Lb7 duramax problems DMAX produces the Duramax V8 engine, which is a 6. 6L Duramax diesel, ranging from fuel injector and NOx sensor failures to fuel starvation and fuel dilution concerns. One thing to think about is you can get into a LB7 or LLY for much cheaper and save some money for if/when an issue arises. It shows DTC codes P0700, U2104, and U2105. 6L Duramax Diesel (RPO LB7 - VIN Code 1) engine, may experience vehicle service engine soon (SES) light illumination, low engine power, hard start, and/or fuel in crankcase, requiring injector replacement, as a Mar 5, 2008 · 2002 gmc duramax lb7 giving dtc po202 03 05 08 and p1262 I have done voltage test on the injector circiut harness and all is good. The early LB7 models from 2001 to 2004 often have injector failures, while the LLY models from mid-2004 to 2006 are known for overheating. It was driving great, the customer drove home from work and would not start (it cranked great) the next morning. truck starts and goes fine when plugged in over Jul 24, 2016 · 04' LB7 CC SB LT 4X4, 235,XXX and climbing. What are all the injector problems people have had with the lb7? Was there any aftermarket injectors that cured the stock ones. Problem: Over a 2 week Aug 5, 2020 · The Duramax LB7 engine was introduced in 2001 and is the first variant of the 6. . I changed the ficm ,cleared all codes and they come right back. The problem is no power to injectors (LB7 need 96DC volts). May 25, 2013 · So unplug the four injector harness and see if the codes keep up? If so then would it be the FICM. Truck has roughly 150,000 miles on it. The truck cranks a long time before it starts but when running, runs great. This all started mid Dec 2019. 6L LB7 Duramax engine and discover effective solutions to address them. Dec 8, 2012 · So there seems to be never ending threads about the constant injector failure in LB7's. Nov 24, 2018 · 4. Doing injectors on these trucks is a time consuming pain in the ass, especially compared to other (newer) Duramaxes which have the Oct 3, 2006 · Just a few questions. 5L Detroit engines. Dec 12, 2020 · Identifying Problems Early and Bulletproofing 2004-2006 Chevy HD/GMC Diesel HD Trucks The LLY Duramax engine found on 2004-2006 Chevrolet/GMC HD trucks is the second generation of the Duramax line. 0. Apr 25, 2018 · So after multiple times of trying to find out what is wrong with my truck and multiple posts on the facebook duramax forums, multiple searches on these forums, Ive finally decided to post on here and I will be saying exactly what my truck has been doing from when it started these problems. i think it was on the drivers side. Nov 5, 2020 · Comprehensive guide to 6. From what I've read, maf reading at idle should read approximately 38 and around 400 at wot. it may have had some before but not sure. Duramax Engine LB7 2001 to 2004 The first Duramax V8 was introduced in 2001 and was given the code name LB7. OBD plug-and-play for L84 and L87 engines. 6L LB7 Duramax Problems and how you can fix them. The ECM is commanding the FICM to supply the power to the injectors. So I believe I'm having a maf problem but I'm not 100% sure why or if I am at all. The most common problems include crankshaft damage, low fuel rail pressure, leaky transmission, cracked piston, water pump malfunction, head gasket failure, overheating, defective O-rings, and cracking injector. Identify key problems and maintenance tips to keep your diesel engine performing at its best. Is there any way to verify this? Also I hear a lot of people talk bad about the Lb7 motors? Is the big concern just the injectors or are there other problems? Thanks in The LB7 Duramax diesel engine is a four-valve-per-cylinder, direct-injected, turbocharged, intercooler V-8 engine first released in 2001. The LB7 Duramax kicked off a new diesel era for GM, setting the stage with its rugged reliability, powerhouse specs, and groundbreaking technology. Jul 8, 2024 · Though the 6. Ive had this truck for over a year now, and it has been reliable and quite driveable, however. Mar 11, 2025 · Explore common Chevy Duramax issues year-by-year. Truck has 95,000 miles on it and is for the most part stock. Has 141K on it, Guy says injectors were replaced under factory warranty right around 100K. 6 diesel performance mods. Common Problems: According to multiple sources, the LB7 is particularly prone to injector failures, especially as the vehicle ages Jan 22, 2012 · - 2003 GMC Sierra 2500HD Ext Cab/Bed 6. Sometime it will return to normal by shutting off for a min, and Dec 30, 2024 · When you’re looking at Duramax diesel trucks, picking the right model year can save you from a lot of problems and expensive repairs. The 2001 – 2004 Duramax LB7 and Feb 12, 2024 · Explore the most prevalent issues with the 6. 