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Truck surging or cutting out

LLY: 
50K views 25 replies 14 participants last post by  pj951 
#1 ·
I'm a member on duramax forum and thought I'd post on here see if I gain any other knowledge from here.

I've got a 2005 chevy extended cab long bed its got the lly in it with 145,000 miles

Truck has 4 inch turbo back exhaust
AFE mouthpiece
Edge juice with attitude

While driving down the road I'm getting an issue where it feels like its cutting our or having spasms going down the road, i originally noticed it at around 55mph and at that speed it only seems to do it with the trans locked in. If I keep constant throttle it jerks back and fourth almost like its cutting out, if I give it throttle or take away it doesn't do it.

Starting today at low speed easy throttle under acceleration it's starting to also do it.

I'm clueless when it comes to diesels, new to this world. I did hook it up to my scanner and inspect a little bit I will most pictures of those results

I also changed the fuel filter about a week prior to this happening, when I just checked my mileage I was only getting around 13mpg if that says anything, and that's using a really light foot




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#3 ·
Does it do it at a lower fuel level?
Hows the fuel filter?
Have you checked for wire harness rub?
 
#4 ·
The fuel filter is new I just put it in the truck, it seems to do it no matter what the fuel level is at

I've checked the harness at the alternator and that seems fine, previous owner had wrapped it up in rubber and stuff I cut it off seemed good to me, I have not tried the ice pick fix yet but everything looks good there too should I still try n ice pick it? Also 2nd tank of fuel it's doing this with and a different station also


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#6 ·
Have you tried removing the Edge? My '05 would die driving down the road, and run like you are describing. I unplugged the edge and all my problems went away. Then I sent my Edge back. It was out of warranty so Edge gave me a new one at "cost"lol and I sold it on Ebay and bought a PPE.
 
#7 ·
I had very similar symptoms when my FPR was going bad. Does it ever surge or lope any when you are stopped like at a red light?

I know your scan data doesn't really back that up since your desired and actual fuel rail pressure seem to mach up well, but it might be something to think about.

I have a stretch of road that I would drive 50 on and at a steady throttle it would feel like a slight miss and kind of jerk back and forth. Definitely more noticeable when the TC is locked in as well for obvious reasons. The second you accelerated or decelerated it would go away though only happened at steady throttle.

I would recommend Ice picking your injectors though first off just to completely rule that out.
 
#11 ·
I had the same issues with my truck, pulled the edge out and I thought my problem went away...but found it still does it when towing. No check engine light...anyone have any other idea's? I had the injector harness done at 54,000mi. I have 157k now. I would think I'd get a check engine light if it was a harness? Was looking into replacing the 'feed pump', anyone have one of those go bad and cause the same problem?
 
#12 ·
There is no 'feed' pump. Only the main fuel pump (cp3). If you have any way to check, look at your demand vs actual fuel rail pressure. If the actual drops below the demand, its your fpr.

If your truck is surging while in power with a load on it, I would look at a few other things. Injectors, fuel filter, air filter, fuel pressure relief valve (which should throw a code and put u in limp mode), and mmaayybbee a gunked up egr bridge and intake elbo.
 
#13 ·
Had the same problem with mine. Ended up being the fuel filter head. After you turn the truck off see if you can pump the plunger that you prime your filter with. If you can pump it that might be your problem. Merchant Auto sells rebuild kits for them.
 
#14 ·
I have both problems. The surging was fixed completely with a FPR replacement. It still wants to get a little air in the fuel so I now have the filter head rebuild kit from Merchant Auto on my desk. It seems to be more of a problem when fuel levels are lower as well as when pushing the truck harder towing heavy or similar. Heat has a lot to do with it as well. Hopefully this solves that problem. I also have the FPRV shim kit and may get that accomplished as well this weekend.



Gar
 
#15 ·
My EGR bridge was pretty gunky, but not anywhere near plugged up, just dirty/gooey. I cleaned that while I was doing the FPR. Talk about a messy job! I would sure like to find a guy local in San Diego area who can help me check my balance rates. Truck runs fine but mileage has never been what I hoped it would be. Too expensive to just start randomly throwing injectors at it. I'll ice-pick them again as it's been about 6+years since I first did all that stuff.


Gar
 
#16 ·
Hey biggar
I know this is an old thread but did you ever find a good mechanic in San Diego?
I am having a few issues with my 05 LLY and have asked around been have not found anyone in San Diego. I am no fan of any of the dealers from my personal experience. I am having the surge issue and a few months ago I had a fuel return line blow. Damn dealer in Boulder charged me a new injector. I am pretty sure I have a FPR issue but just would like to know for sure before I start throwing parts on it.
 
#17 ·
Bruce,

I still have my truck and I still have not found anyone that I really have confidence in to work on it unfortunately. On the plus side, I just towed my trailer to Monterey and back over the weekend without issue, and I did a similar trip last month to a track north of Sacramento, also without issue. I found the FPR online for far less money than the dealer, or NAPA, could get it to me for. Like 75% less. Crazy. That was a few years ago.

