Lb7 running on 4 cylinders. 78 mm3 The main flow rate was 6.

Lb7 running on 4 cylinders 78 mm3 The main flow rate was 6. For me, it was #2 (P0202/P2149). Could May 10, 2012 · Ideally you would first run a compression test on any cylinders with high positive balance rates. 38 mm3 Cylinder 5 0. All those trucks now have a 7 year/200,000 mile injector warranty and your truck might even still have the 5yr/100,000 engine warranty left. 2 I changed the injector with no change to the problem. T Oct 6, 2014 · Chevy / GMC Duramax 01-04. found out it was running on 4 cylinders. a few weeks ago wife went to start my truck and it started and just stalled. Great. Leak at the high pressure pump drive shaft seal. The green coated injector lines (LB7 injector lines)are more susceptible to leaks versus the polished steel colored lines. Would barely pull a slight incline with it to the floor, got pulled over in a safe spot and with it still running - I performed a wiggle/jiggle test on all the injector harnesses and usual contact areas. The duramax has it's leading cylinder on the right so the cylinders on the right bank are 1,3,5 and 7. I replaced the 25amp fuse and it started up but had no power. Mar 23, 2015 · cylinder 1- 400 cylinder 2- 400 cylinder 3 -400 cylinder 4- 400 cylinder 5 -400 cylinder 6- 400 cylinder 7- 390 cylinder 8- 375 Warm with engine temp at 161 degrees. 29 mm3 Cylinder 4 -0. 64 mm3 Cylinder 7 1. It is sometimes constant, sometimes cyclic between idling smooth and misfiring. DTC P2149. It feels like multiple misfires in a row, then a couple cylinders firing. 0 in Neutral or Park (-6. That was a little confusing, but P2149 proved to be the more problematic of the two codes. Airdog sent me out the new 4g pump and truck has been running fine. If a circuit condition is detected on a fuel injector circuit for cylinders 2, 3, 5, or 8, DTCs P0202, P0203, P0205, P0208 will set, along with DTC P1262. The engine might not be getting enough fuel to run smoothly. So today I plugged my tuner up and returned it to stock and read the codes. The width of the HOT RUN band represents approximately 1. Oct 24, 2024 · Story goes the glow plugs were replaced, and on the way home 2 hours into the drive developed a misfire on cylinder #4. The balance rates are relative to each other so if you have a clogged injector or a cylinder with low compression, it will be a high positive rate (ie engine is adding fuel to that cylinder) while the others will typically have negative rates (ie . Obvious injector knock on cold start. 02 mm3 Cylinder 8 1. When there is a short or open circuit on one injector it will kill four cylinders. The colder the temp the greater the fluctuation. 81 mm3 Cylinder 6 0. Nov 29, 2018 · The inaugural Duramax, RPO code LB7, would bring the first aluminum cylinder heads to the diesel pickup segment, introduce the same market to common-rail injection and also make its power in a much cleaner, quieter manner than the competition (i. Customer: 2003 2500 4x4 duramax 6. Balance rates for cylinder 1 fluctuating from +1,+10 when cold starting. on the dipstick. My bone stock LB7 3500 flatbed running on 7cyl has way more power. I have owned it since new, it currently has 94k miles on it, and has had an Edge juice installed on it since 7k miles. Truck white smokes now. Was your truck running on only 4? 2001-2004 (LB7) Duramax Second Generation: 2004. 1 Mar 16, 2011 · Cylinder Numbering LB7 It helps to remember a few things. Sep 19, 2012 · Duramax First Generation: 2001-2004 (LB7) running on 7 cylinders. 0 and +4. Example: You check balance rates because the engine is running rough. He said that the block, head and piston look like brand new. fuel delivery and pressure is good Nov 10, 2014 · The idea is to see the specified range on each cylinder and to see them with in a specified range of each other. 5-2005 (LLY) May 25, 2013 · If a circuit condition is detected on a fuel injector circuit for cylinders 1, 4, 6, or 7, DTCs P0201, P0204, P0206, P0207 will set, along with DTC P1261. Drivers side working passengers side is doing nothing 2005 completely stock 2001-2004 (LB7) Duramax Second Generation: 2004. Balances rates arent good, think its +15-16 on that cylinder. This means that even though those balance rate numbers are within the acceptable industry standards of +/-4 mm³, there is a variation of almost 100% in the actual flow rate Apr 28, 2009 · I have an 03 2500 LB7/allison. 