2006 Dodge Cummins 5.9 injector question

[Dwalk]

I took it in to a local diesel shop to have a bad injector replaced, they put a new stock injector in and still a slight miss at idle. They tore it back down and figured out that the truck has aftermarket 30-90hp nozzles on it. Not being sure where they are manufactured or the exact size, my question is can I put the higher horsepower nozzle on the new factory injector and get the miss cleared up. I'm no diesel mech. But seems like the only difference is the size holes in the nozzle for fuel to spray.

 

[patooyee]

Not sure about on diesels but on an LS the computer has a calibration for the size of the injectors. It has one entry for all the injectors, not one per cylinder. So You can't put a random injector in one cylinder and expect it to fire right because the computer is calculating pulse width based on the specs for all the other injectors. Little injectors will open for more time on the same engine as big injectors would. So if the computer thinks it has a 90hp injector and it really has a 30 its not going to inject enough fuel on the one cylinder which could cause a misfire. Conversely, if it has all 30hp injectors and one 90hp it will inject too much fuel on the one cylinder and also cause a misfire. (Or worse.)

Not sure if its the same on a diesel but I do know the '06 is computer controlled and therefore probably does have an injector table that has probably been modified for 90hp injectors if that's what was in every other cylinder.

 

[Dwalk]

I see what your saying and thank you. I was told that on these Injectors that the solenoid was the same up to 100 hp and that the only thing that changes was the nozzle which has bigger holes for more fuel to enter the cylinder when the solenoid fires.
The reason for all the questions about this is that I really don't want to spend the extra $2,000 plus labor for all new Injectors after I already paid $1500 for a Injector pump and one Injector.

 

[patooyee]

Even if the solenoid was the same a bigger nozzle would require same solenoid to stay open for a shorter period of time on the same engine as a smaller nozzle. Or rather, the ECM is sending the same signal to all the solenoids, so the one smaller nozzle isn't going to deliver as much fuel in the same amount of time as the bigger ones. But I guess what you're saying is that the programming probably didn't change, the nozzle sizes just got bigger to feed more power. But still I would think having a random smaller injector would affect things?

Anyway, let me know what it is as I have an '05 5.9. Hoping never have to deal with your nightmare as I left mine all stock since its all I need.

 

[Jcampbell54]

My understanding of the common rails is that you can't isolate one bad injector and it usually calls for all injectors being replaced in that scenario. Not a pro on common rail cummins but just what I've been told.


Sent from the mans IPhone.

 

[Rohlingoffroad]

Dwalk them boys down there should have ur old injector tell them to pull the nozzle off it and clean it all there is are (7 or 5 holes depending on the year of the truck ) and a pindle that opens and closes and reinstall it on the new one and as for the solenoid there all the same size no matter the nozzle output some company's modify the bodies to follow more fuel once u get bigger then a 300hp nozzles but not all of them and if u need all of them replaced u got my number give me a call and I will save u a headache dealing with those guys

 

[wizzo]

×2 pull the nozzle from the injector your replaced and put it on the new one. Not much labor involved.

 

[Rohlingoffroad]

U can isolate injectors in a common rail by doing a Cly drop out test or capping each injector line off one by one to find the one with a high return rate or stuck nozzle. On a 06 and newer u can scan them and see the return rates on the scanner with out pulling them .But the most accurate way is to pull all of them and have them tested on a injector test stand that way u are 100% which ones are bad or good

 

[Dwalk]

Thank you Josh, you've answered and confirmed the question I had. I do appreciate it.

 

[Dwalk]

Update: I had the mechanic put the old nozzle on the new Injector, cleared it right up..... Thanks again everyone for the help and input.

 

[Rohlingoffroad]

Glad that took care of it !

 

[patooyee]

Just so I understand ... all 5.9 injectors that the aftermarket companies sell for so much are the same except the nozzle? So you might as well just get nozzles and put them on the stock injectors?

 

[wizzo]

Just so I understand ... all 5.9 injectors that the aftermarket companies sell for so much are the same except the nozzle? So you might as well just get nozzles and put them on the stock injectors?

Yes, if you have a good set of injectors you can just put nozzles on them.

The problem is, most of the issues people have with stock injectors are cracked injector bodies.

 

[patooyee]

Re:

If the aftermarket is the same thigh wouldn't they be just as susceptible to cracking? What causes the cracking?

 

[wizzo]

Re:

If the aftermarket is the same thigh wouldn't they be just as susceptible to cracking? What causes the cracking?

Yes they are just as susceptible. If you need a new injector I would buy new not reman if possible.

Most blame pressure but imo it's the material used.

The 6.7 injectors are billet. To me that tells me bosch seen an issue and addressed it.

 

[Rohlingoffroad]

Well in 06 they changed the body design up alittle and corrected the problem then I haven't seen no cracked bodies out of anything older then a 04.5 truck and I personally have only seen 3 cracked bodies in my 40+ injector sets have touched

And I was running around 900hp with stock 180k mile injectors with 100% over nozzles (200hp) with no issues untill I built my new setup and I went with full exergys injectors