Which engine gets the best fuel milage? Do they both over heat? Would I have been better off buying a 2004 LB7 or am I better off with my 2005 LLY?

I've pulled some big backhoes up some pretty good grades and never got the tranny or the engine hot.I like my lb7.

The LB7's typically don't have the overheating problems that the LLY's do, but the earlier ones had some injector problems. I think most of those problems either have been or are being worked out. I didn't have any injector problems at all, but mine was built in December of 03 and by that time they were having very few problems with them.

The best mileage I ever got with my 04 LB7 was 19.7 mpg, but I had the wife and kids with me, the bed loaded with gear and was running 75 most of the trip.

No problems with the LB7 overheating pulling really heavy loads

I seems like I read a lot of negatives about the LLYs:confused:

Our blue truck (04.5) gets good mileage for it's weight (19hwy at 65) and has not had any real issues with overheating while towing heavy.

Here's the problem: An LB7 will not pass the new emissions. It's like a 12v Dodge Cummins or a 7.3 Ford. A very good engine that can never be sold again for light duty use.

My impression is that the picture has changed recently - for two reasons.

1. The latest reflash for the LLY has the truck running cooler and smoother.
2. EFILive will allow one to remove the "overfueling" that is inherent in the LLY programming - this overfueling is to reduce NOx emissions, but cuts efficiency and makes the truck run hotter....

Some folks here are obsessed with creating a cure for the LLY overheating issue. My feeling is that the cure is for the motor to produce less heat - given that my stock LLY with the latest reflash now behaves like my 2003 lb7 truck (warmup, temps while accelerating, temps while cruising, etc.). I think the problem will be cured for many - have to wait for august temps to know for sure.

Otherwise, a focused tune (EFILive) that reduces fueling slightly is the ticket. Kennedy has a nice tow/economy tune that looks pretty nice.

jeff

What is EFI Live? And, What was the latest reprogram that you got? Sorry for being a little off topic, but you bring up some great points that I hadn't thought about. Did you still block your EGR? And if so, did you block it at the EGR to Intake Ports, or at the manifold towards the back of the engine?

One more thing, dmax lover, what is the build date of your truck. Mine was a July 05 build. Thanks for all your help.

Love my LB7!!!!!!!!!! No major issues, just injectors.

What is EFI Live? And, What was the latest reprogram that you got? Sorry for being a little off topic, but you bring up some great points that I hadn't thought about. Did you still block your EGR? And if so, did you block it at the EGR to Intake Ports, or at the manifold towards the back of the engine?

One more thing, dmax lover, what is the build date of your truck. Mine was a July 05 build. Thanks for all your help.


The latest re-program for the engine controls was put out around the first of the year - my build date on my truck is also july '05 and my truck benefited from the reflash.

My truck is stock with no EGR blocking, etc.

EFI-Live is a new programmer that allows a user to create their own tunes. They are given access to all the "lookup tables" to control the behavior of the electronic fuel injection. Kennedy diesel (http://www.kennedydiesel.com) sells this product and he is also reprogramming ECMs with tunes that he has developed with it (look for "kennedy custom" under dmax performance on his site. I think it is better to go the latter route since he has a dyno in-house (and I don't!).

jeff

I've pulled some big backhoes up some pretty good grades and never got the tranny or the engine hot.I like my lb7.
I have pulled horsetrailers and my backhoe all over in the mountains around here too and have had no overheating problems.