Lb7 duramax not starting. HVAC B3770 airflow control 6 feedback circuit. 2001 dmax wont start. #1 · Jan 17, 2014. Always starts right about 1400PSI if it can hit it. I know how to diagnose GM LS1 and LT1 engines very well, but I know next to nothing about diagnosing my Duramax. 0, -1. 0, -0. Oct 10, 2012 · Your rail pressure being 22-23k at startup would be a possible bad FPR. Parked it at home and waited 15 minutes. Everything works on the dash, etc. When I started the truck back up it ran great and sounded Nov 18, 2023 · 01-04. 9, -2. Problem with the ECM, injectors, injector pump, bad fuel, or sucking air into the fuel system. Mileage: 96,000. Mar 8, 2015 · The truck needs 1600psi or more to fire, and should idle in the 4400psi range. Fuel filter and batteries. I've been losing prime below a quarter of a tank. #8 · Nov 6, 2010. with air dog lift pump, race valve, egr delete, and efi reprogram, thanks to husker diesel. The problem continues to happen, but only below a quarter of a tank. sometimes dropping as low as 5k when is was expecting 10k. Play Truck - 2002 LB7 2500HD Crew Cab Short Bed. #9 · Feb 13, 2009. I have checked for boost leaks, checked intake system Sep 13, 2015 · Sep 13, 2015. Click Here: Lincoln Diesel Specialties . HELP. I am working on a buddies LB7 that has a low power problem. 7, 1. Then crank. i went to take a drive after it sat for about 20 minutes and it started then died as i went down my drive way and would not start back. Mar 5, 2023 · Between the fuel tank and the cp3. It takes at least 1 min of cranking to start. After I did my LB7 injectors, I bent a few of the pins in one of the large bale wiring connectors, causing a no-start condition. I joined because I need major help before I go crazy. Sort by Oldest first Nov 19, 2011 · Lincoln Diesel Specialties. It’s a 6. what Apr 1, 2023 · Go from the start lug on the solenoid back to the starter relay and check that wire for continuity with your meter. Might could check rail pressure vs desired of you have an edge or scan tool. (high pressure fuel pump) in the valley of your engine, near the front of the valley. com. That can definitely make a hard starter. Now it still wont start unless i use strating fluid and it will not idle. Look and see if the padlock light on the dash comes on while you are driving too. I went out to start it and it will not start. EFI Live tuning by Duramaxtuner. 17 posts · Joined 2010. if the battery terminals and grounds are good, have someone hold the key in the start postition and hit the starter with a hammer, if it starts when you do that then the starter needs to be replaced, make sure to not hold the key in the start position for more then 5 or 6 seconds at a time. May 21, 2012 · m0t0x66. Any of these will cause the problem you are describing. 284 posts · Joined 2007. The truck was running several months ago, sat for a while, and now it will not fire up. I can get it to run if i reprime the system and the low fuel light does Aug 5, 2020 · Water Pump Failure. Chevy 04. The truck has not started since. 5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors Dec 7, 2012 · Seal the opening around the nozzle at the fuel fill tube. #3 · Apr 4, 2013. Was it plugged in when you were having trouble starting it and used the starting fluid? Once its plugged in, it will still take a while to heat it up- probably more than 30min, maybe an hour. The dealership, Scoggin Dickey in Lubbock TX just replaced my injectors and injector pump, on the LB7 that has 232,000 miles on it due to the dreaded while cloud in exhaust at idle. #7 · Feb 9, 2021. Started right up cold, would not start hot. Four injectors 1,8,6, & 7 were bad, and upon inspection, the rail showed possible metal contamination possibly from the CP3, so it was replaced as Nov 11, 2010 · LB7 hard start problem. No codes. 2002 GMC 2500HD 4x4 LB7 ZF6 CC LB LB7. “Low Voltage to Fuel Injection Control Module” it will not clear. May 22, 2012 · mckenziemt Discussion starter. 41. It will lope hard if it starts, But it's an idea. we had one in a couple weeks ago with the same symptoms. This Duramax was towed in for a cranks no start condition. John Deere Service Manager. if it runs okay after you start it with ether I would guess the CP3 is okay. At first it had no codes, but when I was just messing with it it gave me the following codes. Apr 3, 2018 · 3) Check rail pressure when engine is off, it should 1. Id bottle test and see if you have a ton of fuel returning to the tank. Pick up another fuel cap for cheap at your local parts store as a replacement. I am a new member; I own a 2002 GMC 3500. 