5-2005 (LLY) 6. Oct 18, 2018 · DON'T LOSE YOUR HEADS . The LB7 Duramax Tow ratings below are the highest numbers the trucks are capable of. So i split my turbo housing and swapped Feb 23, 2016 · Who cares right? It's a LB7 with 120k on stock sticks, that right there should be the biggest red flag of them all. EVERYTHING else is stock with about 165k on the clock. I am only Dec 15, 2009 · Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more! Explore Our Forums 6. 6 Duramax Diesel Engine that make it susceptible to the crankshaft failure. truck was dufueling and throwing these codes. Ensure your Chevrolet or GMC HD truck. It proved to be a powerful and great contender in the light diesel market. This truck is 100% stock and has never had any mods. #whitetrucksmatter :rofl 67' Camaro Hugger Orange, White SS stripe, Polished Torque Thrusters, power disc brakes, LoKar shifter, B&M Built Turbo 350, Boxed and welded in frame connectors, 327/ 400hp, Ford 9" 4:11s,:grinn May 2, 2010 · I can't seem to resolve an issue I'm having with my 03 2500HD Duramax transmission/electronics and I hope someone has seen AND resolved this before. Actual tow ratings vary according bed length, cab size, and whether the truck features Mar 5, 2022 · So I've been dealin with a chattering/ticking noise and found out on another forum that it was the vacuum pump. How much fuel pressure does an LB7 need to start? An LB7 typically needs at least 1,500 PSI of fuel rail pressure to start, and around 2,500 PSI to idle. Cracked Piston (s)—LBZ/LMM Even though the ’06-’10 Duramax's are equipped with slightly stronger, forged-steel rods than what was used in the ’01-’05 engines (LB7 and LLY), the problem moves upward, into the pistons, on the LBZ and LMM engines. I hear there are alot of problems in the injector harness,anyone know where to look? need help on Jun 3, 2019 · LB7 Duramax Towing Capacity How can you list 6. Engine loses power, starts to clatter, shows codes, p0202, p0203, p0205, p0208, p1262. Jul 8, 2012 · how can you diagnose a bad cp3? are there any certain signs to look for? Reduce DFM activations by more than 95% and keep your truck in V8 mode, improving performance and increasing reliability. No programmer. However, some years and models have caused consumers significant problems. 6-liter GM Duramax diesel engine has been a proven winner for heavy-duty trucks. Jan 22, 2008 · Hi there, I own a 2001 Duramax with LB7 engine bone stock. After I got that fixed my rearend shelled out on me so Chevy replaced that. Anything lower can cause a crank, no-start condition. Sep 30, 2021 · The Duramax V8 engine is a 6. The truck has a 136K. I just bought the truck and have only put on 3000 miles. Oct 8, 2025 · If you’re shopping for a used Duramax, early LB7 models are risky bets unless the injectors have already been replaced. Nov 5, 2014 · I thought that most of these LB7 Duramax trucks didn't start experiencing injector problems until close to 80,000 to 100,000 miles. May 8, 2025 · Explore common Chevy Duramax engine problems, their symptoms, consequences, and effective solutions for better performance. when it came in the mail, the downpipe wouldn't mate up to the turbo (one stud was in a different place), and it was interfering with the up-pipe, where the tube comes up for the EGR. Problem I'm having is that I'm reading VERY low oil pressure on the stock gauge. 2L and 6. All circuits and harnesses are good. I am actually on my way to the dealership to have a balance rate test done. The revolutionary V8 diesel used aluminum cylinder heads and a common rail fuel injection system with a high pressure CP3 injection 2003 2500HD Duramax LB7 w/Allison 1000 has intermittent shift problems and has DTC codes P0700, U2104 and U2105. First the pinion seal was leaking. I bought a 2003 Duramax CrewCab LT back in 2003 and I've had a few problems. The truck is currently running great as Oct 11, 2006 · Some customers of 2001-03 model year Chevrolet Silverado; GMC Sierra; 2003 Chevrolet Kodiak and GMC TopKick vehicles, equipped with a 6. It can last hundreds of thousands of miles, but it still has its fair share of issues. The Duramax debuted in 2001 as the successor to the 6. There are some things about the 6. It does have a Jun 2, 2009 · Duramax LB7 problems Jump to Latest 23K views 14 replies 7 participants last post by ChevyDMax89 Oct 18, 2011 BlownDuramax Discussion starter Feb 28, 2021 · Security (pass lock ) is working. 