05 cutting out under hard accel

[bgruschy]

My 05 GMC cuts out intermittently under hard accel. It will often do this when I " put it to the floor" and intermittently even when I get on it hard merging into traffic. The truck has 9000 miles on it and is bone stock. The only thing I have done is change oil twice.

When it cuts out the best way I can describe it would be it just falls on it's face and makse a sound about what I would expect from a turbo waste gate opening wide open, the problem stops almost instantly when backing off the accelerator a bit.

any ideas?

[DmaxMaverick]

Welcome to the forums!

What you are experiencing sounds like defueling. Does it happen near redline, or prior to a gear change?

It could also be pilot injection disengaging above ~2700 RPM's, which will cause more Diesel clatter.

[bgruschy]

Thanks for the welcome, I've been a lurker here for a couple years, just never had much to say...

Yes it does happen around 2700 and prior to a shift. This truck also seems like the shift pattern is not nearly as smooth as my 03 was when really geting on it with out a load.

[bgruschy]

by the way, it does not sound like clatter. More like a jake brake.

[CHVYMAN#9]

Have your dealer check for chaffed wires near the FICM or the c107 connector on top of the left valve cover. I have seen this on several occasions and will be worse on engine torque over causing the wires to short out. Will be like shutting the key off.

[Kennedy]

First thing I'd change is the fuel filter. While GM says 15k, the first one on my 2005 was pretty nasty at 3k already. Lots of dust and debris from tank, lines etc. when new. I only regret not checking restriction prior to replacing it...

[REDTRUCK05]

Originally posted by bgruschy:
My 05 GMC cuts out intermittently under hard accel. It will often do this when I " put it to the floor" and intermittently even when I get on it hard merging into traffic. The truck has 9000 miles on it and is bone stock. The only thing I have done is change oil twice.

When it cuts out the best way I can describe it would be it just falls on it's face and makse a sound about what I would expect from a turbo waste gate opening wide open, the problem stops almost instantly when backing off the accelerator a bit.

any ideas? My 05 has made a sound like what we would have heard from an old carb backfire and cuts out for about as long as one too. It has only done this accelerating from about 15 MPH and right away when I punch it. I had it at the dealer today for that and MPG issues when pulling, 7.9 MPG when pulling a 7500# travel traler with cruise set at 72 MPH. There response was as follows...

We tested it at 55 MPH for 30 miles you got 20.1 MPG. We pulled no codes and your truck is fine. Im sorry, 7.9 MPG pulling only 7500# is not fine.
They said bring it back in at 7500 miles ( 2900 now ) I have been talking to every Duramax owner I come accross in the campgrounds, finding out what they are pulling, how heavy, what length, what year truck, how many miles on it and at what speed. I am by far the lightest and the worst MPG.

Are you having MPG problems also? Thanks for letting me vent!
Paul

[aceduramax]

Hello folks, this is my first time posting anything... I too have a 05 duramax and am experiencing the same thing. only mine seems to just do the "coughing" right after the tranny shifts into fifth gear and under light throttle... milage is stuck at 15.9 and wont budge no matter how i drive... if anyone finds a cure for this, please gimme a shout

[bgruschy]

I've had it in to the dealer, they found nothing wrong. They gave me a notice about doggy acceleration between 60 and 70... not the problem. I'm not sure on mileage, the computer shows 15.9 avg so far, I'd est 1000 of that pulling trailers weighing around 7000 lbs. I'm really not to disappointed with mileage at this point.

[Kennedy]

What was the doggy acceleration notice all about?

[More Power]

JK, Will you be bringing your fuel restriction gauge to SLC?

Thought I'd check the filter in Lil Red. The original filter has about 5K on it now. Might be a good demo. smile.gif

Jim

[bgruschy]

The "doggy accel notice" is document ID# 1579256 and states

[I] The customer may be described as a hesitation or throttle delay that occurs when a driver accelerates from a steady crusing speed of 60-70 mph.[I]

It goes on to tell the tech to basically check for codes, compare it to another like vehicle and if there is no difference tell the customer this is a characteristic of this vehicle and nothing is wrong.

This really has nothing to do with my problem, I do notice this truck is a little doggier inthe 60-70 range when pulling out to pass than my 03 was, but that is just for a short lag until the turbo spools up a bit more.

The difficult part of the problem I'm having is it is so intermittent and brief that it's hard to explain and harder to reproduce for someone else.