11 mm3 Cylinder 2 3. 1995 K2500 SUBURBAN, LB7 DURAMAX/ALISON powered See full list on dieselpowerproducts. 51 mm3 The GM L3B engine is the all-new 2. I have switched the injectors around and bought a new one and they still stay the same. 1-2-7-8-4-5-6-3: Cylinder Numbers: Sep 4, 2022 · Running on 4 cylinders. but only on 4 cylinders. truck seemed to be runnning normal. If there is an issue with ONE injector it will shutdown 4 as others have said. 6L V8 with four-valves-per-cylinder. This means the engine isn't burning fuel properly in those cylinders, causing the rough running. 41 mm3 Cylinder 4 -2. Mar 6, 2015 · Almost tolerable it I load level 4 tune, but only with heavy input. Was pulling an empty equipment trailer about a week ago and got on it a bit passing a gravel truck. I was headed back into down and when I got off the highway I noticed it running rough like it has a misfire, but no codes. m0t0x66; Oct 27, 2015; 7 894 Dec 12, 2015 May 22, 2017 · This can save a lot of labor in the long run and customer down time. Now how is fuel rate measured? Well there is no little flow meter installed on each injector to measure the flow. 11 mm3 Cylinder 3 0. Could this be an injector seal Nov 5, 2007 · Duramax Second Generation: 2004. The LB7 Duramax was considered revolutionary at the time and utilized a turbocharger, intercooler, and direct-injection. GM Diesel Engines Apr 8, 2015 · Engine missing on four cylinders Jump to Latest Follow 4K views 6 replies 2 participants last post by whitedog Apr 13, 2015 Dec 5, 2018 · Need some help guys Yesterday my truck drove fine all morning. May 1, 2014 · Check all of your connections very closely, and also the wiring where it passes by the alternator. The oil pressure is normal, compression check said #7 had none. Nov 20, 2017 · That said, the enabling criteria for P2149 indicated that P2149 would not run in the presence of U1800. Drove it home and checked the balance rates and here's what I got. I check fuses and found one fuse for the edm blown. Doesn’t seem to have a lot of fuel in the oil (paper test pic). Jan 17, 2015 · My lb7 is pouring with smoke and I've got a misfire at 4 and 8 cyclinder I've done my balance rate tests and they are all at 7 besides 4 and 8, they are both 15. It is a simple system. New Fuel filter (Dealer tested for restriction in fuel system @ 2hg) Oct 10, 2017 · Started shaking and misfiring, chugging and sounding like shit. Jump to Latest Follow 1K Jun 22, 2021 · The resulting engine was a state-of-the-art 6. 0 liter) 4. I have zero blow by. Make sure they aren't rubbing on the bracket where it turns and goes by the alternator. 4, -2, etc. However, the 2003 and 2004 years are often touted by enthusiasts to be the best years for the reason that bugs from the earlier May 22, 2017 · This can save a lot of labor in the long run and customer down time. You see one cylinder has a +15 rate. Jul 15, 2015 · The only confusion in the system is that some engines, like the small block V8 gas engines, have the leading cylinder on the left side but others, like the 3. LB7: Jump to Latest Follow 21 - 37 of 37 Posts. Dec 16, 2019 · So, for example, if a truck is running at an 8 mm³ CFR, and there are cylinders at +3. I plugged in my cheap code reader when i got home. The FICM separates the high-voltage injector circuits into two groups: cylinders #2, #3, #5 and #8 and cylinders #1, #4, #6 and #7. 5 LB7 Forums. P1261, which just means a circuit problem with injectors 1,4,6, and 7. I tested first bump on 6 and it first bumped to 225, then retested 8 with a first bump of 200. Have changed those 4 injectors, inspected wiring harness and all plug connectors. Still had the cross marks in the cylinders and was clean as new. . :-(I have Torque Pro for logging, but it has its limits. Oct 23, 2011 · Forums. This engine was designed specifically for use in full-size pickup trucks, and by the way, it is the first 4-cylinder ever used for GM's full-size pickups. If the connections show OK after test, possible the FICM is bad. Install the hoses in the graduated cylinders in numerical order. felt like it was only running on 4-5 cylinders, no smoke, no check engine light. He is taking the head to his friends machine shop and checking the head out. 9L Cummins). Feb 2, 2014 · The truck shuts down 1 4 6 7 or 2 3 5 8 and runs on 4 cylinders. Jan 7, 2013 · Crank the engine in 15 second intervals, with one minute cooling time between, until fuel starts to flow into one or more of the graduated cylinders. A bad injector harness or shorted injector could also give some trouble. , it means that those cylinders are 8 + 3. All told, there are six different iterations of the Duramax: LB7, LLY, LBZ, LMM, LML, and L5P spanning from 2001 to the present day. All others stay below +4. Oct 22, 2007 · I am assuming you have a 2004 or older with the LB7 Engine. Oct 28, 2012 · Driving home from dinner friday night my check engine light came on. Oct 17, 2016 · got a problem with my lb7 not starting. 