Expertice needed on lb7 problem..please

[nbloecher@yahoo.com]

i have had this truck for about six months now bought with high miles been running great until about a month ago i went down to the local truck stop to fill her up when i went to fire it up again it wouldnt start dont know alot about these beasts so i figured i would replace the fuel filter,had to once before when it wouldnt run above 2000rpm the filter was dirty dirty that solved the problem,back to the problem at hand i replaced it again primed the hell out of it still wouldnt start so i checked the fuel pump relay cleaned up the contacts put it back in and it fired right up.since then its done this about 10 times between priming and bleeding and turning it over it would eventually fire back up in about an 1/2 hour the last four or five times iwould eventually have to jump the thing and every time after letting it charge for a couple of minutes it would start every time,had the batteries checked-there fine so itook apart the primer today cleaned it up the o-ring that seals the primer to the unit looked a little deformed like it wasnt seated properly,i couldnt find that type so i cleaned and used the old one.put back together,primed and bled it wouldnt fire so jumped it again low and behold she started,by the way my honey has 95000 on her,i am cash strapped and praying for an inexpensive fix.any help would be appreciated more than youll ever know.sorry for the length didnt want to miss anything.

[nbloecher@yahoo.com]

i forgot to ad ive tried loosening the fuel cap and checked to make sure the o-rings on the filter were seated properly all good i live in southern illinois the temps pretty mild.before this prob i was in whyoming on a hunting trip and it was -5 and had no probs.thanks again for ANY help.

[DieselMonk]

Did you clean your battery terminals? Is there air in the fuel system? I take it there are no engine codes...

[jbplock]

nbloecher,

Hard starting can be a symptom of injector problems caused by cracked injector bodies or ball seat errosion..Other symptoms are SES light, low power, and/or fuel in the crankcase oil. Warranty coverage for this type of problem has been extended to 200Kmi or 7 years for the 01-03 LB7's. For more info see the following:

http://www.thedieselpage.com/duramax/lb7injectorwarranty.htm

:)

[nbloecher@yahoo.com]

thanks for the replies,i cleaned the terminals today dont know if thats the problem,all this is intermitent.i dont think theres any air in the fuel system,every time it does this i bleed the system with the primer and the screw.unfortunatley i havent bought a programer yet to tell if theres any codes or not,the dealer wants 70$ to hook it up.i kinda hope its the injectors just to get it over with.does anybody know if the starter is 12 or 24 volts,thinking if its 24 and theres something wrong with the connection between the two then im using one to start it and its running the one down so much that something else is lacking the voltage(ie the fuel pump or something else).ive seen alot of the same problems people are having,theres just to many variables.thanks again guys ill keep you posted.

[DmaxMaverick]

The starter is 12V, and only 12V is available to the entire truck electrical system (except for some of the logic circuits from the PCM/TCM). The two batteries are hard wired parallel, and are "always on" (no isolator or relay like gasser dual batteries). The starter is connected by a single bat+ cable, and the bat+ terminals are connected by a single cable. Each battery has its own ground. The routing is simple and completely visible. There are no hidden connections in regards to the batteries to starter. Unless you have a damaged cable, all connections are very easily serviceable.

[SoTxPollock]

I'm suspecting fuel pressure regulator.

[nbloecher@yahoo.com]

last night i went out and tried to start it no go so i hooked up a charger for about an hour and it fired right up.the regulator makes sense can anybody tell me where it is?i found one on oregon injection for 179.i know very little about diesels but ive always done my own work on gassers,this is the wierdest problem ive ever dealt with,the last 5or6 times it wouldnt start i just put a charge on it and that does it everytime.and when it starts it runs great.thanks guys

[SoTxPollock]

Hey if it runs good once it starts, thats not regulator, that's low battery power. The starter must spin over fast enough to pressure up the fuel injection pump before the ECM will allow it to fire the injectors. If I remember correctly the injectors are firing at 94 to 96 volts. Yeah, that high. You really need great batteries to make things work right. Once it starts the alternator will put out enough currant to keep things going, but both batteries need to be working properly. Get them tested at AutoZone or some place like that.

[nbloecher@yahoo.com]

ok ive narrowed it down to something electrical,like ive said before the last time it hasnt started all it takes is a jump or a charge and fires right up.i had the batteries checked by advanced auto they checked out fine,so being the impatient man i am i went ahead and replaced the batteries 770 cold cranking amps got in tried to fire it up no go so i thought maybe the batteries werent fully charged so i jumped it again got her going put a charge on it over night the next day started up fine went to the quick mart 3blocks away came back home tried again not even an hour later, not happening put the charger on it again,immediatly the charger was drawing 5 amps.when this happens the door bell rings a little slower than normal till i put jumpers on it then its rings a lot quicker.my alternator is running around 15 volts,theres nothing being lft on that i know of.something is dragging my batteries down considerably.im hoping someone has had this experience as well.process of elimination could take a long time and alot of $ for something like this.thanks for all the help so far guys i appreciate it.