With very light throttle and sometimes at idle i'm getting a pulse. Sometimes it sounds like i have cam and other times it sounds normal. But at light throttle it surges. I've heard this could be the FPR or it may just need some lubricity (sp?). If got 55k miles on the truck - if its the FPR then will it be covered under warranty? I'm running the six gun. thanks!

Does it do it with the six gun removed?

Mine pusles sometimes (mine is an lbz thoughy) only if I have it in gear w/foot on the brake.

mine used to do it but has quit i ran about 3 bottles of diesel kleen through and unplugged the egr for a day and then plugged it back and it quit....think the egr was hanging open on mine was the problem

edge made mine do it

Fuel Pressure Regulator took care of mine. Stock 05 with 35000 miles. Now has 39000 and still no surge.

mine has started to do this also not sure what it is but i think i will see if it still doing it after i take it in the shope after next week

i know this is not a solution, but i stacked a predator on top of my six-gun today and it did not pulse anymore. I think i will run some Kleen through or maybe some Stanadyne lubricity. Will report, but so far stacking fixed the pulse :). he he

BTW - my truck is set on tow mode on the diablo and only 2 on the six-gun. DAMN my truck is a freaking beast now and is WAY more drivable. I can only imagine getting it even better with EFI live. maybe someday. So far this is a nice combo. Very sweet.

mine started at about 30k but dealer told me no codes so it must be normal! Yeah sure! I did run kleen through and ran it to Denver twice no pulse as of now

Maybe the infamous parking lot surge. I believe a reflash is the fix for that.

gonna keep my eye on the issue and see what happens.

Subject:Diesel Engine Surge at 1100 to 1400 RPM - keywords calibration chuggle ECM idle software speed update #PIP3328C - (11/18/2005)


Models:2004-2005 Chevrolet Silverado
2004-2005 GMC Sierra
Equipped with the 6.6 LLY Duramax Diesel Engine



The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1730759&psdid=1058&evc=sm#ss1-1730759">Condition/Concern:

The customer concern may be an engine RPM surge at 1100 to 1400 RPM.
This condition will occur at slow speeds, and may be more noticeable when towing.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1730759&psdid=1058&evc=sm#ss2-1730759">Recommendation/Instructions:

<LI type=1>Complete the current SI diagnostics for any symptoms or DTCs set. <LI type=1>A new calibration has been released for a 1100 to 1400 RPM low speed surge.
If the 1100 to 1400 RPM surge has been duplicated, install the updated calibration and evaluate repairs.Note: 2004-2005 6.6L Duramax Diesel equipped vehicles with a manual transmission are not included in the software update. If the 1100-1400 RPM surge is verified in a manual transmission equipped vehicle please submit a Field Product Report. Instructions for completing a Field Product Report can be found in bulletin number 02-00-89-002D.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

I had stumble/surge at idle in gear and it was an injector out of spec/defective. Replaced under warranty and no problems since... maybe check the balance of injectors.

-aj

May be a bad Fuel Pressure Regulator. At about 55k miles, I would be sitting at a light and the motor would surge 100 to 200 rpm's for a split second and if your foot was on the brake lightly the truck would lunge forward. The dealership replaced mine and it was covered under the extended warranty I purchased when I bought the truck. I was only running the Superchip program at the time but pulled the program out before I wheeled it into the dealership to be on the safe side so they had no opportunity to blame it on that.

I had a similar problem that gradually got worse and finally took into the dealer for a look, found 2 injectors were bad and they also replaced FPR and reflashed the computer as someone else already said. I also changed the fuel filter at the same time. No problems since.

Mine pulses a bit at idle in gear, especially sitting at a light after I've been running for a while. You think some of that "Kleen" stuff and maybe some Stanadyne will work?

well mine was in the shop last week for an injector thought to be the cause of this problem, turns out its the i-pump. hopefully it gets done today.

Ouch a new pump, how many miles?

what do you guys consider a surge... ive been having problems just recently with the edge on 1 and after i drove a little then let it idle for about 10 min and i start to drive away and it starts to make a horrible "miss fire" noise and stutters until i put it in edge stock mode, it goes away, drive a little then i can put it back to 1. is it over fueling from idle or do i have a serius problem?

I just got my truck back after 3 weeks in the shop.

Took my 2500HD 2004.5 LLY truck in for oil change, coolant flush and transmission flush/change before doing a pull of my toy hauler. The only other thing I told them was that my fuel mileage had dropped a lot in the last week or so. Truck was running great when I took it in, but was "missing" when I got it back (not running on all 8 cyllinders).

