so picture 1. is mopar cps
picture 2. is new echlin

 

[QUOTE=4x4jeepmanthing;3583435]everything distributor wise is new now. this happened with mopar distributor assembly and aftermarket.[/QUOTE

sorry, my bad on the timeline, feel bit like a detective interrogating a serial sex offender suspect

I admire your determination, at least you will be good to keep your XJ on the road in future

In addition, if you end up having to change timing chain, it will probably be less time consuming than all this electrical work

 

Can you reduce the vertical on the coil? Also, add Measurement, Maximum to each of the channels.

Are you getting a used, or free CPS to try? If not, I'd keep looking for the entry point for that scatter, including isolating the CPS sensor signal back to ECU, and for that matter, all the coil wiring.

Did you replace the coil wire?

When it's pitch black outside take a look around there and see if you can spot any arcing.

 

NM I see you did that by your answer in the quote above
Change thought process. Rather than thinking it's a CPS problem, consider it a coil problem. If you go back to the first waveforms




you've got coil scatter in the CKS too. If all of the Hantek components are away from the coil (these are inexpensive cables so probably very susceptible to interference) then we should consider the coil leak (short) to ground instead of CPS.

You could try doing additional investigatory experimentation (screwing around) by looking at other sensors (injectors or stuff near the coil) to see if there's artifact there as well.

 

It's not that CPS sends a signal, ECU allows the circuit to complete. Maybe that's why the spike is higher when a signal is sent.

 

so can this in turn be an issue with the coil driver in the pcm, or just crappy probes?
now that both sensors are new that spike does have me curious, your graph didnt have any of that, better scope to though.

 

No, it's doing it's job perfectly. I am theorizing that when CPS is at 0.0 volts, the circuit is open, therefore the interference can't come through.
They're fine too, unless you lay them on top of a high voltage wire like the coil or spark plugs.
For all intents and purposes, I believe our setups are identical. I got a lot more channels, but that don't amount to a hill o' beans.
Should make you more than curious. If the Hantek isn't picking up scatter (and if your cables are clear of the aforementioned high voltage wires, it shouldn't) IMO this suggests that the coil signal is grounding out somewhere.

 

test light to wires time? or do you still think i should be able to see arcing in the dark?

 

Hey, it's easy and free, so start there.

After that, unbolt the coil and hold it away from any potential grounds, move wires while monitoring the cam waveform to detect any change.

Did you say you have new plug and coil wires?

 

Spark plug wires came with the engine, accel 8mm.

coil is new as is the harness to it.

 

well i tried checking for arc with at testlight and looking in the dark with no luck. Im still curious as to this spike and what could be causing it. when i went through the harness I soldered, tapped, and ohmed everything before replacing it. I have no idea other of what this code be from, the spark plug wires are the only thing that have not been replaced lol, though I did ohm these while moving them around before I choose to use them vs my old ones when I swapped engines.

more importantly ive put a code reader on the jeep and p1391 is no longer being registered!!!!! looks like I can put my CEL light back in the dash.

 

Congratulations...if its gone for good, (and you didnt replace any parts), that hints at an intermittent wire or connection right up near the harness connector,
and the probes being stuck in has "forced" a better contact, just something to bear in mind if it does return

I had this happen to me and was fortunate to find it was the female pin in a connector had been forced back a wee bit

 

This thread is #10 all-time on the list of Normal Threads in terms of replies!

My morning news thread!

Things just won't be the same...

 

Yes yes, the lack luster diagnostic merry go round is over, I hope, but hey, I haven't tried kerosene yet so there's that.

I do appreciate all of your patience and guidance walking me through some of these diagnostic ideas, it has been a great learning opportunity, and there has been tons of helpful ideas that I'de never read of on related threads. For what it's worth I still spent less on the scope and sensor, even though we still have a weird spike in the signal, then what I would have for a shop+ parts.


thank you

 

Right. The xj AW4 has one. The zj 42RE does not. My bad. 3 years late on the apology but better late than never?