Re: 16v troubleshooting

["Dave Ewing" <rabbit16v@prodigy.net>]

What are you using to check the 02 sensor?  I have found the the best meter
to use is an analog type (you know, the ones with the needle!) then you can
actually see the fluctuatuation.  Most of the digital ones will take an
average since they aren't fast enough to react to the 02 sensors readings.
Besides specs, what does your book tell you about the 02 sensor?  It should
actually fluctuate unless it is cold or dead.  It is sensing the 02 in the
exhaust and should fluctuate between .4 to .8 or.9 volts.  Looks like your
specs are an average of what the reading should be.  The fluctuation part is
really important.  If there is no movement, the sensor is dead.  It would be
like you temp sensor reading 1500 ohms hot or cold.

(Everyone)  Whenever your car is not running, first make a quick mechanical
check (if a rod is sticking out the side of the block, no need to
proceed!!), then check for spark (check at the spark plug wire (I usually
use a spare plug and ground it then crank over the motor) and this will test
the primary and secondary ignition system), then check fuel.  If the car is
already running and has a miss or runs rough, start with a tune-up or at
least verify that the air/fuel filters are not clogged, plugs are not fouled
or worn, wires aren't arcing and ohm out OK,  cap and rotor are good (and
Bosch only) and not melted or arcing to the distributor shaft, check air
boots, vacc. lines, and all obvious things, check fluids and check for any
leaks (if oil is milky white or you see a fuel leak or whatever).  AFTER you
check all of the basics, THEN proceed to specific tests.  As far as specific
tests are concerned, if you have good tune parts and your spark is nice and
strong, move to the fuel system.  Make sure that both pumps are working (if
equipped) then proceed to individual tests such as volume, system pressure,
differential pressure, DPR readings, temp sensor readings, injector spray
patterns, cold start injector, thermo time switch, air flow potentiometer
(hardly ever dies), fuel distributor, plate position (CIS-E has two, zero
and rest with fuel pressure!!), etc. etc.  If you believe your car to have
mechanical problems (engine) then go that direction first.  Check
compression, oil, timing belt position, etc.  I have seen a lot of people
post "what should I test next!" and figured this would help David and maybe
others.  The biggest help anyone will ever get is to get a Bentley, and more
importantly, KNOW HOW TO USE IT!!!  Chilton and Haynes are not satanic or
anything, and are even recommended as a supplement to the Bentley since it
will add insight but start with the Bentley and read the thing!!  Figure out
how to use it and read some of the theories of operation so you have a
better understanding of why and how things do what they do.  It is alot
easier to fix things/diagnose problems on systems that you understand than
just taking stabs or shots in the dark and hope that what you're doing is
right!!  This is not a rant, just hope this helps!!!!  Please don't hesitate
to ask questions though, it's what this list is all about!!!

Dave

> I'm in test mode now and here is the information I"ve gathered so far:
>
> Compression: 195, 180, 170, 195 (I took the spark plugs out to look at
them
> so I figured I might as well check)
>
> OXS voltage: meter was hard to read, but it looked to me like about 0.4v
> with little fluctuation.  It definitely didn't move below that, and might
> have hit .5v, but it was hard to read.  Spec is .5v +/- .2v
>
> Coolant sensor: 3000 ohms cold, 300 ohms warm, 100 ohms really hot. Spec
is
> 3k to 4k ohms cold, 150 to 300 ohms warm (190)
>
> It seems to me that everything looks ok so far.  I'm
> going to try to check the DPR current tomorrow.
>
> I checked vacuum lines again and didn't see anything obvious.  If DPR
checks
> out ok, where do I go next?
>
> David Zanotti
>
>
>
>
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