Fuel Regulators and Dampers
08-08-2011, 09:58 PM
#1
Instructor
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Fuel Regulators and Dampers
I've read through Rennlist about detecting fuel from the vacuum lines that connect to the dampers and regulators. Are you looking for actual fuel or is an odor sufficient to require replacement? Also, what are symptoms of a failing regulator or damper in a car that's cold vs. hot? Would a bad regulator always allow addtional pressure thus causing a rich condition or could you also have a lean condition?
I've just seem some contradictory information in searching.
I've just seem some contradictory information in searching.
08-08-2011, 10:08 PM
#2
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A bad one will allow unmetered fuel to be sucked into the intake via the vacuum hose and cause wild rumbling at idle, etc.
Mine were bad. Liquid fuel would run out when I pulled the vacuum lines. I bought used ones off eBay and they work great. I checked them with a Mity-Vac first.
Mine were bad. Liquid fuel would run out when I pulled the vacuum lines. I bought used ones off eBay and they work great. I checked them with a Mity-Vac first.
08-08-2011, 10:42 PM
#3
Rennlist Member
The fuel lines are typically the first to be concerned about then the fuel regulator then the dampers.
The lines have a bad rep. for splitting and leaking internal and cause catastrophic fires.
The regulator does just that and regulates the fuel pressure at a set level determined by the factory for the engine and model year. They can fail and cause an over rich or the other fail type is over lean......rich is typical and yes is detected by quickly removing the vac. line and inspecting for fuel presence.....there should be none.
The dampers are to remove the 'pulsing' of the fuel cause by the pump and injectors; checking the vac. lines are again a good t.shoot step.
Fuel issues can be deadly and given the age of the cars I advise most owners of cars I work on to replace all.....peace of mind.
The lines have a bad rep. for splitting and leaking internal and cause catastrophic fires.
The regulator does just that and regulates the fuel pressure at a set level determined by the factory for the engine and model year. They can fail and cause an over rich or the other fail type is over lean......rich is typical and yes is detected by quickly removing the vac. line and inspecting for fuel presence.....there should be none.
The dampers are to remove the 'pulsing' of the fuel cause by the pump and injectors; checking the vac. lines are again a good t.shoot step.
Fuel issues can be deadly and given the age of the cars I advise most owners of cars I work on to replace all.....peace of mind.
08-08-2011, 11:08 PM
#4
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More from a drivability, what are symptoms of a failing regulator or damper in a car that's cold vs. hot? I realize starting issues, rough idle, but I'm still confused on how a bad regulator could cause lean running.
08-09-2011, 12:09 AM
#5
Team Owner
when one of the dampers or FPR goes bad the car will be very hard to start and the only way to get it running is to hold your foot to the floor till it starts this will let air in to lean out the extra fuel mixture
08-09-2011, 01:53 AM
#6
Rennlist Member
The brains are adjusting for air flow through the MAF and other sensory inputs but the pressure being low in the scenario cant supply sufficient fuel.
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09-25-2014, 04:53 PM
#8
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I own a 1987 s4 and I just replaced my fuel regulator valve as my old was spitting fuel out the top, after replacement my car won't start, it kicked a bit initially but now nothing? with the old regulator the car started fine? any ideas??
