Any LB7 Duramax guys here?

[Dangiaya]

Hey all. I have a 2004 Silverado 2500HD 4x4 with the LB7(?) VIN#1 Duramax. Owned it for about 6 months now and now matter what we do to it the truck throws trouble codes for the mass air flow sensor and the egr system. It's been to Chevy 2 or 3 times now and both the entire EGR and MAF systems have been replaced but the trouble codes always come back after about 20 miles of driving. There is a K&N intake on the truck but Chevrolet insists that it has nothing to do with the issues I'm having.

Aside from that what kinds of trouble can I expect from the LB7 and the Allison 1000? Both Chevrolet dealers I've had the truck at have mentioned that these motors were problematic from the get-go and should be avoided, wish they'd have told me that when I bought it...HA! I have had a bunch of issues with the fuel system losing prime(random loss of power and stalling) and the trans going into limp-mode.

 

[OregonDMAX]

The k&n filter can definitely have an effect on the maf readings and should be avioded, that issue has been beat to death over the years on here with guys having issues with k&n or any oiled type filter.

What codes we're you getting?

If it were my truck I'd ditch the k&n for a filter setup like afe or banks, I would block off or delete the egr and tune it with efilive.

 

[TheBac]

Specific codes would be very helpful, but Sean is right -- ditch that K&N. They are the worst intake you can have on these trucks. Just find a stocker to put on.

As to the fuel issue, you'll either have to rebuild the filter head or replace it. You can buy the oring kits at part stores nowadays. The replacement head part number is around here somewhere...do a search for that.

Trans in limp mode could be a lot of things. You'll have to get the codes the next time it does it, though.

 

[Bdsankey]

Hey all. I have a 2004 Silverado 2500HD 4x4 with the LB7(?) VIN#1 Duramax. Owned it for about 6 months now and now matter what we do to it the truck throws trouble codes for the mass air flow sensor and the egr system. It's been to Chevy 2 or 3 times now and both the entire EGR and MAF systems have been replaced but the trouble codes always come back after about 20 miles of driving. There is a K&N intake on the truck but Chevrolet insists that it has nothing to do with the issues I'm having.

Aside from that what kinds of trouble can I expect from the LB7 and the Allison 1000? Both Chevrolet dealers I've had the truck at have mentioned that these motors were problematic from the get-go and should be avoided, wish they'd have told me that when I bought it...HA! I have had a bunch of issues with the fuel system losing prime(random loss of power and stalling) and the trans going into limp-mode.

Is your truck a California emissions truck? Being a 2004 with vin 1 it should be an LB7. LB7 didn't get EGR unless its California emissions. As others have said, the oiled filters cause issues with the MAF sensor. I would recommend either getting a dry filter for it or replacing it all together with something with a dry filter (if you cannot get a dry/non-oiled filter for your intake).



Fuel system losing prime can be as simple as rebuilding the filter head. A lift pump would be recommended due to upgraded filtration/water separation and air separation over the factory filter. The 5spd Allison is by far the weakest in stock trim. If it limps already then you really need to start saving for a trans build of some type (ordering a kit and doing it yourself or paying someone to build it).

 

[TheBac]

O/P: heres a stock LB7 intake for the price of shipping: https://www.duramaxdiesels.com/forum/showthread.php?t=81183

 

[Lotter1]

I have a LB7 and am really happy with it. Sure I have had problems, but the truck has 240k on it, 150k that I have put on.

Like said before, the K/N needs to go. The fuel filter head can either be rebuilt or replaced for not that much. Being a LB7, injectors were/are problematic, with a lift pump with 2 micron filter or better could extend the life of the injectors. I am about to replace the water pump for the second time and I don't consider that a problem area. I have had the tranny build, but that is because of the extra power going through it. :woott:

What codes are you throwing?

 

[cdbright]

1 post and will never hear of him again