Minor stutter on fall back to idle

[KurtR]

Not sure if this is normal. But while in park and revving the engine to about 2K the fall back down to idle almost hesitates and some what "steps down". Gotta listen closely. Only 106k miles on it. Drives fine. Not a ton of pep but will get up to speed on the highway but averages 13-15 all day long. Clean fuel filter. S&B air intake filter and S&B air intake elbow. Recently dumped in some fuel injector cleaner into the fuel tank hasn't changed anything. No white smoke or black smoke either running or at start up. Let me know what you guys think.

 

[Darkbloodmon]

Hard to hear from the cab, an exhaust clip or from the engine bay would be better. Your RPM needle doesn't look abnormal.

I recently had a hanging idle at 1K when coming to a stop on my 03. I Replaced my injectors, tubes and FCA (all new) only to find I still had the hang when coming to a stop. My Thread link: https://www.turbodieselregister.com...fter-new-injectors-and-tubes-no-codes.269068/

I just got back from the dealership today after some DRB updates to my PCM and it's supposedly stopped I still need time to confirm but it idles sharper and doesn't hang. I would recommend starting there before you start throwing parts at it. Check and see if you have any updates available then go from there.

 

[Killer223]

personally it sounds like a miss on a cylinder to me. at 100K injectors are suspect,
hows the blow by?

 

[KurtR]

Good to know ill have to look into that. And there isn't any blow by at all. Doesn't smoke while driving or even during the coldest start up. Its just this little revving issue that has me wondering if something is one its way out or stunting my trucks performance because it doesn't has a ton of power i guess and gets like 13 mpg all around. I feel like thats very low for a bone stock third gen.

My buddy did mention the update thing the other day so ill have to research that a little more. Plus if i was actually down a cylinder due to an injector stuck shut I feel like i would def know. Not sure what that sounds like but its gotta be obvious.

 

[Darkbloodmon]

Good to know ill have to look into that. And there isn't any blow by at all. Doesn't smoke while driving or even during the coldest start up. Its just this little revving issue that has me wondering if something is one its way out or stunting my trucks performance because it doesn't has a ton of power i guess and gets like 13 mpg all around. I feel like thats very low for a bone stock third gen.

My buddy did mention the update thing the other day so ill have to research that a little more. Plus if i was actually down a cylinder due to an injector stuck shut I feel like i would def know. Not sure what that sounds like but its gotta be obvious.

For loss of power check the obvious stuff first with air and fuel delivery: Filters, sensors, boost leaks, blockages, Valve Lash, etc. Also I learned from these forums that common rails don't need fuel lube additives, I was skeptical at first but I tried it and picked up 2 mpgs city.The injection system works harder through thicker fuel and it shows in mpg and premature wear. I was around 15.2 mpgs before with lube additives. 13 mpg is pretty low for a Cummins and a cause for concern in my book.

You're right if you were missing or down a cylinder you'd know, it'll sound like rod knock. Example :

 

[Bob4x4]

Your ck engine light is on.Have you diagnosed the reason?

 

[KurtR]

The check engine light does come on due to the air intake heater relay (P0541) but I just replaced the relay yesterday. So I shouldn't get that code anymore but other than that I do not get any other codes other than the one time I got a " low fuel fuel rail pressure" code. That happened once like a month ago but I cleared it and it has never come back. Mightve threw that code when I really got on it one day. The other code I get once and awhile is the "overboost pressure" and thats when I I'm loaded up and the boost pressure get up around 30 psi and I maintain that for about 5 seconds.

The turbo is stock and original. Good amount of surface rust all over the exhaust side so i think the pneumatic actuator is stuck and not limiting the boost pressure and allowing it to get all the way up to 35 psi. I only think that cause I don't think this engine stock isn't suppose to make that much boost pressure

 

[cerberusiam]

Nothing wrong with that. Doesn't tell you anything dead cold like that. You have to test these engines at operating temp or the results are not very valid.