LB7: slow as s**t

dirtymax02

New member
Apr 10, 2012
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new here and just wondering why my truck seems slow and when you get on the pedal on the highway it tops to 79mph and creeps to 85 is this normal
 
Last edited:

LWATSON

future trans limpers
Jul 30, 2008
2,587
1
36
55
Scotland Neck NC
Not normal, could be a number of things. Go to user cp and fill out a signature so everyone can see what truck you have and what mods you've done to it. Sounds like a fuel issue to me are you getting any codes?
 

dirtymax02

New member
Apr 10, 2012
17
0
0
p.s it takes of like a tank, w.o.t. just to keep up with traffic :truestory:
no heavy smoke just a light cloud of soot
 

jraymer

<--Tree Hugger
Oct 31, 2008
1,421
0
0
Las Vegas, NV
stock they are not fast. when mine was stock it would sturggle to get to 95 mph flooring it. It would slowly freep by the miles 91....93.....ect.
Domyou have a cali emiss. truck?
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,610
1,866
113
Mid Michigan
replaced about 1k ago

Was the truck running like this BEFORE the filter change or after?

Is Fuel mileage way down? Possible injector issue?
Any odd noises from underhood associated with accelerating? Possible turbo stating to die?
Have you double checked the drivers side boost tube down by the power steering pump? Possible boost leak there?


General question: if the MAF sensor gets dirty, can that cause this?
 

dirtymax02

New member
Apr 10, 2012
17
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0
not sure if it cail emmision, i dought it is. and before the fiter i remember the same old truck but when driving nomaly then WOT it would let out a pretty dence black cloud.
 

dirtymax02

New member
Apr 10, 2012
17
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0
will the maf cauose any codes? when i hooked up the snap-on scaner and checked every thing out boost is there rail pressure fuel injector pulse fprv ok ect, my truck sound according to the scaner but when you drive it feels like a semi truck.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,670
5,816
113
Phoenix Az
Was the truck running like this BEFORE the filter change or after?

Is Fuel mileage way down? Possible injector issue?
Any odd noises from underhood associated with accelerating? Possible turbo stating to die?
Have you double checked the drivers side boost tube down by the power steering pump? Possible boost leak there?


General question: if the MAF sensor gets dirty, can that cause this?

When mine was bad it never did even on a stock tune

will the maf cauose any codes? when i hooked up the snap-on scaner and checked every thing out boost is there rail pressure fuel injector pulse fprv ok ect, my truck sound according to the scaner but when you drive it feels like a semi truck.

yes, if the MAF is bad for sure it will usually set a "soft code" (wont illuminate the CEL). What are the balance rates like? has the truck always been like this?
 

dirtymax02

New member
Apr 10, 2012
17
0
0
It was like this when i bought it thought it was normal but after a few weeks and red lights it seems too slow.
 

Leadfoot

Needs Bigger Tires!
Dec 27, 2006
904
31
28
48
Western MA
www.matpa.org
I'm not very familiar with the LB7's but don't they have a factory wastegate? If so, could it be partially open causing poor spool up and slow acceleration and low top speed (without any codes or associated noise from traditional "leaks")?
 

dirtymax02

New member
Apr 10, 2012
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0
I throug an over boost code one time when i was testing it so i think the boost is there but could it still leak some?
 

LWATSON

future trans limpers
Jul 30, 2008
2,587
1
36
55
Scotland Neck NC
Check and make sure you dont have a leak between the MAF sensor and the turbo. This leak will alow free air to enter the intake without passing by the MAF sensor and your truck will be very sluggish and spoolup will be very slow. For instance if the resonator, the piece that has 6.6 written on it that sits on top of the engine slips off you will get these simptoms.
 

dirtymax02

New member
Apr 10, 2012
17
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0
just checked resonator and air duck noting noticed so retighten the bolts and still the same as before. while looking around i noticed an exhaust hanger missing obviously noting to do with my problem but wandering were my transmission hanger could of gone, any one no were i could get one. thanks
 

dirtymax02

New member
Apr 10, 2012
17
0
0
Thanks every one for your help :thumb: I found my problem something called a duraminamizer in my dash. after looking it up i relized it reduses power!!!! Pulled it out and GD this truck is alive!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:D
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,727
296
83
Boise, ID, USA
Thanks every one for your help :thumb: I found my problem something called a duraminamizer in my dash. after looking it up i relized it reduses power!!!! Pulled it out and GD this truck is alive!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:D
Haha, glad you found it! I always thought that product was purely a joke, but apparently they sold some. At least you know it works as advertised :spit: