Loss of power 04.5 LLY Duramax

abanda · 07-10-2008, 09:17 PM

I recently have had a huge power decrease. I notice it more on the free way. When i press down on the gas to pass a car going 75, all i see is black smoke and hardly any response from the truck. I have done nothing different to the truck since the loss of power.

After the loss of power I replaced the fuel filer, did trans flush, break flush, and oil change. I also purchased a K&N cold air intake (77 series) and edge with attitude.

I ran 0-60 test on the edge with stock settings and ran it in 10.8 sec. I feel this is very slow even at stock. On level 5 on the edge i only ran at 9.2 sec.

I took the truck in (before i purchase the edge) they said there was nothing wrong with the truck

I have a 2005 Chevy Duramax LLY, Toyo Open Country tires, 20" rims, K&N intake, and going to straight pipe very soon.

Need some suggestions. thanks

**Maverick684** · 07-14-2008, 07:13 PM

Well to start with check and clean the air filter and make sure not to over oil it. Also while you have the filter off, you might want to check and clean the MAF. Clean it with some brake parts cleaner and let us know. It sounds like your getting fuel but enough air to burn it off.

r81ders · 07-14-2008, 10:04 PM

I got the same problem with my truck, i got the same year and mods as your truck..the only thing i was told from edge that i might have to upgrade my edge prod. they tell me to send in my old one and they will give me a new one upgraded and i ask why it go bad and they said due to noise and needs to upgrade..if u come up with a fix can u email me back

abanda · 07-14-2008, 10:38 PM

R81ders I have also been told to upgrade the edge, so I did just that and have not notice any improvements $350 down the drain. I would hold off on the upgrade. If anything I would send your chip to Edge and have them look at for free. The upgrade did nothing for me but everyone’s situations are different. Try turning off backdown for a few mintues to do a 0-60 or 1-4 mile run on level 5. Alot of the problems we are having with the 05 LLy is the EGT's are too high and the edge is defueling. If you go to records on the edge, see how high your backdown % gets too. On level 3 i averaged around 33%-45% backdown. So in otherwords we have to buy mods to lower EGT's to get full power of the edge on level 3. I notice my truck runs best on level one at least responsive boost, and i only see a backdown percentage of 13%. I was told by edge the only two things that will cause the edge to defule is tranny slip % and EGT's. I would do a run with both egt's and slip % on the monitor, i notice my slip % was just fine it was my egt's that was killing me. Im hoping that will all change after my 4" stright pipe

I have done almost everything now. I have cleaned the MAF sensor, changed out my fuel filter, changed oil, trans flush, and purchased a K&N intake (77series). Just paid and had the injectors cleaned professionally. I have also started to purchase diesel from a place I know is very busy. After all this I have notice some power improvements over time.

I ran a 0-60 test again on level 5, disabled back down and turned on tow haul mode. I am now running 0-60 in 7.2 sec.

I just ordered

MBRP Exhaust http://www.xtremediesel.com/index.as...arSel=566,2724

Muffler Delete http://www.xtremediesel.com/index.as...strVarSel=1644

I will let you know how much improvements I see with a new exhaust

gr8shot · 07-15-2008, 01:11 PM

I'd be real careful runnin that much power. Your stock tranny can only hold about 90 extra hp. After that your tranny turns into a ticking time bomb. Plus don't forget that it takes a couple hundred miles for your tranny to fully "learn" the new settings every time you change your settings on your edge module. It won't shift right until it "learns" the new power setting. If you keep runnin it hard, it'll cost you. Maybe not this week or this month, but it'll let you down when you least expect it.

And the exhaust will do wonders for your egt's. If you want more, look into the member named Killerbee. Read up on the work he's done, especially about the compressor mouthpiece. That'll do your truck a lot of good too.

abanda · 07-15-2008, 04:59 PM

Cool thanks for the info. I dont run it hard all the time, the only time I really step on it is on the ramp to get on the freeway. Passing power is really what im after not to race.

The max level I keep it on is level 3 is that ok? I think it would be fine considering my upgrades but I dont know.

r81ders · 07-15-2008, 09:05 PM

ABANDA check this out i got a 4"banks straight,a K&N airfilter system with the bottom cut open and my edge wit attitude,i was jumping on the highway so i guned it on stage 3 and sure thing it happen again my light came on and the truck drop power and i took it to da dealer and they removed the light and told me the codes were trany codes and that nothing was wrong wit the truck but the power is not the same and the light came on few times and my buddy at gmc dealer would fix it for me but he does not know i got the edge on the truck so every time he gives me back the truck i would just put the edge back on and it would run with BALLLSSSS now it runs stock and i sent edge my prod and they said its ok that it past and if the truck does not respond to it that its time to up grade..but u saved me some money cuz i was about to send them 350 to upgrade but im going to hold off thanks for info on that..on stage 3 @ 2000rpm my truck would sream and i had balls to the wall, i mean my truck would just want to go all off the road and to top it off i got 20"s on 38"s..but after they highway problem my truck is just stock and i have no one or any clue on how to get that power back..but the info im geting here is prety good to try out and i will let u all know what workout..and yes i changed out all the simple crap air filter,fuel filter changed out trany oil..the only wonder i got how do we know if the TURBO is not working proper cuz every one says diffrent ideas but never the TURBO so any ideas??

**BigRedChevy** · 07-15-2008, 09:37 PM

The 5 speed allison will limp very easy on the 4-5 shift and the 5-4 shift when at WOT with a tune in it. Did you get a 2000 rpm rev limiter or did the tranny get locked in 3rd gear when you SES light came on?

r81ders · 07-16-2008, 07:35 AM

is that what may had happen my gears,but i dont under stand if the truck runs ok when it is shifting 5/4 and 4/5 do i go dealer and have them look at that again or upgrade and what is the best simple way to up grade do i use GM parts what gears u recomend using. and now that i think about it the truck was in 3rd shift @ 2000 rmps when it limp, but again how do i know if it still not working cuz it shifts ok.thanks for info

luke0490 · 07-16-2008, 07:53 AM

Hey r81ders you got a beautifull truck...I m having the same prob with mine. The truck was running awsome till i limped it a couple of months ago. I changed the fuel filter, tranny fluid, and air filter and i thought it was running fine till i pulled my trailer on a long haul. It actually runs a little better when i pull the diablo programmer off of it. Going to take it to the dealer and have them check it out. They also told me nothing was wrong with it the first time i took it in.