Engine/Transmission (1994 - 1998) Leaky Injector

[SteveAnsley]

Hello all.



Just got through changing all my valve cover gaskets and now and see I have the #3 injector has a 'slight' leak - more of a seaping.

Amazing how getting all that leaking oil out of the way can help.



I would imagine the first step would be to see if it can be tightened a bit.



How best to do this - still learning.

I see there is a hard line that is attached to all 6 injectors along the side, looks like it is designed to equalize pressure - yes/no?



Do I remove this line and then the injector line in order to access the injector to tighten it down?



Are crush washers involved between the injector and block?



It's not bad at all, just want to see if I can keep things clean and problem free.

 

[CWinslow]

the two lines you are looking at are the top is supply, and the sides are return. i would remove the return first and then the supply, you have a little more room that way. there should be a copper washer size depends on the truck that is between the injector and the block, there is also a washer on the return so don't lose that either. good luck it isn't that difficult.

 

[Greenleaf]

Is it leaking oil??... ... or fuel?



Scott

 

[SteveAnsley]

It's leaking diesel. Changing the valve cover gaskets stopped the oil leak.



I was assuming it's a pretty basic job.

(easy when know comes to mind)



Obviously the injector needs to stay in the same orientation in order for the return line to be able to line back up.

Do I need to be carefull to keep the injector from rotating? Or, is it 'slotted' or such that it won't rotate?



It's the 3rd injector that's noticeable. Looks like the supply line needs to be moved completely out of the way in order to get a socket in there (open nd wrench looks tough).

Should I disconnect the supply at both the injector and delivery valve? Or, is there enough play in the hard line to move it around without kinking it?



Is it a problem loosening these lines and then tightening?

ie: It's always best to replace a brass ferrel on a compression fitting when taken apart. Anything similar to be aware here?



Any thing to be concerned about regarding air getting in the line while apart?

I assume it will run rough for a moment until the air is purged.



Sorry for all the questions.

 

[Greenleaf]

Lots of views but no answers?... ... ...



You are not familiar with the diesel and need to know some basics of said construction. There is a ferrel but it is presed onto the line and it's steel. Reusable.



There will not be much air introduced into the system by removing a line.



The injector is positioned into the head via a ball (bearing) pressed into the injector body. This properly positions the injector to the piston bowl to obtain proper spray pattern fuel air mix. It also does as you said. It assures that the bleed-off port is located properly to attatch the overflow manifold to all injectors.



You will not need to remove an injector to solve your problem unless the injector body is damaged. You simply need to loosen the high pressure (supply) line and reseat it by snugging the nut back onto the injector body. Another method would simply involve operating the engine at slow idle speed and "cracking" the line line nut loose (engine running) and allowing the high pressure fuel spray to wash out any contaminates at the line ferrel and injector body. This particualr cylinder will no longer fire untill you snug the line nut back down.



"Cracking" a line loose simply means truning the nut loose "about" one half turn and allowing a small amount of fuel to leak out (engine running) and retightening it. Obviously, should you loosent the line too much (engine running) you'll likely have diesel fuel blowing every direction.



DO NOT PUT ANY PART OF YOUR BODY NEAR THE LINE THAT YOU LOOSENED! You know what blood poisoning is?



This will most likely correct the problem of a line that seeps fuel at the injector. In extream cases, the line or lines will need to be repositioned on their mounting brackets and retightened at the nozzels.



Hope this helps you out.





Scott

 

[SteveAnsley]

Scott,



Thanks for the info.

You're correct, I'm obviously on the Diesel learning curve.



I was going to inquire about 'crackin' injector lines - I've noticed it seems to be brought up often enough.

I'm assuming 'cracking' is also used as a diagnostics such as confirming if a cyclinder is firing or not.



BTW:

The injector is leaking up from the bottom between the hold down nut and the injector body. Therefore, I assume 'cracking' the lines while running is probably not necessary.

I'm hoping it's just a matter of tighening, if that doesn't do it - I assume it's a matter of pulling the injector and replacing the crush washer along with making sure to keep depris out of the area.



Another question:

I have never seen any reference to any aftermarket 'hotrod' books for the Cummins.

ie: similar to all the reference books out there for the small block Chevy, etc...

Would you recommend getting the Cummins service manual? Other?

The Haynes Dodge manual seems to have a LOT to be desired.



Thanks to you and everyone else on this sight.

This is almost as good as hanging out at the local hot rod shop.

 

[Greenleaf]

It sounds like it is leaking AT the injector body. The top half threads onto the bottom half.



I was going to point out that Cummins has various publications. Some re rebuild. Some are troubleshooting. Some are operators manuals. Some are specialty publications that would deal strictly with injection pumps etc. etc. etc.



It depends on how deep your pockets are and how much you want to know... . willing to learn.



Scott





BTW if you DO pull the injector you don't want to bend the high pressure fuel line(s) to the point of actually bending them. Move them as opposed to bending. You'll have to unbolt the fuel hold down(s). Possibly move a valve cover to allow pushing the line(s) off to the side etc.

 

[Greenleaf]

A good book for you or anyone who wants to learn about the injection system;



Cummins Publication3666037-05 $33. 00



Fuel pump timing... How the pump works etc.

 

[PKemp]

Please wear a full face shield AND glasses if you are anywhere near the line when its cracked and the engine is running. Keep hands and any skin away from it also until its turned off AND the pressure bleeds down.

THIS IS A VERY DANGEROUS OPERATION... . KEEP AWAY FROM IT.....

 

[PSchwering]

If The Copper Washer below the injector were leaking, you would get Combustion gas, Not fuel. If fuel is welling up around the injector, you will need to take it apart & Clean it(Minimum) If you do that, you should probably get it pop tested. Also, While it is being pop tested, you can Check the injector Body for leaks. P.

 

[SteveAnsley]

PSchwering,



'welling' up around the injector describes it perfectly.



When you say take 'it' apart... are we talking take the injector out and clean & re-install or once the injector is out - do I need to work on the injector more?



Pop test?

Anyone recommend a shop in the Dallas Ft. Worth area?

Can they do the pop test with the injectors in the block?

I work off Irving Blvd. in Dallas which is Diesel (big rig) Heaven.

We even have a Cummins Southern Plains down the street.

But, I would still like info on local shops... especially one that might adjust timing beyond factory specs.

 

[WadePatton]

Pop-test. Don't you hate those!



Pop-testing injectors is done on the work bench. Injectors are fitted onto a fuel line with a hand operated pump and a high-pressure gauge.



Tech then works the pump handle and notes the pressure at which the injector sprays and the pattern/atomization of the spray.

 

[CumminsPower98]

My #2 injector had a tiny leak. I had noticed a slight dampness around it for some time and when I did my head gasket I had the injectors out for a valve job/head surface. The #2 injector was leaking around the threads of the two halves. I got a rebuilt since the shop didn't have time to check mine out and all is well.