the latest on my 1999 grand voyager 3.3

I posted a while back about my 1999 grand voyager 3.3 flex fuel van.
I've been working on it but it still isn't right. The engine runs
roughly because it is getting way too much gasoline. All spark plugs
are wet with gas when checked. There are new plugs, wires, EGR valve
and PCV valve, which I replaced because they all needed it. Things are
slightly better but the engine still has a severe problem.

It won't start unless I push the accelerator, because of the excessive
fuel. It will not idle. When it runs, it runs roughly and makes a
black mark under the tail pipe as well as a cloud of unburned gasoline.
I haven't been able to find any vacuum leaks. The check engine light
doesn't come on, and a scan tool doesn't show any codes. The injectors
all make the proper clicking noises when checked with a stethoscope, and
it holds fuel pressure when the engine stops, which tells me that I
don't have an open injector.

The only thing that I can point to as being wrong right now is that the
fuel pressure is at 60 psi while running, instead of the 49 psi
specified in the manual. I looked up the fuel pressure regulator for
this vehicle and found that it is a $100 part, so I got one from a
wrecked van at the self serve junkyard for $3. I would rather have a
new one of course, but I couldn't pass up that kind of savings. I
installed the new (used) one, started it up, and read the fuel gauge at
60, just like the one I had just replaced! What are the odds of that?
Do you suppose the former owner junked that van for the same problem
mine has? Incidentally, my other van, a 1999 Voyager 4 cylinder, has
the fuel pressure dead-on at 49 psi, and it runs great.

Considering that I don't have a lot of dough to spare, I figure I could
try another $3 part from the graveyard (it's no so hard to get the tank
up and down, etc), or buy a new one for $100, and see if correct fuel
pressure makes it run right.

Alternatively, I could take it to the local dealer shop for a $90
diagnosis to get an expert opinion of what is causing the problem. I
suspect that if I ask them, they will simply tell me that I have a bad
pressure regulator, even though something else may be wrong with it that
I haven't even considered yet....

What would you do first? I'm kind of leaning toward the $3 part myself.
Can you guys think of any other factors in addition to bad fuel
pressure that may cause this problem? Or should I just shut up and
change the regulator again?

 

A 10psi increase in fuel pressure is not going to soak the spark
plugs. I'd be looking elsewhere.

If all the spark plugs were WET with gas, it wouldn't run at all. Are
you sure they're ALL wet?

Have you put a scanner on it to view sensor data? Has the ignition
system been properly checked? Plug wires properly routed? Injector
wires properly routed?

 

Compression test?

 

If you are using a scan tool and not a code reader what is the MAP sensor
Baro and vacuum reading at idle? A MAP sensor that is reading very low
vacuum at idle would dump alot of fuel in each cylinder and would cause this
problem. If it is out if calibration and sees 10 to 15 inches of vacuum at
idle the map sensor thinks the engine is under a load and holds the
injectors open for a longer time thus causing a rich flooded condition at
idle, Forget about fuel pressure right now.

Glenn Beasley
Chrysler Tech

 

Not sure what book you are using but FYI, The flex fuel pump pressure specs
is not the same as a standard system. Flex Fuel pressure spec is 55 psi.

Glenn

 

Well, it does run, and they are damp but not dripping.

I'm learning more about scanners from you guys. Apparently I misspoke,
and we were actually using a code reader. The ignition and injectors
are set up properly, and I did a visual check where I determined that
sparks are hitting the heads of the plugs. I haven't checked
compression because it didn't seem logical to suspect that.

You guys have some good ideas. Thanks.

 

Wow, this is the kind of tip I was hoping for. Thanks for the info
about the diagnostic devices. We were using a less sophisticated type
that just reads codes. I had suspected that the guys at the dealer shop
would have better equipment that would allow them to read actual
conditions from the various sensors.

Could the MAP sensor be so bad that it even causes rich running at 3 to
4 thousand RPM? It's so bad at idle that it doesn't idle. It gets
better at driving speeds, but not better enough to be right. If I want
it to run long enough to put the charge back on the battery after my
latest cranking experiment I have to hold it at about 3K to 4K, which is
when the black spot appears under the exhaust.

Thanks for sharing your expertise. You guys are great.

 

you need a scantool to look at the engine data esp. the o2 data which will
include the map sensor and barrio such as glen posted and under a global obd2
screen which is were i would look. also the coolant temp sensor and intake air
temp sensor those short out and tell the puter wrong info is the egr stuck open
or weak and being pulled open by engine idle vacuum? what about the evap.
system is it pulling in fuel instead of fumes??? is the gas tank imploded ???
you need to look at the long-term fuel trim and see what it doing at what
percentage? and is it minus or plus at this point ignore fuel pressure unless u
have another gauge to make sure your is working correctly

 

ignore the black spot and look for black smoke

 

You were right about the MAP sensor. I checked the voltage and it was
bad, so I replaced it and it no longer dumps a ton of gas into the
engine. Apparently this van has a lot of things broken...

Apparently cylinder #2 isn't working. When I run it for a few minutes
the exhaust manifold will be finger-burningly hot at #4 and #6, but at
#2 it's just slightly warm. The #2 plug is black with carbon and smells
like gasoline. The ignition system has the correct primary and
secondary resistance, and it has power at all 6 cylinders. Plugs and
wires are all new.

Once in a while, but not always, there will be a backfire through the
intake when cranking. This has happened only a few times. There seems
to be extra noise in the intake and exhaust while running, but this
could be simply due to the necessity of holding the throttle open
slightly to keep it running.

I'm starting to think that a compression test would be in order, as
suggested in another post, although it seems that the dead cylinder
wouldn't drag the engine to a stop if it didn't have good compression.

 

There is a key on key off combination that works on my 3.3 in a new yorker
to show error codes on off on off on within 3 sec without starting check
engine light will flash for codes

 

That worked on my '86 Le Baron GTS and also works on my '95 Concord.
A very handy feature which has led me to several problems I fixed myself.
I have the shop manual showing the codes, I believe I also saw them
online.