This Duramax was towed in for a cranks no start condition. No Codes related to the issue. Fuel system had lost prime due to a leak on the suction line between the tank and engine. Ran a new piece of 1/2" fuel hose.
Thank you for this video. Saved me $. Long day after work truck wasn't starting. Just about to get it towed after trying some basics. After watching your video I went to the fuel filter and it lost it prime through water sensor. Luckily easy fix to limp home. Thank you
I had a similar problem and let some air out of the fuel primer manuel pump as you did and the duramax 2004 GMC Sierra did start. I only have 15.5 k miles so I will check on it tomorrow. Thx. for sharing your work.
Very good diagnostic procedure..thinking outside the box. Nice to see you diagnose first before the parts Canon. Very helpful for people who do not really understand how this works thank you for your professionalism.
This is a great diagnostic video. I’ve got an 03 LB7. Truck has over million Km. I built a new engine about 10 years back. Original was getting some blow by. With this much history, you just get to know their quirks. But yes, these fuel systems leak. Especially at the primer pump. I’ve rebuilt mine 2 or 3 times. It’s basically an O ring kit with a new bleeder screw. And I’ve also had pinhole leaks right by the cooler. So I replaced the main fuel line with braided rubber.
Thank you so much!!! I did not know there was a way to prime the fuel system from underneath the hood. My 2004 duramax fired right up after cracking the bleed screw and pumping the hell out of it. Saved so much money, thanks again!!!! Subscribed and thumbs up for sure
Thanks for the info, I tied in clear line on the motor to can of diesel. Primed it and bam fired right up, check the two lines on motor and they were collapsed, thanks a lot!!!!
Wow!!! Great video, nice to watch and listen to someone who actually knows what they are doing. I’m fixing to have to do this same process to figure out my problem...
I have an 2004 GMC 3500. Parked it after lunch having started it 6 times today and when I went out to pick up one of the kids it wouldn’t start. Turned over nice with plenty of power but sounded like it was out of gas. I’m @ 1/4 tank and was actually planning to fill up after getting the kid. Found your video and primed her back up. A little air came out then fuel right away. Turned her over a few more times and started right up. I’ll take her out for a real drive in the morning and keep and eye on her. Thanks so much for the video.
If you're in the Salt belt you may have a rusty suction line between the engine and tank allowing it to suck air. Otherwise be sure the fuel filter it not loose and could be check valves in the filter leaking. Good luck with it.
I started my 05 3500 dually & when I put it in reverse it shut off. Stranded so I looked at your video & primed it. Never had any more issues as of right now. Thank you for posting.
Love these videos....my '04 has been losing prime since 2007....when my tank is past half full and I park with the nose below the bed by even 6" or on a hill, she will start right up...but if it sits or is parked level the prime is gone. Mine takes 24 prime pump presses in general....but I have got a feel for the right pressure level after all these years. I rebuilt the prime pump but that did not do it... I suspect I have a pinhole leak somewhere
Rebuilding the filter housing usually does not include replacing the inlet and outlet check valves in it in my experience. Try putting a piece of clear line on the inlet near the back of the left valvecover. Prime and run it. If you see a continuous stream of small bubbles then you have a suction leak. No bubbles after running 15 to 20 minutes I'd change the filter housing. Good luck
@@PhillipBailey well, thank you for those suggestions. I will take that advice. I think I also have a compromised fuel pressure regulator and thermostat....I am going to go against my ego and cave and take it into the dealer to have it looked at LOL!!
@@PhillipBailey question what you think about the new 3.0 Duramax diesel ? Is good engine I want buy one but I keep my truck for12 to 15 years and I never owned duramax
@watchmanexpert sorry but I haven't had the pleasure of working on one yet. As far as I know there haven't been significant problems with it but they haven't been out long either.
I got a 2009 chevy express duramax, it cranks over fine , but this one doesn't have a primer deal. I wonder what could it be, i know that when it starts it leaks a little bit of diesel from somewhere. When batteries where replaced it started but next day didn't. Hope you give me some advise. Both fuel filters are new.
So I’m losing prime after a brand new housing, i build about 600 psi of pressure but can’t get higher. It is a brand new housing and I put 20L of fuel into the tank to make sure there’s fuel in it. I can’t find any leaks on the truck and it won’t start. I looked at the lines and can’t see anything. Any advice?
One way to crank the engine while under the hood is to uncover starter relay and tap the tab or make your own remote, my 02 won't fire up hopping to figure it out soon pretty Shure it's a fuel pressure issue
I’m having the same problem with my lb7 ram amazing after new injectors had a fuel leak start on a line running from rail to injector made it tight again ran it for a little trip gave it a good rev and it died won’t start up again can prime it from the filter crank it over and lost prime.
I have a 06 duramax, I drove it from a 13 hr trip and parked it a couple weeks. I got in it and went to town left it running while in store, came back out and ut wasn’t running. I changed the primer filter housing and filter recently, now it’ll run for 20 mins and die and won’t start. It has a half tank of fuel and has brand new batteries in it. Also it doesn’t have any codes and we used a snap on reader. Any help would be appreciated!!!
