[cumminspower7790]

I dont know if hiccup is the right word but its happened twice both while i was idling in drive, in a drive through at Dunkin Donuts. It feels like a sudden buck that shakes the truck a little and then everythings fine. Why does this happen? What causes it? Is it a bad sign leading up to a problem in the future? :confused013:

 

[3500cummins]

Had the same thing happen every once in a while when I had my '03. Never did figure out what it was.

 

[cumminspower7790]

Hopefully it's just a diesel thing that I am not used to yet....it's a whole different world going from having gas trucks your whole life to a diesel. I learn something new everyday just from reading threads on here


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[Markus Verheyden]

Have had the same thing happen with my 07. It's like it farts every once in a while :hehe: and when I have a load on it idling it sounds like I have a big cam. Drives normal, with no problems, but don't know why it does that idling?

 

[cumminspower7790]

It only happens once it's one big pop and then it doesn't do it again, but it is always when the grid heater is doing it's cycle thing when you first start it


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[jerrodlk]

Is it a miss ? Like the engine missed a beat.


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[txhunter1010]

i have it to sometimes.

 

[jmercer]

My 07 does it as well. I see you noted that it does it when the grid heater cycles, which is what I was going to suggest. The grid heater pulls a lot of power and I think the hiccup is caused by that sudden massive power spike with the engine at low RPM. Mine will also do it once in a while with the defroster on. Pretty sure it's just a normal thing they do.

Grid heaters draw something like 30-50 Amps when they kick in I think. I'd grunt too if that came out of nowhere :hehe:

 

[txhunter1010]

well i figured it was normal or hopefully nothing to worry about since it only does it sometimes and nothing else happens with it....thanks

 

[goodriddance]

yep mines been doing the same thing since I got the truck it freaked the hell out of me first time it happened and it mostly occures when the grid heater cycles, BUT I've had it do it to me when the grid heater isn't cycling also

 

[Becauseracetruck]

Mine does it with the defroster on an found it to be the A/C to be cycling on and off. If you want to check turn on your defroster and open the good and watch your evaporator dryer and lines right there going in to the cab will "jump" when it does that.

 

[TCarstensJR]

My 06 does it too but only on high idle

 

[RnEmOvr]

Mine has done it since day I got it, more so when cold. When my truck does that people look at me weird, I say "sorry that ricer it ate earlier isn't agreeing with its stomach"

 

[874mula]

mine does the same thing and I would say that is normal. Keep in mind that these common rails are controlled by computer. So it knows that at idle speed it should be at 800 rpm. When the heater grid or the a/c compressor comes on it loads up the engine which drops your engine speed. the computer then sees the engine speed drop from 800 rpm to say 780 rpm (for arguments sake) and it fuels itself up to get back to 800 rpm. when the load kicks off the rpm will overshoot and the computer wil defuel to get back to 800 rpm. You can see this theory on the manual transmissions. when I let off my clutch it drops engine rpm and then recovers back to 800 rpm. In a gasser the only engine speed control it has is the cable connected to the accelorator pedal. although some newer gas vehicles are "fly by wire"

 

[CantStopCummins]

mine does the same thing and I would say that is normal. Keep in mind that these common rails are controlled by computer. So it knows that at idle speed it should be at 800 rpm. When the heater grid or the a/c compressor comes on it loads up the engine which drops your engine speed. the computer then sees the engine speed drop from 800 rpm to say 780 rpm (for arguments sake) and it fuels itself up to get back to 800 rpm. when the load kicks off the rpm will overshoot and the computer wil defuel to get back to 800 rpm. You can see this theory on the manual transmissions. when I let off my clutch it drops engine rpm and then recovers back to 800 rpm. In a gasser the only engine speed control it has is the cable connected to the accelorator pedal. although some newer gas vehicles are "fly by wire"

Sounds exactly right. When my "hiccup" happens every so often I see the rail pressure jump and then drop very quickly

 

[Grogg]

Mine has done it since day I got it, more so when cold. When my truck does that people look at me weird, I say "sorry that ricer it ate earlier isn't agreeing with its stomach"

THAT is priceless. I want my truck to start exhibiting these symptoms just so people will look at it funny and I can say that. :hehe:

 

[cumminspower7790]

sometimes its just a quick "pop" but other times when im sitting in it, it feels like someone just tapped your back bumper

 

[gunslinger226]

I have it too but only when it's cold on high idle. I figured it was due to the advanced timing. I did trip a code along time ago when I was running a tst box for timing and it did the hiccup thing.

 

[cumminspower7790]

I just have an Edge EZ box which i thought just raised up rail pressure?? that wouldnt have anything to do with it right?

 

[Moochoff]

I thought I had an issue last winter. Bump in revs, could hear in the exhaust, and my EGTs bumped around 20F. I thought it was an injector

Turned out to be my defrost :doh: