96 VW Jetta 2.0L will not start due to lack of spark.

I have a 96 VW Jetta with the 2.0L ABA motor. For the past couple of months the Jetta has been running as if it is misfiring while driving. I have tried to find the problem but without success. VAG-COM software says that I am getting an "implausable signal" from the crankshaft position sensor. I had replaced the sensor and the car ran fine for a day and then back to misfiring. I then proceded to replace the coil, distributor cap, rotor, spark plugs, and wires. Again, with the replacement of each of these parts the car ran great for a day and progressively went back to the now normal misfiring. Keep in mind, everytime the Jetta went back to it's misfiring self, the computer would give out the code for "implausable signal" from the crankshaft position sensor. Since the misfiring problem seemed to have undertones of a ECM problem, I decided to replace the ECM with a working used one. I had replaced the ECM about four years ago due to a faulty coil which fried the thing. With the ECM replaced, once again the car ran great for a day then back to misfiring. A couple of weeks ago the Jetta drove into the driveway and not out. The poor thing will not start at all now. I decided to replace the distributor/hall effect sensor. The car still will not start. I know through testing components that I have power going to the coil but am not getting any spark. At this point I am reluctant to continue replacing parts unless I have a pretty good idea the replacement parts will work. Any ideas from the peanut gallery? Would the engine immobilizer go faulty and cause this? There are many components to the ignition system but only a hand full will actually prevent the car from starting so is there anything I am missing? I have owned many VW's from the Mk I's to the Mk III's and have always worked on them myself without too much trouble, however this one really stumps me.


--
hasenpfeffer-motorwerks

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Get a Bentley repair/service manual and a Volt Ohm Meter and check the
system and it's wiring at the ECM plug.

I have found that aftermarket ign. coils DON'T last and will not purchase
another one. I think some last maybe 1 week and I currently have one that
lasted 2 years. Did you buy a new ign coil from the dealer?

Also the wiring plug, the one that unplugs at the engine, can let water in
it and create some ugly running problems.
This might explain your CPS problem which you may find with the VOM test
procedure. ;-)
I would test it first with the VOM at the ECM plug BEFORE cleaning any
plugs/terminals so you can "locate" a problem. I hate problems that
disappear after you touch something that you don't remember what you
touched! lol

good luck and let us know what you find.
--
later,
dave
One out of many daves.

"hasenpfeffer-motorwerks"
> wrote in message
...
>
> I have a 96 VW Jetta with the 2.0L ABA motor. For the past couple of
months the Jetta has been running as if it is misfiring while driving. I
have tried to find the problem but without success. VAG-COM software says
that I am getting an "implausable signal" from the crankshaft position
sensor. I had replaced the sensor and the car ran fine for a day and then
back to misfiring. I then proceded to replace the coil, distributor cap,
rotor, spark plugs, and wires. Again, with the replacement of each of these
parts the car ran great for a day and progressively went back to the now
normal misfiring. Keep in mind, everytime the Jetta went back to it's
misfiring self, the computer would give out the code for "implausable
signal" from the crankshaft position sensor. Since the misfiring problem
seemed to have undertones of a ECM problem, I decided to replace the ECM
with a working used one. I had replaced the ECM about four years ago due to
a faulty coil which fried the thing. With the ECM replaced, once again the
car ran great for a day then back to misfiring. A couple of weeks ago the
Jetta drove into the driveway and not out. The poor thing will not start at
all now. I decided to replace the distributor/hall effect sensor. The car
still will not start. I know through testing components that I have power
going to the coil but am not getting any spark. At this point I am reluctant
to continue replacing parts unless I have a pretty good idea the replacement
parts will work. Any ideas from the peanut gallery? Would the engine
immobilizer go faulty and cause this? There are many components to the
ignition system but only a hand full will actually prevent the car from
starting so is there anything I am missing? I have owned many VW's from the
Mk I's to the Mk III's and have always worked on them myself without too
much trouble, however this one really stumps me.
>
>
> --
> hasenpfeffer-motorwerks

hasenpfeffer-motorwerks >
wrote:

> I have a 96 VW Jetta with the 2.0L ABA motor. For the past couple of
> months the Jetta has been running as if it is misfiring while driving. I
> have tried to find the problem but without success. VAG-COM software
> says that I am getting an "implausable signal" from the crankshaft
> position sensor. I had replaced the sensor and the car ran fine for a
> day and then back to misfiring. I then proceded to replace the coil,
> distributor cap, rotor, spark plugs, and wires. Again, with the
> replacement of each of these parts the car ran great for a day and
> progressively went back to the now normal misfiring. Keep in mind,
> everytime the Jetta went back to it's misfiring self, the computer would
> give out the code for "implausable signal" from the crankshaft position
> sensor. Since the misfiring problem seemed to have undertones of a ECM
> problem, I decided to replace the ECM with a working used one. I had
> replaced the ECM about four years ago due to a faulty coil which fried
> the thing. With the ECM replaced, once again the car ran great for a day
> then back to misfiring. A couple of weeks ago the Jetta drove into the
> driveway and not out. The poor thing will not start at all now. I
> decided to replace the distributor/hall effect sensor. The car still
> will not start. I know through testing components that I have power
> going to the coil but am not getting any spark. At this point I am
> reluctant to continue replacing parts unless I have a pretty good idea
> the replacement parts will work.

> Any ideas from the peanut gallery? Would the engine immobilizer go

It stumps me too, but you sure do seem to enjoy throwing parts at it.
Wonder what made you changed your mind. But what do I know, I'm just
the peanut gallery. But I digress....

I did a little checking and there is no OBD2 code for "implausible
crankshaft position sensor." There are "implausible" codes for other
things, and many crankshaft position sensor codes, but no implausible
crankshaft position sensor. So now I have to wonder what the real code
is.

Regardless, the computer is giving you a big clue here. Assuming your
interpretation of the code (and thats all I have to go on) is right, its
saying it doesn't like what its seeing from the crankshaft position sensor.
The computer fires your ignition coil based primarily on information from
the crankshaft position sensor (which it uses to judge engine speed and crank
position -- hence the name). I'm not suggesting the crankshaft position
sensor is bad, but the first thing to do is verify whether it is or not.
As long as the computer thinks its bad, it seem pretty unlikely that randomly
replacing unrelated ignition components (plug wires, plugs, rotor, cap, coil,
distributor, etc) is going to make a hill of beans worth of difference.

But thats just 2 cents from the "peanut gallery"