04 lb7 w/ cyl 4 bal rate 15

2004 lb72500hd

New member
Mar 19, 2020
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Truck ran great, got up one morning started it and it was smoking white bad. Running rough and coughing a little thru the exhaust....I think I made the call too early to replace the injectors. I really didnt do any diag on it. So i tore it down. Put new sac00’s, delco c headgaskets, resealed all cups, rebuilt filter head. Everything visually looked ok as far as piston tops, valves, deck surfaces. Put it together and started it. Constant heavy white smoke , rough idle, acts like it doesnt want to clean out. I have only started it twice. So i go and do some checking, resistance is .6 on all 8. Compression is 270-320 across the board cold. Im lost. I just bought the truck, ran perfect for 2 days. It has a holley lift pump edge cts2 and exhaust thats it. Im not sure where to look anymore. All grounds are hooked up clean and tight. About to have it towed to a specialist.. any insight would be much appreciated
 

snowman22

Member
Jan 30, 2018
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0
16
SoCal
I would post your compression for each cylinder, 270-320 is a big range and on the low side. What is the MAF, rail pressure, and fuel rate at idle?

You sure you didn't leave a rag in the intake? (Might be asking from previous experience)
 

Burn Down

Hotrodder
Sep 14, 2008
7,064
1
38
Boise Idaho
Your compression is way low on all 8... How did you do the compression test? A healthy LB7 will be in the 390-420 range. The last LB7 I worked on with+15 had a rod bent so bad the piston and the crank were doing some custom machine work on each other...
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
13,375
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38
Mid Michigan
Oh, that'll be a good one when the piston is lower than the deck. Ask me how I know. :)
 

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