0 to +6. Feb 1, 2014 · 2023 GMC Denali 3500 DRW, Pearl White, Banks I dash and Deringer, 255/80R17 Toyo R/T Trail on spare set of aluminum wheels for winter. 2018 Solitude 310GK fifth wheel with a 12' Haulmark tag trailer to haul toys in. Thursday on my way to work truck started acting like it was running on 4 cylinders then died. the 7. Diagnosing a failed fuel injector which is taking down the injector drive circuit. The LB7 put out a segment-best 300 hp and 520 lb-ft of torque. The FICM has 2 driver sets, they are the front and rear cylinder on one bank and the middle two from the other bank. Check the fluid level reading. DTech DT660033 Injector Line for LB7 Duramax (Cylinders 4 & 5) – Reliable, Brand-New Replacement. LB7: Jump to Latest 3. You can search for "ice pick" to get an idea of the problem, and one solution. 5-2005 Mar 5, 2010 · I am posting this for Dean (wdino73) The truck started misfireing and got the misfire code on #7. May 20, 2012 · I went and got some lucas injector cleaner and didnt have any luck with it. Balance rates for cylinder 1 while the engine is at operational temp is +1. Sep 30, 2010 · In most cases i have found a poor connection between the injector harness and the engine harness. It has a valve train problem. Your truck is missing, and only running on the other 4 cylinders. Nov 7, 2016 · Help lb7 only running on drivers side cylinders! Alright guys the 02 truck in my sig is having a major issue right now. 8K It is running like it is missing on one cylinder, like a gas bunner would if you May 19, 2023 · Although all years of the LB7 potentially had a few issues, including problems with the head gasket, the LB7 Duramax injectors, and the fuel filter housing o-rings, the LB7 is generally considered a reliable engine. 4), 8 - 2 (6), and so on. 3L Power Stroke and the 24-valve 5. Check the wires coming out of the FICM. Richb1422; Dec 16, 2015; 3 10K Dec 18, 2015 Need some help getting my lb7 running. Customer: 2002 duramax lb7, replaced all injectors and getting misfire on cyl 5 with code p1235. checked all harness and wires. 01-04. LB7 running on 4 cylinders and codes. 5-2005 (LLY) 6 Aug 27, 2017 · If your just getting P1261 by it's self Google "Duramax LB7 P1261" lots to read. Feb 5, 2012 · The 4 injectors you are having problems with are all powered together on the same circuit, and any problem in that circuit and the FICM shuts down those 4 injectors. Truck idles rough with a lot of blow by into the crank case. Dec 16, 2015 · When the system sees a problem with the injectors, it can shut down all cylinders in that bank and set P2149 [for this group] or P2146. Mar 3, 2011 · Chevy / GMC Duramax 01-04. P1235: This code indicates low fuel pressure at the high-pressure pump. 0 compression on cylinder 4, the rest are good around 250. Elevate the 4 hoses to retain the fuel in the hoses, and empty the 4 graduated cylinders into a suitable container. Maintain peak performance in your 2001-2004 LB7 Duramax with the DTech DT660033 Injector Line, a high-quality, brand-new replacement for GM OE part# 97188722. Mar 11, 2011 · Duramax First Generation: 2001-2004 (LB7) Running rough. 7-liter four-cylinder turbocharged gasoline engine that debuted in the 2019 Chevrolet Silverado 1500 and 2019 GMC Sierra 1500. Page 43: Engine Coolant Jan 22, 2025 · Whether you currently own a Duramax powered Silverado or Sierra, or you have considered purchasing a used GM diesel pickup, the question will cross your mind regarding what problems you may experience with the engine. 