slightly more out of range. #1 is -3.01, #2 ,is +2.99. #3 and #4 are both very close to 0. Engine smooths right out and injector balance gets better and better as engine warms up.
Once warm, engine runs well.
11k on a complete rebuild.
New cam
One code on injector #3 for Glow plug p0673 electrical fault which I will troubleshoot when i swap the injectot out.
Any ideas gentlemen?
Thank you for looking.

 

[dtrvler]

Injector #1 seems to be the culprit. I'll swap it with known good used and report back here.

 

[dtrvler]

So I replaced the #1 injector with a known good used bhw "bb" injector. Balance problem solved:
-.38, .42, .28, -35.
Not I'll let it sit overnight and see how it starts tomorrow.
I'll report back.

 

[dtrvler]

So balance is good but it still seems like there is a little diesel leaking into the cylinders overnight. The rough start symptom was better today but still present. Thinking about removing the glow plugs and cranking it with the injector harness disconnected to see where the diesel mist is present. Also i will pull the other 3 injectors and put new seal kits on them. Seems like either they are leaking through normal fuel path or past the copper seal. Or the other three may have the same issue as the one i replaced. I had the head done when i did the rebuild....maybe there was some machining debris i missed in the fuel path in the head. Any ideas guys? I've never had this problem before in a tdi. Maybe the head is cracked microscopically leaking fuel past the copper seal or nearby. Any help would be appreciated

 

[dtrvler]

Bump. Thought maybe a tiny crack in the head somewhere....any ideas? Obviously I shoulda had the head checked for crscks....the machine shop didnt ssy anything about it....

 

[TurboABA]

compression\leakdown test?

 

[Windex]

First, are you sure you know the cylinder with the miss?

One of the best ways (other than scan data) is to use a FLIR camera on the exhaust manifold as the car is first started. The manifold runner with the miss will always warm up slower and will be visible as a darker colour compared to the other exhaust runners in the camera. A little hard to do on the BHW with the EGR cooler in the way, but not impossible.

 

[dtrvler]

There is no miss. Just diesel or oil leaking into the combustion chamber overnight causing a rough start and a puff of smoke then smooths right out and starts normally the rest of the day. I guess it could be oil running down a valve but i just had the head done and had them put new seals on it. The PO blew a turbo and ran it low on oil after that and it might have (probly did) get hot which may have trashed the injectors. Its hard to tell if the puff of blue smoke is from only oil or oil that leaking diesel dissolved out of the combustion chamber/cylinder walls....