How mutch does your car smoke?

[Tac]

I have 1991 Jetta ME with 9000 miles on both the engine and the IP. It bugs me that it smokes when I start off and when I step on it. When I'm cruising on the highway or the local streets there isn't any. The certified Bosch re builder said you can't do any thing about it. If I add some Stanadyne to it it curves it down. It's running really good. How much smoke do you guys see on your cars?

Tom

[82vdub]

On ole 82, when I give it about half throttle or more, I can see a little soot in my mirror. Not thick black cloud, but enough to notice it. The Bosch service center probably set the IP to factory specs, so it will likely have some soot at heavier throttle. I've never changed anything on my IP's, but I believe that if you adjust the max fuel screw, this will tone down the soot, but it also may effect power as you're not getting the fuel if you have less soot.

[Tac]

Thank for the reassurance my pump is doing what it's suppose to. That is a good description "a little soot". It's when I look in the mirror. That's what mine is exactly doing. I don't think I'm touching anything because it's running pretty good right now. I'll just stick to a little Stanadyne every once in a while when I'm a little bothered, Red for Summer and Blue for Winter.

Thanks
Tom

[damac]

None of my cars come close stock to the buses, industrial equipment so I don't worry about it.

Mine put out a little puff on a cold start but then run smooth. I pound on my 79 rabbit 1.6td and I don't see any clouds behind me. I guess I would have to follow it to see if there is a faint haze. I have followed others before and seen little spurts between shifts.

I guess if you care what it looks like thats one thing. I'm in california and I don't have smog or any tests that I'm aware of that I have to worry about so I don't think twice about it.

Average joe might not understand and assume you have an old beat up ugly stinky car, but oh well.

[sgnimj96]

Did your injectors get rebuilt, too?

Someone rebuilt the 1.6D engine in my 81' MK1 but not the injectors, when I took the injectors out and pop tested them the breaking pressures were way off spec. Nozzles were all pitted around the pintles but it still ran decent; Smoked a bit, milage average or less. The bad thing about that is poor running injectors can damage a good engine.

Other than crap injectors I suppose the IP fuel screw could be adjusted for less power/smoke (as was said), maybe 1/8th or 1/16th turn or even less- but be ready to put it back to it's original position, as you may not like the results. If you do change it, the idle rpm also changes so you end up changing that too to compensate. You can do small adjustments with the engine running, but don't just "screw around" with those settings (LOL)

After rebuilding my injectors I only get a little bit of smoke at startup. My fuel screw is turned down right now so I never see smoke on the road, but even with it turned up I only see smoke with heavy throttle at high revs, not when starting off. Maybe you just need to lay off the pedal. These engines don't have a lot of horsepower and, overfueling usually ends up as just smoke.

[TylerDurden]

Maybe the more interesting questions are...

Why does the engine smoke when it does?

Warm vs cold?

Low revs vs high revs?

New injectors vs old?

[damac]

I don't even mess with old injectors anymore and have started fresh with each car I turned into a daily driver.

My last project getting my turbo truck on the road I accidentally got rid of the wrong set and had set the timing by the book and all seemed well on the driveway. When I got out on the road and boost hit, I was in shock when cars behind me backed off the grey cloud I left.

Ordered a new set of bosch injectors, installed them and everything has been fine.

Since people say bad spray pattern can do damage to engines I don't think its worth messing with used stuff. My first 85 jetta td injectors I assume were never touched and although it ran pretty clean and got good mileage the spray patterns were definately off.

Early on with my vw diesels I also got tricked into trying to advance the smoke away but I had a set get too noisy so I had to back off and it did not stop the smoke just running on the driveway.

Small investment for a car you hope to drive for a long time like me.

Now a question for me is at what mileage do you check new name brand injectors? I have not hit 60,000 miles on any of my cars yet which I rotate around.

[Tac]

I had the injectors done a little bit before the pump. I don't remember seeing any soot before this motor was rebuilt. It happens when it's warmed up and just before I shift. I'm not going to worry about it since It runs good an some of you hear believe the soot is normal.

Thanks
Tom

[TylerDurden]

At the high rpms, soot is not so likely. More likely is unburnt fuel due to injector lag.

IP hydraulic advance is designed to correct this via internal pressure rise, but often pump age and wear can reduce the amount of advance.

Got a tach?

[Tac]

No I don't have a tach.

Tom

[Tac]

After my 1st couple of post I think I'm getting more soot when I throttle up than I thought. When the sun is in the right place, you can see it better. It's running really good though, but I thought I'd ask. Where is the max fuel screw? Can you adjust it without it leaking after?

Tom

[Fatmobile]

The max fuel screw is on top, near the high pressure end and has a 13mm lock nut on it.

[Tac]

Which way do you turn it? I thinking in to reduce fuel, but better to ask. I'm getting 47 mpg when I figured it out. But I let it idle in the morning for a while and at work before leaving.

Thanks
Tom

[sgnimj96]

http://www.vwdiesel.net/forum/index.php?topic=30340.0

[Tac]

Thanks, book marked it. That should help.

Tom