Is it loosing prime. Try priming the fuel system. Make sure the filter is tight as it's under a vacuum not pressure. You may end up installing clear hoses to check for bubbles. Is it developing fuel pressure cranking? RPM cranking on scanner.
hi, nice video, I don't understand so much English why I come from switzerland, I have a problem in my lb7, so you have only change the fuel hose right? thanks a lot for the answer!!
I’m stuck in a random city and my 2003 duramax won’t start, it will crank but it won’t fire, I’m getting fuel to the fuel housing but can’t get it to start
06 lbz changed fruel return lines both sides due to bad fuel leak Got it all back together cranked up ran for about 30 seconds died now cranks but no start Bled fuel filter housing and primed till fuel came out have frp at 750kpa on cheap scanner Still no start any ideal?
You need 10 times that fuel pressure. Around 10 mega pascals to run. 750Kpa is 0.75Mpa. If you are sure the lines are connected correctly keep priming it.
P1093 and p1094 codes with rail pressure not matching at wot only . Thinking bad pump but replaced pump and now still getting no start unless I spray it , so I know it’s fuel related but hope it’s not injectors cuz I have no sign at all of bad injectors . Hope it’s just a bad pump out of box . What would yall think with the little data I gave ya . P1093-1094 rail pressure 8k and desired at 23 k at wot only , other than that pressure it’s spot on than trucks cuts of sitting there idling . Had to prime filter head to start it . Drove ten minutes cut off at red light . Had to prime the hell out of it even with fass lift pump got it running and dies 20 feet down the road and limped It home . Replaced cp3 . Got no start unless with spray , got the p0089 code and surge at idle but pressures were spot on while driving but now no crank still . Fuel leak at cp3 fittings and somewhere on back of housing . Sent it back , have another pump otw! Help me save some money for diagnostics trying to save money
I have a cranking no start issue. I was thinking it was the ficm. New motor, new tranny, new tcase wrnt to town to get parts it ran fine, the next day started truck to go to town and it will not start. Got a P2146 P0201 P0204 P0206 codes. It blew a fuse and l9ss fuel gauge fixed fuse still no start, i am at a loss. I was thinking ficm but everyone says they dont go bad on the lb7
The codes are likely related. Could be a chaffed wire to one of the injectors. P2146 shuts down at least 4 injectors. Check wire routing for rubbed through wires.
So i just swapped out all my injectors. Truck ran before. Now i prime it and get fuel out the screw but when i crank it, it loses fuel pressure. Any advice? I dont see any leaks anywhere other than the bleed screw. Thank you
If you replaced the injectors the HP fuel system is empty and it takes a significant amount of cranking to purge the air. Battery charger and don't overheat the starter. Max 15 seconds cranking then 2 minutes to cool off. Try see if it will fire up on propane or penetrating fluid. Don't use either.
My lbz just started loosing prime cant find rhe problem anywhere replaced the fuel filter with housing the sensor on the filter is not leaking. Replaced both lines going to the fuel filter housing. Cant see any leaks anywhere from the tank all the way to the fuel injectors its driving me nuts
Try plumbing in some clear line at tge connections near the back of the left valve cover. Prime it and run it for at least 25 min. Watch for bubbles in the supply and return circuits. Could be a leaking banjo bolt gasket at the ficm. If its stock all those lines are suction. Good luck
You have to figure out what's missing, fuel pressure or injection signals. Have you scanned it for codes? Is there an RPM signal cranking? Do you have fuel pressure and if so how much?
I replaced the steel supply line between the tank and the inlet on the engine with neoprene hose. the fuel filter and FICM are still in the circuit as normal.
When I prime it and go to start it the frp stays at 1 after 5 seconds will climb to 2 and when I shut it off it instantly dies back down to 1 and won’t climb past two and I followed your steps just to try to get it started but nothing seems to be working? Any advice?
@@PhillipBailey are you familiar with the 15 second test that shouldn’t exceed 100ml. Mine is barely even returning fuel on that test? Or is there a better way to test the injector return rate?
@Omar Mahmoud well if ots cranking fine and the fuel pump is primed then I would call the cp3 pump but honestly I've never replaced one... Another possibility is a cracked injector body and fuel going into the crankcase. I did have that once. Check the oil for overfill and dilution.
@@PhillipBailey I replaced the cp3 pump finally a month later. And still no start. On the return line hose there is a ton of air in it i used a clear hose. And on the live data the frp won’t build passed 2. And the moment you stop cranking it drops back to 1 right away.
@omarmahmoud9628 are you sure you don't have a suction side air leak. I'd put a section of clear line at the fuel inlet at the rear of the left valve cover to rule out a leak along the frame to the tank. Once primed you should not continue to see air bubbles going into the fuel filter. Check the fittings on the injection control module banjo bolts sealing washers.will it run on propane?
