Nate-03 D

Howdy fellow Cummins owners, I have a quick question to ask that's been bugging me for a while.

I bought my truck a few months ago, everything was nice and dandy. Ran good sounded good without any hitches. Just recently I have noticed a weird noise comming from the engine. At start up in the moarning (it's been about 45-50* the past few weeks) it has a very distinguishable "knock", I dunno if it's a cylinder knock or what but it's there and pretty **** loud. When drivinig the truck everything sounds fine, at a stop is where you can almost here the truck "surging" for power. It's sortive hard to explain the noise but it sounds like it's starving for power so to speak.

I took it to the dealer about 3 weeks ago, they said they ran some tests and they couldn't find anything. Well the noise is still prominent and it's going back Monday. So my drawn out question is has anyone experienced any issues like this? I hope they can get to the bottom of this and not just send me out the door w/ a "everything is fine" answer.

MikeyB

Could be injector knock. Dump a bottle of diesel fuel additive (Power Service Diesel Klean, Luca, Stanadyne, etc) and drive it like you stole it.
Didn't see if your truck has a auto or manual. If you have the manual it could be the clutch. Engage the clutch and see if the noise goes away. My clutch knocks in cooler weather and goes away as it heats up.

MikeyB

Nate-03 D

It's an auto. I use the Lucas fuel addative every other time I fill up.

Hopefully this will be fixed here soon, it's realy annoying.

J BODY

If the rail psi fluctuates with the rpms I would suspect a fuel control solenoid. That surge is usually pretty obvious though. As far as noise, not sure on the Lucas addy, but you might try some Standyne.

GrandpasRam

Had the same thing happen with my '03 last winter, and after Star told the dealership to replace the injectors, still there...then changed lift pump, still there...finally replaced the injection pump and all was fixed. I had guages and noticed that the fuel pressure would drop (this was at idle) just before the engine "stumbled" to 400 rpm then surge back to 1200 rpm then return to normal 750 rpm idle. That turned out to be the key to finding the problem, which was the fuel return valve opening when it shouldn't and starving the engine. All was covered under warranty, or course, but it took a few trips for them to figure it out, and without my fuel pressure guage readings, they may not have figured it out as soon as we did. Might be something to check out. Mine never threw any diagnostic codes of any kind, which is part of what had them stumped for a while.

Nate-03 D

Thanks Grandpa, I'll keep that in mind when I head over to the dealer. Hopefully I won't be making 3-4 trips back.