Surging rail pressure with cruise

[EDankievitch]

Just thought I'd up date on what I found with my 05. When I puled the stock injectors out I found cylinder number 4 nozzle cracked. I'm guessin that it was over fueling that cylinder to the point that the computer was seeing the cylinder produice more power than the rest? and would cut back on the fueling causing the surge? Also the fuel rail pressure would bounce now with the new injectors it's nice and steady. I'm starting to think that the reason that it's also the reason that the number 4 fuel line cracked? All I know is I installed a set of DynomiteDiesel stage one injectors and the truck has never run so smooth. Hope this helps with everyone's simular problems.

 

[blacksheepdiesel]

Good info to know. Thanks for the update.

Godspeed,
Trent

 

[TCDiesel]

Just thought I'd up date on what I found with my 05. When I puled the stock injectors out I found cylinder number 4 nozzle cracked. I'm guessin that it was over fueling that cylinder to the point that the computer was seeing the cylinder produice more power than the rest? and would cut back on the fueling causing the surge? Also the fuel rail pressure would bounce now with the new injectors it's nice and steady. I'm starting to think that the reason that it's also the reason that the number 4 fuel line cracked? All I know is I installed a set of DynomiteDiesel stage one injectors and the truck has never run so smooth. Hope this helps with everyone's simular problems.

Your LV failed,03/04 Injectors (Factory) are more likely to crack do to design. . 04. 5 and up revised. and Now we have the new style. Check LV or Update Valve or you may be revisiting this issue.

 

[blacksheepdiesel]

T & C,

What is LV? I get most of the abbreviations on TDR but this seems to be a new one to me.

Godspeed,
Trent

 

[Tinman]

That's new one to me too. I am still trouble shooting this. I've gotta find a good day to disconnect the alternator to rule out electrical interference. I also just sent an UOA and if the soot is up after I backed off the timing and duration, I am think the injectors may come very soon.

 

[TCDiesel]

Limiting valve or relief valve, and its have a New one also CPRV, Constant pressure relief valve.

 

[steved]

Your LV failed,03/04 Injectors (Factory) are more likely to crack do to design. . 04. 5 and up revised. and Now we have the new style. Check LV or Update Valve or you may be revisiting this issue.

Not to argue, but just because his injector tip cracked doesn't mean he has other issues... if his rail pressure is steady, and within normal limits; would that not imply things are functioning properly??

 

[TCDiesel]

NO... YOU need to Check... Thats ALL... . if everything checks out... Great. CR does NOT conform to logic,they conform to experience.

 

[EDankievitch]

Ok, I had replaced the rail pressure relief valve, where is this limiting valve???

 

[TCDiesel]

Thats It... If you still have the original contact Me, If willing to sell it ,We need as many core as possible,looks like you have it all covered.

 

[DBurkham]

my '07 5. 9 has bucked on cruise control since new. now at 55,000 it seems to buck or slightly miss any time under light throttle. under load its smooth. last january i had the #4 injector fail and it was replaced under warranty, will the local dodge house be willing to replace injectors under warranty? if not who is the most economical shop to buy injectors from?

 

[Tinman]

I just got my latest UOA back and the high soot from the last oil change is better with my changing the Smarty timing from 2 to 3 and running SW 7 instead of 9. But the soot was still higher than all OCI prior to the last. In addition, I now have 2. 5% fuel dilution, something I've never seen before. All of this combined has me convinced I have bad injector even though the truck runs great. I have been planning on upgrading to DDP 50s in the spring but I guess sooner is better than later now. Problem is it's cold out and I don't have a indoor work area.

 

[EDankievitch]

The DDP 50's ae really nice, engine runs smoother than it did when it was new. It took me about 4 hours to install then about an hour to thaw out in a hot bath after. . Lol. But it was well worth it. Mpg on a trip to Va doing 70-75 was 19. 2 bobtail and towing a 17' boat at 65 was 17. 4

 

[EDankievitch]

And NO SMOKE.

 

[steved]

My F1s have been performing well... almost a 100k on them at his point.

 

[Tinman]

Update

Problem solved. I finally got around to pulling the injectors and sending them to DDP for testing and 50hp nozzles. #6 tested "low flow" and the body was replaced. All of the others were OK but showed fast response times which I guess would give me a little more timing advance and perhaps explain the smoke. I did F1 springs, head studs, wild rail, and a GDP Air Boss while it was apart. Back together now and the truck has never been so smooth. Rail pressure is rock solid while "coasting" in cruise. No bucking, or surging. I think the low flow of #6 at the low rail pressure caused uneven fuel delivery and the symptoms. Just one more symptom of these finicky CR injectors not performing correctly or failing.

 

[bcbender]

I found this interesting as I have been having the same problem, My truck is going in a couple weeks to have the AC doors replaced under warranty, what test(s) specifically shoudl I ask the monkeys at the stealership to do to check the injectors?? I've been told leakdown, cyl contibution, any others??

 

[Tinman]

I doubt the dealer would have been able to find my problem. My injectors were tested on DDP's bench machine. Dealer won't do that but it's a good place to start.