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After shutting off my 1990 Bronco 302 I can hear a sort of hissing/groaning noise under the hood that sounds like the fuel pressure bleeding off somehow. Is this normal? I was told my regulator might be bad and that is the area the sound comes from. What is the fuel pressure on these things?
I can tell you this much: You do absolutely, without a doubt NOT want to let that fuel pressure regulator go out! I had mine go out and do about $500 in damage, and I feel I was kind of lucky. The whole crankcase was full of fuel, to the point it was hydro-locking. Could have blown the whole engine apart.
Did it give you any kind of warning signs or did it just die?
Can someone listen under their hood after shutting off the engine and see if you hear anything? It kind of signs like air coming out of a balloon but it has a groan sound to it. Thanks!!
It would die, then I could get it going again and drive for a while. if you pull your dipstick you would be able to smell the gas in the case. Are you sure it's not in the vent control area? (passenger side firewall) because that sounds like it could be the vents releasing pressure when you turn off the engine.
I'm new at this Bronco thing and mine has a 351, noticed same thing when I shut mine down, last about 15-20 seconds, seems to come from some sort of valve located on drivers side, top of engine close to fire wall.
I think you guys are hearing the air conditioner pressure bleeding off after you stop. Turn off the A/C and see if it still makes the same sound when you turn the truck off.
IT DEFINITRLY SOUNDS LIKE THA A/C BLEEDIND PRESSURE FROM THE HIGH SIDE TO THE LOW SIDE. THIS HAPPENS THRU THE ORIFICE TUBE WHICH IS LOCATED IN THE ACUMULATOR.
My AC is also dead and has been for years. The sound is coming from the top center of the engine near the firewall or closer to the drivers side. The reason I wondered about fuel pressure is that my bronco periodically loses power, it feels like it loses 50hp sometimes and then it comes back. I mostly notice it on hills or when towing. I have never been able to solve the problem.
Check the pcv valve way in the back right corner. may have come out of the grommet. Makes noise for 2-3 seconds. 99 % of the regulators I replace start off with black smoke when the pressure jumps to 80 - 100 psi. The other 1 % usually wont run due to 40 psi of fuel pushing through the regulator vacumn line into the intake manifold. Pull the vac. line of and turn the key on, look for fuel squirt.