[Dave]

Originally posted by REDTRUCK05:
</font><blockquote>quote:</font><hr />Originally posted by bgruschy:
My 05 GMC cuts out intermittently under hard accel. It will often do this when I " put it to the floor" and intermittently even when I get on it hard merging into traffic. The truck has 9000 miles on it and is bone stock. The only thing I have done is change oil twice.

When it cuts out the best way I can describe it would be it just falls on it's face and makse a sound about what I would expect from a turbo waste gate opening wide open, the problem stops almost instantly when backing off the accelerator a bit.

any ideas? My 05 has made a sound like what we would have heard from an old carb backfire and cuts out for about as long as one too. It has only done this accelerating from about 15 MPH and right away when I punch it. I had it at the dealer today for that and MPG issues when pulling, 7.9 MPG when pulling a 7500# travel traler with cruise set at 72 MPH. There response was as follows...

We tested it at 55 MPH for 30 miles you got 20.1 MPG. We pulled no codes and your truck is fine. Im sorry, 7.9 MPG pulling only 7500# is not fine.
They said bring it back in at 7500 miles ( 2900 now ) I have been talking to every Duramax owner I come accross in the campgrounds, finding out what they are pulling, how heavy, what length, what year truck, how many miles on it and at what speed. I am by far the lightest and the worst MPG.

Are you having MPG problems also? Thanks for letting me vent!
Paul </font>[/QUOTE]Sounds like you have the same dealer I do or it is a scripted responce. My truck was in the dealer last Wednesday for several things, mainly Cooling fan always running, strugleing to pull a measly 4000 pounds and low mpg when pulling 4000 pounds. In a 3003 mile round trip the truck averaged 9.6 mpg pulling 4000 pounds. I am scared to even try to pull my 12500 pound RV.

Dealer told me truck was fine. Truck has 7512 miles on it. I was told they got 19.1 mpg on a 30 mile loop at 50 mph. I explained it gets 14.4 at 70 mph, the speed limit. I also explained my 01 got 18 mpg at 70 mph.

I now have a File number with GMC for my troubles. They want me to pull the RV to the dealer and see if they can then find a problem.

All I know is I sure wish I had my 01 duramax back.

[Kennedy]

Originally posted by More Power:
JK, Will you be bringing your fuel restriction gauge to SLC?

Thought I'd check the filter in Lil Red. The original filter has about 5K on it now. Might be a good demo. smile.gif

Jim Sure will. Can also show with and w/o lift pumps activated etc. I try to carry the gauge kit, WIF sensor wrench, and strap wrench in the vehicle I am driving at all times.

[REDTRUCK05]

Originally posted by Dave:
</font><blockquote>quote:</font><hr />Originally posted by REDTRUCK05:
</font><blockquote>quote:</font><hr />Originally posted by bgruschy:
My 05 GMC cuts out intermittently under hard accel. It will often do this when I " put it to the floor" and intermittently even when I get on it hard merging into traffic. The truck has 9000 miles on it and is bone stock. The only thing I have done is change oil twice.

When it cuts out the best way I can describe it would be it just falls on it's face and makse a sound about what I would expect from a turbo waste gate opening wide open, the problem stops almost instantly when backing off the accelerator a bit.

any ideas? My 05 has made a sound like what we would have heard from an old carb backfire and cuts out for about as long as one too. It has only done this accelerating from about 15 MPH and right away when I punch it. I had it at the dealer today for that and MPG issues when pulling, 7.9 MPG when pulling a 7500# travel traler with cruise set at 72 MPH. There response was as follows...

We tested it at 55 MPH for 30 miles you got 20.1 MPG. We pulled no codes and your truck is fine. Im sorry, 7.9 MPG pulling only 7500# is not fine.
They said bring it back in at 7500 miles ( 2900 now ) I have been talking to every Duramax owner I come accross in the campgrounds, finding out what they are pulling, how heavy, what length, what year truck, how many miles on it and at what speed. I am by far the lightest and the worst MPG.

Are you having MPG problems also? Thanks for letting me vent!
Paul </font>[/QUOTE]Sounds like you have the same dealer I do or it is a scripted responce. My truck was in the dealer last Wednesday for several things, mainly Cooling fan always running, strugleing to pull a measly 4000 pounds and low mpg when pulling 4000 pounds. In a 3003 mile round trip the truck averaged 9.6 mpg pulling 4000 pounds. I am scared to even try to pull my 12500 pound RV.