1 to 1. If it does start right up, its loosing prime. It's not the FICM, so save your money. Did some research and i desided the cp3 pump was bad so i replaced it with a new one. 2, it would still start okay but during the start up terminal voltage was down to 6 volts or less as Aug 12, 2012 · Tried to start the truck. if you do not plug it in. Aug 8, 2016 · Aug 9, 2016. Pain in the butt when it happens. went back out latter and it wouldn't start again. Died 11/15/2019. Apr 4, 2013 · 4911 posts · Joined 2012. If that's good then you need to check for 12volts at the output of the relay when the key is in the start position. Feb 4, 2017 · As you noted, the Duramax does not have a lift pump like other diesels. You need to find out if that Pink wire (1093) is shorted to Ground. :gearjamin2003 GMC Sierra 2500HD Duramax/Allison Banks six gun 4" exhaust CAI Airdog 2 165 otherwise stock. I recently purchased a 2002 Chev 2500HD w/LB7 & 5 spd allison, knowing full well that it only cranked but did not start. I have put in a brand new GM glow plug controller, brand new GM glow plugs, new GM glow plug "tie bars" (don't know what else to call em) and verified that each glow plug does receive power when the "wait to start" light May 19, 2009 · Fortunately this issue does not happen with all Duramax's. Make sure your batteries are fully charged before starting this. 6 duramax (LB7) all stock (no mods Jul 3, 2011 · Truck: 2003 Silverado Duramax LB7 – Stock. Jan 23, 2018 · LB7 shut off not start u1800. turn it off and back to on again, til it goes out again, and repeat once more, then start it. 305/75/16 DURANGO M/T'S ON EAGLE ALLOYS. Jan 21, 2011 · At any rate take the bleeder screw out, make sure it is not cracked, and that the o-ring on it is good. Some people have had problems with the fuel filters with a plastic housing. No Codes related to the issue. After security light off, turn the key to “OFF: Wait 5 seconds. I disconnected the hose leaving the fuel filter and connected to a vacuum to test for a restriction that may occur from fuel tank>fuel line>through FICM>into fuel filter>out of fuel filter. Jan 18, 2016 · HELP | Chevy and GMC Duramax Diesel Forum. Dec 18, 2016 · I think with that setup you should be able to turn the key to "run" (engine not running) and crack the bleeder screw on top of your fuel filter. Here are the balance rates: 2. Truck will not start. 2003 2500hd ccsb 4x4. #2 · Oct 5, 2018. changed the fuel filter and bled the air out of the fuel system still wont start. Click here: LB7 Injector replacement instructions . Crank the engine--- any fuel coming out of the fuel rail nipple -- the FPRV is leaking fuel-- IT WILL NEVER START. 2006 gmc 3500 xcab lb, with the LBZ. PERFORMANCE: Edge Insight , AEM Bruteforce dry flow air intake. If that doesn't happen you need to trouble-shoot the Air Dog. hooked the scanner back up Aug 23, 2011 · The last two weeks it has become very hard to start. 6 Duramax LB7 - 1973 Opel GT "Racing" Save Share. I drove it back to my house because I was a couple blocks away. Drove about 15-20 miles on Sunday, drove to work Apr 1, 2021 · I have a 2003 lb7 with fass lift pump and it would crank but not start. 5 LB7 Duramax Powertrain LB7 No Start. New CKP sensor. Saturday I was out in the heavy snow here in Maryland driving all day in 4 HI. So I replaced the ficm after reading Thats a common problem, my truck started for about 10 seconds and quickly died to not be started again. I just bought a 2001 gmc sierra with the 6. When Mar 4, 2014 · Mar 3, 2014. Gave it a shot of ether and it started just fine. Logging with efi it does not build more than 1 psi of boost total. 5 LB7 Duramax Powertrain Wont start. New CP3 at 240,000. It was seeing 60 at about 2000 rpm and when I Let it go back to idle Jan 15, 2011 · If no, probably glow plug controller issue, if yes, remove bus bar connecting all glow plugs and test them one at a time. #4 · May 21, 2012. Nov 16, 2012 · 8350 posts · Joined 2010. 1 at idle in park The Injector Pulse Widths are all right at . TCM will not communicate. I’ve replaced crankshaft position sensor. 2003 2500HD 6. . Feb 9, 2021 · 5149 posts · Joined 2009. Dec 3, 2013 · 01-04. Oct 14, 2012 · It does have good fuel pressure to the check valve on the front of the motor with no air. Oct 4, 2018 · 687 posts · Joined 2016. #9 · Nov 19, 2012. The LB7 doesn't have a fuel pump unless it was added by previous owner. I'd like a system with the following qualities: Feb 27, 2019 · Crank, no start. 