Former VWDieselParts.com Forum

1.6L diesel Vanagon. Black smoke under a load trying to get up to speed. I tried to adjust the pump timing, but could only set it to .70mm instead of the .86mm reccomended by the bentley. The pump is turned as far as it will go towards the head. Does this sound like a pump issue or an injector issue?

It sounds like perhaps an "off a tooth" issue with the timing belt. That would be the next thing to try, I'd speculate. Release the timing belt tensioner, then follow the timing procedures, this time being sure that you've got the gear for the pump moved over a tooth's worth on the belt. See if that doesn't buy you the rotational slack you're looking for.

And that should give me more room to turn the pump accurately right, Josh?

Black smoke (soot) is more often a case of overfueling. Timing can't correct that.

Timing usually results in grey smoke that smells like unburnt diesel fuel. Advancing the timing can correct that.

There are times when the pump needs to be slipped a tooth on the belt, but not that often.

Tyler Durden, how do I fix the problem? If I back that one screw out (not the idle screw but the other one), then the idle goes way down. Should I do that and turn the idle screw up?

Yes, but be advised you will have less power on heavy accelleration. Just like using less foot on the pedal.

If you can't get timing to spec, slip the pulley a tooth and reset the timing and see how it performs. Then reduce the fuel screw and adjust idle to your liking.

Sometime black smoke isn't too much fuel,.. it might be not enough air.
Does your air cleaner look good?

Fatmobile wrote: it might be not enough air.

I'm not sure that's possible with a diesel, or any injected engine... the piston is gonna suck in 400cc of somethin, even if it's the air cleaner.

Any unburnt fuel will be grey anyway... no air, no burn.

Stick a rag in the intake hose and you will have black smoke,.. until it dies.
How do I know this??? Well I was lucky it didn't get pulled into the turbo.
Pretty extreme example.
I'm pretty sure a clogged air filter would do the same.

I replaced the air filter and that helped. But what really made the difference was simply backing off the fuel screw. Only problem now is it seems there is a little less power. It's hard to get up any easy hills in 5th going 55 like it used to. Would adjusting the pump timing help this?

Yeah, it might.
Try making a mark and advancing it the width of a pencil line.

So I gotta bring this back up. I still get black smoke under heavy load. I've tried everything I can think of from timing to adjusting the screws on the pump. I don't understand how the belt can be off a tooth. I have the block at tdc as well as the cam. Now if I move the pump sprocket one tooth, it throws off the sprocket so that I can't insert the lock pin. Also, the pump is turned all the way towards the head. I have tried every position on the pump. All the way to the head seems to be the best for now. But still very little power. Any more ideas would be greatly appreciated! Thanks!

Ja, slipping the IP pulley a tooth will prevent the pin from inserting, but the pin is only used to hold the pulley from rocking back when installing the belt in a normal configuration, not at any other time.

I was surprised to read 5th gear. I only have the 4spd, and so would expect to downshift under heavy load from 5th. The vanagon is a heavy beast and not going to be very peppy with a 1.6NA.

You also mentioned "like it used too..." if you mean when you had sooty exhaust? That is somewhat normal... overfueling does reap more power, but with diminishing returns (not linear fuel:power results).

Ok, so I'll try moving the pump back a tooth even though the pin won't line up. The vanagon's are heavy and slow with these engines, but it def. used to have enough power to at least get up to 55. Now only on a downhill can I get to 55. Hopefully this will help, and I'll post back up the results. I should also mention, when moving the pulley back a tooth, the line on the pump pulley will no longer line up with the pump bracket. Hopefully that don't matter? We'll see! Lol.

So I just advanced the pump one tooth. Here's the results. It pretty much illiminated the black smoke. That's good. Unfortunately it still has a lack of power and there is also a much louder knock in the engine. Maybe turning the pump more towards the engine?