[moorelb7]

2002 lb7 duramax wont run
I have a 2002 duramax lb7. This truck is completely stock other than a straight pipe as far as i know. I bought this truck not running and burnt on the inside. We got it home, primed the fuel and it finally fired off. I drove it in our building and it has been sitting for around two years now. We replaced everything on the inside: steering column, seats, dash, carpet, everything. Now this truck will not start to save its life. I have primed up the fuel and it stays prime for days. I checked all the fuses and they are all good. We have a cheap autozone scanner and it only has two codes; P0380(Glow plug heater CKT A malfunction) and P0700(trans control Sys malfunction). I can clear them and the glow plug comes right back but it takes the trans one a while to come back. Is there anything else i can do to try to get this to fire off? It has dead batteries but i have two optimas hooked up with jumper cables to it and it turns over fine. I dont want to buy batteries and this thing still not run and they go dead. Any advice would be greaty appreciated. Thanks

 

[Dmaxed775]

Sounds like maybe security lockout?? I don't know if the 02 has passlock or vats system but it cuts out fuel system if trucks batteries are disconnected or dead for long periods of time.. My 04 does this sometimes.. Do a search on both maybe it might help you..

 

[moorelb7]

I'm pretty sure it's the pass lock system. Do you know how to clear the security? I researched that cause I thought it could be that but I couldn't find anything. Thanks for the info

 

[moorelb7]

How is the security light supposed to flash? Only when door is open? How many times after the switch is on?

 

[Dmaxed775]

I'm not familiar with the 02 but of its passlock it should be the same reset sequence,, it takes 30 min..
Attempt to start truck, turns over wont start, leave key in the on position, security light should stay lit for 10 min, as soon as the light disappears turn key to off position for exactly 5 seconds, attempt to start wont start, leave key on for another 10 min till light disappears, turn off for 5 seconds and attempt to start, wont start, leave key on for another 10 min till light disappears, turn off and immediately try to start and should fire after that if it is indeed your passlock.. If you don't time it exactly you'll have to start all over.. Hope this helps. Let us know if that worked..

 

[Dmaxed775]

And do not open doors or mess with anything till reset is complete,, if you open the door it'll reset security..

 

[moorelb7]

Thank you sir. I'll try that as soon as I get home.

 

[Dmaxed775]

If you wanna know for sure its security try to borrow a good scanner, genesis, gm tech tool etc.
Basic scanners wont show security codes,, if I remember mine was p1631c fuel disable..
Good luck man..

 

[moorelb7]

I had to go through that process twice but then it turned over once it fired off. But when I cut it back off, it won't start back without going through that whole process again. So now my question is how do I figure out what's tripping the security? Do I have to get a more high dollar scanner to figure that out and will it say exactly what's doing it? But thanks so much for the help on pinpointing my problem. It's very appreciated cause I haven't heard this thing run in years and it purred like a kitten!

 

[Dmaxed775]

Does the security light stay on after it fires?? If so you may need to run it or drive around for a while to let everything communicate. If not check codes to see if there's anything else besides glow plug and trans codes that your already getting,, might have something not communicating properly.. If all else fails you can have it bypassed if your not worried about having it..

 

[moorelb7]

No the security light is not up now and the only code I have no is the glow plugs. It won't start but I'm going to try the 30 min thing again and see if it works again

 

[moorelb7]

I did the 30 min relearn thing three times and it won't start now... I'm stuck

 

[Dmaxed775]

I'm stumped,, if your batteries are good you should only have to reset once.. Sounds like there's another problem going on, hopefully some others on here can chime in and offer advice..

 

[moorelb7]

I got a buddy who owns a diesel shop who said he'd come by and hook up to it. So I'm hoping his computer will figure it out. But thanks for your input anyways.

 

[Dmaxed775]

I'm curious to what your buddy finds,, please post when problem is found I think it would help others on the forum..

 

[moorelb7]

He came over to my house and hooked up to the truck and found nothing so we took it to his shop to see what he can find. He will probably work on it tomorrow so I'll let ya know what he figures out. Thanks

 

[Dmaxed775]

:thumb

 

[moorelb7]

Well found out today that it had bad fuel lines and had squeezed them shut from priming the fuel so much and the cp3 is about gone. After you pump it and crank on it, it will start and runs good but if you get on it at all, it falls on its face. I'm gonna put an airdog on it and be done with it I reckon. Thanks for all the helps guys I really appreciate it.

 

[moorelb7]

This truck has been running great ever since I out the airdog on it. Well I went to leave the driveway yesterday and it started pouring black smoke and died. It still won't start back. The airdog is still pumping cause I have fuel all the way up to the fuel bowl. I don't know where to start on this. Could it be injectors or could it be the fact I didn't fix the cp3 and it's causing this issue? Thanks ahead of time.

 

[derekw]

The cp3 could definitely be the problem. The air dog will aid in getting fuel to the cp3 but the cp3 is where you build your pressure. If you don't have the desired frp you will have symptoms like you are describing. I know from personal experience. I would diagnose the cp3 and go from there. The air dog is only set at 8-10 psi I believe.