1) The cylinders/pistons are numbered from "1" at the front of the engine to "8" at the back in the order that the piston rods connect to the crankshaft. Though two seperate things, you often see balance rates associated with compression. Dec 18, 2015 · Cylinder 1 -1. Recently, I noticed the engine seemed to be running rough when coasting to a stop in traffic, almost like it is running on 7 cylinders, once stopped, it idles smoothly, until I take my foot off of the brake and idle forward, then it runs rough again. It read #2,4, and 7 cylinder misfire codes. Balance rate at 11 for cylinder 4. You can also use a dye in the fuel and black light kit to try to pinpoint leaks at the injectors on an LB7. The code was for a cylinder 2 or cylinder 3 misfire. e. m0t0x66; Oct 27, 2015; 7 898 Dec 12, 2015 Apr 6, 2017 · Duramax First Generation: 2001-2004 (LB7) LB7 running horrible LB7 running horrible. 06 quart (1. Likewise if the balance rate for cylinder 2 is +3 then the fuel rate for cylinder 2 is 9+3= 12 mm3/sec. When I removed the glow plugs from the cylinder heads, coolant was present in cylinders 5 and 7 (passenger side rear two cylinders). Replaced the ficm a few months back, the my air dog2 165 went out. Oct 18, 2012 · With the engine running there are not any air bubbles flowing with the water. However, the 2003 and 2004 years are often touted by enthusiasts to be the best years for the reason that bugs from the earlier LB7 running on 4 cylinders and codes. I dont remember and I cleared it. Turbo & Fuel System. I checked the wires running across the altenator and theyre all good and no wire showing or rubbing. A fixed geometry turbo supplied by IHI was installed on the LB7, marking the only fixed geometry unit ever used on a Duramax. 0 in Drive when the brake is fully applied). Designed to fit cylinders 4 and 5, this injector line ensures optimal fuel delivery and Apr 28, 2016 · Then the fuel rate for cylinder 1 is 9-2=7 mm3/sec. The LB7 would run its course into the 2004 model year when a redesigned Duramax diesel, the LLY, began replacing it mid-model year. P1238: This code points to an injection pressure system issue. cylinders 1-7 ranged from 430-450 and number 8 measured at 400. Cylinder 5 reads like a normal injector. 2) Cylinders 2, 4, 6 & 8 are NOT, I repeat, NOT directly opposite cylinders 1, 3, 5 and 7. Safe operating level is within the HOT RUN band procedure to verify the reading. Jump to Latest lb7 runs on 4 cylinders when cold. Oct 8, 2004 · The normal values that should be seen on the balancing rate parameters will range between -4. Suspect a possible problem when the balancing rate of a particular cylinder starts to increase out of the normal operating range. So if 1 goes, they shut down 4. Misfiring on cylinders 2-4-6-8. 3 mm3 so the corrected values are: Cylinder 1 -0. I noticed a faint odor of like something electrical or electronics burning. com May 22, 2016 · I have been having some issues with my 2003 lb7. . 8L V6 have the leading cylinder on the right. Disabling any cylinder's injector results in a change in engine sound and speed. When I pressure tested the cooling system, there is a leak somewhere because the 20 psi that applied leaked down to zero in 45 minutes. On the left they are 2,4,6 and 8. 8K views 5 replies 4 participants last post by Hotdogstand Mar 3, 2011. 68 mm3 Cylinder 5 2. Dec 19, 2009 · Low and behold he found two small spots in the head gasket on #4 and #8 cylinders where it had a minute break in those 2 cylinders. Later that evening on 2-5-15 I wrote: Well it looks as though I will be looking at the inside of my engine sooner than later. P0302, P0304, P0307. Jan 15, 2020 · It seems that GM wanted to get your attention if there was a problem with one cylinder. #1: 0 #2: -2 #3: 1 #4: 3 #5: 4 #6: 3 #7: -3 #8: -4 Apr 23, 2015 · I do know that it is idling off 4 cylinders. Runs fine for first 2 mins after cranking, then misfires complete driver side bank. I mean, it would probably still run pretty darn good on 7 cylinders. 5 LB7 Duramax Powertrain lb7 runs on 4 cylinders when cold. When you get a P0202, P0203, P0205, and P0208 you also get a P2149 which shuts down 4 cylinders and throws the MIL. Repeat the check 4. 6l. 81 mm3 Cylinder 2 1. Ive owned the truck for about 4 months and have put about 6,000 miles on it. 4 (11. Can't afford EFI Live yet. Jun 23, 2000 · Engine has a very bad vibration / rattle at idle which is fuel injection related and does not feel mechanical. Aluminum heads housed a 4 valve per cylinder design, while 6 torque to yield bolts per cylinder provide optimal pressure to ensure proper combustion sealing. 41 mm3 Cylinder 3 -1. I will let y'all know what I find. vpknc zhlqqt syttucv lba loebfx omke aqg ydkzym oby umrwh