4x4jeepmanthing

I'm not following here, so you think it's still a sensor after I've had the diagnostic run?

To be clear I have a 99, why are we concerned with where the TCM is located?

awg

I agree with you that a wiring/solder/harness issue is more likely than PCM..it will cost $187 to check that, and OP will have a spare PCM...or it will be fixed

a time vs $ equation for the OP to consider

The TCM discussion arose as a side issue, as it was mentioned a pre-97 PCM may work for you, I replied giving my reason why i thought not

4x4jeepmanthing

So I have two scenarios that folks keep suggesting after all this:
- follow through with PCM replace as the diagnostic suggests

- try a new ckps even though mine reads that it's working.

Now intermittent loss is wiring related, But ive done point to point reading from each sensor to pcm, and grounds, and grounds to battery grounds, test light on battery shorted circuit test. Continuity reads very well even while jiggling wires. If it's wiring guys I'm lost on where to turn next. If they made replacement harnesses ide have likely tried it.

What do you all suggest, is it safe to bend the PCM open?????

4x4jeepmanthing

So, I picked up a JY pcm today 20$ matching# from a 99.
Disconnected the battery started right up, but seemed to run slightly rougher. CEL wasnt on, let it warm up to operating temp, shut it down, restarted and the CEL comes back. muthaaaaF____r. Not happy about that lol

So NOW what in the world woukd you do next. Thus far I wrote the shop explaining their mechanics theory and it not eliminating the CEL have tried a new comp.

awg

[QUOTE=4x4jeepmanthing;35611
So, I picked up a JY pcm today 20$ matching# from a 99.
Disconnected the battery started right up, but seemed to run slightly rougher. CEL wasnt on, let it warm up to operating temp, shut it down, restarted and the CEL comes back. muthaaaaF____r. Not happy about that lol

So NOW what in the world woukd you do next. Thus far I wrote the shop explaining their mechanics theory and it not eliminating the CEL have tried a new comp.[/QUOTE]

If you have the same code you may have an intermittent, or weak wire or connector.

If you research the OBD code thrown, and it indicates that an OPEN circuit or high value can be the cause

I did find a sensor fault on an Isuzu Trooper this way, turned out a female pin in the connector harness was pushed back a bit

In the instance of not being able to locate the problem in the harness, what I would consider is this;

make backprobes with 5amp wire and safety pins, identify the relevant suspect wires from the circuit diagram...piggyback them...see if the problem go away

I admit this is time consuming & challenging

4x4jeepmanthing

I am comfortable trying this, not to be difficult, but after having done continuity tests on all wires to pcm and 5v signal/supply voltage reading, am I simply back probing harness side into sensors and re routing back probe to pcm?
Would this back probing complicate sensor grounds going from sensor straight to pcm vs anywhere it originally splices in the regular harness?

Here is what i ran through for continuity and signal/supply tests:

awg

You are eliminating as many bad connectors as possible..so as close to PCM and sensor as possible

Continuity test will not eliminate an intermittent open, due to bad wire, connector, solder

an intermittent short would mean having to cut the main wire (once its piggy backed)

the bad "wire" could be earth, positive or sensor wires

Following a logical path if it isnt the PCM, you have tried other crank & cam, it must be the wires

(unless it does in fact have chain stretch )

did you say your truck runs well and has no symptoms ?

this would be very indicative of a temporary dropout of signal

4x4jeepmanthing

to be clear, can I build my wires and connect them directly to sensor and into the PCM plug, I'm to bypass the harness completely yes? And one at a time ide imagine?
is there anything ground wise that I should recreate like pigtail to motor and pcm? I have a bunch of 16g wire I can use.

awg

I am suggesting making piggyback wires with safety pins to probe the connectors. So the original & piggyback will be in place..(unless a short is suspected)

Yes to one at a time. Clearly you need to be sure on which wire is which!...you seem to have that info.

If the sensor has an earth wire to the PCM, that has to be duplicated..each wire to the suspect sensor/s

start, check CEL, try again

I have personally used this method to find some weird electrical faults

If your truck starts and runs perfectly, I do not see how it can be the crank or cam sensor

(all subject to you checking the chain slack, I think you can remove the dizzy & rotate the engine to check)

Dave51

Did you ever inspect the flexplate (the "tone wheel" for the CPS)?

Dave51

So exactly how long have you been 1391ing? Since you first got it? Could the PO have done some transmission work and bent the flexplate, or maybe stuck one in from a Toyota Camry?

4x4jeepmanthing

Yes, a few months back I swapped engines. In doing so I reused the 99 flex plate, I looked it over very close for cracks which I did not find. All torque converter bolts are quite tight. The bottom bolts of trans to engibe were torqued, the top two I just gave hell, probably much more than needed lol.

As for the cam pulse ring I replaced the distributor just In case, which still hasn't changed anything.

4x4jeepmanthing

I will align the harmonic balancer to 0 degree and turn counter clockwise until i see the rotor turn, noting the degree on the timing cover once it does turn.

ive owned the vehicle 13 years. this has been going on for almost two of those years. I dont know how a flex plate would get bent?

Dave51

And the CPS is properly positioned over the windows?

Dave51

A PO could have messed it up, but given the history, I imagine not. At any rate, the position of the windows is critical, and if it wasn't checked it needs to be.