Crabbi

this kind of damage i would hear, and i would have chunks of metal along with my crank sensor would of shown damage to it, it was good when i took it out, i still have the old one, a small crack in the tone ring on the back flywheel i would have to see and considering its getting worse i should see it if thats the problem, i may try this later today or tomorrow,

Dave51

Not necessarily to all 3. Broken flexplates can be very difficult to diagnose.

But listen.

IIWY I wouldn't summarily dismiss anything at this point...

Crabbi

Yeh im trying to be optimistic but after how much stuff i tested and this all started out a simple replace lifters and have the head done while its out turned into a freaking nightmare, I never seen anything this crazy with diag,fuel spark and compression, check, runs good NOT CHECKED lol, im thinking pull the valve cover again and do a leakdown test on every cylinder, check flywheel, but it still feels like its sensor related and having no cam sync, until cam sync is fixed any of this could be from that error, from popping to studder all of it, i think getting the cam sensor to sync is paramount or the reason this runs so bad, now its just WHY LOL

Crabbi

ok, just so im getting this strait, i should not have milivolts on that wire correct?the brown with yellow tracer? would those be signal and when i unplug the TPS it loses one less sensor making resistance less?
im probly not understanding it is all

Dave51

I think finding trace volts is OK on circuits but if key off this part:

isn't. Wish I knew why, but I don't.

Meanwhile, until you can see the above waveforms, and if the sensors and PCM are good, you're SURE the flexplate didn't shift, I think you have to methodically check the harness. Another vulnerable spot might be in back of the head (because you had it off and maybe the harness is stuck between the head and block)(j/k)(ok, maybe not).

There could also be more than one issue.

Try disconnecting all the sensors on K167 one at a time to see if that reveals anything. Are you checking the resistance between sensors and Pin 4? Try checking K167 between sensors.

Dave51

When one says a circuit "has power", I (and I think everybody) takes that to mean "the power that it's supposed to have when it is energized", in this case 5 volts. Does this circuit "have power" or is it "trace voltage"?

Crabbi

i just looked over the flexplate from underneath, i can see some of it, i dont see anything that looks out of sorts and no metal shavings or anything inside,
So trace voltage is ok?
i have the harness unraveled all the way to the master cylinder, nothing is caught anywhere, i dont see any burn or rub through on the harness as of yet, i started at the cam sensor and unraveled to maybe a few inchs from the master cylinder,
I will sart checking all sensors agin on k167 for resistance with key off, if thats a true ground for the PCM i should have zero going back to the pin 4 correct? that wire should not have resistance?, or should it have some resistance? any ideas?

Crabbi

why would i have trace voltage on a ground wire? thats like checing for a parasitic draw on a system, if the key is off and i have trace voltage at those sensors then its a parasitic draw on the system isnt it?, which in which case it would be a draw? or am i missing something?

Crabbi

i ran a voltage test across the tan wire, outside wire on plug, i get a roaming milivolt reading that goes as high as 190 then down to even negative voltage, so i tried to unplug all the sensors looking for a change, i unplugged everything uptop and down below, i unplugged the alternator the AC, all sensors all injectors, all oxygen sensors, TPS. MAP AMbient air, coolant, IAC cam sensor crank sensor, oil sending unit, i unlugged the relay to the fuel pump, i would get some mnor fluxuations and would even go negative but it still keeps roaming cycling up and down in milivolts, i inspected the flywheel, its hard to see the tone ring, what i could see looked fins, im going to remove the starter and see if i can get a better look at the tone ring all the way around, but there was no metal shavings it actually looks pretty clean,
the test i did had the PCM plug disconnected from the PCM, so with the plug carrying the tan wire unplugged at the PCM i still have milivolts on that harness, i can only assume it runs other sensors off the other two plugs also which is were its getting power, but that last plug appears to have a bunch of the sensors on and it thhey all wind up on k167 on the wiring diagram
any ideas?
this is getting insane folks, this is a 2000 jeep lol, between the lot of us we probly have 500 years of experience, we have to be able to figure this out,
this all started with as soon as it went to close loop it had a misfire, it has steadily gotten worse with time to wear it does it at startup, it starts but its popping through intake and the only good scanner i had showed no cam sync but the crank sync was good, is there another process on the scanner to sync the crank sensor to the cam sensor? it should do it on its own i think, i still need to have it zeroed on the cam sync but my buddy is now in the hospital with a health issue, im hoping i see him later this week, im stuck, this thing has been in my garage for almost two weeks of replacing and testing, i checked alternator output today its fine, battery holds 12.8 volts, its old but it holds a charge and tests good, the alternator was replaced last year with a carquest which is why i tested it today,
any ideas?

Dave51

Yeah I'm stuck.

Good luck!

Crabbi

just for the heck of it, i pulled my new crank sensor, looking to see if it was damaged or something, no damage found, looked clean, i ran a ohm meter across it and the new one has 11 ohms on the AB terminals and the one i took out the original has 0 ohms on the ab connector, which one is good?

Dnnt give up on me now Dave51 lol, theres no way a 2000 jeep can beat this many folks,

Crabbi

Hey DAVE51

I just saw this on here in another post,
TESTING PROCEDURE 1991 – 2001 4.0L H.O. engines
1. Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
2. Place an ohmmeter across terminals B and C (SEE Image). Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace sensor if a low resistance is indicated.
If this is correct my new crank sensor is defective, and thats about when it started to pop through the intake, i may have added a problem which is masking the older issue which is how this all started, once it got warm it would start skipping and missing, then it progressed to pooping through the intake which slowly happend after i installed the new crank sensor,,
come on DAVE51 dont give up on me lol,
I LOVE BUYING PARTS LOL
it has a warranty im sure, was NAPA, ill get another one maybe test it at the store?

Crabbi

DAVE51

should a crank position sensor have resistance when checking across terminals on a bench?

my original one has no resistance on any terminals

my new one has resistance of 11 to15 on BC terminals i thing might by AB, but both test different

which one is bad or are both bad?

Dave51

I believe it is possessed. Next I would take it for an exorcism.

Dave51

IDK if you can test a Hall Effect sensor accurately using resistance, or if it needs power, or if whatever that's in there is unidirectional resistance (one of mine does) or if it's manufacturer specific.

I would use one of 3 ways:

1. The above o-scope.

2. Hook up a DVM to the signal wire, turn on ignition and look for a 5 volt pulse while turning the engine over slowly by hand (disconnect the coil cause God forbid it should choose to start).

3. Hook up a DVM with a DVA to the signal wire and crank the engine and look for peak voltage of 5V (not very accurate. All that tells you is that it probably works).