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Troubleshooting diesel engine stall under load

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  • smitty477
    replied

    Originally posted by smitty477 View Post
    - are your reaching WOT +3-5% when fully loaded on a hot and humid day?


    Seattle area. Nope.
    1st step is to always make sure you can reach rated WOT plus 3-5% of rated rpm


    Originally posted by smitty477 View Post
    - are your tachs known accurate



    Nope. But they're getting replaced soon with a hall sensor and new tachs
    Good - that will allow you to review and record your correct rpm for baseline and future diagnostics


    Originally posted by smitty477 View Post
    - is your fuel in good shape


    Unknown. It's dyed red for some reason. Red suggesting possibly kerosene additive?
    Red just means it is not intended for road use (taxable) - fuel condition can play a role in diesels when it is fairly old.


    Originally posted by smitty477 View Post
    - when was your last valve adjustment


    Unknown.
    Incorrect Valve clearances can cause smoking and inefficient operation


    Originally posted by smitty477 View Post
    - when did you last time your fuel injection pump


    Hm? What about the fuel injection pump?
    The fuel injection pump requires checking and/or adjustment for correct injection timing for best use- incorrect timing can cause smoke and larger problems


    Originally posted by smitty477 View Post
    - how many hours use since your fuel injectors were serviced


    Fuel injectors are the key ingredient in efficient fuel burn - most often they need to be checked/adjusted at 1,000 hrs or less. A typical injector check rebuild is less than $100 each when pulled and brought in by an operator that is handy with tools ...and it will pay for itself in fuel savings alone.
    If there are no records on injector servicing and the hours are higher than 800-1,000 suggest you give this area attention.





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  • Norton_Rider
    replied
    If you don't have records indicating new or rebuilt injectors, I suggest you get them done. When I bought my boat one engine appeared to have original injectors, while the other one appeared to have injectors that were changed. As a result of a hard starting issue I changed the ones that looked original. About a year later the other engine had high blow-by. A compression test revealed one bad cylinder and the engine had to come out. The worn cylinder resulted from a bad injector.

    Leave a comment:


  • infy
    replied
    Originally posted by smitty477 View Post
    - are your reaching WOT +3-5% when fully loaded on a hot and humid day?
    Seattle area. Nope.

    Originally posted by smitty477 View Post
    - are your tachs known accurate
    Nope. But they're getting replaced soon with a hall sensor and new tach.

    Originally posted by smitty477 View Post
    - is your fuel in good shape
    Unknown. It's dyed red for some reason. Red suggesting possibly kerosene additive?

    Originally posted by smitty477 View Post
    - when was your last valve adjustment
    Unknown.

    Originally posted by smitty477 View Post
    - when did you last time your fuel injection pump
    Hm? What about the fuel injection pump?

    Originally posted by smitty477 View Post
    - how many hours use since your fuel injectors were serviced
    Judging by the color of the fuel injectors... they're probably originals that came with the boat in 1989. The bolts have scars so someone has likely serviced them to some degree.

    Leave a comment:


  • smitty477
    replied
    Originally posted by infy View Post
    Got new air filters on. They look great! But it's still showing that smoke when approaching 2k RPM.

    It also occurs to me that the smoke (pictured in attachments above) could be just normal water vapor from combustion? What do you guys think? Is it too much smoke from twin 8 liter V6 diesels near WOT?

    I have no experience with this type of engine or boat as a baseline. I know that if I send my car (gasoline 4.4 twin turbo V8) I'll have extra water vapor out the tailpipe.
    Congratulations on remediating your engine stall/rpm issue.
    You now are trying to address the smoke that you see.
    You will find that in order to solve this there are many of the same concerns as before so please reread the posts for clarity:
    - are your reaching WOT +3-5% when fully loaded on a hot and humid day?
    - are your tachs known accurate
    - is your fuel in good shape
    - when was your last valve adjustment
    - when did you last time your fuel injection pump
    - how many hours use since your fuel injectors were serviced

    I would start at the top of the list in searching for a black smoke issue ...

