auszookers.com :: View topic - Fuel Rail Pressure.

OK.
I have got the engine kicking over but it only runs for a short time about 3-4 secs then stops. Its smells very fuely.

Is it possibly to over supply fuel to the fuel rail?
I am running a VL efi pump and was wondering if I need to put in an aftermarket fuel regulator prioir to the rail and adjust it to the recommended 220kPa.

I can see the anti pulse diaphram work when the pump starts but it looks like it goes to full travel and stays there when the pump works.

Thought for my logic is that the fuel rail may have its own regulator but if the return line is restrictive and can't return fuel quick enough to the tank.
It would negate the factory regulator and cause a greater pressure in the rail hence suppling more fuel via the injectors and flooding the engine.

Ok I'll test return performance I just get a little nervy with fuel under pressure.

Just have to research output pressure of pump. I would expect return pressure to be the difference between rail regulator and pump supply pressure. Just so I have an idea what to expect.

Should have about 33 psi in the fuel rail according to the FSM.

Ok I'll test return performance I just get a little nervy with fuel under pressure.

Just have to research output pressure of pump. I would expect return pressure to be the difference between rail regulator and pump supply pressure. Just so I have an idea what to expect.

Should have about 33 psi in the fuel rail according to the FSM.

Mobile Injector Service will come to you. They will test and clean them, that way you'll know if they were faulty. 0400 008 007

I'm sure they'll do it for you but they'll charge accordingly.

I wouldn't think the return line would restrict that much. Do you know the history of the head? Has it been sitting a while?

havent got the hoses on the wrong way around and you arent getting enough fuel in the rail?

if you hold the revs up a bit I doubt you could generate enough pressure to make it die form being rich, youd at least know by the smoke

I'm sure they'll do it for you but they'll charge accordingly.

I wouldn't think the return line would restrict that much. Do you know the history of the head? Has it been sitting a while?

Scrawn wrote:

I'm sure they'll do it for you but they'll charge accordingly.

I wouldn't think the return line would restrict that much. Do you know the history of the head? Has it been sitting a while?

I ran a mild 4age on std return....

steak_knife wrote:

Scrawn wrote:

I'm sure they'll do it for you but they'll charge accordingly.

I wouldn't think the return line would restrict that much. Do you know the history of the head? Has it been sitting a while?

I ran a mild 4age on std return....

Heathen!

what pump though? big ass pump would make it worse

:oops:
I think I have found the possible cause my problem.
After reading Jonno's comments on his not idling and being a manifold leak.
It hit me last night like the salmon in that fishermens friend ad. :steamroller:

I haven't connected the vacum hose to the brake booster.
I take it that this would cause it to run like a dog?

Author:	DMAC [ Wed Apr 13, 2011 8:19 pm ]
Post subject:	Fuel Rail Pressure.
OK. I have got the engine kicking over but it only runs for a short time about 3-4 secs then stops. Its smells very fuely. Is it possibly to over supply fuel to the fuel rail? I am running a VL efi pump and was wondering if I need to put in an aftermarket fuel regulator prioir to the rail and adjust it to the recommended 220kPa. I can see the anti pulse diaphram work when the pump starts but it looks like it goes to full travel and stays there when the pump works. Thought for my logic is that the fuel rail may have its own regulator but if the return line is restrictive and can't return fuel quick enough to the tank. It would negate the factory regulator and cause a greater pressure in the rail hence suppling more fuel via the injectors and flooding the engine.

Author:	JrZook [ Wed Apr 13, 2011 11:42 pm ]
Post subject:	Re: Fuel Rail Pressure.
DMAC wrote: OK. I have got the engine kicking over but it only runs for a short time about 3-4 secs then stops. Its smells very fuely. Is it possibly to over supply fuel to the fuel rail? I am running a VL efi pump and was wondering if I need to put in an aftermarket fuel regulator prioir to the rail and adjust it to the recommended 220kPa. I can see the anti pulse diaphram work when the pump starts but it looks like it goes to full travel and stays there when the pump works. Thought for my logic is that the fuel rail may have its own regulator but if the return line is restrictive and can't return fuel quick enough to the tank. It would negate the factory regulator and cause a greater pressure in the rail hence suppling more fuel via the injectors and flooding the engine. This makes sense. How bout for a check take the return line off the rail and let it just return into a nearby jerry can or something. Fuel rail should have its own reg somewhere and for a port injection system fuel pressure should be up around 3 bar (43psi). You could have a faulty reg or a stuck injector but try testing your return line first. Dan

