Undertaker

When starting my truck in the morning and letting it warm up it sounds like a cylinder miss or backfire. Does anyone have any thoughts?

cbrahs

need more info on year of truck? mine does the same thing and has since brand new and only does it when cold and the grid heater cycles on and off

klx650a2

Do you get any smoke? white, black? Does it go away? Does the exhaust smell like antifreeze? Are you making oil? Have you replaced your fuel filter?

If its cold enough, the 2nd gens have the 3 cylinder high idle. My 2000 would sound like a rod was coming through the side of the block when it would kick in and would kill the engine. But the engine has to be 0F or colder for it to kick in I believe.

My 6.7 now sounds like a jet engine spooling up when the engine brake is turned on warm up through the open pipe (my neighbors love me).

cbrahs

all of my fluid levels are good. no headgasket issues, not making oil. only does it when grid heaters cycle. I did have to have the rail psi sensor replaced last winter and after that it did not do it after replacing but will test it out this winter

Undertaker

its a 2007 5.9. I get a constant light amount of black smoke during idle when first started.

jamesbfishin

Mine has a tendency to do this also when cold, sounds like it stumbles while warming up, normal or high idle, doesnt seem to make a difference. Thought it was connected to the cp3 "timing" issue I think i have.

Monkey 456

Ditto min dose the same thing. Have had it to the dealer a couple of times for different things and told them about it twice and they checked it out and found nothing. Even after reflash.

Hummin Cummins

My 03 rig use to do this until I got the 'low power' flash (I think it's the most recent flash from DC).

It sounded like an engine flutter, wasn't a full miss.

Had something to do with the timing and fuel delivery of #6 cylinder (and possibly #4) as when #6 was disabled the condition didnt change (any other cylinder the condition got worse).

The 'low power' flash doesnt state anything about correcting this condition but does, along with remodulating the throttle pedal and adding a little more top end (at least on a stock truck).

...it's worth checking out with DC to see if the 'low power' flash is applicable to 07 rigs.

Ron

NJMurvin

I had a similar condition with mine. It also "ticked" a bit too much at certain speeds making me feel that an injector might be on its way out. I'm a bad boy in that my commute is only about 3mi each way - so, while my particular usage of the truck is considered very light, it's actually very hard on the engine.

So, I found a thread on this forum that led me to try Howe's Meaner Kleaner fuel treatment. I thought it might help to clean the injectors. Anyway, the improvement was nearly instant. I'm sold on this stuff and just ordered another 4 qts. from Ryder Fleet Products. I toss in 8oz with each fill-up and the engine has never run better.

cbrahs

here is a video of mine a couple years ago. about the 12 second range is where you will hear it. this one was not a loud one like normal but was finally able to catch it on my cell phone one day.

cbrahs

I complained about mine to the dealer and each time they checked it they told me i was on crack (very good friend is the service director) UNTIL I was hired there and one night after work we were all around and mine was on high idle (did it on high idle or normal idle) and it POPPED and he turned and looked at me like WHAT WAS THAT! I was like HAHA! There it is and you heard it yourself crack head! Our disctrict rep heard it too and he was floored.

jamesbfishin

Yup, that's pretty much what it sounds like, mine doesn't quite pop like that but probably due to a more restrictive exhaust than your rig

BIG DUB

I've had the same issue too. Usually when cold. I've had times while sitting in the truck, it shakes so bad I thought I got hit by another car.

cbrahs

a few times I have looked under the truck to see parts under the engine. freaked me out

bigdave

Mine will do it to. I have the grid heater unplugged and it hasn't done it since so it has something to do with that. I'm not to concerned about it now though.