    Leave a comment:


  • Jim_Gandee
    replied
    This is what I installed Pete.

    https://www.aetnaengineering.com/mod...cd-tachometer/

    Leave a comment:


  • Pcpete
    commented on 's reply
    I might be interested in your tachs. What kind of digital are you looking at?

  • infy
    replied
    Originally posted by MacPhid View Post
    Until you verify the rpm's the engines are actually turning with an electronic tach, changing anything is just maintenance at this point.
    I'm working on completely replacing the instruments and installing digital tachometers and sensors. Should have accurate RPM readings soon

    Leave a comment:


  • infy
    replied
    Got new air filters on. They look great! But it's still showing that smoke when approaching 2k RPM.

    It also occurs to me that the smoke (pictured in attachments above) could be just normal water vapor from combustion? What do you guys think? Is it too much smoke from twin 8 liter V6 diesels near WOT?

    I have no experience with this type of engine or boat as a baseline. I know that if I send my car (gasoline 4.4 twin turbo V8) I'll have extra water vapor out the tailpipe.

    Leave a comment:


  • MacPhid
    replied
    Until you verify the rpm's the engines are actually turning with an electronic tach, changing anything is just maintenance at this point. If it was me, I'd warm up the engines and then go down to the engine room and verify the WOT rpm attainable. Disconnect the ball and socket throttle cable at the governor and manually move it to WOT position and retest. Only needs to be a few seconds and won't hurt the engine. High idle tests don't require much boost or fuel flow and verify governor settings. Then run it at the known WOT and have someone at the helm mark the position of the dash tachs. That will give you an idea of the tach mismatch from actual rpm's. Then take it out for a speed test and repeat the tests.
    From the pictures I'm guessing you are now getting close to rated rpm's as you're up on plane and have a good clean wake. If you were actually running the engines 500 rpm below WOT I wouldn't think it would be up on plane. Make sure the bottom is clean, the boat isn't overloaded. Boost pressure would be nice but only gives you a reference port to starboard without knowing original design boost specs. Clean air filters, clean aftercoolers will all affect boost pressure, so inspection may be warranted.

    James

    Leave a comment:


  • Pcpete
    replied
    Get K&N’s. They are easy to wash out, spray with the oil and reinstall it.

    Leave a comment:


  • MacPhid
    commented on 's reply
    Saw a copy of an article in the Western Boatman from 1988 about the release of the 4285 stating the engines were 380 HP Hino turbo intercooled diesels.

    https://bayliner.com/wp-content/uplo...pec-sheets.pdf

    James

  • infy
    replied
    The smoke starts visually at about 1600 RPM.

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  • infy
    replied
    Hey everyone great news! Took it out today for some power tests and it looks like the stall has been resolved. We were right on this being a fuel problem all along. I replaced the port Racor and secondary fuel filter. I also did an oil change but that wouldn't make a difference.


    now that the engine doesn't stall when I give it the beans I took the time to watch the exhaust under power. You guys are right it is smoking under load.

    I checked both turbos. They're free and spin. There is zero shaft play.

    Both the air filters are in poor condition. Gummed up with oil. I think I'm going to go to an O'Reilly's or AutoZone and pick up a high performance automotive air filter to replace the current air box completely.

    Leave a comment:


  • infy
    replied
    Originally posted by TX H210 SS View Post
    https://www.dieselcraft.com/fuel-test-kits/

    I see there are several home diesel fuel test kits that are inexpensive....this was just a simpleton thought and maybe others can advise if these are worth trying in your situation....it does say one symptom of degraded diesel is lower rpm but they are also selling test kits
    My plan right now is to just burn it all up. Even if I found the fuel is bad it would be a pain in the ass to try and get rid of it all. I don't know how you dispose of hundreds of gallons of diesel without a hassle.

    Leave a comment:


  • TX H210 SS
    replied
    https://www.dieselcraft.com/fuel-test-kits/

    I see there are several home diesel fuel test kits that are inexpensive....this was just a simpleton thought and maybe others can advise if these are worth trying in your situation....it does say one symptom of degraded diesel is lower rpm but they are also selling test kits

    Leave a comment:

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