I got time.

Besides, we only need to look at 2 channels. And we keep coming back to "the engine runs fine" (BTW JMT your idle video, where you claim "fluctuations", half the people here would kill to have an idle like that!)(the piece of electrical lap dancer is still on the table!)(and I'd do that before I pulled the flexplate out).

With the coarseness of the voltmeter we've gone as far as we can. The oscilloscope will be able to look at hundreds of signals, make sure power is consistent, draws down to completely to ground, and insure signals are synced.

Stuff still on the table - how much deflection was there in the timing chain? Did you test the cam sensor for 0.0 - 5.0 voltage? Also for the second time you go to start the engine, how long from start crank to appearance of the CEL?

If you want to get a cheap oscilloscope, get one designed for automotive use so you get a pile of automotive software that does most of the setup work for you and gives you some useful leads.

Y'know, this has been such fun I may join you on that route.

 

typo I know, but that is indeed what seems to be happening to the OP here, his vehicle is surely giving it to him

 

What, I never said that!

 

Deliverance style lol

 

Poetic license.

 

Paul Danner says a draw-down ground signal of 100mV or less (0.1 volts) is acceptable.

 

Of which signal?
So I'm ok There?

 

The cam and the crank, but that's on the scope. If you only have several data points using different methodology, IDK if you can write this one off completely yet, but I guess this is good news (or bad, depending on how you look at it). Did you do the cam?

 

Here is a good scope diagnostic explanation read showing (jeep wrangler, from the address bar on his scope ) generic waveforms for cam and crank, also pictures of the trigger holes in the flexplate/ flywheel

http://abautomotive.ca/2017/02/22/ve...ad-ckp-sensor/

 

That's a nice write up.

 

Watch "Cmps" on YouTube
This was back first testing this a few months ago.

 

Coil pack 4.0s have a dual spark system. IDNK that.

 

Yeah, that's much too coarse to be of any value.

To refocus our refocus:

We are trying to fix a perfectly running engine.

Alternatively--

How do we make a CEL go out that has (apparently) no reason to be on.

We need to start thinking like a PCU.

What about the timing chain?

 

Never had the timing cover off to measure deflection, i just had the video of me poking the chain. Didnt seem like a lot, but old.
I added the oil pan back on with more rtv to stop it leaking in the front. Pulling the cover would be a bit crummy if I don't need to pull it.

Nothing in the fsm on measuring, just what was posted on here.



Still haven't heard back from this mechanic, I think it's nothing they care to try with another scope?

Will a cheap scope work?
Does this give us enough info with only 2 channels?

I tried unplugging the tcm and measured grounds as requested, which we decided was good based on that danner comment yes?

No use testing ohm on 3ft of new wire now right?

I can get new readings from the pulse ring while turning the crank by hand if that's helpful. you said the video isn't clear enough.

 

one thing i meant to suggest a while back...slot the CPS holes, and try it moved both ways...that would be damm lucky!, I would also try shim it out