For 2000 to 2007 they are available from Dorman through most parts suppliers. There are several different kits depending upon wheel base and brake options.
I’m currently having issues with my truck. It’s a 2004 LB7. Ran perfect before I changed the transmission lines. I removed the passenger side wheel well covering and only unplugged the MAF sensor on the intake. I started the truck after installing new lines to check for leaks and turned it off. I had the passenger side intercooler pipping disconnected during start up. But it still fired up. After putting everything back together. The passenger side intercooler pipping made contact with the positive post on the battery cause a small quick spark. When everything was back together and plugged in. The truck didn’t want to start. Cranks, no code. DFRP is 6.1k and it makes 6k. There RPM signal, on a scanner I can see .1 or .01 MAP reading can’t remember. Again, truck ran perfect before line replacement. And fired up 30 minutes before putting it all together. Any suggestions
I'm not sure what's going on. So you say you have an RPM signal on a scan tool and rail pressure reaches 6000psi? What's the Barometric pressure reading and the MAF sensor cranking. Try unplugging the maf sensor.
@@PhillipBailey I’ll have to go check the Baro reading. I tried unplugging the MAF several times also tried disconnecting the battery cables for 10 minutes, twice, and 1 times for 45 minutes. No luck. I’m thinking a fused popped when the turbo piping contacted the battery positive. I just can’t find a popped fuse. 30 minutes before putting everything back on. It was running just fine
@@PhillipBailey 3 things happened. 1 disconnected the MAF during the transmission line replaced. But also connected it and started it up without the turbo pipping connected. 2. Pipping contacted the positive. Which sparked up for a split second. 3. The windshield washer supply line was cracked right next to the fuse block and it sprayed water all over it.
mY 07 DURAMAX after sitting for the winter wouldnt start. Bleed and start for 30 seconds and quit, turned out the water in fuel sensor on bottom of filter seals on the paint of the filter and the paint was cracking and stuck to the o ring, obviously did'nt change the filter often Over a hundred bucks at lordco
I have an 04 durmax with 140,000 thousand but it cranks put it won’t start just like that but there’s no rust on the truck I’m not sure what it is. Does anyone know.
Hey bro did you get your truck fixed ? I have the same truck yesterday morning it started and then died and now it’s just cranking like this did that happen to you? Or did it not start at all until you changed that primer pump
@@Yommamommafucksme it did put I had someone try to start it wile I was pushing on the primer pump to get air, it starts, don’t let it sit to long or it will turn off, but replaceing the pump soon.
I have a 04 with the lb7. That has fuel filter deleted with a lift pump. Im losing prime and crank no start. With a lost comm with ficm. Its been driving me crazy to what be going on. Because ive done all power and ground checks with ficm and ecu. I get a weird reading on 12v reference going to the cam sensor. It should be battery voltage but its dropping at least a 1 volt. If you could help or anyone has a idea. It would be greatly appreciated.
@2dogsmowing cam sensor power to pin 1 should be near 12 volts. Unplug it and try to start, it should set a code for missing signal. What is the history on this truck? What happened in What order. Will it run on propane? Does it consistently set the code for loss of communication with the FICM. Have you load tested powers and grounds to the FICM? Checked can bus wires to the FICM?
@PhillipBailey do you have a email or some other way to contact you? I don't want to run a bunch of comments back and forth on here. The thing is I'm not sure what the parameter numbers are. I have ALLDATA account but I can't find what the within spec numbers are on the stuff. The cam sensor is a volt lower then battery. Which I'm not sure if its to low on spec. I haven't tried propane yet. Which I do havebsome in a green bottle same as what you had in a video. Your the only one on RU-vid that I've finally came across that knows what is going on with lb7 duramax. Mine is a California emissions but fully deleted. What original happened for the truck to not run. Was the tension pulley wore a hole in the hose to the reservoir tank. Just as I was pulling in a parking lot of a store. I fixed that with a coupling and filled with water. Go to start it and ran for 2 minutes roughly and died. Same thing a second time. And third time ran for 4 minutes or so and died. Then that was it. Just crank no start. When I got stop in the parking lot. I did pull the reservoir cap off and straight water blow everywhere. I don't believe I have a head gasket bad. Because there were leaks in the radiator and a hose. Plus I've done a comparison gas test with the color change dye. The thing is the truck was running just fine the rest of the day before that happened. Today I think I've found why I was losing prime. From the rubber fuel hoses under everything by the cp3. They were soft like cooked carrots. And they looked fairly old. Which I took them off to order new ones. I think that's it at the moment. If you do have a email. I can send pictures and my scan tool report. To see what all is going on. There are other issues but they work fine. The truck has been ran through by someone else before me. And I've been slowly fixing stuff over 5 years now roughly. The truck looks way different then it originally was when I got it. The first day I bought it. I sat in the parking lot of the dealer for 3 hours figuring out what was going on with the tail lights. Come to find out it was missing the junction block in the back where the tail lights split. There's many story's I've got with working on this truck. Which I knew of when I bought it. It's a beast when it runs right. Lol
