90 Caravan CV emissions?

I have a 90 Caravan Cargo Van. The state says it must pass their emmissions
testing.
The switch/on-switch/off test doesn't show any codes and the Miller code
reader doesn't register anything either. I don't think a 90 is an OBD II,
is it?
Wondering if this cargo van does have the usual controls like an Oxygen
sensor. Do you have and information?

 

If it did not pass (I am assuming) please post what readings were exceeded
if you
want any help.

Ted

 

The 90 is NOT OBDII. That did not start until 95-96 models. Yes, it
does have O2 sensors. Give the van a good tune-up and make sure it has
a clean/new pcv valve. If you have not changed oil recently, give it a
oil/filter change. Make sure the fuel is fresh and full and drive the
van a bit before you get to the testing station. Make sure the engine
is good and warm and MAKE SURE the air conditioner is OFF. Some
testers will NOT turn it off during the test because if it is hot out,
the cool air feels good. This can cause more emissions because of the
strain on the engine. If it is hot out in your area, go in the
morning( cooler air = better combustion ).
GOOD LUCK

 

None of this will help if the EGR valve is bad, and many times bad EGR
will not set a code.

This is why I told him to post the readings. Please don't encourage people
to throw away money on new plugs, etc. unless the emissions readings
justify it.

Ted

 

Ted,
As far as posting readings, there aren't any readings. The check engine
light will not flash codes and neither does the Miller code reader record
anything. That car has not yet been to the state testing station.
I don't think SDC communications maintained this van well. The Oxygen
sensor was frozen badly in the manifold and the dist cap had pits. So, I am
tuning it up with new plugs, O sensor, wires, cap and rotor and air cleaner.
I've run into a problem in that I can't find a place where a new PCV valve
will fit. This one only seems to have a rubber pipe running from the head
cover to the air cleaner.

Al

Ted Mittelstaedt wrote in message ...

 

Then either something is *very* wrong with the engine control computer, or
neither the flash code procedure nor the code reader is being used
correctly (Or, for that matter, the "Check Engine" bulb is burned out).
The correct procedure to obtain flash codes is:

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.

Be sure to use a Mopar, NTK, Napa Echlin or Standard BlueStreak O2 sensor,
and NOT a Bosch, or you'll just cause yourself more problems.

Which engine have you got? The 2.5 litre 4-cylinder or the 3.0 litre V6?

DS