Engine/Transmission (1998.5 - 2002) Injector install problem.

[rluft]

I installed my 275 injectors and now I have a leak. The #6 injector is appearantly leaking where the line goes into the head. The leaking diesel is one thing, but then the truck has crank for about 30 seconds to start after sitting for an hour. I did not tighten the nut with a torque wrench but it is tight. I decided to put a new o-ring on the injector tube in the hopes the leak would stop but it didn't.



Has anyone had a similiar problem and found a solution? I may remove and reinstall the injector just to be sure that everything lines up correctly as the #6 injector was not the easiest to reach.

 

[GeneralMachine]

injector install

I think your on the right track, you may have not got the injector hold down in the slot that aline's the tube. I sure would be ckecking to see if I was getting fuel in the oil. good luck. Harv

 

[rluft]

Fuel in the oil was one of my first worries. As far as I can tell no fuel is getting into the oil, the level appears to be staying the same.



I towed my trailer the week after the install and following that the hard starting began. I could smell diesel but I figured that was residual diesel lost while changing the banjo bolts.

 

[Ncostello]

You should take the #6 line completely off and really inspect the flared end where the big head nut is. It should look nice. Also inspect the threads to make sure they are clean. The threads in the head should also be inspected to be clean. Do your best to make sure by using a mirror. Try compressed air to blow any dirt away from the nut before removing. The high pressure line and the tube must have perfect mating surfaces. The 28 ft lbs is important too. Any more and you could side load the injector too much and damage or crack it. Any less and you could get leaks. But I know its almost impossible to get a torque wrench back there. Use your best feel to get it tight.



Pull the tube out and inspect both ends for damage or nicks. Maybe just replace it as they are only 11 bucks. I'd also pull the injector, make darn sure you have the copper sealing washer and it is the right one. THickness is very important for alignment. I'd just replace that too with a verified new one to be sure. Check the injector for cracks real good. They only install one way so that ones easy. Look at the hole where the tube lines up. Make sure that surface is perfectly nick free.



I'd take a shop vac and try to suck out any dirt or debris in the head threads where the large line nut tightens down. Thats critical to me for a good job. I'd also assemble everything loose first. Then snug down the injector hold down a little... then the large head nut a little to get things lined up real well. You can torque them tighter as you go back and forth to each one. Make sure you tube is pushed in to full seat by hand before you start installing the large nut end of the HP hard line. All being said you should be leak free if it all checks out.



Hope this works out.

 

[rluft]

Do you think I have the nut too tight? Perhaps backing off the nut would help. I never thought about to much torque throwing the injector out of alignment.



I pulled the tube and it looked fine. I'll inspect the flare on the fule line and pull the injector to ensure it is oriented correctly.



Thanks for the advice, any other advice is welcome.

 

[Ncostello]

Too much torque probably wont throw the injector out of alignment... I suppose it could but mostly I've read here where it pushes too hard against the side of the injector and can "bend" the injector and crack the body... which is a whole lot worse than throwing it out of alignment.

 

[rluft]

I have completely removed the #6 injector tube and the injector. Inspected everything which looked fine, no appearant burrs cracks etc. Installed the injector without tightening then I installed the tube. I fitted the line and threaded the nut tightening to finger tight. I tightened the the injector hold down to 18 ft/lbs and then tightened the fuel line snug. Result, leaks like a seive. In small increments I would tighten the nut and start the truck checking for leaks. I continued this routine 8 or 9 times but it still leaks and the nut is pretty tight. I check for leaks by placing a clean paper towel tightly under and around the nut and then running the truck for 30 seconds accelerating to 2000 rpm a couple times.

I am about to give up and take it to a professional unless anyone has any other ideas. About the only thing I have left is to replace the line in case the end is buggered and I just can't tell.

 

[Steve St.Laurent]

That injector hold down should be 89 INCH lbs - 18 ft/lbs is WAY too high. The fuel line nut should be 28 ft/lbs. My guess would be that the connector tube is messed up. You could swap it between two cylinders and see if the problem follows the tube - if it does you've found the problem. If it stays at #6 it could be either the injector or the line. You could then swap the injectors between two cylinders and if the problem still stays at #6 then you need a new #6 line.

 

[HVAC]

What Steve Said

The injector hold down needs very little torque. Use a 1/4" drive ratchet and be gentle.



On the other hand, I tighten the injector line as tight as I can go with one arm. Go ahead and push on it.

 

[jwilliams3]

Use 10 Newton Meters on the injector hold down clamp bolts.



--Justin

 

[rweis]

I'm changing my OEM's to DD2's this weekend and reading this post with GREAT interest.



