Opinions on LB7 Duramax

[WyoUltra]

What do you guys think of the LB7 (01-04) Duramax's? I'm looking at possibly buying one with pretty high mileage, but the truck appears to very clean. What have you guys reached for mileage on these things? Have you had any major issues besides regular maintenance?

 

[tt m1000]

Bring it in and find out what the injection rate... The lb7 is a awesome engine but poor injection

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[WyoUltra]

Injection rate? Wouldn't that involve pulling all of the injectors?

 

[05M7]

I have one it's a great truck! Stick 1000 dollars on top of what you pay for it and you will never be happier. Efi live and exhaust and it will do whatever you want and get 20+mpg.

Around 150000 the injectors start going. Get the flow rates checked, it can be done at a dealership with the tech 2 scanner or if you know anyone with a efi live v2 scanner they can do it too. If the truck smokes or has a lope to it even though the injector rates test good that's still a sign they need replacing.

Tie rods are a known weakness if you use your 4wd a lot but cheap to fix.

All in all you won't be disappointed


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[WyoUltra]

I have one it's a great truck! Stick 1000 dollars on top of what you pay for it and you will never be happier. Efi live and exhaust and it will do whatever you want and get 20+mpg.

Around 150000 the injectors start going. Get the flow rates checked, it can be done at a dealership with the tech 2 scanner or if you know anyone with a efi live v2 scanner they can do it too. If the truck smokes or has a lope to it even though the injector rates test good that's still a sign they need replacing.

Tie rods are a known weakness if you use your 4wd a lot but cheap to fix.

All in all you won't be disappointed


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Thanks, that's what I was hoping to hear! This pickups an 01 3/4 ton with 246XXX miles. Its really clean, all leather, and no cracks. And I planned on going with EFI Live, exhaust, and intake.

 

[jwentzer]

Find out when the injectors were last done. With the experience I had, they were more prone to going out around the 100K mark. It's about a 5K dollar bill at the dealer to get them redone.

I really liked my LB7 and some days still wish I had it. Always got 17.5 with a light tune of extra 40 HP from a Diablo Predator programmer. IMHO, stay away from EFI live, especially in the LB7 motor. There is a glitch in the electronics where the EFI live will just completely shut the truck down. It didn't occur with all of them, but was VERY common.

Go over to the dieselpage.com and read all the threads you want about the LB7 motor and the issues it can have with EFI Live. Nothing wrong with EFI live, it's a great product, just a glitch with that particular model that will leave you stuck along the road.

Check the front end, if minimal maintenance was done, it could be slopped out. Great truck and great motor. The Allison transmission is one of the best tranny's out there, just be careful. The more HP you throw at it, the more pissed off it will get. Trust me, them programmers are fun but they make everything expensive in a fast hurry.

The more you up the power, the smaller your bank account gets.

 

[Coldfinger]

From what I've read, the Duramax engines made prior to mid-2004 have injectors which are very costly to replace and in later 2004 models and newer they made it so the injectors are easier to get to and therefore don't cost near as much to replace.

Like said, see if they have documentation on when the injectors were replaced and if it was done by a reputable shop. After the initial injector replacement, I don't know how long one could expect them to last, though as I understand it, it is definitely longer than the originals.

 

[WyoUltra]

From what I've read, the Duramax engines made prior to mid-2004 have injectors which are very costly to replace and in later 2004 models and newer they made it so the injectors are easier to get to and therefore don't cost near as much to replace.

Like said, see if they have documentation on when the injectors were replaced and if it was done by a reputable shop. After the initial injector replacement, I don't know how long one could expect them to last, though as I understand it, it is definitely longer than the originals.

I'm not so worried about replacing the injectors, because my brother is a Diesel mechanic. However, I do understand the difficulty in changing them, as well as how complicated they are. So it's not really that big of a deal, however if the fresher the better.

 

[bootz1981]

on a lb7, the big o **** was the injectors, if they leak and go bad they leak diesel into the chamber and then could fill up your crankcase, thats really bad if you dont catch it in time. the newer lly lbz lmm and lml engines had a diff way of mounting the injector in the head so that was the benefit to a newer series. one of the benifits of a lb7 is no emissions. bought a 02 new and put 300k miles on it with no prob what so ever. keep a clean fuel filter in it and never never never fill out of farmer bobs service tank. dirt in the injector is the worse case thing. i put a conversion on mine from nicktain.com that lets you put a 2 micron cat filter on it, one of the best mod for under a $100. you keep a clean filter and fuel in it, it will never let you down, plus if you put exhaust on it they sound awesome, they have a none variable vain turbo

 

[boondawgee]

I've got an '02 and i love it. Injectors got replaced by GM after a recall years ago. It's been programmed(hypertech) w/ a larger exhaust since 45k miles. It's got about 170k now, and the only problem I've had is w/ the transfer case from the internal pump knocking a hole in it. Pretty big deal if you don't catch it in time. It's a known fault w/ these trucks. Bad design...
I've used the truck to haul my tow boat all over the west coast as well as my Haulmark loaded to the gills. It just pulls n pulls.

 

[05M7]

I've got an '02 and i love it. Injectors got replaced by GM after a recall years ago. It's been programmed(hypertech) w/ a larger exhaust since 45k miles. It's got about 170k now, and the only problem I've had is w/ the transfer case from the internal pump knocking a hole in it. Pretty big deal if you don't catch it in time. It's a known fault w/ these trucks. Bad design...
I've used the truck to haul my tow boat all over the west coast as well as my Haulmark loaded to the gills. It just pulls n pulls.

Merchant auto sells a fix it kit for that cheap.