2003 Chevy 2500HD Extra Cab 4X4. So if you open the fuel filter, and no fuel came out, you may have a cracked pick-up tube, or collapsed fuel line or the primer Jun 6, 2009 · If your problem happened suddenly then it's likely not injectors returning too much fuel. 5, 1. With a diesel there are only a few things that will make it not start. This all started mid Dec 2019. Future plans. Connect one end of test light to battery +, touch point of test light to center terminal on glow plug, if it lights, it's ok, if not replace. New injectors at 208,000. #14 · Feb 9, 2010. Feb 13, 2009 · jon5212. the IGNITION in "OFF". 63 posts · Joined 2011. Preliminary check on the wiring and fuses revealed nothing, but I don't have power on pin 118 Injector supply voltage at the FICM. Pull the "U" hose from the fuel rail-- plug the hose. Dec 4, 2016 · I have not checked voltage drop at the starter yet, great thought I will give that a shot, it honestly depends on the day some times it's intermittent and sometimes it's a constant issue. It just cranks and cranks. Some trucks have a hard time drawing fuel when the fuel level is below 1/4 tank. Crawl underneath and look at the front side of your fuel tank and see what you have there. after buying a new glow plug control Feb 1, 2016 · John6363. You may need to rebuild the filter head if its sucking any air. BCM B1440 power mode master input circuits. It will fix a pin hole vacuum leak causing hard starting. Or call us 920-361-7700 . '03 CCLB 2500HD 4x4 SLT LB7/Allison. Does anybody know what could be going on. Nov 6, 2010 · 4513 posts · Joined 2007. The problem is i will crank it and it will only build up 200psi in the rails. Limped it home about 60 miles. Sep 29, 2012 · Sep 29, 2012. Check everything on your fuel filter head. GM 5. According to my multimeter my ground to the starter isn’t showing anything. I have an 03 lb7 too. 270,000 Miles. i have a 01 lb7. If you have fuel at the filter with no air in it, prime the system till the primer is hard. -Or use compressed air regulated to 10 psi and make a fitting on the fuel cap for a perfect seal. Crank sensor low voltage. Sep 28, 2009 · Remote (Autostart) Start for 04 LB7. . Replacement injectors were used (about 30k) and are stock injectors. Jun 11, 2017 · Also check your CP3 Lines. I shut off the truck check the oil its completely full. #1 · Jan 7, 2012. 5. You may have forgotten to tighten one. Recently my 03 3500 Chevy started to have trouble starting. You could have high return rates on the injectors that is not allowing the cp3 to build enough pressure at starting rpm's. Jan 17, 2011 · if not, try this, turn key on til glow plug light goes out. The Air Dog should pump fuel or fuel/air out that bleeder. Like. It may be injectors returning too much fuel, but you most likely would have noticed a trend starting to happen. 296,000 miles. Nov 2, 2020 · A couple months back I drove the truck to work, shut it off, and it wouldn’t start again. Repeat the above procedure (steps 2 through 4) 2 additional times for a total of 3. It commands about 6000 May 27, 2008 · Turn the key forward but do not start. 8 MPa, depending on the engine model. May 11, 2013 · 2011 Black GMC 2500 Crew SLT Z71, leather, pretty much like a denali, without sunroof, Pioneer Avic 940BT, two backup Cameras, B&W Turnover, Airlift air bag helpers, Wilson Booster, 2000W Inverter, LED's all over, HID hi and low, DPF/DEF Deleted, H&S XRT Pro,red calipers (for looks), XD 20's, Dick Cepek FCII 305/55/20 Jul 6, 2022 · This attachment shows you the fuel injection lines that need to be clamped. This will allow the air to be pushed out of the fuel lines. We have limited diagnostic tools, volt meter and an OBDii. It was cold that night about 20 degrees. Not a single fuse is blown and I am getting diesel to the injectors. hi I have a 03 lb7 that will only start with a shot of starting fluid (I know its bad for it so I im only using to diagnose) I had 5900 psi on the rail pressure so I replaced the cp3 got it back together and it fired right up. Apr 11, 2015 · When my CP3 was going out it actual fuel rail pressure would not match desired (it was maxing out around 14k when it was calling for 22kPSI). Originally threw a p1550 code. I didn't think Battery at first because it seemed to start okay. 12 volts to the starter. I pulled connectors to the ficm. each 10 minute relearn procedure. jus replaced the injectors