Hey friends, I've got a really rich, rough and fumy idle and I'm concerned my fuel sync is off.

When I scoped the relationship between individual cylinders' spark and injector waves, I found that the injectors are shooting in the middle the exhaust stroke. This doesn't seem right.
Am I wrong to think that the injectors should be firing right around TDC of the exhaust stroke?
Is there any way to set fuel sync with out a fancy tool?
Can I just set it by watching ignition and injector waves while turning the cap until I have an injection closer to TDC of exhaust?
Also, I'm curious if anyone has a known good waveform of a CKP and CMP relationship, or a cyl spark and injector relationship. If so, please share!
Thanks all!

Here's CKP/CMP. (CMP is blue)

Here's a parade capture of the coil with CMP for reference. The first cyl fires just before the blue line rises. (Firing 1-8-4-3-6-5-7-2.)

Here's cyl 7's spark (green) and injector for reference of where injection is occurring. Each blip between the ignition and injection should represent a half stroke, right? Please correct a fella if he's wrong...

 

Looking at the first graph, it looks like cam position sensor is switching one per 8 coil firing incidences? That's not right. Should be four. Are they on different scales?

 

That's a yezzer, the time scale is the same.

 

To be clearer the first image is the cam/crank, not the cam/spark.
The second image is the coil/cam where you see that there are 8 ignitions per full CMP cycle/rotation.

 

Ok, 8 windows in the flex plate that the crank sensor reads.

Is it just me, or is spark energy tapering off in that graph?

According to theory, the injector fires right before the intake valve opens. Idea is, with the pencil beam injectors, the fuel vaporizes on the back of the toasty warm intake valve. It does *seem* like your are firing early........

 

Good info on the injection theory. Much obliged.

That tapering off in the spark line does have me concerned as well. What could that mean? Leftover voltage in the secondary winding?
It's not always there but here's a good capture of it in the coil parade view. The second image is when it doesn't appear.

 

Ok, green graph is coil? That's REALLY inconsistent. Another member saw that type of thing, and it was due to his aftermarket crank sensor, but, as I recall, your crank sensor gives good, consistent signal, so, I don't *think* that's it..... How old is the coil?

 

Yep, that's a NEW coil giving us that green spark line.
CKP is definitely giving us that consistent signal, whether or not the PCM is receiving it could be another thing.

Looks like the first pic didn't attach correctly - here are a couple that show the tapering. Look at that cyl 7 (middle) firing line - extra hich on the first capture and not even there on the 2nd capture.

 

Bad transistor in the PCM? Bad ground somewhere? Check the connectors at the pcm, make sure they are clean, and tight. Might wanna open 'em up, and make sure there aren't any problems where the connectors are crimped on.

Just out of idle curiosity, what are you using to generate those graphs? (I want one. )

 

Haha, yeah, I'm a kid in a candy store with this thing! I'm of the mind now that I should have ALWAYS had one. There's so much you can see with a simple back probing of an injector or ignition wire.
With an amp clamp on your starter cable you can quickly check your relative compression too. I could have saved SO much time in diagnostics with this or any engine if I had one before.

The scope is a Smartscope by a company out of Belgium called LabNation:
https://www.lab-nation.com/

For folks looking for a reliable 2 channel oscilloscope that's fast enough for automotive, it's the best I could find short of buying a cheaply made one from China. I'd definitely recommend it. Wayyy more affordable than a Picoscope or Snap-On variety. What I really love is that you can connect the scope to laptop, tablet or phone and the software is really user friendly - especially easy scaling on a touch screen.

In the meantime, I suppose I should check the primary ignition voltage from the PCM transistor which I'm imagining is a ground side switch. Then I'll double check the ground on the coil.

Next thought, the inconsistency of the individual cyl's firing lines makes me think that the fuel pressure could be oscillating too much at idle.
I have checked fuel pressure and got an even 49 when primed but not running. As soon as it's idling, I'm seeing pressure fluctuation up and down (maybe +/- 8 PSI?).

Question being: is fuel pressure fluctuation normal or should I be seeing a very constant pressure? Maybe the fuel pressure regulator is shot?