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Discussion Starter · #1 ·
Alright this is a Bible post but i need help on a customer’s truck.

customer states the following-

Super long story but I'll try to hit the basics here. 2003 lb7 federal emmsions truck, deleted, tuned, I rebuild top end with reman injectors, cups, drop in ddp 64 mm, fass lift pump, intake, etc. Truck ran amazing for about 3 months after my rebuild putting out more power than ever. Then ran into power issues that started randomly and now truck is hurting and have been to 6 mechanics and Noone can figure it out after I gave up.. Put it to the floor, no black smoke, smell of raw unturned fuel out exhaust, takes about 8 seconds to hit 20mph to the floor, turbo won't build more than 8 psi u til it red line sand then will shoot to 22 ish psi, all new sensors, no codes, no issues with frp, injectors, heads, ect. I'm missing about half my Hp and torque and Noone can figure it out.

Alright i get to the truck right off the bat i see no no’s

Mods to the truck-
New reman injectors
Dans Diesel performance Turbo 64mm
S&B intake
4”straight pipe
New cups
New MAF sensor
over 300dollors in new sensors

Alright the things i found. he had a DSP5 tune stacked with a edge juice with attitude🤦🏼‍♂️
unhooked the edge started up ran the same no power.

noticed a weird idle fass is at 30psi at idle so it’s got a little bit of a lope, truck has 365,000 miles on it has a stage 2 trans built bottom end, all new top end kind of. Still has the 365,000 mile cp3 on it but makes 23,000 psi of rail pressure, you smash the pedal the truck does nothing you can hear the turbo trying to lite no smoke out of the exhaust no turbo spooling then it hits about 3100rpm and it pulls a little harder then shifts and falls on its face again, customer states it was just slowly losing power and now it’s just plateaued at this 8sec to 20mph.

when i first got the truck i had a code for the map sensor cleared it took it for a rip never came back. once it gets to about 3100rpm it starts to grab power so i was wondering if the waste gate was stuck??? Has no wheel speed sensor signal in the front.

what do you all think??? the thing that’s got me is the power was decreasing gradually? i was thinking the cp3 but it makes 23,000psi?!
 

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Welcome to DieselPlace

Any codes?
CP3 should max out at 26,000 psi.

Any performance difference in stock mode?
FASS needs to be turned down if it is at 30psi
 

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yes bosch reman and maf he put a O’Reillys one in
Aftermarket parts will bring in gremlins on top of any other issue you may have making proper diagnostics hard.

I would change the MAF to OEM
 

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Not to stir the pot, but I’ve had lots of oreilly parts that are identical to acdelco. Same numbers stamped on them, etc.

My question is, how does it do if you don’t stomp the pedal, but roll into it? Also, how much fuel is being returned? Have you bottle tested it?
 

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Discussion Starter · #10 ·
Not to stir the pot, but I’ve had lots of oreilly parts that are identical to acdelco. Same numbers stamped on them, etc.

My question is, how does it do if you don’t stomp the pedal, but roll into it? Also, how much fuel is being returned? Have you bottle tested it?
all good you aren’t stirring a pot idc lol just seeking help.

does same thing if you roll into it but the other day was headed up a mountain hunting and lol the power cam back after unhooking the battery cables. now the power is gone again but all my computers aren’t detecting limp mode now it says the oil needs to be changed🤦🏼‍♂️ i’m leaning towards the ecm
 

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all good you aren’t stirring a pot idc lol just seeking help.

does same thing if you roll into it but the other day was headed up a mountain hunting and lol the power cam back after unhooking the battery cables. now the power is gone again but all my computers aren’t detecting limp mode now it says the oil needs to be changed🤦🏼‍♂️ i’m leaning towards the ecm
what about the power wires that feed the ecm? are they good? what about the connectors? are they loose or have any bad pins?
 
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