and cp3. I suggest replacing since they are reasonably cheap now (something like $140 and you can get a new Racor filter included, which I think is the best). I have tried returning to stock. If you get air (bubbles) at the bleeder screw, let it run till it's just diesel Apr 2, 2010 · It could be a loose bleeder screw, WIF sensor leak, loose filter, or dry O-Rings in the primer pump. I pulled over immideatly. Lots of times the lb7 and lly into lbz the filter heads need rebuilt or they have a Crack in the housing somewhere allowing bleed down causing a no start. Which would indicate a problem with the cp3. Run starter in a 15-second burst, 45-second rest, then another 15-second burst. If it is good reinstall it, but leave it cracked. All engine components original. Jun 11, 2019 · The joint venture (and resulting engine) was known as Duramax, and the LB7 was the first of many models to come. Blown Head Gasket. I have a 2001 gmc duramax with lb7 was running great until a week ago when i pulled into the driveway and died. Fuel rail pressure low pressure. y guys I’m new to the forum here. The injectors are most likely bleeding off and causing the hard starting. the lift pump was on. My CP3 psi was a bit low so I had a shop replace my cp3, and the truck still cranks but won’t start without ether (I know it’s bad for it) now when the truck starts with ether it runs and drives fine. injectors according to the manual leak because the elctrical resistance off at least that is what your supposed to check. lb7 not starting. changed the sticks and shes better than new now. Jan 17, 2014 · J. Connect a hose to the nipple on the fuel rail. Fuel pressure was down considerably according to edge insight. G. #1 · May 22, 2012. 268k miles. 7 diesel that would not start below 50 unless plugged in It was the glow plugs but I Dec 19, 2016 · To start I am new to Diesels, I have worked on cars my whole life just not diesels. It would not start back up. 6 litre Duramax LB7, and I had both batteries disconnected for about 4 weeks while I was installing new injectors. 10 minutes. Ok, so you're in a cold climate with an LB7. 8, 0. monitored the fuel rail pressure while cranking and the command pressure is 50ml Jan 7, 2024 · We may earn a commission for products purchased through links on this page Sep 22, 2012 · IL. #1. com App. Once it sits for a while, everything will work again, and the tech 2 will communicate. 8. Feb 6, 2017 · If it were the EDU fuse the FICM might be the suspect module. Jan 3, 2018 · 0. 4 MPa which is approx. Possible the in-tank line is cracked- fuel hose at the driver side of the Mar 23, 2018 · If it only fails in the start position then try pulling the starter relay and crank fuse in the under hood fuse box and the TBC and Ign 0 fuses in the Instrument Panel fuse block. 4927 posts · Joined 2013. G. Oct 25, 2011 · 112 posts · Joined 2011. That's how my truck started acting then it got worse now it won't start at all. The other night I went to drive my 2003 Chevy Silverado 2500HD Duramax which I didn't drive the day before so it was just sitting for only a day. Its a free test and you can eliminate a couple things by doing the test. New CMP sensor. Problem: Starts hard cold, No start hot. Try Disconnecting the batteries and on the driver side hold both terminal wires together for 1 minute. BACK RACK w/4 OVAL MAXXIMA LEDS, BLACK DIAMOND PLATE CROSSOVER TOOL BOX Mar 4, 2013 · The truck stays running until you shut it off, then it won't start. Overheating (fan clutch problems, radiator gunk) In addition to the above common engine problems, there are also a few worthwhile to mention problems that affect high horsepower LB7’s: Crankshafts + connecting rods break at high hp. Bleed screw replaced also. Dec 29, 2008 · 01-04. 5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors, BU cam Dec 11, 2011 · If the primer does not get hard, you have a fuel supply problem. If you don't find a leak the I'll put 100$ on your injectors being the culprit to bleed down. #10. When the truck is acting up, and the gauges are at "rest", if you slam the drivers door hard enough, the gauges Jun 26, 2011 · Replaced both fuel lines going to the fuel head along with the WiF sensor with a billet plug and a new fuel filter. 223000 miles without electrical problems, but halfway out the driveway today it shut off and refused to start. Sep 8, 2014 · Give it a shot. #4. Obviously, you will need 2 people to do some of this stuff. I have replaced the fuel filter housing cause it was leaking, pumped it up and bled the system. 