Black91SHO
SHO Member
I'm not sure if this is the right forum area to post this, but here goes nothing:
I was driving my '91 SHO with 115,000 on it today when it started to stumble. Kind of like the current to the spark plugs dropped out completely for a second. It's different than a miss, which is rhythmic. This was more sporadic.
The tach would accurately read 3,000 rpms, then the needle would start dropping and recovering, but it was doing it really rapidly, like lots of tiny little misses, but not misses. When it misses, the tach needle doesn't usually fall. It seems it's more of an electrical issue where the current drops suddenly, causing the needle not to read the voltage. It would jump back to the correct rpm during these quick flutters of the needle.
This seemed to happen more readily when the engine was under load. The more load it was under, the more likely it was to happen and the more harsh it was when it did happen (more stumbling, sometimes harder stumbling). So more current equaled more stumbling, which again, I'm guessing, means something electrical is breaking down when it gets too much current or gets too many bursts of current too rapidly.
It kind of acts like a crank sensor going out, which it very well could be. But before I got breaking the bank to have that replaced, is anyone else thinking it could be something else?
It's had the crank sensor replaced on it a while back, but there was a short in the wiring harness that was affecting the electrical components, which is why I replaced the crank sensor. But the wiring harness was changed later than the crank sensor, which means the crank sensor was probably getting some bad voltage mojo when the wiring hardness would short out (it would cause the rpms to flutter like what's happening now, sort of). That could've worn it out more quickly and it's about to **** over on me now.
Any thoughts?
Thanks guys.
- Brian
I was driving my '91 SHO with 115,000 on it today when it started to stumble. Kind of like the current to the spark plugs dropped out completely for a second. It's different than a miss, which is rhythmic. This was more sporadic.
The tach would accurately read 3,000 rpms, then the needle would start dropping and recovering, but it was doing it really rapidly, like lots of tiny little misses, but not misses. When it misses, the tach needle doesn't usually fall. It seems it's more of an electrical issue where the current drops suddenly, causing the needle not to read the voltage. It would jump back to the correct rpm during these quick flutters of the needle.
This seemed to happen more readily when the engine was under load. The more load it was under, the more likely it was to happen and the more harsh it was when it did happen (more stumbling, sometimes harder stumbling). So more current equaled more stumbling, which again, I'm guessing, means something electrical is breaking down when it gets too much current or gets too many bursts of current too rapidly.
It kind of acts like a crank sensor going out, which it very well could be. But before I got breaking the bank to have that replaced, is anyone else thinking it could be something else?
It's had the crank sensor replaced on it a while back, but there was a short in the wiring harness that was affecting the electrical components, which is why I replaced the crank sensor. But the wiring harness was changed later than the crank sensor, which means the crank sensor was probably getting some bad voltage mojo when the wiring hardness would short out (it would cause the rpms to flutter like what's happening now, sort of). That could've worn it out more quickly and it's about to **** over on me now.
Any thoughts?
Thanks guys.
- Brian