- They did the #7 wiring swap - still "missing"
- After more Tech 2 looks, the decided to change #1 injector - still "missing"
- More tech 2 looks - now need to change #6 injector - still "missing"
- Now blamed fuel - dropped my 52 Gal supertank - fuel "looks" strange - been buying fuel at the same place for 3 years - never any problems - station says no one else has had problems
- Found that my 52 gal supertank is leaking from the pickup hole
- Called supertanks - yup, known manufacturing flaw - they will overnight a new tank and pay for R&R for the tank (Great service from supertanks!!)
- Dealer got tank - blew out the fuel lines - replaced fuel filter - put in tank - got new fuel from a different station - "still missing".
- Now dealer says that they reflashed the ECU to change my tires size, since I put on 265s - still they say fuel was bad - still "missing"
- Service Manager now says to change all 8 injectors - now no more engine "miss"
- Picked it up and drove it 10 miles and took it back - now it is surging like it has a cam in it - dealer says they didn't hear it and after 30 minutes of "listening", now they want to keep it again.
- researched the forum - told the dealer to replace the fuel pressure regulator - they don't think it needs to be replaced as they still don't hear the surging and there are no codes picked up by the tech 2
- Dealer called and says that they are going to replace the FPR because when they started it up first thing in the morning it was surging bad - still no codes.
- Just picked it up and after 10 miles, all seems well again. Dealer still blaming fuel - all warranty work except for the fuel filter swap.

What do you master mechanics think? Was it fuel?

Sounds like the FPR to me:think:

I'm no master mechanic, but the fuel? I don't think so.

jdman, 80,000. barely broken in:D . the pump definatly fixed the low pressure. now i have another injector that came up bad with the new found pressure. so hopefully i'll get it in soon. also just a side note. i get my fuel from the same station every week. the last couple of tanks it has been smoking real bad, just excessive for the "regular" driving i do thats what made me check it out. yesterday me and a couple techs tried the old burn test with some other samples we had, plus we had a truck that gets its fuel from the same station with the same smoke issue, sure enough the fuel in my truck burns real cool, versus the other sample, known good fuel we had. very smoky like there was enough air. strange though. just food for thought if your milages suddenly drop or what not.:)

an update on the surge. It came back on Friday after i filled up again. The only difference now is that i did not run an additive in the fuel this time, just straight up ULSD. Felt like I lost a little power too. Lubrcity gone is my thoughts... ULSD is BS!

I'm with mcbride! FPR! May be a bad Fuel Pressure Regulator. At about 55k miles, I would be sitting at a light and the motor would surge 100 to 200 rpm's for a split second and if your foot was on the brake lightly the truck would lunge forward. The dealership replaced mine and it was covered under the extended warranty I purchased when I bought the truck. I was only running the Superchip program at the time but pulled the program out before I wheeled it into the dealership to be on the safe side so they had no opportunity to blame it on that.

I just got my truck back after 3 weeks in the shop.

Took my 2500HD 2004.5 LLY truck in for oil change, coolant flush and transmission flush/change before doing a pull of my toy hauler. The only other thing I told them was that my fuel mileage had dropped a lot in the last week or so. Truck was running great when I took it in, but was "missing" when I got it back (not running on all 8 cyllinders).

- They did the #7 wiring swap - still "missing"
- After more Tech 2 looks, the decided to change #1 injector - still "missing"
- More tech 2 looks - now need to change #6 injector - still "missing"
- Now blamed fuel - dropped my 52 Gal supertank - fuel "looks" strange - been buying fuel at the same place for 3 years - never any problems - station says no one else has had problems
- Found that my 52 gal supertank is leaking from the pickup hole
- Called supertanks - yup, known manufacturing flaw - they will overnight a new tank and pay for R&R for the tank (Great service from supertanks!!)
- Dealer got tank - blew out the fuel lines - replaced fuel filter - put in tank - got new fuel from a different station - "still missing".
- Now dealer says that they reflashed the ECU to change my tires size, since I put on 265s - still they say fuel was bad - still "missing"
- Service Manager now says to change all 8 injectors - now no more engine "miss"
- Picked it up and drove it 10 miles and took it back - now it is surging like it has a cam in it - dealer says they didn't hear it and after 30 minutes of "listening", now they want to keep it again.
- researched the forum - told the dealer to replace the fuel pressure regulator - they don't think it needs to be replaced as they still don't hear the surging and there are no codes picked up by the tech 2
- Dealer called and says that they are going to replace the FPR because when they started it up first thing in the morning it was surging bad - still no codes.
- Just picked it up and after 10 miles, all seems well again. Dealer still blaming fuel - all warranty work except for the fuel filter swap.

What do you master mechanics think? Was it fuel?