Injector Quality

[CAROLINA CUMMINS]

Hello,



A friend of mine has a 04. 5 w/about 60,000 mi A couple months ago he lost the #1 injector. Body of the injector just split, about 1/8" long. He's running a Edge EZ, so we just replaced the injector, no use fooling with the dealer. Through the process of diagnosis the new injector ended up in #2.

We also installed a set of DDP 90hp nozzles. All this work is by-the-book as I am a prof. diesel mechanic and try to be as perfect in my work as possible, but I am human, so there is still the possibility for error.



Well, this weekend he lost #1 again:{ he was running with EZ off. just cruising about 55. These inj are splitting/busting in the body and pumping the fuel out under the valve cover. Lots



We pulled it out, swapped o-rings/conn tubes. No change.



Is there any coincidence that this is #1(but orig #2 inj) again, or could there be a diff problem?? Am I missing something that's not in the "book"



Any help would be appreciated. He can't really afford $600 an injector everytime one goes. Thanks



Steven

 

[raychem]

Not saying that these injectors are perfect, b/c they are not but I would run a rail pressure gauge to see where your at all the time. Injector bodies do split from time to time but I myself have only seen it with certain pressure boxes. The injector you guys purchased... was it new or rebuilt? He may have recieved a rebuilt injector that may have been previously damaged. The only way to see the damage on the injectors is by x-ray which I do to some extent in marine apps. These are some ideas that come to mind.



Richard

 

[jglasgow]

I replaced an Injector in a 04. 5 truck last week with a new, not rebuilt one from Cummins, the truck would not build enough rail pressure to fire off the motor so I bought another new, not rebuilt injector.

Truck runs fine .

hope this helps,

John

 

[betterthanstock]

Running the injectors at higher pressure (edge box) is like running headlights at a higher voltage. Once one has cracked, the others are no too far behind. They all have micro-cracks that will join together until it starts to leak. It's just the nature of all materials. The higher the stress, the shorter the life. (humans are like that too)



He should get rid of the pressure, now that he's running honed injectors, and not be too surprised if others may soon crack, though some may go on for a lot longer.



So did you put the new injector in #2, and swapped another old one in #1, and it so happened that #1 cracked again? I think it's just a coincidince, though many people have noticed that if you feel the #1 injector line, it has stronger pulses than other lines. I have zip tied a nearby wire harness to the #1 line, and it takes away some of the vibration and noise.

 

[cerberusiam]

Unless there is something really wrong with the rail pressure the injector bodies should not be splitting with the extra pressure of the EZ. Tips maybe if one is really playing hard but not bodies. IIRC, the stock bodies and tips are rated to around 28k. You should not see that kind of pressure.



I would lean towards some bad from the factory injectors that are starting to fail prematurely. The 04 models seem to be more prone to this type of failure and I believe it was a QC problem Bosch had when they moved their production facilities.



The only reliable fix may be a whole set of injectors to make sure the potential for failure is addressed.

 

[CAROLINA CUMMINS]

Thanks for the replies guys,



Yes, the new inj. is in #2. And it was new. It is another original stock one broken this time(in #1)



Our next step is to get a rail pressure guage. Does the EZ on these 04. 5's raise rail pressure?



Even If we could get the 150$ core back on these broken inj. $418 apiece is still kinda steep



Steven

 

[sag2]

I disagree that pressure boxes should not have any negative effect on the injector body like. If you watch the pressure on a stock truck it very seldom gets above 23,000 PSI in normal driving, and most of the time is significantly lower than that. A pressure box bumps the pressure up to near the maximum rated design limits of the injector. And the only cracks I have seen are in the plastic upper section of the injector as it is the weakest part. It only seems like common sense that running anything to it's limits will make it fail sooner. Although some stock injectors have cracked, the vast majority are from modified systems.

 

[raychem]

I disagree that pressure boxes should not have any negative effect on the injector body like. If you watch the pressure on a stock truck it very seldom gets above 23,000 PSI in normal driving, and most of the time is significantly lower than that. A pressure box bumps the pressure up to near the maximum rated design limits of the injector.

Boxes like the EZ and the MP8 which I sell don't push rail pressure above 27k. Now there are boxes out there that I have seen that keep that rail pressure at peak and I can only assume above b/c they have craked injector bodies and unfortunatly the stock rail pressure sender is only reads to 27k. I wish we had a higher reading sensor and that everyone with a cr ran rp gauges. Trust me I have replaced more than a few cracked injectors. Also different boxes ramp-up pressure differently as the mp-8 is a very good box but is also more agressive than the ez by far.



Richard

 

[Shifter]

I have replaced four cracked injectors in an 03 with 162,000 miles using a pressure/timing box. Three injectors cracked the tips and I was able to just replace the tip. The third cracked the body and the tip so I had to replace the whole thing. I tend to think more pressure is harder on the injectors but have heard of stock trucks with bad injectors. My . 02

 

[cclark746]

i am no mechanic or metal specialist but any thing that is mass producded has a problem with maintaining really high quality control IMO and with these things running at 27k pressure all the time that is a extreme stress just a ticking time bomb for the weak that make it though the assembly line, and cummings clearly states there fuel systems are designed for 29k psi i believe

 

[hotram03]

Rail pressure boxes do add more stress to everything, I do believe also that there is some type of metalurlogy problem in the casting of the injectors some type of QC problem. I think with pressure boxes if you don't run a very low micron # on the fuel filter (I run a 3 micron, always have) that the factory one being a 10 micron lets oversize debris in and this clogs the nozzle and with the ramped up pressure from the RP box it is going to force it thru or clog up and crack something, someone needs to do a poll about guys who have cracked them and with what type of fuel filter micron level they have and how long they have had it on the truck? Just my . 02