Thanks to all for the info,



Bob Weis

 

[rluft]

I made a clerical error. I did torque the injector hold down to 89 IN/lbs. You guys really jumped on the 18 ft/lbs, how about some good advice on fixing the leak. ;-)



Meanwhile, I bought a new #6 injector line and installed it tonight. In the process I had to remove the #5 line and guess what, now #5 leaks. I had to lift the #5 up to get the #6 out and back in so I may have got it out of alignment. The ball on the injector line seems to have a line/groove which I would say indicates the point at which the seal is made against the connector tube. The new line was smooth. I was wondering if there was a tool to smooth the fitting, a hone of some sort. I tried cleaning up the old line with 320 grit and the metal is soft enough that it worked well but I can't be sure that the fitting is true. At $60 a line I am not looking forward to replacing all of them.



I admit I don't know what I am doing so any help is appreciated. I am going to call and see if I can talk to a Cummins tech tomorrow and then baring any good info from him admit defeat and take it to the shop.

 

[HVAC]

Grasping At Possibilities

Did you back the inner injector tubes out of the head before you extracted the injectors?

 

[rluft]

Yes. Using a screwdriver, as described by the various instructions, I gently pried the connector tube out before removing the injectors. All of which came out easily.



The plan for this evening it to remove the injector end of the line for #5. Inspect it for roughness. Dress it up with the finest grit paper I got. Reinstall, and check for leaks. If this fails the truck goes to the shop.



RWEIS, if I had to do it again I wouldn't. Call me a wuss but the advice a friend gave me to save the agrevation and spend the money on a mechanic seems to have been a good one.

 

[Steve St.Laurent]

I definately would NOT do that! It is an extremely precision fit between that connector tube and the injector body to withstand ~16,000 psi of fuel pressure. I'm sure the metal is specially surface treated as well which that would potentially ruin. Lastly if you get any debris into the tube which then goes into your injector you could clog the nozzles. JMHO

 

[rluft]

Steve,



I agree. I would not want to monkey with the connector tube and the injector body.



The leak appears to be at the injector fuel line and the injector connector tube. The fuel line has a mushroom shaped fitting that the nut pushes into the connector tube. This fitting is quite soft and has a ring where it had previously seated to the tube.



I talked to a diesel tech at the local International truck dealer where they are a Cummins certified repair shop. He indicated that I could try the 'sanding' method that I suggested. Obvioulsy postion of the line to the tube is very important for a leak free connection.



Has anyone else noticed the ridge or ring around the line fitting? I am wondering if they were installed with too much torque from the factory.

 

[kaptn]

I installed an over size injector line that was off a little bit ( not a perfect cone) and it let go after 4 months. I tried cleaning it up to no avail. I had it sent out and a new end was put on. No problems since.

 

[ynot]

Easy fix...

Hope it's not too late, but if it isn't, return everything you bought. Take any (or all) leaking lines off, extract line adapter from the head, remove orings, clean with solvent or brake clean, chuck adapter in a drill press, put a red Scotch Brite pad on a board, spin adapter and push onto the Scotch Brite for 4 or 6 seconds. Clean the Scotch Brite out of the hole in adapter and clean adapter, install orings. Loosen nozzles to contact plus 15 in. lbs. (or so), install adapters (grease orings), lines, clamps. As HVAC said, put the hurts to the nut (mine are at 40 ft. lbs or so), re-torque nozzle hold down (1/4" ratchet tite), run and check for leaks. Common problem, but don't let Cummins tell you that you have to replace the adapter and line. Clean em, torque em, and run em. The new ones aren't much better, but they look GREAT after the drill thing. Good luck... T

 

[HVAC]

I've Not Seen This Before

I would not discourage folks from doing their own injectors. This is an unfortunate experience no doubt, but I think it's the first one of it's kind for folks on this board.



I have installed many dozens of sets of injectors without a single leak problem. I just don't see it.



I would strongly suggest you try the procedure "Ynot" outlined. He wrenches on a daily basis and from his tone I believe this has worked well for him in the past.

 

[ynot]

Hey Nowel, tsup?? I only had it happen once, after tossing the head and stuff around last time, but the guys at Cummins see it all the time (pulling injectors and beating around the lines). They keep replacing lines and adapters until it quits. You don't have it happen 'cause you pull the tube out far enough so it doesn't catch the sharp edge of the feed in the base of the nozzle. Rip and tear doesn't always work with some stuff. Scotch Briting the sealing lip of the fuel line on these softer seats works well also. Cat uses better lines than Bosch, but ya can't bend em. Did ya see the new fix for lifter cover gaskets? Got 'er this time! Took a while and too much work, but it's permanent. Bigger clutch and fix the cruise (again) and she's done for a while (or until the next malfuction ;-) Be cool... T