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  #1  
Old 02-28-2018, 01:02 AM
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Dry fuel injector

OM617

https://imgur.com/a/6Zy47

Car starts after 45-60 seconds of cranking. I've ruled out glow plugs. When I took the injector hard-lines off, I found that one injector was almost completely dry of fuel. Here is a picture of the dry injector (right) and wet one (left).

Is it air in the fuel system? Is the fuel-return hose clogged somehow? Any information is a huge help. Thank you.

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Old 02-28-2018, 01:52 AM
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Most likely air incursion causing partial loss of prime.

Other than removing the hard lines, any recent opening of the fuel system connections?
There should be no air bubbles in the clear return line from the IP to the fuel filter housing.

Usual suspects are the old style white handled primer pump, rubber hose connections, secondary fuel filter hollow bolt o-ring(s) and/or crush washer, banjo bolt crush washers, and etc.
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Old 02-28-2018, 11:02 AM
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Air in the Fuel System can cause that and also cause the loss of prime. But, once the Engine is running smoothly you have passed the air out of the system at least till it sits again.
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Old 02-28-2018, 02:01 PM
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Could also be low to no fuel feed pressure in the base of the injection pump element supply area. If fuel is coming out the return hose on the injection pump when cranking.


Close that hose off to make sure the relief valve on the injection pump is not remaining open. Nothing coming out of the return hose? You may have lift pump or other supply issues like a pretty obstructed filter. As the supply pressure and fuel cannot reach whatever the relief valve opening pressure is.


Worse scenario is an element in the injection pump has failed or is stuck. Or pretty much a total failure of a delivery check valve. These last items are not that common.


Also with the return hose immersed in a container would indicate if too much air is present in the returning fuel. There should be none on a good fuel supply system in decent condition.


It sounds like you are describing fuel starvation to the injectors more than anything. Shooting some wd 40 directly into the intake. If the engine starts in your case that is probably your problem.


Not hard to service if you approach it with a method. Guessing is pathetic usually. It is very wise to get a real understanding of these older fuel systems. If it fails in some way probably a lot of service shops will not do much for you. Even though the system is pretty simple.


Also there are other benefits to keeping it in decent shape yourself. Basically milage, reliability, power, and better cold starts. Plus on certain engines especially the 616 and to a lesser degree the 617. Maybe longer engine life. This last item still remains a little subjective in my mind.

On all our cars both old and new. Reliability is very important. A breakdown on the road will cost both money today and usually the loss of a days time overall or better in the scenario if far from home.

Living with a fuel system that is sub par after thirty or forty years of probably no attention. When in most cases it is easy to check and tune up usually at low cost is a no brainer. Plus once you have done this it becomes easier to diagnose any issues that may arise in that system at some time. Plus you are far less likely to experience them.

Last edited by barry12345; 02-28-2018 at 02:11 PM.
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Old 02-28-2018, 09:02 PM
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You also started another thread on basically the same no easy start issue. Always better to bump the first one so no confusion occurs with people reading two threads about the same issue. Basically the simpler it is with only one thread the better has been proven over time.


For example there was a good suggestion by a member to pump up the system just before starting after sitting overnight. To see if fuel drain back has been the problem.
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Old 02-28-2018, 10:16 PM
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Quote:
Originally Posted by barry12345 View Post
You also started another thread on basically the same no easy start issue. Always better to bump the first one so no confusion occurs with people reading two threads about the same issue. Basically the simpler it is with only one thread the better has been proven over time.


For example there was a good suggestion by a member to pump up the system just before starting after sitting overnight. To see if fuel drain back has been the problem.
Sorry, I'm new to posting to this forum, I didn't even know bumping existed. :/

But the reason I made a new one is because I posted a comment that showed the picture of the injector, and then it sort of died before I got as many answers as I wouldve hoped for. Bumping is nice though, thanks for letting me know!
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Old 03-01-2018, 12:06 AM
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With engine running, crack the fitting at the top of the dry injector and see if fuel gets up there. Don't worry, it would just dribble out. The return hoses couldn't stop fuel flow since pressure could build to >1000 psig and the hose would pop off with 5 psig. If air filled the tube, I would expect it would eventually be swept thru, but never tried.

If no fuel, something is wrong in that circuit in the injection pump. First, remove the delivery valve and inspect the internal elements. Take many photos to not mix up assembly. It is basically a check-valve, so if it doesn't seal well, the output may never build pressure. Hopefully, you find a little piece of junk blocking the valve seal.
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Old 03-01-2018, 01:10 AM
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Quote:
Originally Posted by BillGrissom View Post
With engine running, crack the fitting at the top of the dry injector and see if fuel gets up there. Don't worry, it would just dribble out. The return hoses couldn't stop fuel flow since pressure could build to >1000 psig and the hose would pop off with 5 psig. If air filled the tube, I would expect it would eventually be swept thru, but never tried.

If no fuel, something is wrong in that circuit in the injection pump. First, remove the delivery valve and inspect the internal elements. Take many photos to not mix up assembly. It is basically a check-valve, so if it doesn't seal well, the output may never build pressure. Hopefully, you find a little piece of junk blocking the valve seal.
Thank you for the reply. I'm gonna try it out tomorrow.

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