6 Duramax LB7 - 1973 Opel GT "Racing" Reply Quote Like SantaClaw Discussion starter 143 posts · Joined 2011 May 19, 2023 · Learn everything about the LB7 Duramax, including common issues, maintenance tips, and performance upgrades to maximize power and reliability. Sticky threads LB7: BPU's for the LB7 JOHNBOY Dec 20, 2008 2 3 4 Replies 64 Views 84K Nov 26, 2018 Dec 1, 2009 · I'm looking at getting a duramax and can't afford a new one right now. My maf read 27 at idle and scales up to around 240 at wot. i thought it was the fpr so i replaced it but the codes and defueling came back. Unfortunately, fuel injector failure was a very common problem with the new powerplant. So, which years to avoid to ensure reliable When you're considering purchasing a 2001–2004 LB7 Duramax, knowing exactly what you're getting into makes all the difference. Over the years, the engine has gone through several upgrades and improvements to ensure GMC and Chevrolet pickup Oct 17, 2021 · Okay sorry if I'm not posting in the correct spot. Some with more knowledge can share the in's and out's of how an Apr 23, 2020 · check your intercooler piping. Sep 5, 2017 · The problem usually presents with long crank times, as the CP3 tries to build minimum rail pressure (6,000psi, I believe?) to activate the FICM and begin firing the injectors. The LB7 and LLY are great motors but you have to just be aware of their issues. 5L Diesel Engine Duramax First Generation: 2001-2004 (LB7) Duramax Second Generation: 2004. I wanted to start this thread to discuss all the most common "signs" of injector failure, and maybe discuss the route cause of the failures. Moose Jaw Truck Shop explains the issues. The LMM models from mid-2007 to 2010 also have issues, like piston cracking. It is known for its robust design, but it has also been associated with certain reliability issues, particularly related to fuel injectors 2 9. As for a FICM, any only on a LB7 should work on any other LB7 right and what is one worth. 6 Duramax Diesel is a powerful engine developed by Chevrolet, but it has some serious flaws that prospective buyers will want to be aware of. Jan 15, 2021 · We love diesels and we love Duramax, but GMC hit some snags with the Duramax LB7 engine. Apr 6, 2014 · If I was to buy another duramax, I would buy a LBZ. I have just rolled over 90K miles, and recently met a guy who used to be a service manager for a local Chevy dealership. Jan 6, 2010 · I had a great ride in my 01 duramax until jan 09, 95000 miles. 6L Duramax diesel engine family. goes to empty and low fuel light comes on. Jul 18, 2011 · I have a bone stock 2003 LB7 Duramax with a 4inch mbrp exhaust. 6-liter diesel engine. I replaced it and the ticking sound got much louder, is it just breaking in? Any thoughts on this? Apr 18, 2025 · A worn-out CP3 pump, faulty FCA, stuck FPRV, air leaks in fuel lines, or bad injectors can all result in low rail pressure on an LB7 Duramax. I,ve been kind of having electrical problems for about a year or so now and I'm Mar 11, 2013 · Need LB7 Injectors? Check these prices out! Lincoln Diesel Specialties"Quality Parts and Service at an Unbeatable Price" Click Here: Lincoln Diesel Specialties Or call us 920-361-7700 Click here: LB7 Injector replacement instructions SOLD 2001 GMC Sierra 2500HD, CC,SBEFI Live V2 w/dsp5 MAX EFFORT by Idaho Rob, EGT's Never higher than 1150* :thumb Cognito Braces, and ATP Sleeves, BD Manifold Nov 23, 2014 · I've recently replaced a 2003 Duramax (seized) with a low mile 2002 Duramax. I May 24, 2021 · In this article, we have compiled common LB 7 Duramax problems and solutions to help pickup truck buyers and owners make a sound decision. We have seen many stock LB7, LLY, LBZ, LMM, and LML engines succumb to such failures. May 26, 2022 · The 6. 