D
David Farber
I have a '97 Legacy wagon GT, 2.5L engine with about 72k miles. My car was
going along just fine on the freeway at 65mph when all of a sudden it lost
power. I was able to safely coast to a stop away from traffic. I had the car
towed to a local mechanic. He called me the next morning when he had time to
debrief me about the failure and whether or not it had overheated or I heard
any unusual mechanical noises. I told him the temperature gauge never moved
above where it usually sits and there were no extra noises. He said he could
not pinpoint the trouble right away. The engine check light did not come on.
The timing belt was good and nothing else seemed wrong at first glance.
Later that afternoon he called back and told me that two of the cylinders
were not getting spark. That made sense because when I tried to restart the
car after it shut down, the engine was shaking pretty good like it was
missing on two cylinders. It would not run like that of course. The mechanic
decided to replace one of the coils as an educated guess. It took about a
day to order and receive this coil. He said that there are two coils and
each coil is responsible for firing two cylinders. The new coil however did
not change the situation. Still two dead cylinders. Now the mechanic seems a
little bit lost as to what to do next. He works on all types of cars and
probably doesn't get very acquainted with any one type very well. My feeling
is that it should be fairly easy to hook up a scope and see if there is
signal getting to the coil that is not sparking. My guess is there isn't any
input signal to the coil since the new coil did not fix the problem.
Tomorrow will be day 3 in the shop for my car and still no correct
diagnosis. So my questions are these. What part of the system sends the
signal to the coil to fire? I know there's a cam sensor but is that
responsible for the ignition firing? If so, is there a cam sensor for each
coil? Any explanation of this would be appreciated. The last time I worked
on cars they had points and a distributor. (-;
Thanks for your reply.
going along just fine on the freeway at 65mph when all of a sudden it lost
power. I was able to safely coast to a stop away from traffic. I had the car
towed to a local mechanic. He called me the next morning when he had time to
debrief me about the failure and whether or not it had overheated or I heard
any unusual mechanical noises. I told him the temperature gauge never moved
above where it usually sits and there were no extra noises. He said he could
not pinpoint the trouble right away. The engine check light did not come on.
The timing belt was good and nothing else seemed wrong at first glance.
Later that afternoon he called back and told me that two of the cylinders
were not getting spark. That made sense because when I tried to restart the
car after it shut down, the engine was shaking pretty good like it was
missing on two cylinders. It would not run like that of course. The mechanic
decided to replace one of the coils as an educated guess. It took about a
day to order and receive this coil. He said that there are two coils and
each coil is responsible for firing two cylinders. The new coil however did
not change the situation. Still two dead cylinders. Now the mechanic seems a
little bit lost as to what to do next. He works on all types of cars and
probably doesn't get very acquainted with any one type very well. My feeling
is that it should be fairly easy to hook up a scope and see if there is
signal getting to the coil that is not sparking. My guess is there isn't any
input signal to the coil since the new coil did not fix the problem.
Tomorrow will be day 3 in the shop for my car and still no correct
diagnosis. So my questions are these. What part of the system sends the
signal to the coil to fire? I know there's a cam sensor but is that
responsible for the ignition firing? If so, is there a cam sensor for each
coil? Any explanation of this would be appreciated. The last time I worked
on cars they had points and a distributor. (-;
Thanks for your reply.