BRM White Smoke At Startup

[06Jetta-Lane]

Shortly after purchasing my '06 BRM Jetta, it has produced a white plume of smoke at startup. It's white and smells like fuel for the most part. Any sitting longer than 30 min and it's almost guaranteed to smoke. Started smoking around 245k miles and now at 265k. It seems there's 2 factors that make the smoke worse: 1) length of time parked and 2) temperature. If it has sat a full day, then it's guaranteed to produce a large plume. If it's under 40 F, it's also bad. It doesn't consume oil or coolant and never has since I've owned it. Within the past 5k miles I have installed a straight exhaust (no cat, muffler, or resonator), PD140 turbo, Colt Stage 2 cam, timing belt kit, SB Stage 2 clutch, 3bar MAP, EGR delete, ASV delete, and oil cooler delete. Injector lash and timing was set also. After all of this was accomplished, there was no affect on the smoke plume. This leads me to believe it may have something to do with the fuel injectors. I seriously doubt it's a head gasket since I've never seen a drop in oil quantity or coolant (I check both once a week). Any other possibilities I'm missing?

 

[Yoohoo48]

On larger diesel engines upon initial start up, especially in cold weather, a bit of white smoke can be normal. It is unburned vaporized fuel exiting the combustion chamber. Not quite sure how these little engines are with glow plugs but the wait to start light is much to short to ignite the glow plugs properly. Basically an idiot light. Most systems run for up to 2 minutes below an average temp of 60 degrees f. Try counting to 25 with key on engine off and then start. See if maybe that helps?

 

[06Jetta-Lane]

I normally just wait for the glow plug light to extinguish before cranking. I’ll double the wait time before cranking tonight and report results. Then keep adding wait time if needed. Thanks

 

[chase345]

Mine does this also. I've been told it is a leaky fuel injector that causes excess fuel in the engine that gets partially burned off during engine start.

 

[06Jetta-Lane]

I haven't been able to narrow down the root cause of it. I'm thinking the only 2 possible culprits is a leaking fuel injector or a glow plug issue. No CEL on the dash though.

 

[oilhammer]

Some white smoke at cold start and during warm up is considered normal (this is even in the manual). However a giant cloud may be cause for concern. You've lost the catalyst, so that will make it worse. The current state of tune may also be part of it (a more aggressive preglow cycle may help). But it could also be injector health to some extent. So long as it starts easily enough, and doesn't run poorly, I am not sure I'd lose a lot of sleep over it. Some TDIs seem more "puffy" at start up than others. My PD has had a cold start puff since it was brand new in 2004. 17 years and 225k miles later, it is maybe 10% worse, but has never missed a beat.

White smoke in your case sounds like unburnt fuel, which means the combustion in one or more cylinders in not taking place or is less than ideal.

I have had some success with fuel additives to help with this, such as BG 245 (but there are certainly lots of others). Cheap and easy to try anyway.

 

[dtrvler]

How is your injector balance? ( just curious about that)

The test:
I would pull the glow plugs and have have someone crank it just for a moment and see which cylinder is the culprit by watching which cylinder has the obviously bigger cloud of fuel mist. Then get a known good used injector, replace the offending injector, and see if your symptoms go away. If you have one bad leaky injector causing a big cloud, it won't be hard to tell which one it is.
Of course, there is always the possibility of more than one leaking injector. Of course you will have to simulate the preconditions under which the cloud appeared just prior to the test.

 

[06Jetta-Lane]

Some white smoke at cold start and during warm up is considered normal (this is even in the manual). However a giant cloud may be cause for concern. You've lost the catalyst, so that will make it worse. The current state of tune may also be part of it (a more aggressive preglow cycle may help). But it could also be injector health to some extent. So long as it starts easily enough, and doesn't run poorly, I am not sure I'd lose a lot of sleep over it. Some TDIs seem more "puffy" at start up than others. My PD has had a cold start puff since it was brand new in 2004. 17 years and 225k miles later, it is maybe 10% worse, but has never missed a beat.

White smoke in your case sounds like unburnt fuel, which means the combustion in one or more cylinders in not taking place or is less than ideal.

I have had some success with fuel additives to help with this, such as BG 245 (but there are certainly lots of others). Cheap and easy to try anyway.

The only things I haven't touched so far is the injectors and glow plugs/harness. I'm actually afraid to pull the glow plug harness as it's looking quite brittle. About once a month I throw in a bottle of Diesel Purge into the tank when it gets down to around 1/4. And also fill the filter bowl with 100% Diesel Purge after a filter replacement. It seems to help just a little but not much. The car starts fine and runs great so I may just forget about it. Still gets 42mpg+ and has tons of acceleration under boost. I'll bring the thread back up down the road when I end up replacing injectors, glow plugs or the harness to give the results.

 

[oilhammer]

The ECU monitors the glow system. If you have no glow plug related DTCs, your glow system is fine.