Click for Burger Click for Cross Click for Westport Click for Abeking Click for JetForums

Smokey Detroit Diesels?

Discussion in 'Engines' started by Dusty, Jul 13, 2005.

You need to be registered and signed in to view this content.
  1. Dusty

    Dusty New Member

    Joined:
    May 2, 2005
    Messages:
    4
    Location:
    New Jersey
    Have Detroits 671 TI's with 1900 hrs. One smokes more then the other but they smoke upon start up. When they are in gear they are fine no smoke. I'm pleased with the speed but would like to get rid of the start up smoke. I have installed heaters on engines. Any suggestions would be grreatly appreciated. :confused:
    Last edited: Jul 13, 2005
  2. DieselJoe

    DieselJoe New Member

    Joined:
    Feb 15, 2005
    Messages:
    5
    Location:
    ft lauderdale, fl
    Hmmmm, did you not ask this question a few months ago? Well anyhow, let me word it a little different but the end results will be mostly the same.....

    I suspect the start-up smoke you speak of is white? If it is there are a few causes that could be easily diagnosed. Here is a list of a few possible causes.

    1. Faulty/leaking injectors. If the injector seal(s) are bad this will cause the fuel that is in the injector to leak into the combustion chamber when the engine is stopped and sit there until the engine is started causing white smoke until the engine warms up or load is applied. Bench test the injectors and replace as/if needed.

    2. Low cylinder compression when the engine is cold. If the cylinder compression is low, when cold, not enough heat is generated to ignite all of the fuel that’s being distributed, the unburned fuel is what you see (white smoke). Once the engine heats up the compression rises, therefore heat rises and all fuel is burned (no smoke) or once you engage the transmission which puts a load on the engine will burn all of the fuel due to demand. Remember, white some is incompletely burned fuel. Perform a cylinder compression test, make sure the readings are taken when the engine is cold. Factory says do at operating temperature, but it sounds like its fine once the engine heats up. If the compression is low when cold you will have to rebuild the engine or just live with the cold-start smoke. Compression readings at operating temperature should be: 425 PSI min 475 PSI is like new condition.

    Low cylinder compression is the most likely cause due to the hours. 1900 would be considered high for that type engine. I have rebuilt several in my day at even lower hours then yours. The 450 HP engines tend to last a little longer then the 485's, but not by much. And as for the block heaters, if you start without the heater on (COLD) is the smoke even worst? If it is then compression is your problem.

    Hope this helps.
    Last edited: Jul 19, 2005
  3. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    14,432
    Location:
    Fort Lauderdale
    It sounds as if they need a tune-up which is usually done every 500 hours or so. It includes adjusting the valves, adjusting the fuel injectors and injector pump among other things. Also try starting them and holding down the shut down button for 3 seconds while starting them.........Also smoking can be caused by old fuel, as well as not running them often. They should be started and run to temp every two weeks to keep condensation out of the engines and the valves from corroding.
  4. DieselJoe

    DieselJoe New Member

    Joined:
    Feb 15, 2005
    Messages:
    5
    Location:
    ft lauderdale, fl

    Detroit Diesels do not have an injection pump, so rule that out. The man has 1900 hours on 671TI's or TIB's, he needs to do a cylinder compression test and check for low cylinder compression and Ill bet its low.