1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

smoking problem

Discussion in 'Mitsubishi Minicab' started by nick2010, Jul 5, 2010.

  1. nick2010

    nick2010 Member

    my truck driving down the road smokes, sitting at a idle it doesn't, just does mainly around higher rpm's...what could be the problem? it doesn't look like it uses oil, if it does it doesn;t much.
     
  2. fupabox

    fupabox Active Member

    black.white or blueish smoke ?
     
  3. nick2010

    nick2010 Member

    smoking

    its blueish smoke.
     
  4. TRAX and HORNS

    TRAX and HORNS Well-Known Member

    Do a compression test on all the cylinders. That will rule out rings. Cheap and easy.
     
  5. fupabox

    fupabox Active Member

    2nd that ...blue means oil burning and it's pointless to try anything till you know whether your compression in good or not...adjust your valves before you do the compression test..a tight valve can cause false low compression readings and point to rings when that may not be the problem...If you are using 5w30 oil in the summer that can cause excess oil burning as well...a plugged pcv can also cause oil use and smoking, as can worn valve seals
     
  6. nick2010

    nick2010 Member

    oil

    i'm running 5w-30, i'm pretty sure that is what is causing it because before the oil change, i'm not sure what was in it i just bought the truck but i put mobil 5w-30 in it. Before i changed the oil, the oil was low but the truck never smoked. if i change oil and it stops smoking, should i worry about it?
     
  7. TRAX and HORNS

    TRAX and HORNS Well-Known Member

    Wont hurt it to go one step higher on the wt. I woundnt go more than a flat 30 wt. The oil in these little engines needs to flow well.
    Chicken is right. Syn. oil in a high mileage will clean out the seals to much and in most cases you will start burning and leaking somewhere. Been there done that.
    I would still check the compression first then go with some 15/30 and see if that helps. Check you air filter, you maybe dusting the engine with a little. Make sure you have the right size air filter. Someone before you may have installed a shorter air filter. If your air filter is a 32nd. to short thats to much. Got to have the exact length and both ends need to seal.
     
  8. nick2010

    nick2010 Member

    check

    i check the air filter, the air filter is fine, i check the compression, the compression is are 160-175 that is ok isn't it? i put 10w 30 in it, and it still smokes, should i drive it maybe it would wear off or what?
     
  9. TRAX and HORNS

    TRAX and HORNS Well-Known Member

    160 is a little on the weak side but do able. 170/175 is alright. There really shouldnt be more than 10psi difference between cylinders. It is what it is. I'd run it for a while with the 10/30 and see if it cleans up a bit. If it doesnt try 15/30 or 30. Valves might be a little weak. With all that said run it and enjoy. Keeps the bugs down.
     
  10. renchjeep

    renchjeep Member

    Make sure the pcv system is working correctly, as well as the crankcase vent and breather. (Probably a good idea to just replace the pcv valve anyway.)Also, don't know for sure if these carbs are similar to regular downdraft automotive carbs, but a rich mixture can wash the piston rings with fuel, and lead to oil smoke. Check your vacuum lines (especially the pcv hose) for collapse under vacuum. If these lines become oil-soaked, they can be sucked closed by the vacuum, especially under high-vacuum "cruise" conditions.

    Let us know how it goes.
     
  11. nick2010

    nick2010 Member

    smoking

    been driving it around for a bit but still is smoking. where is the crankcase vent and breather? i'll mess with it in a bit and see
     
  12. renchjeep

    renchjeep Member

    There should be about a 1/2" diameter hose that runs from the top the valve cover to the airbox. That will be the breather line. Be sure to check the PCV hose too. And make sure the pcv itself is not clogged.
     
  13. greg0187

    greg0187 Moderator Staff Member

    You didn't happen to use synthetic oil did you? Might be your problem if you did.
     
  14. renchjeep

    renchjeep Member

    Another thought--how much oil did you put in? If it's overfilled, it may smoke. If the dipstick reads correctly, maybe it's the wrong dipstick, installed by a previous owner? Or the dipstick tube itself is wrong, modified, or improperly installed?

    My 1994 Mighty Mits owner's manual says capacity of oil pan is 3 quarts and 1/2 quart for the oil filter. This is for the 1994 3G81 engine, not sure how many years/engines this applies to though.

    Don't recall how much oil I put in mine, but I used non-synthetic 10w30 oil and a NAPA 1334 oil filter. No problems.
     
  15. renchjeep

    renchjeep Member

    Yet another idea, (apparently, I'm full of ideas, or something else according to my wife!) but are you SURE it's oil smoke? Does it smell "sweet"? And is your coolant level dropping? If so, could be coolant you are burning.
     
  16. nick2010

    nick2010 Member

    smoking

    i had mobil in it but then it started smoking it was 5w 30, now i changed in to penzoil 10w 30
     
  17. 3banger

    3banger Member

    3g83 smokes under load

    How many kms does it have on it? How is the vehicle condition? Does it look neglected or very well cared for? How good of a deal was it....

    Just trying to make sure it's not the worst case scenario... piston rings. I bet it's PVC related. I'm not sure how the PCV prob works. Does it pull the oil through the intake and burn it or does a dead/clogged PCV cause a positive crankcase to burp it up into the combustion chamber somehow?

    Good luck, smoke sucks.
     

Share This Page