18 posts · Joined 2009. Fresh fuel filter. #9. There appears to be a small air leak in the fuel filter housing area. 0-1. jim107r Discussion starter. It will crank and not start. Jan 2, 2018. CP3 fixed the no-hot-start issue and brought rail pressure back up. the engine was a junkyard engine pulled from a running wrecked vehicle. Or you can try to pressurize the tank with about 10psi and try starting the truck. Primed, checked for leaks and started right up. K. com over the weekend, primed it up, and he fired up like a champ. If it won't fire but is smoking, it's getting some fuel, just not enough. If it doesn't then plug the relay back in and try again. I have a bone stock 2003 LB7, and it will not start. Fuel system had lost prime due to a leak on the suction line betwee Jan 7, 2012 · 6 posts · Joined 2012. Replaced the injectors in an 02 LB7 with 220,000 miles and now it will not start. The truck started up and then died right away. 4. I had just fueled up within 30 miles so I thought it was bad fuel. Feb 25, 2022 · First, welcome to DF, second, never,ever, use ether to start your truck. it ran fine for the first few hours i had it. "Quality Parts and Service at an Unbeatable Price" . All circuits and harnesses are good. Jan 22, 2013 · Once they are nice and warm and charged, they should start the truck just fine, assuming they are just old and not total junk. 145-160psi. Originally pulling the codes, it showed P0341 (cam pos sensor performace), and later showed crank pos sensor Feb 29, 2020 · If not, it probably needs it. May 10, 2010 · It's happened to me twice now seems like after a long trip I'll shut vehicle off for a while n when I go to crank it back up it runs for 10 seconds or so n then dies n won't start back up. I was on a trip yesterday with the fam and got a p0087 code. Sep 2, 2011 · Sep 1, 2011. May 20, 2013 · P0087 now won't start. Good backyard mechanics (We did the injectors and CP3). The ECM is commanding the FICM to supply the power to the injectors. All batterys are connected OK & it does turn over, And the dlow plug indicator comes on & goes out BUT NO START. 8 MegaPascals (MPa), or 160 to 261 pounds per square inch Oct 13, 2009 · I was driving home I looked at the gauge and I see 0 oil pressure. Sep 21, 2012. We have even bypassed the fuel filter with a new Racor filter and raised fuel tank and bleed until the line Nov 27, 2018 · Lb7 crank no start. #1 · Oct 17, 2011. Sometimes it's helpful to cycle the key 2 or 3 times to make sure you have good pressure. I was driving down the road at cruise speed and the truck "popped" (unsure if it was out the intake or exhaust) and it died. Then OHM the Pink wire from each end to Ground, with. The ignition voltage pin has no voltage Dec 29, 2009 · The Duramax does not have a lift pump. Then see if it still does it. 6 duramax. Diagnostics/Fixes and results so far: 1) Checked for DTCs – No Codes present and no history of Codes. Oct 4, 2011 · Oct 3, 2011. Truck ran fine before injector replacement other than smoking and starting hard. -Splice in a electric/hand crank fuel pump of any kind temporarily. – problem started gradually. So I rebuilt the filter head and it was all fine. gave it a hint of wd 40 and it tried to run. You should be able to start your Duramax hot if you depress the primer pump on the top of the fuel filter until it is firm. It may help the CP3 prime itself. When I finished the injector job I primed the fuel system. Feb 28, 2021 · The problem is no power to injectors (LB7 need 96DC volts). LB7, LLY, 01-04 At key ON, engine OFF, fuel rail pressure should be 1. If it is not, DTC P0191 may set. Sep 13, 2015. I have a 2002 Silverado with a 6. Unless one has been installed, the CP3 [injection pump] has to pull the fuel from the fuel tank, through the filter and FICM before it has fuel. Checked for leaks again before taking it on an hour drive. Check it with your meter. After start up I can get 23000psi driving done the road. If it was one or two bad injectors, it would still start or at least try and fire on the cylinders that were receiving proper amounts of fuel. If the wires are disconnected, cut, or the FPR is bad it will default to 100% fuel. Mar 4, 2011 · the service manual say there should be 1. I have had to prime the fuel system to get it to crank. Currently the truck has 160,000 miles and has been a fantastic vehicle. Jul 29, 2021 · It shows almost no rail pressure when hot. #6. If you have the lift