Need any advice to temporarily reduce smoke for smog check

Jazer3 · Sep 20, 2019

My pd TDI blows a little smoke when I hit the throttle hard. It has a stage 1 tune and low compression crafter pistons. I'm assuming I can advance the timing a little or add cetane boost to complete the burn a little better for less smoke? Please advise

My_name_is_Rob · Sep 20, 2019

Can't you turn the fuel down manually on those ones? Or is it just the ALH and AHU that allow that?

scooperhsd · Sep 21, 2019

Go do an "Italian tuneup" - run it hard (blow smoke) like up to close to redline in 3rd or 4th gear.

johnsTDI · Sep 21, 2019

I would fill up and run a strong cleaner like BG245 or 244 run it wide open safely when You can of course use the tank up refill & make sure your air filter is clean on day of test change Oil & filter refill engine but keep oil level just above Low Mark reason being? it will emit less oily crankase fumes from rising creating less emmissions.

Jazer3 · Sep 21, 2019

It's a brand new engine build so there's no build up to burn off in the engine but they're might be in the exhaust

Jazer3 · Sep 21, 2019

Not on these pd tdis

tikal · Sep 22, 2019

johnsTDI said:
I would fill up and run a strong cleaner like BG245 or 244 run it wide open safely when You can of course use the tank up refill & make sure your air filter is clean on day of test change Oil & filter refill engine but keep oil level just above Low Mark reason being? it will emit less oily crankase fumes from rising creating less emmissions.

Another vote for the BG245 as a professional grade product. Here is a recent thread that discussed it:

http://forums.tdiclub.com/showthread.php?t=501037

Some people add this product right before the 10K mile oil change. Do your own research about various approaches suitable to your situation of course.

Lightflyer1 · Sep 22, 2019

I guess you missed his post (#5). Brand new engine, no need for a cleaner.

turbobrick240 · Sep 22, 2019

Get there early and let the car cool down. Chill the intercooler.

Giberish33 · Sep 23, 2019

Jazer3 said:
It's a brand new engine build so there's no build up to burn off in the engine but they're might be in the exhaust

EGR blocked up? How much smoke are you talking? Like roiling coal or just a slight haze?

Jazer3 · Sep 23, 2019

Egr is good. When you giv it more than 60%pedal it rolls some coal because of th tune. I'm not sure how much throttle they use when they smog. I bet adding a couple gallons of cleaner burning gasoline might reduce the smoke

Lightflyer1 · Sep 23, 2019

California already has some of the highest cetane fuel around, so I am not sure that more will help necessarily. Probably the best thing you could do is have a tune just for passing emissions and load that when needed. Then reload your current tune. Why the low compression pistons?

oilhammer · Sep 23, 2019

If it is smoking that bad the tune is not a very good one. Because it is overfueling, more than the engine can get air in. Assuming this is black smoke.

Do they check OBD at all? If not, you can just unplug the MAF and it'll put the engine in a reduced power mode and it shouldn't smoke at all (it will barely have any power either, of course).

KLXD · Sep 23, 2019

In Kal the CEL can't be on, readiness monitors must be set.

The smoke test is purely subjective on the part of the tester. It's not done on the dyno so there's no load on the engine.

tikal · Sep 23, 2019

Lightflyer1 said:
I guess you missed his post (#5). Brand new engine, no need for a cleaner.

Yes, you are right. Next

oilhammer · Sep 24, 2019

KLXD said:
In Kal the CEL can't be on, readiness monitors must be set.
The smoke test is purely subjective on the part of the tester. It's not done on the dyno so there's no load on the engine.

OK, so the OBD test they have is the same we have. We thankfully have no opacity testing.

So really I think this falls back to having a DEtune performed. Whether or not the OP wants to keep it that way I guess depends on how well it runs. But really, mildly modded TDIs do not have to smoke any more than a modern gasoline DI car would to make decent power. I think it is still undetermined at this point what the source of the smoke actually is. Black smoke = too much fuel/not enough air. White-blue smoke = unburned fuel due to a bad combustion event. I also know that the catalysts, while just a simple 1-way type, do reduce smoke quite a bit when they are working correctly.

Jazer3 · Sep 25, 2019

oilhammer said:
If it is smoking that bad the tune is not a very good one. Because it is overfueling, more than the engine can get air in. Assuming this is black smoke.
Do they check OBD at all? If not, you can just unplug the MAF and it'll put the engine in a reduced power mode and it shouldn't smoke at all (it will barely have any power either, of course).

The car had a tune before I got it and put a completely different build in it with a larger turbo so I still need to adjust the turbo and check it's vacuum to make sure it's not the culprit and then I do plan to tune it again

Jazer3 · Sep 25, 2019

oilhammer said:
OK, so the OBD test they have is the same we have. We thankfully have no opacity testing.
So really I think this falls back to having a DEtune performed. Whether or not the OP wants to keep it that way I guess depends on how well it runs. But really, mildly modded TDIs do not have to smoke any more than a modern gasoline DI car would to make decent power. I think it is still undetermined at this point what the source of the smoke actually is. Black smoke = too much fuel/not enough air. White-blue smoke = unburned fuel due to a bad combustion event. I also know that the catalysts, while just a simple 1-way type, do reduce smoke quite a bit when they are working correctly.

It's a brm so i can't just swap tunes. I do believe it's something else causing the smoke but I'd like to drive it legally while I resolve it and since it won't be under load I don't think it's going to smoke enough to fail me. It's black smoke by the way and mostly at lower rpms so I think I'm under boosting with the bigger turbo I put on it

Jazer3 · Sep 25, 2019

Lightflyer1 said:
California already has some of the highest cetane fuel around, so I am not sure that more will help necessarily. Probably the best thing you could do is have a tune just for passing emissions and load that when needed. Then reload your current tune. Why the low compression pistons?

It's a brm so it's not easy to swap tunes. I chose the pistons because I wanted to build a 2.0 that could handle lots of boost and I live in a very warm climate.

oilhammer · Sep 26, 2019

I would just find another ECU, have the tuner do that one along with an immo delete, and swap that in there, keep it for the future for this sort of thing.

Need any advice to temporarily reduce smoke for smog check

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