Former VWDieselParts.com Forum

Sorry in advance for the long backstory,

Car was running great (mk2 1.6td) until a few weeks ago. Typical start off right? Anyway, it all started after I decided to replace my oil pan and gasket (rubber one, highly recommend), valve cover gasket (also rubber, seals beautifully would also recommend) oil change and filter, and fuel filter.

Car is now billowing huge clouds of white smoke! Never used to smoke at all, a little puff of black between shifts etc but not this much white! It's not a head gasket issue, yes I am sure.

Car has always started easier without the use of the cold start lever in any weather so I'm thinking the pump might be a tad too advanced (correct me if I'm wrong). I know these pumps can be quite sensitive and I don't have the proper tools, dial, dial adapter etc (yet!) to get an accurate reading of the current timing but I've not changed the timing of the pump yet in my ownership and I've had no complaints or issues. Not 100% sure how too either I'll be honest. I'm hoping it's just a failing injector(s) as I have new Bosch nozzles and heat shields coming in the mail just have to take mine to go get pop tested/rebuilt/fitted with the new nozzles, but it's having weird symptoms...

Only after I kick on the regulator *huge cloud of white smoke* (blip the throttle to kick off the battery light in the dash on startup) it seems to have a slight hiccup. Not necessarily a "miss" as it's not nearly as noticeable as a miss and there's no predicting the irregular pattern of which this hiccup cycles. There's no spike in rpms at all during this. One would think this would be air in the lines... however as soon as this started I decided to diesel purge it to clear up the injectors, hopefully rid the smoke, and see if air is traveling in the fuel lines... No air at all. Still smoking, still having this minor idle hiccup... is this a sign of pre-ignition?? Any input is well appreciated, thanks in advance!

The more backstory, the better!

That said... Air in the lines.

I know, you checked, but air in the IP is sometimes hard to detect as it moves out of the IP and back to the tank - the air will be a very fine "mist" of tiny bubbles.

Did your weather turn cold? Cold lines, cold seals will tend to stiffen and let in air. (Please add your general location to your profile.)

The first diagnostic I would try is to "bottle feed": clear lines in and out of the IP to a clean container of fuel. This will determine if the issue is supply or IP/injectors.

Welcome aboard.

Also white smoke on startup and a little rough idle is a sign of retarded timing.
Try pulling the cold start lever and see if the idle smooths out.
You don't need/want a dial gauge,.. put that money toward a pulse detector setup and use a timing light.
Meanwhile if you want to play with the timing; just mark where it's at and turn the pump top toward the head to advance it.
Do you have clear line coming from the pump,.. going back towards the tank? No air in that one either?

See that's the thing though, I bottle fed that pump when I did the diesel purge and it showed no sign of air at all, no bubbles at all... none in the supply and there was virtually none out of the return (I did see a rare bubble or two in the return but nothing concerning). I was told if it starts easier without the cold start lever in cold (or any) weather than that's a clear sign of advanced timing but I'd rather take your word for it.... it could be anything at this point. Did I mention some sludge forming (not dripping, it's not THAT much sludge) in the exhaust/tailpipe??

Location is Delaware (USA) not cold here quite yet. Enlighten me on this pulse detector setup

But in all honesty, this whole thing started after basic maintenance. Like I said it never used to smoke but now it's to the point were if I put my foot down I can't see who's behind me, and it's white! It drives fine, just a fog machine at boost. Sometimes when I coast to a stop (a stop sign or whatever) the idle sticks at 1050-1100 +/- rpm, similar to like if you were to pull out your cold start lever to the very first inch... but the cold start lever is still flush against the dash... when that happens I'll play with it a little bit (phrasing! ) pull it out and push it back in and the idle goes back to normal 950+/- rpm. Is it really just a coincidence that maybe an injector is failing after basic maintenance, or something I managed to do?? The smoke has got to go.

your last post, especially this -

when that happens I'll play with it a little bit (phrasing! ) pull it out and push it back in and the idle goes back to normal 950+/- rpm.

makes me think that perhaps its as simple as your cold start cable sticking. if your timing is on the advanced side anyway, this could explain bad combustion and white smoke/ poor running (like your always running with cold start out).
have someone pull it while you watch the lever on the pump. move the lever on the pump all the way to the "not advanced" position with a long screw driver or something and see if the problem goes away

... also, often the timing is set so that the car doesn't want to start with the cold start pulled. both my cars are like that, in which case you use the cold start to crank for a few seconds, then push it in to start while still cranking . it will start (or put in a damn good effort) when you push it back in. in my experience, this is a pretty good place to have your IP timing

Sounds like air in the fuel.
The goal of bottle feeding is to remove the stock fuel system from the equation so any of it's problems don't affect how it runs.
Did it smoke white while bottle feeding?

I think the cold start lever does help fine tune the timing but I use it differently.
If it has a random miss when you goose it a little after a cold start then it's slightly retarded.
I don't think just because it doesn't start easy is enough to blame the timing,.. it could be something else like a slow starter etc.

The high idle at a stop sign could be anything from the accel lever sticking to a bad injector causing fuel to be left over after the burn,.. which also causes white smoke.
I'd install clear fuel lines to and from the pump and see what's happening.

Alright, smoke has been reduced by a noticeable margin, appears to be a lot darker (more so grey than black but at least it's not white anymore)... injectors are officially rebuilt and all pop test great, braking pressure set to spec... also when I pulled the injectors, one of them (assuming from the previous owner ) did not have a heat shield/washer installed, so did my best to clean out all that carbon and installed the injectors WITH ALL new heat shields washers.

Afterwards it turned over a lot easier than I thought it would've. Doing that on any diesel always seems to be a headache and takes a LOT of cranking but this time not so much.

HOWEVER....

The injectors are nailing or knocking or clacking or whatever you want to call it. (more so with throttle of course) Pretty bad and pretty loud I might add. Tinkering with fuel delivery and idle really make no difference. Been dealing with this for a couple days.

Any and all input is greatly appreciated!

Loud injectors can be caused by advanced timing.
They quiet down some when the timing is retarded.

Car is officially running better than it ever has in my ownership and couldn't be happier! After about 2 whole tanks of diesel with 3/4 of a bottle of blue label standyne and 1/2 a bottle of diesel kleen, and after adjusting the fuel screw, idle, and boost controller it has never been better. Injectors are quiet and now "broken in" I guess you could say, smooth idle, better cold start, and an obvious acceleration difference... as well as a difference in the amount of smoke.

However, with it being your typical older diesel engine it does seep oil out of a few crevices, as expected. Tailpipe is still drowning (I'm exaggerating) in black gunk. And even after replacing the valve cover with the one piece rubber replacement it still seems to have an oil leak/seep on the exhaust manifold side of the engine, ABOVE the head with oil level "decreasing at a rate" (haha) of about a quart every 2 - 2.5 weeks or so (120 miles a week, no more). With the exhaust still dripping black gunk and with virtually no blow-by in this engine would this be a sign of a bad turbo seal???

Sometimes the oil fill hole gasket gets brittle and doesn't seal.
That'll run oil down the back onto the intake.

I'd probably pull the exhaust off the turbo and see if there is oil right at the turbo exit.
Oil in the exhaust could be something that built up over time.

Glad to hear it's running so good.