TruckerGirl,

Where do you buy your fuel?

 

Talk about a case for an emulsifying fuel additive....Truckergirl I hope you changed fuel sources to say the least!!

 

Just turned 3K. My injectors are knocking. Started when I changed fuel stations. Switched back to my original station. The mileage is falling off too. Went from 16.5 to 13.8 over the same commuting distance. Think it is time to bring it to the dealer?

 

These engines are the "Vipers " of the Cummins family , very sensitive to fuel quality cause it is HORRIBLE !!! I had mileage woes like many others and noticed a big difference between stations . I started using an additive every fuel stop and I am hitting 19 mpg now if I can keep her at about 63 or so . Shell station here has a Diesel Supreme and I throw in half a bottle of Diesel Kleen every fill up and she has really quieted down and runs like a BEAST !!! For what were paying for fuel it is really sad how quality has dropped .

 

2004 2500 4x4, 305/555, 17800 miles

I, too, developed the "injector knock" that sounds like a rod is coming thru the block at idle and up to 1500 rpms, when warm. Went to Dealer on Monday, and they installed new #3 injector yesterday. Knock gone now. I have been running Rotella DFA every other fill up. Going to look for something better as an additive and swith fuel stations too...

And, the Dealer ordered me new front door seals under the TSB, even though mine aren't ripped ( I spray Silicone on them once a month). They didn't know about the TSB and we're really glad I told them. They've been adjusting doors thru the bodyshop..

 

I use my truck for towing a trailer to races, so I usually stop at truck stops like the Flying J. Ever since the second occurance I've started using Diesel Kleen. I try not to let the fuel get too low either. The first time I went to a local place and then it started having problems, so it could have been the fuel there. Insurance is being a pain still. They want to test the fuel themselves now even though it is clearly visible that there is water in it. The dealer won't warranty it b/c I had already gone more than 12k miles since the first time.

 

does the fuel filter not filter out any of the impurities in the Diesel fuel??

 

The stratapore fuel filter used most commonly in our trucks is actually pretty good for a stock filter, however it does not stop all particulate matter by any means. I believe when I once dug up the specs for the filter it's considered 'nominal' at 10 microns and 'absolute' at 30 microns... which means it stops most 10 micron particles and larger and stops all particles 30 microns and larger. Particles as small as 5-10 microns cause wear on the injection system per Cummins and many other engine manufacturers. Thats one of the reasons I installed a Racor 2 micron absolute (97+ % efficiency) filter in between my aux and main tank. The fuel I fill in my main tank from the pump just gets filtered by the engine filter like a stock truck unfortunately. Those FASS systems and pusher pump setups that incorporate an additional filter are ideal IMO.

A cheaper way to help ensure your injection system lasts longer is to find a clean fuel source and stick with it. Fuel tests are around $50. I sampled my two favorite stations (high volume, close by). One had 7 times more dirt than the other. Had I not tested, I wouldn't have known. The lab speculated that the dirty station was contaminated with microbes. Buyer beware. When the station has the older style pumps with the filters visible on each side, check to see if they are rusty and old looking. If they are totally rusted (which I've seen in many stations), it's likely the station owner/manager has gutted the insides of the filter and simply screwed on the filter housing again. That way they never change the filters until it's too hideous looking..mmm unfiltered fuel and tank sludge straight into our tanks..

 

there's a way to find out what the problem is with injectors. if you are skilled enough remove the injectors and solinoids and take them to a injector shop and have them tested. if you have a problem they will tell you. at that point the dealer has a real problem.

 

So it seems like this 600 knockinng noise is unquestionably bad injectors, right? All these posts seem to point in that direction.

My truck doesn't fit into what many are saying here though. I have the knocking noise up to about 1200 rpm but I get about 22 mpg going 65-70 mph. Also, the fuel economy has been getting better since the truck was new. So what the heck is up with my truck!? Don't get me wrong, I'm happy with 22 mpg...

 

Mines about the same as HightTen, I have the knocking but my mpg isn't all that bad. I have 2500 miles on mine now. Is the problem with these motors the high pressure fuel rail?

 

You can add me to that list as well. I have a knock, only when warm and only up to 1400-1500 rpm. However, my fuel mileage seems right in line with everyone else...although I can't say I'm getting 22mpg.

 

I have a similar but different knock which starts at around 1500 rpm, is loudest at about 1800 rpm, and is gone at 2000 rpm and above. It's been this way for over 20K miles. I finally took it to the dealer this morning but I have little hope that they will diagnose it correctly and fix whatever it is. However, if they do figure it out, I'll let you know.

 

I have had the knock since new. Knocking injectors but still getting 19 mpg at 75 mph. However, I just noticed the oil level was high and it started smoking on accelleration (still stock). Called the dealer and they said to bring it in. They said it sounded like a leaking injector (as I suspected). I'm hoping that if they replace some injectors the knock will go away also.

By the way it's a 2004.5 600 with a 48RE

 

I think a lot of people here, especially new diesel owners, are letting paranoia get the best of them. DIESELS MAKE KNOCKING NOISES, it's the nature of the beast...it will not sound like a gasser no matter how many times you replace the injectors. I think people need to realize a little knocking is normal, and only take it in if there is a severe noise or performance issue...