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Loud vacuum sound coming from engine... help!

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Hello all,


I have installed the 4 port fuel injectors referenced from this forum:



The problem that i have encountered is that after i installed them, There is a loud vacuum sound from the engine, when running. Which was not there before. I'm not sure if i damaged the fuel pressure regulator or if something else has happened. Has anyone had this issue after installing fuel injectors?


Also, i was told that when i installed the injectors, the truck would not idol as high... but, the idol now caused me to stall on the highway when i was in traffic. It started right back up, just worried that it's going to be more frequent now. Is there any other adjustments that i need to do??


Your help would be greatly appreciated. Thanks in advance

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i think that i figured out what it is.. after doing some research. I have found that the symptoms that i am have with the truck happens with most that have a bad fuel pressure regulator.


This is one of the forums that i was looking at and what they had to say:


What happens when the Fuel Pressure Regulator starts to Fail?


The most common issue is the spring-loaded diaphragm in the FPR. When it begins to fail, the excess fuel (being supplied by gravity and the fuel pump) are not returned to the tank.


The result? Your fuel Mixture becomes incredibly rich. Symptoms include:


-Poor MPG (15-30MPG) - check

-Poor Performance - check

-Fouled Spark Plugs

-Strong Fuel Odor when running - check

-Bogging down - check

-Stalling - check

-MAP Sensor Error (2 Flashes)

-Exhaust 'Popping'

-Non-standard and erratic engine temperatures - check

-Cool Exhaust Gas Temperatures

-Gas in Oil

-Difficult to start - check

-Low/Erratic idle speed. - check


"check" issues that i'm having.

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Check up under the green plug on the firewall, there is a vaccum hose that connexts right there. I did this same thing when i installed mine and the truck would idle horribly, hooked the line back up and all should be well jamminz.gif


I checked that vacuum hose and is connected... also i checked to see if there was any cracks or holes in any of the hoses and couldn't find any... the only thing that i can think that it could be is the fuel pressure regulator

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  • 3 weeks later...

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