Shake at low RPM's after replacing fuel return lines

[Chappy]

The truck was running great, I noticed a fuel leak coming from the injectors. Replaced all the lines per SOP on this forum. Before I put steel lines back on I turned engine over and made sure fuel was coming out of each line. Put it back together and it feels like it is missing. You can feel it at idle and at low rpm through each gear (gets worse through the gears). Tonight I broke each line to check for RPM changes with no luck, it stayed at a steady 700 RPM. Hooked a mulitmeter to the glowplugs and they all checked out between 3.5 - 5.1 MV. Any words of wisdom to smooth her out? Thanks in advance

 

[mjs2011]

No leaks now? New return caps are all fully seated? All injector nuts are tight? Nuts on the back of the IP all tight?

 

[Chappy]

yep, no leaks now. I felt all the caps seat, tightened all injector nuts. I haven't checked the nuts on the back of the IP though...

 

[mjs2011]

They shouldn't be loose, but who knows. That happened to me a day after I installed a new IP, one nut wiggled loose and it ran like ****.

One thing you can do is Crack each injector nut at the injector one at a time and listen to the engine. If it sounds worse, tighten back up and move on. If the noise does not change, that is your fault cylinder.

 

[Chappy]

yeah, I already tried that. I cracked each one loose and each one made the engine run worse, and the RPM's remained constant. As I was doing the return line replacement I did notice that one of the heads of an injector had come loose so I hand tightened it? All the injectors showed minimal carbon buildup and the engine supposedly only has 103k on it...

 

[mjs2011]

You pulled all the injectors? Did you replace the copper washers, and did you look in the bore for buildup around the seat?

 

[riotwarrior]

..... As I was doing the return line replacement I did notice that one of the heads of an injector had come loose so I hand tightened it?

All the injectors showed minimal carbon buildup......

...

I wish people would fully understand this this type of information needs to be in the VERY FIRST POST ....not later on as an addendum.

Fully disclosing all information is paramount to accurate diagnosis and help.

I'm curious why you said....

The truck was running great, I noticed a fuel leak coming from the injectors. Replaced all the lines per SOP on this forum. Before I put steel lines back on I turned engine over and made sure fuel was coming out of each line. Put it back together and it feels like it is missing. You can feel it at idle and at low rpm through each gear (gets worse through the gears). .....

SOP is we don't pull injectors to replace return caps and lines, so where that comes from I'm not sure.

A loose injector...head? Now are you talking about the tip that copper washer rests against with the 12pt head? If so it could be it's not assembled correctly.

Did you replace all those copper washers? Did you get all the old ones out? Did you clean the bores??

What torque did you tighten the injectors too?

I'm throwing a WAG out and saying that the loose one is the problem....and may need replacement

JM2CW

 

[Brad S.]

Did you loosen any of the steel lines on the IP side/end???
(From your description doesn't sound like it...)
Just thinking what else this miss could be...

 

[Chappy]

Thanks for the help, sorry for the inexperience but it was the tip that was loose, the very bottom of the injector.

So when do you need to replace the copper washers? When the o-rings, caps, and lines don't fix the fuel leak?

And, yes I replaced all copper washers, and got the old ones out. I did clean the area around the injectors but I did not clean the bore itself

Injectors torqued to 33 psi

 

[Chappy]

That may have been where I went wrong with not cleaning the bore holes. debris may have entered the hole which could cause the miss?

 

[riotwarrior]

Thanks for the help, sorry for the inexperience but it was the tip that was loose, the very bottom of the injector.

So when do you need to replace the copper washers? When the o-rings, caps, and lines don't fix the fuel leak?

And, yes I replaced all copper washers, and got the old ones out. I did clean the area around the injectors but I did not clean the bore itself

Injectors torqued to 33 psi

This all sounds good, seems to me that the issue is that one injector that had a loose tip.

No worries all info is best up front...no guess work then..

I'd say see bout another injector and replace it.

Copper washers only need replacement when you remove injectors...no reason to remove them for a cap/return line fix...

 

[mjs2011]

Just to be sure, you mean 33 lb ft correct?

Psi is a measure of stress, lb ft is torque.

 

[Chappy]

sorry, yes lb-ft. Ill try the bad injector and post the results. Thanks for all the help