Dealer told me truck was fine. Truck has 7512 miles on it. I was told they got 19.1 mpg on a 30 mile loop at 50 mph. I explained it gets 14.4 at 70 mph, the speed limit. I also explained my 01 got 18 mpg at 70 mph.

I now have a File number with GMC for my troubles. They want me to pull the RV to the dealer and see if they can then find a problem.

All I know is I sure wish I had my 01 duramax back. </font>[/QUOTE]Same exact problems please call me.
Paul 651-308-3348 651-276-8936

[Uncle Wally]

Aceduramax

I have the same issue with mine. 4000 miles on the OD and when it's not fully up to operating temp with a moderate acceleration (ie. not over 2000 rpm), and she shifts into 5th, it coughes something serious and clunks so loud it startles a guy. I can only get it to do it once and then the temp is warm enough that it won't do it anymore. If you get anything out of GM, let me know. Mine is going in to get looked at in the next week or two.

Waldo

[Marvin Pace]

I had the same problem, the dealer change the fuel filter and problem when away. Try it.

[Kennedy]

Met a guy on the Interstate in UT. Actually we blew by him on the hills and ended up stopping at the same truck stop for fuel. He was going into limp mode when he stepped into it deep. He had recently run out of fuel in Denver AND had 15k on his filter. His restriction was 12+"hg at idle.

Having the ability to check restriction on the spot is priceless.

FYI, I had 2 filters that loaded up in 3k and 2k respectively. I haven't checked since our return, but at the Campground in UT it was looking normal after about 1600 miles. ONE bad tank of fuelcan plug a filter and now that we have a filter that actually appears to be doing something it will plug much faster...

[bgruschy]

I finally got around to changing the fuel filter, have not had a problem since....

[Kennedy]

Originally posted by bgruschy:
I finally got around to changing the fuel filter, have not had a problem since.... May prove over time that we need a lift supply pump to overcome filter restriction as the new dual media units load up. For fast and easy check of filter condition:

http://www.kennedydiesel.com/detail.cfm?ID=289

[JD Diesel]

05 cc 4x4 trip oregon 2 months ago flat lands 11mpg hills 9.5mpg. this last weekend trip to bishop ca 10.2mpg with lite head winds. Coming home sunday got 8.8mpg with realllllllly bad head winds. when stop for fuel the winds felt like 40 mph. a little scary coming home. trailer 14780pds. otherwise am real happy. JD :D :D

[Black95TD]

Useful thread! I had several bad loads of diesel with my old 95 and several with my VW diesel before. Sounds like the filters are doing their job. I have become so paranoid about fuel quality that I only buy fuel from two well known local dealers that advertise "Premium" diesel. They are more expensive than the lowest prices around but since I have followed this routine I haven't had any fuel or filter problems. On the road is a different story and every time I buy on the road I pray there is no problem. Sounds like there is plenty of poor fuel out there!
I need to change my filter as I am at about 5K on my new truck. Glad to hear of the new longer dual pleat with more storage room for water.

[Black95TD]

One last thought - I guess a spare filter would be a good idea. If we have this problem, we'll change the filter anyway just to be sure.

[bgruschy]

Well, I have about 500 miles on the new filter and the symptoms are back. It's really hard to tell if they actually went away since it is such an intermittent problem.

Brian

[Kennedy]

Originally posted by bgruschy:
Well, I have about 500 miles on the new filter and the symptoms are back. It's really hard to tell if they actually went away since it is such an intermittent problem.

Brian Measure filter restriction. A bad batch of fuel can fill up a filter quickly...

[More Power]

So, what's the final word on the cause of the backfire mentioned in this thread?

Jim

[JD_Diesel]

Well I had the update done to my truck for the back fire noise has not done it since. So for now I'm guessing that was the cure. JD

[CHVYMAN#9]

There Have Been Several Pcm Updates For The Lly That Could Help Your Issues. There Is One For Turbo Bark,one For Light Throttle Surge Etc. I Have Seen Good Results With The Latest Updates. Just
A Side Note: If You Previously Had A Hypertech Installed For Tire Size Etc. And Removed Prior To The Updates I Can Bet When You Go To Reinstall It You Won't Be Able To. For Some Reason The Hypertech Won't Recognize The New Software And Will Set A 6d Code And You Will Have To Send It Back To Hypertech To Unlock It.
I Found Them To Be Ok With One Time And Jerks Another. They Do Tell You To Remove Prior To Going To Dealer However. Just My 2-cents On The Subject.