As for efi live problems on a lb7 I have never heard of such a thing. And we have turned Prob 20+ trucks. May have to do some more digging I'm interested to learn about that.

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[Racer220]

Love my LB7. At almost 250k miles I would doubt injectors or pump rub would be an issue. It's either happened and they've been replaced/fixed or you are a lucky sob and got parts that were built to last. Never came across any threads about EFI glitching with that motor, but I guess it doesn't hurt to check. Exhaust and programming and you'll have a heck of a truck. Mileage is killer compared to other Dmax's. You should see 20 mpg all day long with 31-33 tires. I just went to 34s with 20s and I'm still running about 17-18 mpg mixed used. There are a ton of things you can do depending on the size of your wallet down the road. Good luck.

 

[mike_s]

If its in good shape, and fair priced, get it. Period. The first gen engine (LB7) after the revisions to curb head gasket issues was in my opinion the best one of the bunch. Easiest to tune, you dont have 35 different tables to deal with just to get the injection timing where it needs to be, get the best mileage, dont have to do a bunch of electronic trickery to upgrade the turbo, no emissions garbage (unless youre unlucky enough to have a cali standard truck). Also, something to think about, the LB7 engines have the largest injectors of the entire line...so if youre looking for most stock HP....

As far as EFI Live having trouble with them, every truck is different, and some have funky quirks. I have flashed one that would reject the bootloader every time unless the door was open...figure that one out. but the only ones i have had trouble with are the 4th gen ones, and that issue has been fixed.

Injectors arent as bad as people think they are. The price has come down dramatically since everyone seemed to think it would total the truck if the injectors went bad. You can buy an entire set of brand new (not remanufactured) Bosch injectors for $1700 give or take a hundred.

Only thing i wish i had with my LB7 is the 6 speed alison. I know there is a conversion for it, but then you lose access to the TCM for tuning purposes.

 

[mike_s]

Find out when the injectors were last done. With the experience I had, they were more prone to going out around the 100K mark. It's about a 5K dollar bill at the dealer to get them redone.

I really liked my LB7 and some days still wish I had it. Always got 17.5 with a light tune of extra 40 HP from a Diablo Predator programmer. IMHO, stay away from EFI live, especially in the LB7 motor. There is a glitch in the electronics where the EFI live will just completely shut the truck down. It didn't occur with all of them, but was VERY common.

Go over to the dieselpage.com and read all the threads you want about the LB7 motor and the issues it can have with EFI Live. Nothing wrong with EFI live, it's a great product, just a glitch with that particular model that will leave you stuck along the road.

Check the front end, if minimal maintenance was done, it could be slopped out. Great truck and great motor. The Allison transmission is one of the best tranny's out there, just be careful. The more HP you throw at it, the more pissed off it will get. Trust me, them programmers are fun but they make everything expensive in a fast hurry.

The more you up the power, the smaller your bank account gets.

The glitch i think youre reffering to was not with EFI Live, it was with GM. GM put outa TSB for a reflash for select '03 duramax engines (could have included more years, dont remember for sure) to resolve some suspected issue. Trouble is the calibration ID or the operating system they used for this reflash left the ECM corrupted. It was still fully functional as far as running the truck, but could not be reflashed, by anything, including the tech2 from what i understand. Simple fix by installing an ecm from an '04 truck.

I wouldnt shy away from EFI Live because of that, simply beacuse there is absolutely no other platform out there that gives more precise control over more functions of the ECM and TCM.

 

[jnj]

duramax

Had my 02 for 167k miles swapped injectors at 125k runs perfect did 2inch kit and run 285's sled deck with two summits... then in the summer tow 23foot grady loves it no problems go go go..

 

[WyoUltra]

Awesome, I'm glad to hear all the positive feedback and responses about the pickup!!!

 

[NDFARMER95]

Check balance rates on injectors. If/when replaced. Get EFI live!! S&B intake and some straight pipe. Your pickup will love you. Just start putting cash away into a tranny fund. If you need anymore help, go on duramaxforum. Them guys on there are smart and know their sh*t. Good luck to ya!

 

[AZ800]

In general, LB7 is a great truck. 01 was the head gasket problem trucks, not an epedemic by any means though, and injectors.
At 250k I'd be less worried about these issues, unless of course it hasnt had injectors in the last 100k. A pattern I'd seen with the LB7s were either they seemed to eat injectors regularly or they were very reliable. Look at the pattern for inj replacement on the truck.
With the miles youre looking at, I'd be more concerned with the truck in general. Trans maint/condition, front unit bearings, u joints, T case pump rub, etc.

 

[rulonjj]

The glitch i think youre reffering to was not with EFI Live, it was with GM. GM put outa TSB for a reflash for select '03 duramax engines (could have included more years, dont remember for sure) to resolve some suspected issue. Trouble is the calibration ID or the operating system they used for this reflash left the ECM corrupted. It was still fully functional as far as running the truck, but could not be reflashed, by anything, including the tech2 from what i understand. Simple fix by installing an ecm from an '04 truck.

I wouldnt shy away from EFI Live because of that, simply beacuse there is absolutely no other platform out there that gives more precise control over more functions of the ECM and TCM.

I couldn't agree more. By far the best tuning program for the duramax.

 

[DAKOTAKIDD]

I have a 03 Silverado LB7. I love the truck. About a year after I bought it 250000 Km's I lost the head gasket. I checked the injectors at the same time and 2 were toast. Changed both gaskets, 1 head, 8 injectors, lines, glow plugs and now its great.

I would suggest as mentioned about--balance rates on injectors and a pressure test on the cooling system.

You will enjoy the truck