Failed emissions opacity
 

My 87 tdt just failed the opacity test 40% max is 20%. My buddy was driving and i wans't their. The car runs good any suggestions?

Biodiesel

Last time it pass easily but probably had bio in it. What might be wrong with it. He is buying car. do these 25 year old motors just smoke

You could screw the ALDA in all the way. I have also burned 'Jet A' with good results....

If you get on the accelerator Pedal fast and hard most Diesels will smoke.

You did not say the mileage on the Engine. The more worn out the Engine is and if the Injectors have never been checked it cold also be them helping the cause of smoke.

Fuel Injection Pump Timing?

The other stuff mentioned in Posts #2 and #4 could do the trick to get the test passed.

Motor has 160k on it, did monark injectors 2 years ago from s. watts. We only drove the car once or twice a week. I sure we can get it to pass just wondering why it might be smoking to much. Could the cat. be plugged/not working properly?

Sounds like it was run on a cold engine with unknown timing and they mashed the pedal.

I'd make or buy some biodiesel and redo the test with a hot engine.

Are you in Phoenix? When I took in my 1980 300SD with 315,000 miles (at the time), they tester romped on it hard and it still passed well below all the requirements. And that was with diesel.

If you want to try a tank of biodiesel in order to pass emissions, Western States Petroleum at 450 S 15th Ave, Phoenix, AZ ‎has B99. It's been about 50 cents a gallon cheaper than diesel, too.

40% is a lot of smoke. Does your car belch smoke when you floor it? Have you taken it for a good high speed run?

-J

Go out for an Italian Tuneup with some biodiesel and try the test again.

X2....

Worth checking the Air and Fuel-Filters are good, and any/all turbo hoses are tight and not leaking...

You could stick some 'Millers' or similar fuel-conditioner/injector-cleaner in first then-

Drive it like yer stole it, to blow the crud outta the exhaust system, running up to max revs for a short time at full throttle--while driving.
--Prob notice clouds of greyish/black crud in your mirror for a bit which should/will clear, at sustained full power.

Then re-test.

Used to be a Tester here in UK--and this was the general 'cure' for this problem

Smokes when floored, Western states is where i was getting bio. we will try that with some heavy driving before next test

It isn't that high revs are needed, it is high load for a extended period of time. Have a trailer hitch? Can you tow some weight around?

Diesels wet stack when run lightly loaded, this leads to carbon in the combustion chambers ( and injector tips ) and exhaust system.

Go out for long hill climb or something that can run it hard without ultra illegal speeds...chances are the exhaust system is holding 20lbs of soot and it is blowing out on the test. I have removed exhausts that were packed with soot, it does happen (twice as heavy as the replacement exhaust!).

When I had the exhaust off my 85 300D w/ 330K miles, the mufflers were heavy with soot. I shook and banged them for a long time and got a lot out. The car didn't smoke that I knew (engine failed 3 yrs ago), but maybe people driving behind me would disagree. The rear bumper never showed soot and it had the 85 CA "trap oxidizer" which is a catalytic converter.