TD-14 Injector Problem

thebunns · Nov 13, 2014

One injector on my tractor appears to squirt just fine outside the cylinder but when installed will not fire. Should I back off a bit on the spring tension & retry it? I just had it repaired but the repairman has no way to duplicate it operating in a cylinder.

rustred · Nov 13, 2014

if its squirting then it needs an o/h. on the test bench it should spray with a mist. I believe the opening pressure on those is 700 psi. appears like you need more spring pressure to hold the needle down.
you need the proper equipment here to check and adjust injectors. the test bench duplicates it firing. there is also about 3 different tests to do on them. leakdown, popoff, chatter tests.

thebunns · Nov 13, 2014

First, what is o/h? You say that the injector needs more spring tension to hold the needle closed. True, but isn't that the problem, that the needle is not opening to allow fuel to squirt into a cylinder under compression? Obviously there is enough fuel pressure getting to the injector because another injector works fine in that spot.

rustred · Nov 13, 2014

o/h... means overhaul.
another injector will work in its spot because it is set properly . its the injector that causes the pressure for the needle to jump off its seat to mist a spray into the cyl. if you have no spring pressure the diesel will just run out or shoot out the end of it.

jm. · Nov 13, 2014

You say when installed will not fire. Do you mean that cylinder will not fire with THAT injector in the hole but if you put a DIFFRENT one in that cylinder it in fact will fire? Or are you saying the injector cracks and sprays out of the tractor but when installed that cylinder will not fire. Could be a stuck valve if that is the case. Takes good injector but also takes compression to make the cylinder to fire.

thebunns · Nov 13, 2014

I rejected o/h standing for overhaul because you said: "If it is squirting it needs an o/h". I thought it was supposed to squirt! I did forget to mention that I swapped the bad injector with two other injectors and all cylinders are working properly. The "good" injectors worked fine in the cylinder that the bad one came out of. The malfunction follows the bad injector. As I mentioned before, I just got it back from a shop so I assume input pressure was tested after the repair. The repairman said that it was bad when he received it & that he couldn't determine exactly why it wouldn't work. He put a "kit" in the injector & said that after testing, it worked.

jm. · Nov 14, 2014

Well I think you have it down to being the injector. That being the case your repairman must have not done the job. Let me know if you can,t find another injector. I am sure there are some laying around here. Might let him have another go at his work. Has to be the injector if problem moves when you move the injector.

JDemaris · Nov 14, 2014

Testing an injector is not like testing a spark
plug. A spark plug can fire in open-air and not
fire under compression. And injector though? When
an injector is set to open at over a 1200 PSI
(usually MUCH more) it exceeds the pressures in a
combustion chamber with a 17-1 to 21 -1
compression ratio with 400 PSI of pressure. I
don't get it. Injector should work the same inside
or out.

thebunns · Nov 14, 2014

I appreciate your offer to help locate another injector if need be. The repairman is working with me & is sending another one for me to try. I'll let you know what happens. Again, thanks!

thebunns · Nov 15, 2014

One more thing while I'm waiting for the second injector to show up in the mail---how about some ideas on how to get a compression ring out of the nozzle body. I tried picking one out with a 90 deg. awl but that's not going to do it. Will soaking it with WD-40 or something similar help?

thebunns · Nov 21, 2014

(quoted from post at 18:31:53 11/13/14) if its squirting then it needs an o/h. on the test bench it should spray with a mist. I believe the opening pressure on those is 700 psi. appears like you need more spring pressure to hold the needle down.
you need the proper equipment here to check and adjust injectors. the test bench duplicates it firing. there is also about 3 different tests to do on them. leakdown, popoff, chatter tests.

While I'm waiting for another injector to show up, would it make sense to tighten the plunger spring one full turn & reinstall it. Would that be enough to make a difference? Thinking back, the injector shot fuel out when testing it outside of the cylinder but it didn't appear to be misting.

rustred · Nov 22, 2014

give it a try. that's how a person learns is by hands on experimenting.

TD-14 Injector Problem

thebunns

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rustred

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rustred

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jm.

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thebunns

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JDemaris

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thebunns

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