1991 Buick park ave 3.8l crank sensor

Hi guys I had a question I’m working on a 1991 Buick Park ave 3.8 when it gets hot loosing spark I have 2 photos of scoping the crank sensor at the ignition module it’s changing the pattern but still running in both photos it never dies but when hot you shut it off then cranking it and it won’t start. the first photo shows what it’s supposed to 18 on one and 3 on the other for every time the crank pulley spins 1 revolution. Thanks 

Your waveforms are suffering from a lack of sample rate. You have your scope set at a 500 ms screen. On Snap-on scopes, you cannot zoom in. You can, only, zoom out. You need to set the screen time to match the sample rate that you are trying to achieve. Set the screen time so that it is "zoomed in" as far as you want to go to achieve the detail that you want, when recording. Then, stop recording and zoom OUT to the desired viewing resolution. 

Retest and set the screen time to 2ms, as Paul (Scannerdanner) has done in this video.

Also, I could be wrong but, It appears that your Battery Voltage has a significant amount of AC ripple. You may want to look into that.

 

Great thanks. I think I have this one figured out I think it just needs a new crank sensor. but wanted to now what I was doing wrong because I think I got a bad new crank sensor. I really appreciate the help I’m new to using a scope.

Ok thanks