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2011 Chevy Silverado 1500 Fuel Pressure Problem?


bassmaster

Question

Does anyone know where the fuel pressure regulator is on a

2011 Chevy Silverado 1500 with the 4.8l V8? I ask this because I am experiencing

problems with my truck that lead me to thinking that the pressure regulator may

be bad. The truck is hard to start after it has sat for a while say overnight

or like 8 hours. Its seems it is worse when it is cold outside. The problem has

recently started occurring and has seemed to get worse. Once I go to crank the

car, it doesn’t crank the first time then the set cranking time is disabled so

you have to hold the key. The starter motor turns fine and then it finally

cranks then bogs down for a second at 200 rpm’s, then fires up to 1500 rpm’s

like it should. It idles rough for about 15 seconds before it smooth’s out. You

can see the antenna shake when it does that. Once it cranks you have to step on

the gas petal to keep it from stalling. If you try to put it in reverse quick

it will stall. If you give it gas while it is cranking it seems to crank

easier. After that it runs perfectly

fine. It does not do it when the engine is hot, nor does it idle rough when it

is hot. So that is what leads me to thinking that the pressure is leaking out

of the system because it acts as if there is no fuel there. I’ve had the

battery and starter checked so that eliminated that. I took it to the

dealership and they couldn’t figure out what was wrong. They hooked it up to their

diagnostic system and it couldn’t find anything wrong. No codes are showing up.

I let it set overnight there so a technician could crank it in the morning to

try to figure out the problem. They suggested that I have the throttle body

cleaned along with the fuel injectors and that might fix the problem, but they couldn’t

guarantee that. . They never checked anything with the fuel system. I guess

they didn’t think that was the cause? But it wasn’t doing it as bad then as it

is now. It didn’t stall then or not crank on the first try, just bog down when

they looked at it. If it were a sensor, I would think a code would show up. That’s

what makes me think there is something wrong with the fuel system. The truck doesn’t

act up once it cranks for the first time so I figured it wouldn’t be the fuel

pump. Is there any way of testing is the fuel pressure regulator is bad. Or do

these sound like symptoms of it. If so where is it located? I posed something a

couple weeks ago about it but this is it now. Here is a video of it having the

problem. At the end you can hear the engine finally crank and hear it “bog down.”

The first video is what it was doing when the dealer looked at it, and the

second is what it is doing now.

 

 

 

 

 

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Bassmaster (or anyone .....),

 

My 2010 GMC Sierra is doing the same exact thing. Started right around the same time I replaced the intake manifold gasket due to a leak. So far I have

 

- replaced the MAF

- replaced the O2 sensors

- replaced the fuel pump

- cleaned throttle body

 

When cold I have ZERO fuel pressure - suspected clogged fuel filter thus the fuel pump was replaced but the issue remains. In order to get the truck started when cold I floor the accelerator while its turning over it that gets it to fire up. The fuel pressure remains at 0 for about a minute or two and then it slowly rises to about 43. Once warm the system operates as it should - key on pressure at around 60, starts fine and idles at around 50 and then settles down to 43 ish.

 

I suspect now that I need a PCM.

 

I am receiving faults P01175 and P0172 (system too rich).

 

How did you finally resolve your problem? Was it the PCM? I'm doing all the work myself so I am nto paying a ton, but I hate to spend good money after bad and keep throwing parts in it that I don't need.

 

Thanks

Andy

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Fuel System Description





Fuel System Overview

The Fuel System is an electronic returnless on-demand design.
A returnless fuel system reduces the internal temperature of the
fuel tank by not returning hot fuel from the engine to the fuel
tank. Reducing the internal temperature of the fuel tank results in
lower evaporative emissions.


An electric turbine style fuel pump attaches to the fuel
sender assembly inside the fuel tank. The fuel pump supplies high
pressure fuel through the fuel filter and the fuel feed pipe to the
fuel injection system. The fuel pump provides fuel at a higher rate
of flow than is needed by the fuel injection system. The fuel pump
also supplies fuel to a venturi pump located on the bottom of the
fuel sender assembly. The function of the venturi pump is to fill
the fuel sender assembly reservoir. The fuel pump and sender
assembly contains a reverse flow check valve. The check valve
maintains fuel pressure in the fuel feed pipe and the fuel rail in
order to prevent long cranking

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govtech4:

 

I take it you have some access to GM database, or service database, are these sites publically available to browse? Can you access them without using VPN, or remote access of some type?

 

Do all mechanics in a GM dealership also get access? Do they all get individual access credentials? I realize that no shop is going to either supply or allow a terminal or terminal connection at each workbench, so do they provide a room with terminals available to mechanics. I also understand that there is likely no single policy regarding this, each dealership will likely manage their own particular policy, and also that not all dealerships wish to be included in this century's technology. Sure wish they had this back in the 70's and 80's.

 

Back then the shop would get a monthly package of new service bulletins, new special tools if bulletins required them, and a package for each registered mechanic in the shop. Mechanics package was an up to date listing of the bulletins, that months new bulletins, binder to store them in once a year, and once a year there was also a "gift". Stuff like voltmeter, gold socket sets, screwdrivers, pliars, and other assorted hand tools engraved with whatever that program was called. Also would get a plaque if you attended new model release sessions. Still have all that stuff, only the voltmeter was of any real use, and after 33 years, it still works.

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Second video are you pressing down the accelerator? Had a co-worker buy a used 2010 and was pressing the accelerator pedal to the floor when trying to start and that was happening. Took his foot off of the gas pedal to start and it was fine. Otherwise warranty should fix the problem... in time.

 

Edit: just noticed that I'm in the ask a tech section, not my place, my bad.

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they are not public ,they are setup at the dealer level within their system,where programing etc can be done ...

 

i have no idea what VPN is

 

programing is wireless in the shop so a laptop on the bench/toolbox can be used and wireless to the veh for programing

 

it is way cool beans !!!!

 

govtech4:

 

I take it you have some access to GM database, or service database, are these sites publically available to browse? Can you access them without using VPN, or remote access of some type?

 

Do all mechanics in a GM dealership also get access? Do they all get individual access credentials? I realize that no shop is going to either supply or allow a terminal or terminal connection at each workbench, so do they provide a room with terminals available to mechanics. I also understand that there is likely no single policy regarding this, each dealership will likely manage their own particular policy, and also that not all dealerships wish to be included in this century's technology. Sure wish they had this back in the 70's and 80's.

 

Back then the shop would get a monthly package of new service bulletins, new special tools if bulletins required them, and a package for each registered mechanic in the shop. Mechanics package was an up to date listing of the bulletins, that months new bulletins, binder to store them in once a year, and once a year there was also a "gift". Stuff like voltmeter, gold socket sets, screwdrivers, pliars, and other assorted hand tools engraved with whatever that program was called. Also would get a plaque if you attended new model release sessions. Still have all that stuff, only the voltmeter was of any real use, and after 33 years, it still works.

GM has a tech guild and holds 5 exams through out the year to answer several questions/problems ,find bulletins etc ,,,,if ya get 'em all rite ,ya get Grand Master status and receive a collector plate and an updated certificate all framed and stuff ,,,,,i have 2 plates !!!! lol and a nice Bulova watch !!

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