Yeabut---

The vehicle is running well so arbitrarily picking a few windows one would expect to see normal activity. And you're doing about 1 RPM. Might be a little different at 2000 RPM. We only need 20 events to trigger the code and if you've got a little skip in there that could be what's setting the code.

To 97G's point it's going to be very subtle.

And admittedly, although fiddling with air gap and sensor position is purely trail and error, the alternative is pull the flexplate out (and we're (I'm) talking flexplate cause it's like, what's left?) or go back to your garage guy and see if he's reading CPS signal (and the cam too for that matter).

But it started in the other engine!!!

Another great puzzle...

 

quick one...I gotta go out

dial gauge on the flexplate to check for runout

should be reasonably easy to do ?

flexplate runout could theoretically cause this issue imo??

its almost to repetitive to be an intermittent ?

 

Runout= flex? Like to or from bell housing?

Would an intermittent airbag light or my new missing brake lights be related?

 

Is two channels all that's needed to see scope overlay of cmp/ckp?

I don't understand why if 20 times the code is set, why will it not show until 2nd start?

 

 

[QUOTE=4x4jeepmanthing;3562102]Is two channels all that's needed to see scope overlay of cmp/ckp?

Yes. NOW, you're thinking good. Set the external trigger to either one of the channels. I have been watching the oscope sales on Ebay they can be had for $100. SO tempted. If you watch Danner's video he is using the pico scope, but, any oscope will work. And you can see on that what a good and bad signal looks like, 100% precisely, and the timing in relation to the ignition spark, and other sensor.
Maybe take it back to that shop and insist on viewing those waveforms with the tech?


IMO you're overlooking the cam sensor's role. Easy change out there, and the codes will mess with each other on the obd2.

 

Yeabut--

Your guy said the signals were synced so IMO if you can even get a one-channel that should work. Based on all this it would seem that it can ONLY be the wiring or the flexplate, so looking at each signal separately should uncover the issue.

BTW you now have a distributor? And the 99 PCM?

 

Oh hold the phone! This could be a problem indeed! 99 did not have a distributor, did it? The cam sensor signals could be entirely different that the pcm is looking for. THIs could be it.

Its not just that the signals are synced, if you look at the video you'll see the square wave for the ckps is not intact all the time. So the leading and trailing edges may start and stop when supposed to, but as in the vid if the wave itself is broken up, the pcm will try to trigger from the erroneous breaks instead of the leading and trailing edges.

 

Having done this one might think it could ONLY be the flexplate, but you appear to only have supplemented the wires rather than bypassing them. IMO in order for this workaround to cover all possibilities you would need to put in 6 new wires (or at least the grounds and signals. I'm thinking if you had a power problem along the run there's be something smokey).

 

No, it did, and it looks like the OP is using the 99 distributor:

But that would have been a good Aha Moment!

 

Inspector Cousineau says "I am still suspicious!!!!!! Some sing is not right here!!"

 

OK..step back..the problem existed before..it has not been introduced by something new

once you confirm the OBD codes are clear from the PCM, have inspected the connectors with a magnifying glass, and checked the flexplate isnt warped with a dial gauge

then it is time to go back to the pro with what you have learned, and scope it again

also may be worth trying a cheap cam or crank sensor to see if anything changes

cutting the wires in case of an intermittent short is your last step imo before you have reached the end of diagnostic options to have the vehicle economically repaired

 

Will the dial be able to tell if the flex plate is warped when turning it slowly? i thought we were worried about what it was doing at speed?

Why cut the wires, is this to rebuild pins, I'm not following? This would be only if the harness didn't ohm out good?



also i picked up a spare Jy harness, ill need to test obviously but hell its something. i figure i can at least learn where is splices wires in it. cheap 20$ worth it

 

cutting wires is only done if I strongly suspect a short somewhere, and a bridging wire is made to cover from point A to B to eliminate the short..ie in a connector

It does not sound like this is an issue in your case

with respect to the flexplate..if its out at hand turning speed, that would be magnified at speed.

the next step would probably be to to replace the flywheel with another one

 

Because there could be an issue with the wiring which needs to be ruled out. IMO I don't believe the flexplate is bent. How could that happen out of the blue?

However, I could see there still being a flexplate issue if there were 2 different causes for 1391 (one you inadvertently fixed while doing the engine change, and a new issue after the engine change)(it'd be about the same chance of it starting to rain blood in the next 5 minutes, but theoretically still possible).

That said, we're really starting to reach here, so let's get back to the wires. Hall sensors should be reading 0.0 or 5.0 volts. There is an acceptable range for power, but zero should be zero. However, you have some residual voltage there:


562023]

Does your meter autozero?

You should do this test on the camshaft sensor as well. We shouldn't get tunnel visual and keep thinking crank sensor.

IMO isolating the circuits as much as impossible is a worthwhile direction because cam and crank sensors share a TON of other grounds, and the issue could be in there someplace else:



Searching the harnesses along the K167 circuit for issues might not be a bad idea.

Anyway, rewire the 2 sensors, make sure the multimeter is zeroed, repeat the test for both of them and see if you can get 0.0.

If you still get residual voltage then put those new wires on the PCM ground (should be A4) and take everything else off.