Author:	Fity [ Thu Apr 14, 2011 12:42 am ]
Post subject:	Re: Fuel Rail Pressure.
If it is a G16B then the fuel reg is on the rail. Even a restricted return line will let it run, but a blocked one will not. Like Dan said it could be a stuck open injector.

Author:	DMAC [ Thu Apr 14, 2011 12:46 am ]
Post subject:	Re: Fuel Rail Pressure.
Ok I'll test return performance I just get a little nervy with fuel under pressure. Just have to research output pressure of pump. I would expect return pressure to be the difference between rail regulator and pump supply pressure. Just so I have an idea what to expect. Should have about 33 psi in the fuel rail according to the FSM.

Author:	JrZook [ Thu Apr 14, 2011 12:57 am ]
Post subject:	Re: Fuel Rail Pressure.
DMAC wrote: Ok I'll test return performance I just get a little nervy with fuel under pressure. Just have to research output pressure of pump. I would expect return pressure to be the difference between rail regulator and pump supply pressure. Just so I have an idea what to expect. Should have about 33 psi in the fuel rail according to the FSM. Just remember to pull the pump fuse and turn it over so it releases all the fuel pressure before you go undoing things

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Author:	boostedbrick [ Thu Apr 14, 2011 1:19 am ]
Post subject:	Re: Fuel Rail Pressure.
DMAC wrote: Ok I'll test return performance I just get a little nervy with fuel under pressure. Just have to research output pressure of pump. I would expect return pressure to be the difference between rail regulator and pump supply pressure. Just so I have an idea what to expect. Should have about 33 psi in the fuel rail according to the FSM. My old VL pump put out 42 psi if this helps... Im useing one on my set up now, useing the carbon canister line as my return to keep pressures down. I was worried about the size of the stock return line..

Author:	zooker [ Thu Apr 14, 2011 6:56 am ]
Post subject:	Re: Fuel Rail Pressure.
I used the stock return line with no issues. I re-routed it back to the surge tank

Author:	DMAC [ Thu Apr 14, 2011 10:09 am ]
Post subject:	Re: Fuel Rail Pressure.
OK I tested the fuel supply. Plenty there alright. Looks like it might be an injector issue. Going to put a temporary exhaust on to see if that helps any. How do you check the operation of injectors?

Author:	Fity [ Fri Apr 15, 2011 2:03 am ]
Post subject:	Re: Fuel Rail Pressure.
Take them out and get them serviced. If they are stuck open it is the best thing to do, if they are ok at least you will have nice clean injectors and you can start to look somewhere else.

Author:	Scrawny [ Fri Apr 15, 2011 2:20 am ]
Post subject:	Re: Fuel Rail Pressure.
Mobile Injector Service will come to you. They will test and clean them, that way you'll know if they were faulty. 0400 008 007

Author:	foolsp33d [ Fri Apr 15, 2011 2:36 am ]
Post subject:	Re: Fuel Rail Pressure.
just some random input in regards to pressures.. nothing to do with suzuki thou... love these engines "The Duramax engine employs a common-rail fuel system. Each bank of cylinders is supplied with fuel from its own rail, just as a multi-port gasoline engine would be. The fuel injection pump, known as a CP3 pump, is located in the front of the engine "V" and is gear-driven from the camshaft and controlled electrically by the ECM through a fuel rail pressure regulator. The injection pump has a fuel supply pump that is located at the rear of the unit, along with a high-pressure pump. There is no external lift pump on GM pickup trucks. The supply pump moves fuel from the fuel tank to the inlet port of the high-pressure pump. The fuel pressure regulator varies the amount of fuel from the supply pump to the high-pressure pump in order to control the output pressure. The fuel injection pump generates a peak fuel pressure of approximately 26,000 psi. Typical pump pressure at idle is 5,000 to 6,000 psi."

