Advice/Options for LLY Towing

[acm]

I just picked up a 04 LLY Duramax.



(gotta love the King Ranch inspired paint job)

1 owner TX truck with ~200k miles.

The transfer case was just rebuilt sue to the “wear” issue. Has new water pump, front and back breaks and was mostly dealer maintained. Truck has hauled a horse trailer but never been a work truck. Overall, it’s in very good shape and I got it for what I thought was a good deal.

The original plan was to leave everything stock and just drive it. Well, that plan has changed!!!

On it’s maiden voyage it died 2 hours into a 4 hour trip due to a leaking fuel filter. Luckily, I was hauling my minivan on the trailer and was able to throw the truck on the trailer and haul with the minivan. Truck averaged 15.1 mpg while the minivan averaged 15.6 mpg (speed was much lower on mv…)


Truck is running again. Now has a real lift pump instead of the original fuel filter housing and the mods have begun!

New plan is:
· Delete EGR (possibly just a block off and fingerstick)
· Tune (either get it tuned like 06 LLY or use the Banks Economind)
· Exhaust
· Air Intake

Not looking to role coal or have an excessively loud truck. Just want a little more torque, better fuel economy & reliability…doesn’t seem too much to ask for!

Open to any suggestions of what to avoid and what combos have worked well for others.

Thx,
acm

 

[red EOD]

Rather than a complete air intake just get the intake horn from the LBZ unless you are wanting to go balls to the wall with the build.
EFI live for the tune, able to adjust everything.

A fuel filter setup with 2 different filters, a water separator followed by a fine micron filter (ideally 5 micron or lower).

Larger transmission cooler (or remote with it's own fan) would be a good idea but not absolutely necessary. For a towrig with a mild build, that's about all I can think of. Good looking truck.

 

[acm]

Rather than a complete air intake just get the intake horn from the LBZ unless you are wanting to go balls to the wall with the build.
EFI live for the tune, able to adjust everything.

A fuel filter setup with 2 different filters, a water separator followed by a fine micron filter (ideally 5 micron or lower).

Larger transmission cooler (or remote with it's own fan) would be a good idea but not absolutely necessary. For a towrig with a mild build, that's about all I can think of. Good looking truck.

The intake horn from a LBZ sounds like a good/economical upgrade.

I'm purposely staying away from EFI Live...adjust a parameter, modify a few things. Adjust something else and modify a few more things. Gets to be a dangerous cycle real quickly. I don't have the discipline to leave well enough alone & I have enough unfinished products to prove this.

Already did the duel fuel filter setup. Added an airdog 100 to replace the leaking factory filter.

More trans cooling...good idea, hadn't thought much of that.

Thx

 

[diesel4me]

I think the mini-van needs a trans cooler too !....
Surprised that didn't fry the trans pulling that big truck..

 

[red EOD]

I can understand wanting to stay away from the ability to adjust things with EFI live haha. Banks programming is usually pretty good, better than some of the cheap ones that just dump fuel in.

Good choice on the fuel pump/filter setup.

 

[acm]

Maiden Voyage - Take II
Replaced the factory fuel filters with a lift pump/filter system and drove it about 300 miles. Did great.
I'm used to towing with a GMT400, so the brakes on this truck are impressive. Mileage wasn't great at 13ish...but that might be more driver related.

At least it made it home under it's own power (I did take few extra tools...mini-van & a trailer! )

I think the mini-van needs a trans cooler too !....
Surprised that didn't fry the trans pulling that big truck..

& air bags!

I took it pretty easy with the truck on the back but was surprised how well it did.
It goes to the dealership for some warranty work next week...we'll see how well it held up!

 

[max 02]

Stay under 90 hp over stock,use the 5th gear lock out while towing up hill. LLY`S Tend to over heat,you can address that with a add on radiator. But most importantly make sure your radiator stack is cleaned out good. They build up with crap real bad.

Good looking Duramax!
Impressive towing with the BMW! That would have made me take a pic for sure!

What is the BMW rated to tow anyway? We have a TDi Touareg rated to tow 7500 lbs. I wouldn't try it but I`ve seen some big boats and travel trailers behind them.

 

[beags86]

Funny how you have matching brushguards......

 

[acm]

@max 02
Not sure of the actual tow rating on the BMW. 6k if I remember correctly. Mine didn't come with the rear air suspension and I added the factory hitch & wiring. It's the older M57D/ ZF 6speed.

I have been towing with it more than I should. Usually, the same trailer with a zero turn and lawn equipment (maybe 3.5-4k) back and forward between Dallas & San Antonio. Makes very little difference at that weight.
Also moved a 2 dr Tahoe and a 3 serries down here on the same trailer (maybe 7k max). Was able to load the vehicles were the BMW didn't squat too badly and had no problems at normal highway speeds.