Before last month's trip I needed to get it smogged, and I think my Fingerstick had long ago failed somewhere, so I got new EGR gaskets, removed my blocking plate, removed the Fingerstick and put wiring back to stock, and have not had any engine codes since, and I actually think the truck runs better.

FPR is not an awful job. A little time consuming, but it's just nuts and bolts. Carefully flop the AC compressor back and you shouldn't have to open that system up. Watch a video, and have at it. I pretty much just have my Banks intake on the truck now, and everything else is totally back to stock, and truck is running great.

No one seems to know where Clyde is these days. He was great. Maybe he'll check in here? He was a bit north in Lake Elsinore area. Not sure what he's up to these days. I finally put pads and rotors on the front of my truck after 187,000 miles on the originals. They still had a lot of meat on them. Amazing. I was replacing the hub bearings for the third time and just figured I was already dirty so get it over with. I do think it's time to rebuild my boost pump, and I have the o-ring kit to do that, but haven't gotten around to it. It leaked a bit, but now it's not dripped for months, so hmmm...

Time for a Hoot Method trans flush one of these days, and I should do the transfer case before it gets a hole in it. New trucks are so expensive I can't see doing anything but running this old girl for the duration.
 
#18 ·
FPR replaced in Feb because of surging and what a difference that made. Towed back to wa st and it ran like a fine tuned machine. Local chev dealer in Casa Grande did the work.

chevman
 
#20 ·
surging

I had similar issue. After several fuel filter changes and inspections, turns out the fuel lines going to and from the fuel filter housing (wich are rubber) were bad. Wouldnt hold their shape. Caused a starving for fuel condition.
 
#21 ·
I had similar issue. After several fuel filter changes and inspections, turns out the fuel lines going to and from the fuel filter housing (wich are rubber) were bad. Wouldn't hold their shape. Caused a starving for fuel condition.
I had same problem & mine the suction line imploded so it started this way & finally would shut down, so replace those fuel lines, it's cheap insurance.

Also it would pull down the prime pump button, so it's another clue to the puzzle.
 
#23 ·
My truck sat for the past 6 months in limp mode. no luck finding a trustworthy tech in SoCal. I am sure there are some good techs but.... decided to purchase a scanner Autel MS906BT.
DTC:
P0101
P1404
P0299
P0404
also found coolant temp would not reach opertating temp. So started with changing thermostats and got temp up. cleared codes after a few miles limp mode again blowing black smoke looked like James Bond. no power barley made it home.
same codes again but was able to view fuel rail readings and found under full throttle fuel pressure would drop at 21K PSI. replaced fuel pressure relief valve.
Pressure problem solved but still in limp mode this time P01404 and P0404 and P0299.
did active test on EGR and found sensor was dropping out between 40 and 60 %. Replaced EGR and Sensor. All is good now except after sitting two days started truck like normal then stalled and would not start. found fuel filter pump soft and pumped up and truck ran fine. looks like a filter head rebuild and also fuel lines is next. truck has 132k and lived in SoCal entire life. but looks like most of the rubber fuel lines are badly weather checked.
Unfortunately for me it looks like age is taking its toll. Just needs a little more TLC
 
#24 ·
I alos found fuel leaking out of fuel pressure test port. i have never used the port, but just on a whim I removed the cap and found fuel covering the Schrader valve. Could be why pump is loosing prime?? is that valve replaceable?
 
#26 ·
I found my test port that way, I think it's OK, the plastic cap seals too.

On a 2005 you will eventually replace every rubber hose in the fuel system from the tank to the HPFP. You'll replace the FPR itself and the filter head (a couple of times). There are several small elbow fuel hoses in and out of the HPFP beneath the AC compressor, don't forget those. Yes, I've thrown a few parts at my truck, but when a suction fuel system is involved you just can't "see" every problem.

I even bought that $$ Lang suction gauge. Not much help really. When the motor would cut out on a road test..of course the gauge dropped. The rest of the time it was as expected. My cutting out issue was temperature related. Replacing the FICM seems to have stopped that.

My own truck runs "as new" currently, after 2 years of chasing hiccups (all the time) stalling and gremlins (cutting out in high temps). Summer will the final test.

Fuel system parts replaced last two years:
FPR, FICM, all suction fuel hoses, filter head, fuel tank pick up module.

The HPFP, fuel injectors and FI harness are still original.

Still cheaper than buying new truck...
 
#25 ·
Bruce, I'm also in SoCal. North San Diego County. No idea who to use to diagnose and repair sensor and code issues. P101 keeps coming up on my truck. Fuel mileage has never been great but it's now due for SMOG check. Truck runs pretty well, but SMOG check doesn't care about that if there's a code present or pending. BTW, I would not recommend rebuilding your filter head. Just buy an entire new unit. I rebuilt mine a few years back and it helped, but I believe the pot metal eventually develop fissures that allow air into the system when the truck gets warm. Usually right when you're towing heavy up Grapevine . . . New ones are not very expensive at all and easier than screwing around with a rebuild.
 
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