was working fine, now runs poorly. can someone pls help?

[mango-smoothie356]

I'm running out of ideas and have searched and searched here.

i have version 3 MJ.

I've been running it for years. on my way into work a few weeks back it just started running like a dog (poorly, felt like it had misfires). i did a uturn and went home, put the ca in the garage and i've been trying to figure it out since.

I'll be brief:

* worked fine until this

* starts fine, idles pretty good although i can hear subtle backfire pops

* VR sensor bracket and sensor secure (very) and close to trigger wheel (~1mm) confirmed at 4 points of the trigger wheel in case it had some how become out of round.

* unplugged MJ and confirmed limp mode with timing light.

* plugged back in and confirmed MJ seems to be working (with timing light on crank wheel, when i rev, i can see the shift in timing - this is good)

* thought it was a coil pack or half a coilpack. i'm currently running 2 GM style (and have been this whole year). i tested them, seemed fine. tried my extra single EDIS style. tested it and worked fine.

* plugged in all 4 inline spark plug testers. pretty cool to see at night. (all were working with wasted spark)

* plugged in laptop. can read / write / flash.

* when running, laptop / MJ software seems like normal behavior

* tack works (running off of CTO on EDIS)

so - logically it sounds like the timing is just off. but i didn't change anything - it just happened while i was driving

i think the next step is to test the voltage at 12v and when running. i searched for this, but couldn't find the specs.

this is where i think i need help (unless something i said above triggers an 'ah ha!' moment for someone.

thanks.

[mango-smoothie356]

i found these, but have not done them yet. is this is best place to start?


PIP Pulse

Test: Measure at EDIS pin 1 and MJLJ pin 2:
- should be battery volts DC stationary
- should be around half battery volts DC when cranking
Demonstrates: A working VR sensor and a probably working EDIS module with regard to generating PIP pulses


SAW Pulse

Test: Measure at MJLJ pin 5 and EDIS pin 3:
- 0 volts AC stationary
- 0 volts DC stationary
- typically 0.14 volts AC cranking
- typically 0.06 volts DC cranking
Demonstrates: A working VR sensor, a probably working EDIS module with regard to generating PIP pulses and a probably working MJLJ with regard to producing SAW pulses

[brentp]

It sounds like your ignition system is running fine.

As a final test I would verify with a timing light that it's setting the ignition timing correctly (e.g. fix timing to 20 degrees - are you measuring 20 degrees advance when running?)

If you can verify correct ignition advance, you should look at other problems; like fueling issues, running lean, etc.

Please let us know what you find out!

[mango-smoothie356]

thanks for the tip Brent. i did do this test (see video)

ignition is bang on. 8 degree and 15 degree global maps

so, looks like MJ is working fine

except...

on my timing light (you'll see in the video) every once in a while, it skips a timing flash

i tried an extra coil pack (edis) with the same behavior

is this somehow related?

http://www.youtube.com/watch?v=jGEVrOlF ... e=youtu.be

[brentp]

Timing lights tend to do this occasionally - they don't always trigger on the ingition pulse. I've observed this as well. The key is: do you hear a misfire exactly at the same time the light skips?