Engine/Transmission (1998.5 - 2002) Lifetime of Injectors

[jeepit]

What is a "normal life" of injectors? Other than a Smarty and AirDog I am stock. Approaching 100,000 miles on stock injectors. Just wondering if I should start to consider new ones and then what brand and size?

 

[ILIANBG]

I like the RV275. A lot! If I had to do it again I would do the same or DDP 50hp injector.
But that's just me. Everyone's different.
Ilian

 

[hsmith]

I have a few customers with 125k or so on their original units. Just a matter of time though before one starts leaking with those miles. I have read where some have gone over 200k.

 

[FourBarR]

My truck has just passed 530,000kms (320,000k ) with original injectors and vp-44. I have a set of rv275 in a box for the last 3 years waiting for these to crap out ,so far running great with no loss of mileage . has always run 22-23 mph or 25 -26 mph converted from liters.

 

[jeepit]

My truck has just passed 530,000kms (320,000k ) with original injectors and vp-44. I have a set of rv275 in a box for the last 3 years waiting for these to crap out ,so far running great with no loss of mileage . has always run 22-23 mph or 25 -26 mph converted from liters.

Ok, whats your magic potion for the VP44 and injectors lasting this long?

 

[FourBarR]

the only things I have done that might explain the long life of the injectors and vp-44 are : clean fuel always fueled from large card lock used by truckes, from new always add marvels mystry oil to every tank ,also add howes meaner to each tank, check for water at fuel filter,and no added mods to increase power . thats it. the fuel system is original using the carter lift pump moved back by tank at about 200,000kms. I have replaced 4 lift pumps. also have had gauges from new (Westach).

 

[hsmith]

I was a bit out of line with my statement. Was thinking of the CR systems.

 

[JLandry]

What is a "normal life" of injectors?

Some thoughts on this subject...



I recently pulled the original stock injectors from my truck at about 111,000 miles. The engine seemed to run fine. After I had them out, I bench tested each injector using a military surplus pop-tester made by Kiene Diesel. I checking for leakage, pop-off pressure, and the nozzle spray pattern.



Now according to the Dodge factory Service Manual, the normal target pop-pressure for stock injectors is supposed to be 4,500 +/-250 psi. The nozzles should not leak fuel prior to popping open. Every single one of my original injectors popped open in the range of only 3,800 to 3,900 psi. Four out of the six injectors leaked and literally squirted streams of fuel from the nozzle holes about 100 to 200 psi below the pop off pressure. In other words, all six injectors were complete rejects and I was surprised the engine ran as well as it did! I guess it says a lot for how forgiving the ol' Cummins is.



I'd bought a set of used stock injectors on eBay a few months ago said to have less than 25,000 miles on them. The original owner said he'd removed them only so he could install a set of RV275 injectors and he stored these originals on a shelf until he ultimately sold the truck. When I received them, I immediately tested them on my Kiene pop tester to establish a "before" baseline, as I intended to disassemble, clean, reassemble, adjust, and install them in my truck in place of the originals.



What I found was the old diesel fuel left inside these injectors over the years had temporarily gummed them up enough so that it took well over 5,000 psi (the limit of the pressure gauge on my pop-tester) to get several of them to pop open for the first time. I wouldn't have wanted to put these directly in an engine because I'm not sure all would have worked. But after a thorough disassembly and cleaning (using an ultrasonic cleaner and solvent), I got them all looking like new, working properly, and adjusted to 4,500 +/- 25 psi. The spray patterns were perfect and there were no leaks.



So I swapped out my original injectors for these refurbished ones and I could immediately tell the difference in the idle quality of my truck... much smoother.



But back to the original injectors: I disassembled, cleaned, reassembled, and adjusted a couple of them. No matter what I tried I found I couldn't stop the leakage and squirting from the nozzles. Apparently the nozzles do wear out at some point, the internal tolerance become too great, and replacement is the only option. The injector bodies and other internal parts seem as though they could last the lifetime of the engine.



In the future I plan to replace the current injectors (the used ones I bought on eBay and refurbished) again in about 50,000 miles when they've accumulated about 75,000 miles on them.



Regards,



John L.

 

[ROADWARRIOR]

Nice post John.



Dan

 

[mhenon]

Nice post John.



Dan

I agree... excellent post! I thought my injectors were OK at 120k. The engine started, idled and ran just fine. Mileage has been slipping lately but I wasn't too concerned. It's making a little more sense after reading John's post.

Great information!

Mike

 

[Vaughn MacKenzie]

Ok, whats your magic potion for the VP44 and injectors lasting this long?

I think FourBarR gave revealed the secret in the previous post- he said he generally drives only 22-23 miles per hour (which works out to 25-26 miles per hour when you convert from Liters- some sort of fuzzy Canadian math I suppose) :-laf

 

[BEnglish]

Other than decreased mileage and poor idle quality, what other symptoms could you expect from poorly adjusted or failing injectors on our trucks? And what do you get when one fails?

 

[FourBarR]

I should read my post more carefully ,of course I meant MPG. The conversion factor for liters to usg is 0. 26417. i dont claim to be a recent expert but I was a diesel mechanic for 15 years in the 1950 thru 60 and 70. The technolgy then was not much different then what is used in the 1st and 2nd gen cummins. I spent quite a lot of time in the injection room doing injectors and pumps for cat,gm,and international. Getting old and forgot a lot . injectors do of course wear and subject to lots of things that can increase the wear, water, poor fuel, carbon which plug or restrict the small holes causing dribblin,altered spray patterns . The pop off pressure do decrease over time . If I thought the injectors were starting to go ,I would expect to see , black smoke, increase fuel consumption , change in idle (roughness) fuel in the oil etc. my truck does not show any of the signs. Until it does I will continue to run the original injectors. Excellent post John all the best. Vaughn seems I remember you are an A&P ,I have been an AME w/A&P for 30 year now .

 

[waltk]

when the injectors fail, you will notice a misfire when the injector doesn't seal anymore, and sort of dribbles fuel into the cylinder. White smoke is another symptom.

 

[Silver_Ram]

At 75,000 I replaced mine for the 300 hp rv injectors, due to crankcase fuel dilution. 3 of the 6 were dribbling fuel on a test stand.

 

[jeepit]

At 75,000 I replaced mine for the 300 hp rv injectors, due to crankcase fuel dilution. 3 of the 6 were dribbling fuel on a test stand.

Was the oil tested or could you smell the fuel in it?

 

[Silver_Ram]

Initially I noticed my oil level kept getting over the full mark on the dipstick. Then checked with oil analysis & changed injectors - all is good now.