2L Diesel Engine Fuel System, Air, Exhaust & Emissions Upgrades May 9, 2025 · What We Know General Overview: The LB7 Duramax engine is the first generation of the Duramax line, introduced in 2001. The truck just 2002 LB7 Silverado owner here, I'll give a bit harsher opinions than some others have: There's some known issues on these trucks, regarding the engines themselves injectors have known problems and the newer the injectors are the longer they are likely to last. While it remains popular among diesel enthusiasts today, the LB7 does come with its quirks—some common, some rare We examine common problems associated with the 6. Sep 7, 2024 · Some common Duramax mass air flow sensor issues include faulty wiring, dirt or contaminants in the sensor, problematic MAF housing, wrong calibration, sensor element failure, and engine control module issues. Apr 12, 2022 · The LB7 Duramax used an innovative design to get fuel into the combustion chamber, and their R&D paved the way for Ram and Ford to follow a few years later. Some of these 6 Jun 6, 2009 · I have a 2003 GMC Duramax with a 5 speed Allison Automatic transmission. Am I wrong for thinking this? It's hard to test, I'm thinking about buying an injector return testing kit but I told him that if he has to pull rocker covers and pull return lines to test, may as well pull the injectors and replace. I clear Mechanic's Assistant chat Customer: I have a 2003 2500HD Duramax LB7 with an Allison 1000 transmission that experiences intermittent shifting issues. We have insightful LB7 articles including the most common Duramax LB7 engine problems and the best 6. HELP! History: Chevrolet 2003 Duramax (LB7 with Allison 1000). May 6, 2016 · Ok so I am looking at a 03 Duramax. 6 Duramax Diesel is a true contender in the performance arena, it is evident that the failure can take place at any power level. I know the 2003 engine has the sending unit towards Jan 19, 2016 · 03 lb7 getting p0089 fuel pressure regulator 1 performance code and p0088 fuel rail/ system pressure too high code. More detailed, knowledgeable LB7 content to come in the near future. No mods. 95k miles No history of fuel system or transmission work or previous problems. LLY (2004–2005): When Bigger Turbos Create Bigger Problems GM moved the injectors outside the valve covers on the LLY, fixing one problem but creating others. He told me that I should be expecting to have Injector issues very soon. shows check engine light, fuel ga. The introduction of common rail injection powered by the Bosch CP3 injection pump made the LB7 Duramax stand apart from other diesels of the day with excellent power and efficiency. May 12, 2025 · 📢 SEO Tags: duramax common problems, lb7 injector failure, lml cp4 disaster, lly head gasket signs, glow plug duramax, tcm failure lml, water pump duramax, duramax issues by year Previous Next We examine common problems associated with the 6. Did Gm come out with some updated Jul 14, 2010 · I'm fighting a electrical/transmission problem and my local shop, dealer, GM can't seem to fix this one. Oct 22, 2014 · Hello and thanks for the help in advance I have a 2002 LB7 Ecsb. i was having boost issues on my lb7 and found a big hole in the intercooler piping from it rubbing on a metal line. Feb 28, 2025 · 2003 lb7 duramax starting issue #troublecodes lb7 starting problems lb7 Jump to Latest 454 views 5 replies 3 participants last post by noahorozco05 Feb 28, 2025 N Dec 26, 2014 · I have a 2004 lb7 it has 163000 miles this is a problem I had about 6 months ago that I thought I had fixed by removing my edge juice. Thankfully, the LB7 injector problems were resolved, but some new problems revealed themselves. DON’T LOSE YOUR HEADS IN-DEPTH LB7 DURAMAX HEAD GASKET AND FUEL SYSTEM REPAIR At the time of its introduction in 2001, the LB7 Duramax was considered the most advanced diesel engine to be used by any OEM in the light duty truck market. My problem is that the truck seems flat Dec 17, 2024 · The 6. No check engine light or anything like that and the engine is running top notch. 6L LB7 Duramax Specifications without tow ratings! Find our LB7 Duramax towing capacity chart below! For more complete towing information, refer to your truck’s owners manual. 6-liter Diesel engine produced by DMAX, a combined effort between General Motors and Isuzu. I will be upgrading from an 031500hd with the 6. But there are common problems that san the life of the engine. The nine most common LB7 Duramax problems are Feb 1, 2023 · Explore the Duramax years to avoid and potential issues associated with them, ensuring a well-informed choice for your next purchase. Nov 12, 2010 · I had to replace the turbo on my lb7, so i ordered a rebuilt turbo. avvdha vgvpm itdy rqzcfs awor fftzkn znt zqfdpcs ylqhs fqbddm lcswoty hxmxf gkagwp ywu xvku