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Broke down 6.2L!!

Discussion in '1982-Present GM Diesel' started by arveetek, Jul 29, 2002.

  1. arveetek

    arveetek 1/2 ton status

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    My K-10 left me stranded the other day. It just died with no warning. I assumed I had an injection pump problem, but after removing the top cover and upon closer inspection, I found the actual problem.

    The injection pump driven gear (the actual gear that turns the pump) is missing. That's right, it's totally gone. It must have broken up into small pieces.

    Has anyone else had this happen to them? I've never heard of such a failure! /forums/images/icons/confused.gif

    Casey
     
  2. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    I've never heard of an internal hemmorage like that either!!!! ANy guesses on what caused it?
     
  3. Tybee

    Tybee 1/2 ton status

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    What top cover? The fuel shut off little selenoid or the front gear cover?
     
  4. DieselDan

    DieselDan 1/2 ton status

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    Nope, seen alot of diesels but none ever did that. Ask John Kennedy maybe he's run into that before.
     
  5. arveetek

    arveetek 1/2 ton status

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    Sorry, I should have been a little clearer.

    Yes, I removed the top off the injection pump to inspect the fuel cut-off assembly.

    Here's what happened:

    I was just driving down the road, about 30 mph, and the thing jerked and died. It wouldn't fire at all after that. The way it was acting, I decided that the fuel cut-off solenoid was bad. But, after looking inside the pump, I couldn't see anything wrong. Having someone crank the engine over, I watched the pump, and noticed the shaft inside wasn't turning. That's when I removed the oil fill tube on the front cover to inspect the pump gear. It wasn't there anymore.

    I haven't got a clue as to what happened. I'll know more once I get the water pump and front cover removed. This engine was rebuilt right before I bought the truck, so I hope it wasn't assembled wrong.

    My biggest concern is that the pieces of the gear have probably ended up in the oil pan, which means I'll have to drop the pan to clean it out. /forums/images/icons/mad.gif

    Casey
     
  6. arveetek

    arveetek 1/2 ton status

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    My mistake, ya'll!

    I looked a bit closer this time, and I discovered that the pump gear is still there, but it's not turning. I can see some broken pieces laying inside, so probably just a few teeth stripped off.

    Still, it's an odd thing.....

    Casey
     
  7. René

    René 1/2 ton status

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    Poor Casey, I can only hope that you will find all parts of the broken drive wheel.

    So far I saw only such a case. It was at an AUDI TDI and the drive wheel was from plastic. The wheel is broken, because the injection pump blocked.
     
  8. arveetek

    arveetek 1/2 ton status

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    This morning I inspected a bit further.

    I can turn the pump gear 360 degrees, so obviously all the teeth are sheared off. This also tells me that the pump is not locked up. I also discovered that all three gear to pump bolts were very loose. I'm wondering if the bolts being loose is what cause the gear to break in the first place.

    Hmmmmm.....

    Casey
     
  9. BlueBlazer

    BlueBlazer 1/2 ton status

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    Bolts being loose probably caused a momentary seizure of the head and rotor assembly due to the drive being misaligned, then when the gear broke there was no more side loading on the head and rotor and now it spins freely, just an edumicated guess though.
     
  10. Tybee

    Tybee 1/2 ton status

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    Ive seen a injector pump shaft break before, not on a 6.2 though. Thats kinda wierd that the teeth are all missing
     
  11. arveetek

    arveetek 1/2 ton status

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    Well, have I got egg on my face!! /forums/images/icons/blush.gif

    It was late at night in the dark when I first inspected the problem, and I could have sworn the teeth were gone on the injection pump driven gear.

    But, last night I pulled the water pump and front cover off, and discovered that the gears are fine. The key on the camshaft is what broke, allowing the drive gear to spin freely on the camshaft.

    The bolt holding the drive gear onto the camshaft was loose, as was the three bolts on the pump gear. I'm sure this caused the gears to wobble and put stress on the camshaft keyway, shearing that key pin.

    The timing chain and camshaft sprocket are fine, and it's the same key that holds the cam sprocket in place that got sheared, but it only sheared off where the pump drive gear slides on.

    Anyway, turns out all I have to do is buy a new key pin and some sealant, and that's all the repairs I'll have to do.

    I must admit that I'm worried about the rest of the motor now. This engine was rebuilt right before I bought the truck, and now I'm wondering what other bolts might not have been tightened properly (READ: main and rod bearings, etc.).

    Casey
     
  12. Tybee

    Tybee 1/2 ton status

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    Thats good news and bad news.
     
  13. arveetek

    arveetek 1/2 ton status

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    Okay.....
    What a major job for such a simple problem! I went ahead and dropped the oil pan to check the rod and main cap bolts for proper torque. I pulled a rod bearing to inspect it, and it looked brand new. The timing chain looked new, as did the water pump and other important parts. Whoever assembled this motor must have gotten in a hurry and got sloppy in assembly. I torqued all the bolts, including the camshaft sprocket bolt, and used loctite as well.

    I got it running again last night, but now I have a major knocking noise coming from the top end of the motor. After using a stethoscope, I determined it's the injection pump. I didn't know it until I went to assemble the motor that the locating pin on the injection pump had broken off (the pin that goes into the driven gear). I found the pin in the oil pan. My guess is that the loose bolts made the gears wobble, which sheared the key pin on the camshaft, which then broke the pin on the injection pump, possibly bending the shaft of the pump a bit. It seems to run just fine, although it might be smoking (black) a bit more. I'm surprised the pump can make such a noise and still run just fine.

    I've got a spare pump on another engine, but I don't know if it's any good or not. I think I'll swap it out first and see what happens.

    Any other thoughts? Ever heard an injection pump knock?

    Casey
     
  14. arveetek

    arveetek 1/2 ton status

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    Thinking I might have a bad injector, I loosened each injector line one at a time with the engine running to see if the knock went away. Sometimes it got softer, but it never disappeared. I've never heard what kind of knock a bad injector makes, so I'm not sure about that.
    I called and talked to my local Stanadyne shop, and they couldn't think of anything inside the pump that could make a knocking noise. This noise didn't appear until this break-down, however. Of course, they'd like to sell me a reman pump for $388.70 exchange. I'm sure the pump and injectors need replaced, but this is a bad time for repairs (but is there ever a good time?). The truck does seem to smoke black too much on acceleration, but I just can't figure why it's knocking now.

    I can put a hose, a stick, my hand, whatever on the pump while it's running, and that's definitely where the knocking is coming from.

    I guess when I get some more spare time, I'll pull the pump off.

    One other thing, the shop said that the spare '82 pump I have won't fit on my '86. I know that there are different spec pumps for different years and codes, but why wouldn't the pump still work? The shop was quite helpful and I don't think they're just trying to get my money. I've dealt with them before.

    Casey
     

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