Hate to jump in - what did you use to chart this?

Thanks.

 

If the distributor was rotated or turned slightly couldn't that also cause the PCM to shift the spark advance around a bit causing something like this?

 

"The cranks sensor has 8 falling edges ... "

Thanks for the reply Hahns, we might be getting on to something. Can you elaborate on exactly how these "falling edges" work, look like, and interact with the CKPS? Is it possible that some of these "edges" are being read by it better than others? In short, I'd like to know exactly how the CKPS reads a signal and sends it to the computer. Thanks.

 

Aren't both sensors just reading one spot or one lobe?

 

Thanks for that, but I just tried moving the distributor slowly between advance and retard and it did nothing to smooth out the erratic firing; just wanted to stall completely when it got too far out of range.

Brian, I (again) examined and cleaned the connector to the computer, and everything looked bright and clean. Couldn't find a black/grey wire, but everything looked good. Even banging on the computer didn't fix the problem, which is particularly puzzling.

I'm with you - a boneyard computer swap wouldn't hurt. Still have to figure out exactly how the CKPS works though, and determine whether or not it's properly detecting each cylinder position. That's one of the few things that would seem to make any sense whatsoever.

As always, I'm open to any ideas from anyone.

 

"Aren't both sensors just reading one spot or one lobe?"

If so, how does the computer (and then the coil) know to fire each individual cylinder? I need to know more about the "falling edges".

 

[QUOTE=John D in CT;2604379]Thanks for that, but I just tried moving the distributor slowly between advance and retard and it did nothing to smooth out the erratic firing; just wanted to stall completely when it got too far out of range.

So when you test straight off the output of the coil, you see both strong and weak flashes, and then when you test each plug, its always certain cylinders that are always weak or always strong?

 

Not mine, this if from a fellow Dakota owner.
It appears the flexplate for the autos is different from how it's does on the flywheel on my manual but essentially the same. Here you can see, there's 8 square holes in the flexplate (or "falling edges"), this is what the cranks sensor "senses".

 

So I'm Googling "Dodge crankshaft position sensor" to try to find out exactly how it works, and I come across this question on Fixya.com:

Problem with the 2000 Dodge Caravan
The Car will start ,but it will not turn over

http://www.fixya.com/cars/t10519144-car_will_start_but

So let's see - the guy can get his minivan started, but he can't get it to roll over onto its roof?

This represents a new low in the never-ending confusion between "turning over" and "starting". The scary part is that this guy is probably a registered voter.

OK, back to plumbing the depths of the inner workings of the CKPS, and the legendary "falling edges".

 

"Here you can see, there's 8 square holes in the flexplate (or "falling edges"), this is what the cranks sensor "senses"."

Ah-hah! I wonder if some of mine might be crudded up with 17 years worth of goo. Sounds a little remote, but I don't have much else that makes a whole lot of sense. I'll pull of the CKPS tomorrow and crank the engine over (being careful not to roll my van over onto its roof) and see what they look like. Thanks a million for the excellent info!

***

By the way, that's a great-looking engine. Those valve covers are beautiful, and tall. Is that to accomodate the roller rockers? Also, where is the turbo located, and do you get any appreciable lag with it being a remote? Lastly, how much torque/HP you getting outta that thing? Maybe I'll just put one of those in my van; problem solved.

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OK, really lastly, how the heck does that flywheel work? I'm old-school, where they drive a clutch disc.