With the truck on it, kept speeds pretty low (45ish) but I never planned on pulling that kind of weight. Always thought these folks pulling large campers/boats with these small SUV's were idiots and asking for trouble...seems that I may have joined their club though.

Hopefully, the BMW has been retired from towing duties for now (it rough on the tires).

Funny how you have matching brushguards......

They are ls repellent!

 

[KirsL]

Looks like a good clean rig.


For a tuner I second running Banks setup. I had the banks sixgun on my Dodge for about 160,000 miles. Does it make the absolute most power, no. But it's nice being adjustable and it gives good safe reliable power.

 

[BadDog]

For a Duramax, I chose the Juice/Attitude setup. Easy configurability with multiple presets, ability to control fueling, readouts of choice, etc.

I've been running it on mine since it was almost new, no complaints other than the first year when Edge was having trouble with heat related failures in the Juice modules. Guess where I live, Phoenix. Guess where in the US it gets hottest earliest. And why I got to be the first to report, and ultimately a test mule. Learned a lot and got some nice benes for my trouble.

 

[acm]

@BadDog
Thx for the input...can you turn off program the EGR off w/ the Juice/Attitude?

 

[BadDog]

No idea, mine has no EGR.

 

[acm]

Looks like an injector or injectors are going bad.
So far no codes on my basic scanner, but the truck has more of a rattle than before and the mileage is dropping some.
Have not noticed any white smoke and the oil doesn't smell like diesel. So that's a plus.

Looking for a place near New Braunfels to diagnose which injector/s are bad.

Question is whether to use new or reman injectors? Initial thought is to just replace injectors as needed with a new Bosch unit.
Anyone had good luck with the remans? If so where did you purchase them?

Thx

 

[max 02]

Looks like an injector or injectors are going bad.
So far no codes on my basic scanner, but the truck has more of a rattle than before and the mileage is dropping some.
Have not noticed any white smoke and the oil doesn't smell like diesel. So that's a plus.

Looking for a place near New Braunfels to diagnose which injector/s are bad.

Question is whether to use new or reman injectors? Initial thought is to just replace injectors as needed with a new Bosch unit.
Anyone had good luck with the remans? If so where did you purchase them?

Thx

I got Bosch remans in both our Lb7 trucks.
They are updated from the original design... supposedly. Don’t think the llys neaded any updates for the injectors.

I’d have a hard time gambling on replacing one at a time. Get the balance rates checked before anything.

Look up the ice pick fix for the lly, could be the harness giving you troubles?

 

[acm]

I got Bosch remans in both our Lb7 trucks.
They are updated from the original design... supposedly. Don’t think the llys neaded any updates for the injectors.

I’d have a hard time gambling on replacing one at a time. Get the balance rates checked before anything.

Look up the ice pick fix for the lly, could be the harness giving you troubles?

Thx.
The plan is to check the harness first. The extra rattle is intermittent so ruling out the wiring makes sense.
IF the wiring checks out I'll have all 8 injectors tested for flow/balance rates and go from there.

Not a big fan on replacing injectors 1 by1 either. Also not a fan of the price of 8 injectors.
I am a bit concerned about the quality of the Bosch remans though. Glad to hear you had good luck with them.

My biggest issue is that due to some health BS, I had to take the truck to a shop to do all this. Not used to other people working on my vehicles.

 

[max 02]

Fuel pressure regulator will make it run ruff too.
Dump a good dose of 2stroke oil in the fuel tank, see if that helps. We had harness trouble and Fpr problems with my father in laws 05 LLY.

 

[max 02]

If you do need anything I like Merchant Automotive. I have bought their injector install gasket kit, good price and extremely complete kit!

 

[Truckman4life]

My buddy did injectors on his '04 and Merchant was the best price and best quality injectors. Don't bother with any other knock off places. I have used Industrial Injection a lot over the years for work and they do good work too but if I remember correctly Merchant had the best price. I think he used Dorman fuel lines from Napa and they worked out ok too.

 

[acm]

Just got the Duralug back. 8 new injectors and it's good as new. 3 where bad, so why stop there?
Truck runs great, almost too quiet for a diesel. Transmission even seemed to be happier.
Good news is that the EGR is deleted and it already has the LBZ turbo inlet on the truck.
Down side is the place that did the work is pushing a custom tune. Might throw a Banks Ecomind on it if it can make it a month or two without braking down...

Thanks @max 02 & @Truckman4life for the advice/help.

just for @beags86
Tows great, barely notice it on the trailer!
Gotta love an old L29 truck.