Hard starting - Chevy and GMC Duramax Diesel Forum
01-04.5 LB7 Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

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post #1 of 7 (permalink) Old 08-20-2007, 01:55 PM Thread Starter
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Join Date: Jun 2007
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Hard starting

Have a friend that has an 2003 LB7 Duramax he says when it is hot it is really hard to get started , he had it in to a GM
dealer and they checked it for codes .
The only code they could get is ( P0093 ) they have it as high return rate fuel pressure - 160 mpa to 77 mpa .
The truck seams to run ok around town and on the hyw.
the dealer told him that it is the Injectors .
I would say more the fuel pump or pressure Regulator . Has anyone had this problem with there's , can you let us know
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post #2 of 7 (permalink) Old 08-29-2007, 08:04 PM
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Location: mckinney tx
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i have 03 lb7 does the same thing,i was using an after market fuel filter,was told fleetguard filters do not seal good at upper ring ,go back with a ac delco filter?
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post #3 of 7 (permalink) Old 08-29-2007, 10:29 PM
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if the return rate is high most likly the injectors are going bad

Last edited by gm tech; 08-29-2007 at 11:03 PM.
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post #4 of 7 (permalink) Old 08-30-2007, 05:40 AM Thread Starter
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Hard starting

Just wondering if the injectors are bad would the engine not be smoking or running rough if the injectors are going .
One of our other trucks had 2 go and it was smoking badly .
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post #5 of 7 (permalink) Old 08-30-2007, 09:18 PM
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if they are leaking internal not into cyl it would not smoke
they leak into the return line high return rate
causing the presure to take along time to build hard start
if you have access to tech 2 scan tool look at regulator flow at idle should be 700mm to 1200mm what you discribed you will probley see 3600mm or higher.
injectors on that motor are warrented to 200,000 miles
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post #6 of 7 (permalink) Old 08-30-2007, 09:30 PM
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Some customers may comment on the Service Engine Soon light becoming illuminated. Upon investigation, the technician will find DTCs P0087, P0093 or P1093. Additional customer comments may include a lack of power, a fuel smell on the oil indicator (dipstick), fuel in the engine oil, fuel coming out of the crankcase breather, the engine cranks but does not run, or a hard start condition. This condition will not cause an engine misfire. Do not apply this bulletin to any diagnostic other than what is identified in the chart below.

The fuel injectors have internal conditions that may cause them to return an excessive quantity of fuel to the tank, as well as leak fuel into the crankcase. Due to the return flow and/or leakage, the fuel injection pump may not be able to build up adequate fuel rail pressure.

this is part of a gm bulleton

Last edited by gm tech; 08-30-2007 at 09:32 PM.
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post #7 of 7 (permalink) Old 08-30-2010, 06:52 PM
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hi,i live in honduras,i own a 2003 lb7,i have problems starting my car,it takes to long and suddenly it wont start,i recently changed the fuel filter and after that my problem started,when my car doesnt start,i have to prime it and then it starts without any problems,but when i turn it off it wont start again.when i push the fuel bleeder located in the front of the block it has air in it.it seems like it has some air filtration.please help me.......and i wonder if the warranty for the injectors is valid here in my country.thanls a lot
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