fuel in plenum problem

I have an 89 Dynasty 3.0L. I am having a problem with the way it runs and
starts. It is very hard to start and will usually die a few times before I
can keep it running. If I unplug the hose into the pcv it helps a little, I
replaced it and no change. I then noticed that the air box had a milky
substance in the bottom. I checked the coolant and oil, everything is fine.
Also, if I disconnect the breather hose going into the plenum fuel pours
out. Not very good because it drips onto the exhaust crossover. The computer
never turned the check engine light on but it did give me codes 13 and 22, I
have replaced the MAP and TPS sensors and nothing has helped. Has anyone
seen this or have any more ideas how so much fuel is getting up into the
intake plenum?

 

There shouldn't be *any* fuel in the plenum, just air. The plenum is not a
mixing point for fuel and air.

I suspect that you've had a failure of the vacuum diaphragm on the fuel
pressure regulator that has allowed fuel to be sucked into the plenum. The
fuel pressure regulator is a *small* canister that is located directly on
the fuel rail, which runs under the plenum.

If you're saying that when you disconnect the accordian hose that runs from
the air filter box to the throttle body fuel pours out, *stop immediately*!
You've got an explosion hazard, never mind a severe fire hazard. Don't try
to start the engine if you have *any* quantity of raw fuel in the wrong
places under the hood.

I would use a vacuum pump to check the diaphragm in the fuel pressure
regulator. I'll bet you find it leaky.

--Geoff

 

I concur. There's only three places for fuel to inter the intake system. The
injectors, evaporation canister, or the fuel pressure regulator. Since the
injectors are in the lower intake manifold, the possibility of fuel where you
say it is would not come from these. Since you say that you are also haveing a
starting problem, I'll bet that the fuel pressure is bleeding off and the pump
is not able to keep up with the possible diaphram damage in the fuel regulator.
At least to me it sound like the most likely choice. However, a faulty evap
purge solenoid might cause raw fuel to be sucked into the intake as well. Try
plugging the rubber hose that is between the canister (at the passenger side
engine compartment) and the intake manifold.


V/R
Wink