pump put it in right away. Used this as a filler between other work so it was spread out over Apr 13, 2024 · 2002 lb7 duramax no crank no start. The problem generally gets worse. joearizona Discussion starter. I have already performed the high idle switch (don't know if it works this way for everyone, but I have to have the CC on and I have to push the "Set" button twice to engage). No matter how you sell it, when you wake up and smell it BO stinks. The FPR is located on the CP3. Fuel pressure regulator. All of a sudden only half cranked then there was nothing. Sep 5, 2017 · If the injectors are returning too much fuel, the high-pressure side can not build the pressure needed to inject enough fuel into the engine to get it to run and thus causes the no-start issue. Fuel filter was changed 2500 miles before. Sent from my SCH-I500 using AutoGuide. Apr 7, 2011 · LB7 won't start after injector replacement. this truck has120psi cold 109 hot. Clamp both sides until youget starting pressure. I am prepared to spend some money on this truck, as I picked it up for a very good price and that I plan on using it for my 'new' work truck (so I don't have to beat up my '11 in the Dec 30, 2013 · Mine would go 2-3 days with no resets, the I would notice to clock was off. 0. Oct 20, 2017 · 2001 C2500HD Duramax LB7. blk smoke lb7 said: If it started and then stopped im betting its not the filter head im betting you have 1 or more injectors stuck open. After it has been run (warmed up), push the primer button until its firm, then see if it starts right up without excessive cranking. Everything was put back together after headgasket replacement. Jump I had one of the O. That will restart the system. Okay, So I'd like to install a remote start setup on my rig. Nov 28, 2016 · Help-help-help. Ill prime the filter for a sec n then it'll crank up n it's fine! 04 GMC 2500HD lly. Duramax Diesel W/ No Mods Except for Upgraded Air Intake. 3 posts · Joined 2013. The priming button on top of the filter Aug 3, 2014 · Always a good idea to add 5 gallons of fuel just to eliminate that. Restarted the truck it sounded fine. Other than that it is stock. injectors would be my guess. Name: Matt. The problem now is, we cannot get it to start, We have bleed the fuel system over and over again, we have checked the fuses, we have checked the electrical plugs for bent or damaged terminals and all looks ok. I suspected the filter head assembly so I rebuilt it and replaced the two fuel lines on the head with a kit from DMaxStore. In the past the truck would start right up , recently taking 4-5 cranks to start, now will not start at all. If you do not have fuel in the CP3 pump- only air- it will NOT build rail pressure. 5 LB7 Duramax Powertrain. If you're not getting fuel out of the bleed screw when priming, then your problem isn't electrical. #3 · Feb 11, 2012. Fuel pressure is right at desired, pulse seems to never be above 1100us. replaced starter and batteries even though I think they were fine at this point. 2001 GMC Sierra 2500HD, CC,SB. ASE Certified, former GM Parts guy. Jump to It still does not start, so I am wondering the specs on fuel pressure when cranking. It is plastic so be careful. truck has ran great for a month while i was driving it down the highway it jus died. Jump to Latest Follow 2K views Jan 16, 2020 · I've noticed my LB7 doesn't like to start smoothly when below around 20F. Might be pushing fuel to the injectors but not holding enough pressure to start. Besides the glow plugs being bad thats about it since a diesel runs on detonation not spark. The CP3 draws the fuel directly from the fuel tank. 2023 GMC Denali 3500 DRW, Pearl White, Banks I dash and Deringer, 255/80R17 Toyo R Jan 4, 2019 · 18259 posts · Joined 2008. pulled engine apart and injectors and cp3 looked to be new. No codes other than "loss of communciation with **CM" codes in each module. here is a list of the current codes in the truck, ECM U0101 lost communication with transmission. 6L Duramax LB7. My truck wouldn't start because of this. I installed new injectors, new high pressure fuel lines and a new fuel filter. Virginia. I'd suggest removing the fuse. I bought a 01 duramax that was running strong just needed head gaskets (supposedly had just had all 8 new injectors)I replaced the head gaskets myself and fixed that problem. Now prime it with the bleeder screw cracked. SOLD. May 7, 2012 · This relearn period always takes. It can damage your engine with one use, so you will hear more on that. 06 RCLB 4x4 (The OG Farm Truck) EFI live, Built trans, 30% sticks, 68mm stg2r, Tons of supporting mods. It sounds to me like the injection pump failed. 