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86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

Question about FPR Blocking

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Old Apr 14, 2010 | 04:55 PM
  #1  
Guardian_Saint's Avatar
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From: California
Question about FPR Blocking

Have anyone attemp or done this before by blocking their fuel pressure regulator off? I have treid it once and it still run but scared that the fuel pump may die out of that. So have anyone done this w/o any problem?


Blocking the fuel line to the FPR. Attemp to block.
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Old Apr 14, 2010 | 05:28 PM
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myyota's Avatar
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From: GrangeVille, Idaho
You need the vacuum hose connected to the fuel presure regulator for it to operate properly, so leave it hooked up. You will gain nothing by unhooking the vacuum hose from it.
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Old Apr 14, 2010 | 10:37 PM
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I want to see if this will help to save gas cause fuel are giong back to the tank.
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Old Apr 14, 2010 | 10:45 PM
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milehigheric's Avatar
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Are you kidding? Are you trying to break something?

The fuel pressure regulator is there for a reason. Once the fuel pump is on, its on...it keeps pumping away and doesnt stop until you turn off the key. Some vehicles have two stage pumps, but on the good old yotas there just on or there off. Now if the pump was just let to run by itself without regulation it would just keep building pressure in the lines and the fuel rail. Eventually something will give, either the fuel pump will die, a line will burst etc etc - my guess is the pump, but prove me wrong lol.

The regulators only job is to keep the fuel rail pressure within range, it has no effect on fuel economy. If there is to much pressure it opens and the excess fuel is just returned to the tank to be used again later.
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Old Apr 15, 2010 | 04:25 AM
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If you disconnect the vacuum line to the fuel pressure regulator it will run rich all the time. The computer sets the mixture by the amount of time the injectors are open, on the "assumption" that the pressure differential across the injector is held constant by the regulator. Remove vacuum: pressure on injector rail too high: too much fuel used on each injection.

If you disconnect and block the return line, not only will the injector rail pressure go through the roof, well, the pump will eventually blow up
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