LB7: No start, shaking, sounds terrible

AubleAK

New member
Aug 5, 2011
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Glennallen, AK
I've just rebuilt my motor, after dropping a valve and taking out a piston. Put in lbz rods, arp studs, all new bearings and rings. 2000 miles on rebuild, with 475 over stock twins.

Last night, i finally found some pavement and wanted to get some good pulls in. Got one hard run in, from 55 to 100, pulled over at the local gas station. When i pulled over, the truck had more of a shake to it the usual. I slowly revved it up, and the shake got worse till 1400 rpms, then cleared up, sounds and felt fine.

I figured i better get it back to my shop, So gently drive it home. Sounded like absolute shit. Had a really loud "diesel" sound, like the old ford diesels. It honestly sounded like an up pipe had fell off. I got it to the shop, and went to bed sick and fed up with things going wrong.

This morning, went to go log it, and will not start at all. Doesnt even try to fire. Whit smoke comes out the tail pipe, and fills my shop with raw fuel.

Any ideas guys? Getting a tech two today some time to see if i can find anything out.
 

AubleAK

New member
Aug 5, 2011
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Glennallen, AK
I had that happen once. Was a bad copper washer on an injector. I guess you aren't supposed to re-use those. :(

Did not reuse any seals/gaskets/washers on the build. Anything is possible tho. I believe that this is fuel related.

In the mean time ive been looking at the 2013 sierra Denali duramax. :D
 

BlkMax

Member
Sep 1, 2008
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Wasilla, AK
Michael,
Did you replace the injectors when you did the build? How many miles on them?

I should have asked this last night....
 

AubleAK

New member
Aug 5, 2011
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Glennallen, AK
well, i tried to compression test it tonight. on all cylinders, the highest compression i got was 325, but i do not think they are accurate. so i am going to try again tomorrow. seems like on of the fittings on my tester was leaking, so i will have to make something else up again there. while most cylinders are up around ~300, two of them were at 200, so i have a feeling that i have a couple bent rods.
 

adeso

wait, what?
May 30, 2011
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Minot, ND
sounds like hung injector and bent rods to me, sorry dude. Hope it is just a hung injector and a bad tester