Crabbi

Thank you for the reply

it is a pain in the rear but not to bad, with the scanner i can zero it in also, they are tuff to get exactly to zero but being patient helps, I have a PCM coming for it, im trying to ohm the other two wires on the cam sensor, 18 on plug 1 is the signal wire i ohmed it all the way to the cam sensor showed perfect, were on the PCM do i check to OHM the other two wires?
any ideas?

Dave51

Wiring schematics in here:

https://cdn.xjjeeps.com/pdf/en-us/20...ice-manual.pdf

Crabbi

HOLY SMOKES,

Thank You Dave51, i can use this to trace down the other two wires, PCM comes in friday, im stumped until then, i can ohm those wires though and at least get it narrowed down to that, Or timing chain at 140k, dont look like it would be that bad i have no problem doing it, just dont want to if i dont have to lol,
any other way to test the chain just spin it and watch cam sync assembly top? like you would a distributor?

Dave51

Yup, and you can figure out degrees of slack, but by the symptoms you describe I'm thinking less "worn timing chain" and more like "catastrophe".

Have your "buddy of mine who owns a shop bring over his brand new snapon scanner, it comes with little folks that jump out and run wire leads to stuff for you" and do this:

https://www.scannerdanner.com/chapte...n-or-belt.html

It the flex plate cracked and wobbly? Although this would show in the CPS/CKS signals, IIMW I'd take a look mostly because it's cheap and easy.

Dave51

BTW 2000 has a dual ("waste") spark system so there'll be an extra spark in there.

Crabbi

I have a bore scope and i did not see a crack in the flexplate through the cranks sensor hole, doesnt mean there isnt one and i had a good shot of it while i watched it go around, the timing chain has some play but nothing crazy, and any of those should show up with a code of some sort, this is a complete no code failure, if i unplug a sensor it will show a sensor failure it but it will not show anything while its sputtering misfiring and shaking along with popping through the intake, and i have good signal on scanner for cam wavelength etc, the scanner can see the cam sensor and see it working, but the PCM will not sync them leaving it with no timing and no fuel injector pulse which is messing it up pretty bad, the only good thing is its getting worse, so something is going to fail, if this thing didnt run like a clock immediately following a valve job i would even bother, but it ran perfect until it warmed up, its funny but thats how this started, valve job was done it ran perfect until it warmed up then it skipped and shook, it didnt used to start until about 160 now it does it when it first starts, its progressively getting worse, all with no codes, i thought maybe they missed a crack it is a 0331 head, but they magnafluxed it and valve job etc, vac tested for valve leaks, dont mean when warm a crack isnt there but the test at the shop showed it had no cracks, and i showed them were the head gasket had blown between the cylinders, compression test is good, all valves are moving when turning engine, everything on the top end is new except the head which was rebuilt by a machine shop. when i resynced the cam sensor it lines up perfect on top dead center, if im off a tooth i should see it there correct? it should be off trying to sync sensor if it jumped a tooth? at least i think it should be

Dave51

It does sound like an open/closed loop thing. Can you look at the actual O2 sensor outputs? Make sure they're not like 0.00 or 1.00 V. Yeah, they should throw codes, but looking is cheap and relatively easy.

After that, I guess PCM is the only thing left!

Crabbi

all 4 o2 sensors are brand new, NTK, all 4 show on the scanner and appear to be functioning, it did the same thing with the old o2 sensors, and the scanner can see them working, doesnt mean they there ok but no codes and they fluxuate with the eng temp, im trying to ohm all the wires on the cam sensor looking for shorts etc, i can ohm the signal wire and its good, i can see a 5 volt reference wire, and i am trying to ohm the yellow or orange or black back to the PCM,
im trying to ohm the yellow wire back to the PCM which should be pin 4, i ohmed both yellow/tan back to pin 4 and at the PCM plug, i get 90, i ohm the orange wire back to the same pin 4 and i get 1.56 wich looks ok but why is the yellow and orange both ohm on pin 4? i know one is the 5 volt reference,
what ohms and what pins on the pcm plug should i be checking? any ideas?, the wiring diagram helped me find pin 4

Dave51

Which tooth are you talking about? This (these) ones?



OK this is a little severe, but it is possible to jump a 4.0 timing chain (this owner said it was merrily spinning away, potato, potahto...)

Anyway, the above test outlined by scannerdanner will match up spark against TDC.

BTW did you run a screen of the coil outputs?

Dave51

Dave51

The coil may be good but the drivers are fried.

Dave51

Can you make a graph to see the actual volts?

Also reset the PCM just for laughs. Cheap and easy.

Dave51

And since this all started with fiddling with the injectors, run waveforms of all of them too. I have a graph someplace...

Dave51

Dave51

Cause you could have fried all those drivers.