'91 Plymouth Grand Voyager; Cutting Out and Oil Pressure

My parents own a 1991 Plymouth Grand Voyager SE with a 3.3 V6 engine
and a 4-speed automatic transmission.

When they were taking some big stuff over to a store for refunds, they
ran into a couple of problems with the van.

1st:
During the day, the van was running fine at first. But when my parents
accelerated from a stop from a red light after getting on a busy major
road, the van started exhibiting a strange behavior after getting into
3rd gear at 35 MPH. It stopped picking up speed even when he floored
it. Despite that, it then started to lose speed and then went to 0 MPH.
The engine cut out and stalled. He put the shifter to "N" mode and
restarted the engine. He tried to accelerate again but it wouldn't
hardly go and cut out again when applying pedal pressure. Again, put it
in "N" and restarted it. Instead, he slowly gave it pedal pressure and
managed to get to a parking lot. He parked it and checked underhood.

2nd:
The next problem. The oil pressure gauge was showing 'nil'. Basically,
it was showing no oil pressure. They said this happened all day while
they were driving.

Before the two scenarios occured:

--I drove the van over Christmas week because I had to borrow it due to
some wheel bearing repairs that had to be made to my '91 Plymouth
Sundance RS. While driving it, oil pressure was ok (almost 1/2 driving
and 1/4 hot idle) and no drivability problems.

--I checked the fluids while I put gas in like my dad asked me to. The
oil level was full, though it looked kinda old, 'dark' brown and kinda
blackish. My dad uses 10w-40 oil in this engine based on the oil
bottles I saw in the van.

--The coolant, on the other hand, was pretty low. The overflow tank was
way down and appeared to have tap water. The radiator? I could see
almost nothing in it. I took about 1 gallon of 50/50 antifreeze and
water mix to bring everything back up to level. The engine never ran
above normal or anything nor did the temp gauge swing. My dad told me
that the van was bad on coolant loss but didn't notice visual leaks.

Anyway, my parents got the van towed that day to a mechanic and it's
currently getting checked right now. They told them to change the oil,
run oil treatment, and check the true oil pressure with an actual
gauge. As far as the drivability problems, they want them to hook a
scanner to the van and drive it around, but they want the oil pressure
thing rectified first.

What's going on? What could be causing the above scenarios?
Thanks.

 

To your question, "What's going on? What could be causing the above
scenarios?", I'd speculate that this is lack of proper maintenance. On the
lack of power when accelerating, this could be a clogged fuel filter or
possibly a bad fuel pump (caused by a clogged filter?) Have the fuel line
pressure measured.

On the coolant loss/consumption, I'd speculate that the radiator cap is no
longer holding pressure or there is a leak, or you have a blown head gasket.
Have the cooling system pressure tested.

Based on other hints you have provided, it sounds as though maintenance has
been neglected on this vehicle. In addition to the oil change, a tune up,
good throttle body cleaning, and trans filter/fluid change are likely in
order as well. Good luck and post your findings.

Bob

 

I would bet they blew the head gasket, possibly warped the head.
A leaking cooling system is nothing to fart around with. People that
have them always think they can just keep adding water to them
instead of fixing the leak, but then it is cold and raining and they
don't have the time because they are running late, and they don't
check the cooling system. After that it gets easier and easier to
forget to check it, and eventually it runs dry for too long and you
get localized hotspots that finish off the engine.

Let this be a lesson to you, what your parents did is a textbook
example of what NOT to do.

Tec

 

Ok, big update about what has been going on with this vehicle.

The mechanics called us back Monday and told us that they did all of
the following in sequential order:

1)Checked the oil; looked bit dark brown/blackish; thought oil was in
there long time

2)Tested true oil pressure with mechanical gauge to rule out oil
pressure sensor; Bad Oil pressure was 6 lbs at BOTH hot idle AND cruising engine speed. :-(

3)So, then they drain the oil that was in there, pull the pan, and
clean pickup screen, clean the pan, and inspect oil pump. They said
pump looked alright. They found nothing unusual in oil as far as they
could tell. But they did drain some sludge out.

4)Then they run engine flush with some fresh oil for some time at idle.
They drain it out along with a little more sludge from what they say.

5)They add more fresh oil and check pressure again: 28 lbs at cruising
engine speed and 13 lbs at hot idle; better

6) They drain it and then put more oil and add a bottle of Marvel
Mystery Oil and run it a bit. Pressure came up a little more=39 lbs
drive RPM; 18 hot idle

7) Then they change it again, putting 10w-30 fresh oil in again.

They ran out of time, getting tied up, so they had to resume again
Tuesday. They planned to check the oil pressure again with that newly
fresh oil. After they got the OP issue solved, they would see about the
cutting out/power loss problems. On the phone, the mechanic told my dad
not to use 10w-40 oil in that thing anymore.

Then yesterday, they called back and said that they are now getting
good oil pressure on the van again; 56 lbs cruise RPM; 27 lbs hot idle


They got to the drivability problems today. They think it's the O2
sensor. What they are saying is the O2 sensor isn't putting proper
signals to the computer and is saying that there's too little fuel
relative to oxygen. Basically, it's putting the van in "fuel starvation
mode" causing it to cut out and sputter and hesitate/lose power and
other stuff. So, they replaced that sensor today.

They still had problems when they test drove it again.

When they drove, with the same scanner, they noticed another problem.
They found that the transmission (the A604 4-spd) isn't engaging in 3rd
gear causing the van to refuse to continue picking speed at times (like
past 35 MPH that day). It does the 2-3 shift, though, but just doesn't
engage. Also, they think the RPM sensor/interface or something, that
somehow goes to the shift controller, may not be working properly, and
they may have noticed some problems with kickdown as well. They noticed
that it wouldn't kick down to 1st at times. They are going to look at
the module that controls the shifting (possibly the TCM?) to check all
that stuff to see what needs to be done.

So, what do you think could have cause the oil pressure problems?

And the transmission. Why do think 3rd gear isn't engaging. It doesn't
slip, and it does the 2-3 shift, but it simply doesn't engage (doesn't
continue picking up speed). And how would kickdowns be adjusted?

My parents aren't sure yet about having them check the coolant
situation, though, but they might have them do it after all of these
repairs are said and done.

 

Ah, the good ol' A-604.

It is a fully computerized transmission. There are no "bands" to
adjust or anything like that.

If you hear it do the 2-3 shift but nothing happens, then it is my
opinion that the trans is shot and will likely need to be rebuilt.
Only way to know for sure is take it to a reputable trans shop and
have them read the computer. They can tell error codes, and also some
operating parameters of the transmission. From this they can form an
opinion on the condition of the trans.

My local shop rebuilds these for $1495 CDN$ plus tax, that includes
all labour to re&re and a one year guarantee.

How many miles / kms on that trans??? Has it ever been rebuilt?

 

Not sure. The van is on its 2nd transmission. It's a '93 transmission
and was taken out of another vehicle (probably). It was replaced when
the engine was replaced. The engine is also a '93 engine.
These tranny/engine replacements were done by the previous owner. The
reason the motor was replaced was because the previous owner severely
overheated it.

Anyway, they called today again and said they did fix some stuff on the
trans already by tweaking the module. It now engages into 3rd, and the
RPM to shift controller interface thing (or whatever it is they called
it) works properly now, which probably is helping 3rd gear to engage as
well.

Still, they are having problems getting that passing gear to work
properly. They will check that tomorrow and may get to the coolant
leaks afterward.

Don't wanna know what the repair bill is gonna be for all that work...
:-(

 

Sounds like you will be pushing $1000 to $1500 to me. Ouch!