S-Coupe Turbo(UK) misfire help needed

  • Thread starter Thread starter Awptech
  • Start date Start date
A

Awptech

Hi
I have a 1995 model S-Coupe MVTI 1.5 and for ages it intermitently looses
spark on the 2nd cylinder.
HT leads have been replaced 3 times, plugs twice new coil fitted recently
and the ECU reports no error codes...HELP
It could drive a few days without problems then suddenly looses spark
COMPLETELY on 2nd cylinder, where that particular lead connects to coil,
at the coil end it is dead too, what else can this be
Any answers are much appreciated.
PS 60k miles on clock.
 
If I understand correctly, you have verified there is no spark coming out
of the #2 coil tower. Do you know if the coil is being commanded to
fire?

I heard of a case where the crankshaft sensor wheel was damaged causing a
false TDC read and a lack of injector pulse or spark on #2 cyl. (Firing
order is 1-3-4-2). I believe this car set a crank sensor code, however.

But this case does remind me to ask whether you've checked to see if the
#2 injector is firing?
 
Yes that is right the spark isnt present at the #2 coil tower. The coil
must be being comanded to spark ok as the other 3 are ok. Not unless they
are all independant of each other meaning the fault might not be anything
todo with the HT line voltage at all?
As far as i know injector 2 is just fine.
What confuses me is the way the engine can run fine for quite a while then
this happens for a few secs to mins at random intervals.
Is the crankshaft sensor wheel easy to change?
Another point to make, when idling the engine can idle a bit poor at times
when warm but once throttle is added it runs at full power just fine, this
is when the misfire is not present. A plug,lead change didnt help.
 
After double checking injector 2, it is working ok, just no spark from the
coil tower for cylinder number 2.
Can you recomend any parts/sensors that could be changed/checked to
rectify this? coil/plugs and leads already done.
Just to add, the car ran ok for 2 days then the spark dies off again for a
few minutes today. the local hyundai dealer cant find anything or cant get
the car to misfire while in shop!!!
 
I believe the 1995 Scoupe has two coils and no distributor. The coil for
cylinders 2 and 3 could be having an intermittent problem.

The sensor wheel doubles as the flywheel (manual) or flexplate
(automatic). As such, you'll need to remove the transmission to replace
it.
 
Here is a simple thing you can try , the crank sensor is magnetic in
nature and on a manual transmission equipped car will get covered with
metal particles . Just remove the sensor from the transmission and
wipe off the particles if present . This fix the problem I had on my
95 Scoupe .
 
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