93 Dodge Caravan Stalling Problems

All of a sudden my 3.3V6 93 Dodge Caravan has started having stalling
problems when I stop at a light for a length of time. It seems to be
getting worse as the weather gets colder. To the point where it didn't
start on the first shot (although it was cold last night)

I did notice a Check Engine light was on while driving a few weeks
ago, but it hasn't come on since. But since then the stalling problem
has occurred. I bought some of that fuel system additive by STP and
hopefully that works. Would a tune up cure the problem as well? Or a
fuel injection flush? I don't anything has been done for awhile ( I
bought it used last year)

I went to a local garage and the guy wanted to charge me 70 bucks to
do a diagnostic test on the van to determine the problem. I don't like
being at a garage's mercy like this, so hopefully somebody here can
give an idea of what the problem could be.
Thanks

 

All sorts of different problems can cause this. Some will be picked up by
the vehicle's onboard computer and stored as a "fault code" which can help
direct you to the problem, and some will not.

The mechanic who wanted to use his diagnostic computer for an hour was not
being unreasonable. Nevertheless, you can check for any of the grosser
failures that will both cause stalling and be picked up by the computer by
checking for flash codes.

To check the computer codes:

With the engine off, switch the ignition key on-off-on-off-on,
leaving it "ON". Do not
go to "start", just "on" during this procedure.

Watch the "Check Engine" or "Power Loss" light. It will turn on, then go
off, then will begin to flash-out any trouble codes that have been stored.
For instance, if it flashes:

flash <pause> flash flash
<long pause>
flash flash flash <pause> flash flash flash flash flash
<long pause>
flash flash flash flash flash <pause> flash flash flash flash flash

Then you have a 12 (one flash followed by two) a 35 (three and five) and a
55 (five and five). 55 means "end of codes" or, if by itself, "No codes
stored. Check the codes and report what you find.

Other problems that can cause this symptom and will NOT be picked up by
the computer include a dirty throttle body and/or AIS motor, faulty wiring
to the AIS motor, a plugged or improperly serviced PCV system, and others.

DS

 

You may have an O2 sensor starting to go south or some other issue causing
the check light. Best there to get a diagnostic. You can do the key on off
on trick but it won't catch some things. Another good thing to do is clean
the throttle body. Don't just spray stuff in it it should be removed and
thoroughly cleaned. You may also have a cracked PCV hose. All simple issues
though. Don't waste your money or risk damage putting snake oil in it
though. Waste of money.
Larry

 

Check fuel pressure and or change the fuel filter, chances are it has
never been changed and being as its 11+ years old.

REMOVE the NOCRAP in my address to reply.

 

The fuel filter is good advice, but I also suggest a thorough throttle body
and throttle plate cleaning as well and replacement of the PCV valve. These
are easy to do and very low cost. From my experience (and others) this
engine seems to get a dirty throttle plate every 25-30K miles and it usually
affects the vehicle when it is idling.

Bob

 

I went to a garage today, and the guy reccomended the computer be
changed for some reason. I got a used one, and while the stalling
problem has stopped, the van doesn't run well at all. It starts idling
roughly when stopped at a light. It seems to lose power while I am
driving. And I also hear a popping noise sometimes when I give it gas.
So far I have spent 300 bucks. Is a tune up the best reccomendation?

 

thanks for answering. I went to a garage who a freind reccommended.
The mechanic told me the computer was the problem. He used what looked
like a small laptop computer to diaganose the problem. He said the
reading he was getting he had never seen before. So I got a used
computer for 100 bucks and he installed it for me .

While the stalling has stopped for now, it still idles roughly like
its going to stall. And there's a hesitation sometimes while driving.
Also a popping sound occurs sometimes when I give it the gas.
Obviously the guy I went to can't figure out the problem. Would a tune
up help?
Thanks.

 

I was told fuel filter by somebody else as well. To me its obviously
something to do with the fuel line. I will check into that one.
Thanks.

 

The computer is almost NEVER the problem. They simply almost never break.
It's sad that thirty years after the first engine control computers
appeared, we still have ignorant and/or lazy and/or dishonest and/or
stupid "mechanics" like the one you picked saying "It's the computer".

Translation, he didn't know how to use his diagnostic computer.

Still waiting for you to post codes, see below.

 

Actually, you'd be surprised how many times the computer actually IS
at fault.

The problem you had is now gone, and a different problem now exists.
It is pretty obvious the computer is involved in the problem - and my
guess is you either have another bad computer (a risk when buying used
- but even new or "rebuilt" units have been known to fail) or you got
one for a different application and the calibration is off.

Is there a "learn cycle" on this computer? Many do. Untill they have
gone through the cycle all the adaptive and block learn settings are
wrong, causing poor running.

 

Actually, no I wouldn't. On what grounds do you claim otherwise?

Sounds to me as if the selfsame problem still exists.

DS

 

No, I wouldn't be surprised. As Daniel said, the computer is very
seldom the problem, but they do go bad occasionally. I'd say probably
95% or more of the failures are sensor failures. The computers fail
probably less than 5% of the time. However, they do fail. I have an
out of service rear window washer on my minivan due to the failure of
one output on the BCM.

I'd say the only obvious thing is that you aren't doing a very good job
of diagnosis. Plug and pray isn't a very good way to fix electrical
problems.

Why not just pull the diagnostic codes? It is rather easy on Chrysler
vehicles.


Matt

 

I will try that test and give you the results.
I think you were right about the computer. While the stalling problem
has stopped (for now), I don't know if the guy adjusted something else
besides the computer to stop the stalling, and didn't tell me?
But I'll get back to you on the flash results.
Thanks

 

I will try that. And I wasn't the one who wanted to change the
computer. It was the mechanic I went to. On Sat, 10 Jan 2004 13:20:26

 

Okay. I just did the test. Here's what I saw

First the Check Engine light came on, then went off.

Next there were three flashes- a pause- and then five flashes

After that came 5 flashes- a pause- then five more flashes

I did start the van, and while its freezing cold out, it did start
okay. But started getting a bit rough after about a minute. In my old
camaro with a carburetor I'd say it loses its idling speed.
Ihope this info helps.
Thanks.

 

Ok, just change "you" to "your mechanic" and my comment still applies!

Matt

 

Something isn't right. You should have received a "12" at the start, a
flash, a long pause (long being relative here as it really isn't all
that long), another flash, a short pause and another flash.

Then you should have had another long pause followed by the flashes for
the real code(s) that are set ended with the "55" as you saw. Are you
sure it didn't flash 12 at the start?


Matt

 

He won't necessarily get a 12 at the start.

--Geoff

 

I don't think you read the flash codes correctly. Those first three
flashes were probably actually a "12" (one flash, a short pause, then 2
flashes).

You read the last code correctly (five and five = 55, "end of codes").

So go run the test again and watch the pauses more carefully -- I'm
betting that middle five is actually two groups of flashes. 14, 23, 32 or
41.

DS

 

He will necessarily get a 12 at the start if any code is stored.

DS