In the past 2 days I have noticed an engine rattle that wasn't there before and doesn't sound like the happy rumbling of my D-max...I'm a little worried.

It is an '04.5 LLY with 70K on her. the only thing major ever to happen was an injector control module was replaced shortly after I bought the truck. I've been religious about PM and have no mods.

At idle and when the tranny is in between gears at RPM below 2000 I'm getting what starts out sounding just like the pilot injection noise and ends up sounding like I've got a Powerstroke Instead of a Duramax. When I accelerate slowly the engine stumbles a bit as well.

When I mash the pedal all noises go away and the truck runs like it always has. The noises and stumbling only show up while I'm "taking it easy"

Anybody got an idea if I should be concerned or not?

mine too ive got 55xxxkms have yet to take it in, sounds like piston slap to me on mine around 1400rpm when its cold

how long have you had your truck?

just asking because they sound significantly different when it's below 40 degrees outside... even more so when it's below 30...

you probably already knew that but figured i'd ask.

-chris

very possibly the new fuel noticed it on my o3 this week has a little louder diesel rattle but no wheres near the cement mixer fords

very possibly the new fuel noticed it on my o3 this week has a little louder diesel rattle but no wheres near the cement mixer fords

No, it is not the new fuel.

I think the pilot injections are what makes our trucks so much quieter than the fords. Maybe your injector control module is acting up again. Is it showing any codes?

Could be dirty injectors, or that module. My friends LB7 was ratteling, and he had the injectors cleaned, and the ratteling stopped. My LLy sounds like what you are describing at start up below 30 degrees, it goes away after the engine starts warming up though. I started using the block heater, and it made a world of a difference! It has to be alot easier on the engine too. You can just start up and go. The heater starts working alot sooner too.

...little louder diesel rattle but no wheres near the cement mixer fords
You think the sick-liter fords rattle.:) A old 6.5 or cummins rattles. Started mine once, 30 deg out, walked 2 blocks and could still hear it, now thats rattling.:D

Well as long as it does not perfomr like a 6.0, you will be ok!!

I dumped some injector cleaner/ctane booster in today and ran her around unloaded. At 80 mph climbing a hill heading into NH the engine stumbled badly and started dumping white smoke out the tail pipe. It did this a couple of times and now the rattle is gone????

Maybe the injectors were fouled?

It isn't throwing any codes but I've got to do an 800 mile trip to MI with the truck at x-mas so I'm taking it into the stealer this week.

I'll be sure to post if I learn anything good/bad.

I would check the injector harness recall , sound like it in some ways not in others , but it will rattle real bad but usually goes into limp as well.

Could be the drop in temp? Mine runs a little rougher when the temps drop.
I doubt if it sounds like a ford. All of the ones around here are quiet (Read Busted) LOL

It's probably not a drop in the temp. Mostly because we haven't had one yet. It was 60 F all last week and it got close to freezing last night but didn't quite make it.

I'll be sure to ask about an injector harness recall when I take it in. I didn't know one existed. The truck is running fine right now which leads me to believe it is something that comes and goes...like electronics acting up. It's probably not something real bad but it sure is a pain to have a good truck bumbling around.

I had a harness failure on #7. If it was that you would know it. Truck hardly runs.

Too much timing causes significant rattling, and the injection timing advances quite a bit until the ECT comes up to operating temp.

Thanks for your help folks!

If you were one of the people that guessed something was wrong with the injector wiring....I guess I owe you a beer.

The service guy just called and said they replaced the injector wiring harness because one of the wires was rubbed bare from hitting a near by mount. Apparently the bucking, stumbling and white smoke happened when the wire grounded out through the bare spot. I never got an engine code because the problem never stuck around long enough for the computer to log it as a system failure.

I also got the latest version of software....hopefully that is an improvement....I'll let you know if it's not.

Thanks again!

I had my '01 LLY stutter, then like it almost like it shut off,, push a cloud of white smoke and took off like a vet. I found a lot of water in the filter. Over the following days I added fuel conditioner and kept draining the pet**** on the fuel filter.