4) Excessive idle time can cause white smoke when cold due to carbon build up on the injector tips. (You will also be able to SEE where the leak is coming from) 2003 2500 6. At the age of the LB7/LLY/LBZ's, the soft lines may leak air in, or collapse under vacuum. I modified the wire harness and i did accidentally cut one wire but i fixed that. 2) Changed fuel filter (10K Oct 13, 2014 · Possible someone shimmed the valve and lost parts-- COMMON. i think that the juntion block on the return side when hot does not seal itself. If your pressure is really going that high it Oct 18, 2012 · LB7 not starting :) Jump to Latest Follow - 2003 GMC Sierra 2500HD Ext Cab/Bed 6. If you pressurize the fuel tank you will find a leak. Runs great and lots of power when it starts. Oil pressure was back up. Feb 11, 2012 · J. #1 · Oct 24, 2011. Further testing showed if I let it sit for a couple of days, the terminal voltage would be 11-11. It was driving great, the customer drove home from work and would not start (it cranked great) the next morning. Disconnect the fuel line at the CP3 and put a LITTLE pressure in the fuel tank, use a rag around the air line- check for flow out the hose. Oct 17, 2011 · fergymoto Discussion starter. Skewed rail pressure readings will usually not cause a hard start. It may take 3 or 4 tries on the starter. ECMRPCV, and also the ECM Connector C2. Feb 26, 2022 · I have a 2002 lb7 duramax. Fuel Filter Housing O-ring Leaks. I have a code u1800 for no communication between ecm and ficm. We are continuing to have a no start !!! 2002 GMC Sierra 2500 HD, LB7 Duramax, Stock. When injectors start returning too much, the first sign is that it will start when cold, but will crank for a long time once the truck is warmed up. If all the dash lights go off and the padlock is blinking, you will have to wait for 3-5 minutes truck should start and fire right up . 6L & Allison. Feb 23, 2015 · 2002 LB7 No Crank/ No Start. I also installed a lift pump and put in a new fuel filter. Question, how are you getting good oil pressure, have fuel pressure? For 2006 and newer engines, at key ON and engine OFF, fuel rail pressure will be close to 0. cluster U1000 loss of serial communication for. Worth checking. 1, 1. 2003 GMC Sierra 2500HD 6. cranking rpm is 180ish. More than 20% idle time is excessive. Generic code reader has fuel rail pressure at 1000psi during cranking and 5500psi idling. #3 · Jan 7, 2019. EFI Live V2 w/dsp5 MAX EFFORT by Idaho Rob, EGT's Never higher than 1150* :thumb. The motor was just put back in after having a piston replaced. If you want to re-start the truck later, you're probably screwed though. If it does then you have a wiring problem under the dash. broken CB, broken strobe, B&W turnover goose. Feb 7, 2010 · 1413 posts · Joined 2003. 1-1. The injectors do seem a little loud to me but this is my first Duramax, but have Jul 4, 2022 · Upon crank, it would go to ~700-800psi, and peak at ~1100psi. Unplug the FPR wires and try to start it. Both the GMC and Chevy dealer indicated it was the injectors, but indicated their tests did not provide all of the incormation to Jun 19, 2010 · 2003 LB7 w/ 135k miles. (Fuel pressure regulator). It will make the CP3 work at 100%, and create 100% rail pressure. The only change made to the vehicle was an Edge dash mounted unit. They tend to gradually get worse, making longer crank time as the truck gets warmer and over time not starting. Make sure the bleeder screw is snug and that the primer actually builds up pressure. However, if it starts fine when cold, then prime would not be an issue. Feb 8, 2017 · I have a 2003 Duramax/Allison and have recently been having trouble starting it. LB7 injectors have lots of issues on the return side. 6-liter, common-rail injected, 32-valve, V8 turbodiesel which put out 235hp and 500 pounds of torque in its first year, and for the final year of ‘04 the LB7’s output had grown to 300hp and 520 pounds of torque. Fuel flowed quickly and easily so I eliminated the possibility of a low pressure fuel side issue. I have a 2004 GMC LB7, that I am not sure what to do next. start-relearn-attempts, remembering to turn the key to “OFF” (not run) between. U1000 loss of serial communication for. #3 · Feb 1, 2016. No smoke at idle, has good power. 391 posts · Joined 2008.
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