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IDI No start

Discussion in '6.9L IH & 7.3L IDI Diesels' started by 1983idi, Oct 18, 2020.

  1. 1983idi

    1983idi Registered User

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    My 83 6.9IDI won't start. If I put a little gas down the intake it fires over a few times and dies. I figured it was air intrusion as in the past I have had problems with it starting, dieing, and then requiring a long crank time to start again. I wasn't sure where it was coming from. A couple of the injectors are wet on top where the hard metal line meets the "nut". I thought that might mean the hard lines where cracked? I couldn't see how it could get fuel up there if the injector caps where leaking but maybe it can. Looking for an answer on that.

    Anyways it wouldn't start today. The only way it fired for a minute was if I cracked all the lines at the injector and then cranked for a minute and closed them back up.

    I'm thinking that air is leaking thru the injector caps and back to the return line that goes back to the filter housing and making it so the injector pump just can't make pressure? Does this sound right? I ordered this kit from ebay to replace the return caps & lines hoping that will fix the issue.

    https://www.amazon.com/gp/product/B07KK17RC2/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

    Thanks for any help or advice guys
     
  2. david85

    david85 Full Access Member

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    1. What is the level of fuel in the tank? Anything below 1/2 could indicate a broken fuel pickup tube. If equipped (and functional), try switching tanks.

    2. Try Removing the fuel filter and filling it with fuel (or automatic transmission fluid if it's easier to find). Chances are you'll find it only filled about 2/3, but it should be full.

    3. Yes, it should still run even with leaks at the return lines, but it will make it hard to start after it's been stopped for a while.

    4. Crank with your foot to the floor until the engine catches. This will help clear air from the lines and injectors.
     
  3. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    PLEASE DON'T PUT GASOLINE INTO YOUR INTAKE! If someone thinks ether is bad, this is just asking for a major problem in my opinion. You're putting a lot more explosive material into your engine by dumping gas into the intake than you are with a big shot of ether.
     
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  4. Randy Bush

    Randy Bush Full Access Member

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    When trying to start are you getting any smoke out the exhaust? How is your glow plug system.
     
  5. 1983idi

    1983idi Registered User

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    1) Fuel tank is 3/4 full on my front tank. I've had it down to 1/8 recently with no issues

    2) I'll have to check this when i get home. This will verify air intrusion correct?

    3) It used to run but was hard to get started sometimes. It would start right up and then chugg and die and require a lot of cranking to start again. Now the only way it even sputters up for a second besides using gas in the intake is to crack all the lines at the injectors and crank 30 seconds till fuel dribbles out of them. Close them back up and it'll fire up for 10 seconds and die.

    4) During all this I have been keeping the throttle wide open.
     
  6. 1983idi

    1983idi Registered User

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    Glow plug system is bypassed to a switch. All plugs are 2 years old beru plugs. I run them for 6-8 seconds before cranking. Always worked great.

    Just about no smoke at all when cranking. Sometimes a whisp of white smoke right at the tail pipe but it disapates so you can't see it unless looking directly at the tail pipe. Before i replaced the glow plugs 2 years I would get a big cloud of white smoke when trying to start on the bad plugs. This is nothing like that tho
     
  7. riphip

    riphip Supporting Member Supporting Member

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    May have in-tank pick-up screen(s) deteriorated.
     
  8. 1983idi

    1983idi Registered User

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    With my electric lift pump turned on I have a decent flow of fuel out of the schrader valve located on the fuel filter "head"
     
  9. david85

    david85 Full Access Member

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    Air leak is most likely, but it could also be a bad lift pump. I had this with my truck to the point where it wouldn't idle even after filling the filter up with fuel. Lucky me (sarcasm), I parked pointing uphill where it died so I had to swap the pump where it was. Since then it's been fine.

    Another possible source for air would be if any of your fuel sending units at the tank have rusted to the point that air is getting introduced there. I would expect to see some fuel running down the side of the tank if this were the case.

    I was able to ultimately condemn my lift pump by removing the fuel filter and cranking the engine with a catch pan under the filter head. Once I saw no fuel gushing at all, I had my answer.
     
  10. 1983idi

    1983idi Registered User

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    With fuel flowing out of the schrader valve at the filter head and no air in that fuel I'm thinking that any issues from the filter head on back (tank pick-up, any filters, and lift pump) are pretty much eliminated? Maybe I'm wrong tho. With the fuel leaks around several injector caps I know I'm not wasting money replacing the injector return lines, orings, and caps but would like to figure out if there's anything else I need to replace and get it ordered ASAP so my rig isn't down for too long.

    I appreciate all the help/replies so far guys!
     
  11. david85

    david85 Full Access Member

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    Strange, yes I agree it seems like your low pressure side is pushing fuel. I wonder if it's in the injection pump. Have you checked for power at the electrical plugs on the top of the IP? There should be clicking sound if you have the key on and try plugging in either of those connectors.
     
  12. 1983idi

    1983idi Registered User

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    I did forget to mention that I did pull the Connector to the fuel shut off switch and it clicks. Also pulled the cold advance thinking it might not be on and just making it real hard to start and that one clicks as well. The engines are so darn simple I'm thinking it's gotta just be the leaking injector return caps. I can't really think of anything else it could be.

    Also when I cracked the lines at the injectors to attempt to bleed air out of the high pressure lines and pump fuel just oozed out after about 20-30 seconds of cranking. I was expecting a severely messy spray of fuel all over. Is the "ooze" normal or should I have gotten more of a spray?
     
  13. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    It depends on how far you opened the fuel lines. If you just barely open (crack) them, then all you will see is a little bit of fuel. If you open them more, you will see more fuel. If there's air in the lines, there won't be a lot of fuel come out either before all of the air has been removed. To get a big spray, open them while the engine's running. I don't think that the pressure builds very quickly while the engine is being turned over by the starter so there never be a true spray without the engine running.
    Here's another thought besides the injector o-rings leaking. Your engine needs to be turning over fast enough or it will be very hard or impossible to start. What is the condition of your starter, batteries, and battery cables? A starter can sound like it's turning over fast enough and be turning slower than optimal. Recently,the batteries in my truck went bad. Until the day that I barely got it started, I thought that the starter was turning over fast enough. It had slowly been getting slower and slower so gradually (from dying batteries) that I didn't realize it. Once I put new batteries in the truck, WOW! what a difference it made. I asked and mentioned this because in post #5, it sounds like it's been getting harder to start your truck. It may be air intrusion getting worse or it could be from the starter turning the engine over slower. Even with a short cranking time with a rest in between, long cranking times are hard on starters. The more they have to work, they more they wear out.
    Edit to add: one more thought is that as the engine is turned over slower, and white smoke from the exhaust will be harder to see and there probably will be less smoke as well. No matter how much the fuel is compressed in the cylinders, it won't try to ignite if it isn't being compressed quickly enough.
     
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  14. 1983idi

    1983idi Registered User

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    My batteries are worn out for sure. I put a jumper pack on in and also jumpered it to a running car on the other side and it turns over way faster than it ever has in the 4 years I've owned it. At first the batteries where my thought because I knew they where wearing out but even after jumping it I couldn't get it to start. I am trying to hold off on replacing the batteries until spring time. I hardly use the truck in winter and am hoping to use the jumper pack to get me by until then. If it comes down to it I will replace them tho.
     

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