Hey everybody i'm new to the forum and have an 05 Duramax lly, So my truck started giving me a lop when I blip the throttle, goofy starting when engines warm but never when cold. Lag upon harder acceleration with a puff of black smoke and only when cold I was getting a injector fuel knock but warm it went away. I purchased a chinese tech 2 and right away when it was cold I could pinpoint that #6 injector was knocking as I could shut it off and the knock went away. Took out all the injectors out of the drivers bank, removed nozzles and gave them an ultrasonic bath to clean them up and where very dirty(maybe that's what they are suppose to look like). Upon cleaning them it didnt help balance rates or the knock but went ahead and replaced #6 with a bosch reman. Fuel knock went away cold and hot and seems to run better except i still have a lop when i blip the throttle which to my understanding is the ficm trying to balance the engine out. My second worst injector was #7 so i decided to take the passenger side bank out to do nozzle cleaning and swapped it with #5 once again didn't help my situation but the bad rate followed. Did an individual return test on the passenger bank and found that #5 injector was returning way over spec so I replaced that injector with another bosch reman. Truck now seems to run better for sure and my injector rates are all floating around 0 to +\- 2 but my fuel rate has always been very low before and after changing the bad injectors. Cold it shows a fuel rate of 12mm but once its warm it drops down to 4mm and less and i drive warmed up is around 12mm. Should I be worried about that low fuel rate? If i add the difference from injector rates it would deem that all Injectors are out of spec. Sorry this is my first diesel so a learning game it is and thanks for all the help in advance!
LLY Fuel Rate Low?
- Thread starter Mike_Champ88
- Start date
Whoops forgot to mention....my actual fuel rate is also all over the map going up and down compared to desired. I have also replaced the fpr with a new bosch one and have also done the fprv shim kit as it was popping before and have rechecked it using the scanner to raise rail pressure with not a drop going into a bottle.
your correct. You need to replace the rest of the injectors. you should be seeing 8-10mm3 fuel flow rate at idle
Sorry for my ignorance but if the return test comes back good whats there to go wrong with the other injectors? Just for my own experiences it would be nice to know what to do to find out which ones are bad. I understand if money wasn't an issue I would love you to replace them all. Can 1 bad injector cause that fuel rate to be that low? I just figured since replacing the 2 worse ones the rate would have came up a bit but it didnt. I appreciate the help though.
I realize this is a couple of years past but I also have the same situation . Any resolution to your low fuel rate. I have an LLY with 180,000.I recently needed injectors as some of my balance rates were 'almost' out of spec. They had also never been changed. My calculated fuel rate was also low. I thought the two went hand in hand. I replaced all of my injectors with Bosch OEM remans. My fuel rate is still low 2.5-3.5MM3 at idle in park at working temp. I understand the Fuel rate should be 7-9ish MM3. Any thoughts on what would cause this low fuel rate? Truck seems to run fine...
Did you figure anything out? My 2004.5 is doing the same thing, just replaced all the injectors 2 weekends ago and the main injection rate is still low.
If the engine runs good and it doesn't smoke more than it should then don't worry about the main rate. Or balance rate for that matter. It is good for diagnosis when you have an issue but doesn't really have much use outside that
Also, if your truck is tuned then the main rate can be off. More likely bringing it down
Also, if your truck is tuned then the main rate can be off. More likely bringing it down