Author:	DMAC [ Fri Apr 15, 2011 7:50 am ]
Post subject:	Re: Fuel Rail Pressure.
Scrawn wrote: Mobile Injector Service will come to you. They will test and clean them, that way you'll know if they were faulty. 0400 008 007 Thanks scawn just might do that. Do you have to remove them or do they do it for you? My question still is it possible to over pressurise the fuel rail if the return line is to restrictive, hence overfueling the engine?

Author:	Scrawny [ Fri Apr 15, 2011 7:54 am ]
Post subject:	Re: Fuel Rail Pressure.
I'm sure they'll do it for you but they'll charge accordingly. I wouldn't think the return line would restrict that much. Do you know the history of the head? Has it been sitting a while?

Author:	DMAC [ Fri Apr 15, 2011 8:26 am ]
Post subject:	Re: Fuel Rail Pressure.
Scrawn wrote: I'm sure they'll do it for you but they'll charge accordingly. I wouldn't think the return line would restrict that much. Do you know the history of the head? Has it been sitting a while? Since November last year. About 4 months.

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Author:	royce [ Fri Apr 15, 2011 8:28 am ]
Post subject:	Re: Fuel Rail Pressure.
havent got the hoses on the wrong way around and you arent getting enough fuel in the rail? if you hold the revs up a bit I doubt you could generate enough pressure to make it die form being rich, youd at least know by the smoke

Author:	DMAC [ Fri Apr 15, 2011 9:20 am ]
Post subject:	Re: Fuel Rail Pressure.
royce wrote: havent got the hoses on the wrong way around and you arent getting enough fuel in the rail? if you hold the revs up a bit I doubt you could generate enough pressure to make it die form being rich, youd at least know by the smoke No, I checked the connections were correct with jonno_racing, and confirmed once I found the FSM. Checked the flow from the return of the regulator as per JrZook. I'm confident its connected correctly.

Author:	steak_knife [ Fri Apr 15, 2011 9:24 am ]
Post subject:	Re: Fuel Rail Pressure.
Scrawn wrote: I'm sure they'll do it for you but they'll charge accordingly. I wouldn't think the return line would restrict that much. Do you know the history of the head? Has it been sitting a while? I ran a mild 4age on std return....

Author:	royce [ Fri Apr 15, 2011 9:27 am ]
Post subject:	Re: Fuel Rail Pressure.
steak_knife wrote: Scrawn wrote: I'm sure they'll do it for you but they'll charge accordingly. I wouldn't think the return line would restrict that much. Do you know the history of the head? Has it been sitting a while? I ran a mild 4age on std return.... Heathen! what pump though? big ass pump would make it worse

Author:	steak_knife [ Fri Apr 15, 2011 9:30 am ]
Post subject:	Re: Fuel Rail Pressure.
royce wrote: steak_knife wrote: Scrawn wrote: I'm sure they'll do it for you but they'll charge accordingly. I wouldn't think the return line would restrict that much. Do you know the history of the head? Has it been sitting a while? I ran a mild 4age on std return.... Heathen! what pump though? big ass pump would make it worse Holley blue lift & Vl pressure.. I swapped the line's over in Sully, but only cause i fitted a vit tank.

Author:	DMAC [ Tue May 10, 2011 9:04 pm ]
Post subject:	Re: Fuel Rail Pressure.
I think I have found the possible cause my problem. After reading Jonno's comments on his not idling and being a manifold leak. It hit me last night like the salmon in that fishermens friend ad. I haven't connected the vacum hose to the brake booster. I take it that this would cause it to run like a dog?

Author:	JrZook [ Tue May 10, 2011 11:39 pm ]
Post subject:	Re: Fuel Rail Pressure.
DMAC wrote: :oops: I think I have found the possible cause my problem. After reading Jonno's comments on his not idling and being a manifold leak. It hit me last night like the salmon in that fishermens friend ad. I haven't connected the vacum hose to the brake booster. I take it that this would cause it to run like a dog? Fark oath if its there open and sucking in what ever it wants, un-metered after the TB