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General Information => General => Topic started by: JGVWDiesel on June 05, 2010, 11:12:10 pm
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I have an 86' NA diesel golf that tends to smoke a fair bit under moderate - heavy throttle. (WOT it leaves a fair bit of smoke behind.) I was wondering, where is the fuel screw to reduce the amount of fuel being put in? As far as I know, these are the original injectors (363k on ODO.)
thanks
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What color is the smoke? Have you ever turned the fuel screw up? If the pump is stock turning the screws is not where to start in diagnosing/repairing a smoke issue.
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Black/grey haze. I have no idea if the previous owners messed with it or not, but I personally have not.
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Depends on when the smoke is happening my good sir. Mashing the Go-Go pedal at 2000 in any gear will cause the engine to over fuel and blow black unburnt diesel out the back. If your in the torque band and you mash it even with the screw up a tad you should see very little smoke. if it is set correctly.
However it could be an ailing pump and injectors that are causing your problems. An incorrect internal pump pressure and worn injectors will cause a bad spray pattern which will affect the swirling with the air, that affects how it burns (or how it doesn't ie. black smoke)
How is performance?
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Well I have no tach, so I can't tell what RPM it is but most of the rpm band except lower areas smoke and then high rpm it smokes pretty good. Performance I have no way of telling as I have no comparison as to what it should be putting out.
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bump
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well if its smoking down low (ie too much fuel for the engine to handle) or smoking up high (ie can't get enough air in and enough exhaust out because of restrictive intake and exhaust) than that is completely normal for a stock engine.
I find on my N/a that it smokes its least around 2700-4000 rpm after that it starts getting thick because i still have stock intake and exhaust as well. I do not have a tach either but I can guess where I am in the power band as to what the engine is reacting like to my foot.
Do you have any plans to open up the intake or exhaust? How about doing the Gov Mod? the link in my sig has a good right up on it, and it frees up a lot of fuel and power. It shouldn't be done till after the intake and exhaust though. I'd take a look at this link on "How to make your N/a a faster car" ;) http://www.vwdiesel.net/forum/index.php?topic=4391.0 (http://www.vwdiesel.net/forum/index.php?topic=4391.0)
Good Luck! :D
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Yeah I can imagine the smoke is somewhat normal. I'd like to play with the fuel screw a tad bit perhaps just to see what it's like turned down a slight bit. Where is it located?
Somewhere down the road I may do some exhaust, I'm just trying to be as cheap as possible with this vehicle as the rust is beyond reasonable repair.
As for intake, not sure how I'm going to open that up some. Is the airbox the most restrictive part or is it just it needs colder air?? My air intake ends at the head so it's missing pieces it seems.
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If you can hook the airbox up to the stock fender CAI you'll notice an improvement.
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The fuel screw is the screw sticking out to the right above where the fuel lines would attach in this picture. The nut will need to be backed off and then the fuel screw will be able to be turned.
(http://www.cs.rochester.edu/u/jag/vw/engine/fi/BOSCHVE2.GIF)
Smoke on a diesel is always normal, as long as it's black and not gray or blue ;) You can alternatively meter smoke by not putting your foot down as far.
Yes. having the intake suck hot air will hinder some performance for sure, cold dense air is what these engines want. a 2" piping to a cold air source will have a slightly noticeable gain for sure.
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Here is what some people have done to open up their intake.
(http://dieselinside.com/howto/1.6na/1.jpg)
(http://dieselinside.com/howto/1.6na/4.jpg)
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Both of those pictures are of a mk1. On a mk2 you have the stock location for the CAI where the windshield washer reservoir is in those pictures.
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my bad, this is an mk2 box isnt it?
(http://dieselinside.com/howto/1.6na/2.jpg)
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Yep that's a mk2 box but it's in a mk1
Here is a mk2
http://img.photobucket.com/albums/v603/burnyourmoney/DSC08119.jpg (http://img.photobucket.com/albums/v603/burnyourmoney/DSC08119.jpg)
and it is plugged into this
http://img.photobucket.com/albums/v603/burnyourmoney/DSC08148.jpg (http://img.photobucket.com/albums/v603/burnyourmoney/DSC08148.jpg)
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yeah but that doesn't matter :P why go to the fender for air when you could get a ram air beside the rad set up?
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There isn`t any room because the headlights are so big, the alternator so high and the rad so wide.
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Ahh good point Tyler, Very wise are you. Can you tell I don't frequent much mk2? lol
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Sadly I don't frequent enough MK1 :(
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a little update! I turned the fuel screw out about 3/4 a turn. it was definetely slower, just below my tolerance I think. however, I did shoot up to 43 US MPG. ( 52 mpg imperial). I think I'm going to turn it in a bit to get a bit more power and settle for about 40 mpg. considering how worn the engine is and I believe it has a decent amount of blow by (none visible from exhaust) i think 40 mpg will be a good number to stay at.
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forgot to mention, I also now get no visible smoke from the exhaust even in the higher rpm range so that might indicate (based on the wear on the engine) that I turned it out too much.
thoughts?
thanks!!
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I'd put the screw about halfway back to where it was before and do as BYM suggested about ducting some kind of hose to the passenger CAI. It makes a good benefit.
Lets ask BYM what the application was for that radiator hose he is using. Looks like a good fit !
I've been using heat riser/air intake flexible ducting from bigboxautopart stores. About $6-8 and they only last about 18-20 months.
Supposed to order some better stuff from spruce aircraft, but keep putting it off.
How many NA-AAZ's can there be with yellow valve covers and purple pumps ? Gotta be a low number .... ;D
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Yeah I turned it about halfway back from the original position. A bit more power and theres a small puff of smoke at higher rpm WOT.
Yeah I should definetely look into the pvc intake ors omething. I don't think it would be very hard at all to make up a nice pvc intake, even if I have to make a bigger hole in the side of the intake box.
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I'm nearing completion on my cold air intake, I will have pictures up later today I think. I ended up using pvc pipe roughly the same diameter of the stock tube and took it all the way down beside the radiator but below it where there is a big air gap between the bumper and something else. I put my hand down there and I could feel cold air breezing around so I think it should be good.
My only other decision is whether to leave the tube that goes down the pointing straight down or add an elbow pointing towards the front of the car to let air push into it on the highway??
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Lets ask BYM what the application was for that radiator hose he is using. Looks like a good fit !
It's from a 91 F250 with a 7.3. I think the 6.9 and 7.3 use the same rad hose so there are quite a few years to chose from. It is about a 1/2" too short though. It pulls the fender scoop thing out of the fender on a hard pull. It is a 1.9 so the hose does have a bit farther to go but I don't think it is significant.
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So, here's the cheapo intake I made out of pvc my dad had around the house. It's just about the same diameter of the stock elbow piece that came out of my airbox, so I used the elbows and butt connecting pvc pieces and then pvc cemented them together. I used super glue for the pvc to air intake tube because the tube isn't pvc, I think it's abs or something.
I ran it down beside the radiator and just below the bumper where there is a nice big pocket for cool air to rush in. In the picture it looks like the intake is close to the alternator pulley, but it's not and I have it strapped to the side of the fender so it won't move into the alternator.
Does anyone think I should put an elbow on the bottom of the intake pointing forward to get a bit of a ram air or you think it's good enough as is? It does seem to smoke less for sure, but I don't think there's much of any more power haha.
(http://i83.photobucket.com/albums/j313/Jared360/07062010716.jpg)
(http://i83.photobucket.com/albums/j313/Jared360/07062010717.jpg)
(http://i83.photobucket.com/albums/j313/Jared360/07062010718.jpg)