I just tested the crank sensor and with an ohm meter on B and C I got 29.93 steady. I thought that was supposed to be infinite??

 

It is.

 

How are going to 'check' the cam sensor?

 

By swapping it with one I have in my garage. I have no other way to test it. What is your take on the crank sensor reading? I seem to have a lot of issues that point to the crank sensor being bad but, it starts just fine.

 

There's only a few tests you can do on the cam sensor but I wouldn't be bothered. Swapping it out may be the best way to go.


While you have the distributor cap off check the up & down play on the distributor shaft. You should see only about .030 play.


Normally, the crank sensor should have no resistance but I've seen posts by others that stated they see a resistance and their Heep's start just fine.


Also, the crank sensor has a bad habit of breaking down when it gets hot.

 

This may sound stupid but, can a bad crank sensor cause the gas gauge to act funny? When these problems started, my gas gauge started to act up. Sometimes it works,sometimes it doesn't.

 

Here is a link to a video I just made. The jeep had been sitting since last night and I started it up and just let it idle. Just as the temp gauge got to about 190 or so, it started to idle like this. It has been idling like that for about 35 seconds prior to the video starting because I am a retard and never hit the record button. At no point in time did I touch the gas. Please watch and tell me what you think. Also, I have no idea why the video is flopped on it's side and I have 3/4 of a tank of gas, the gauge is just being dumb.

 

Remove the connector from the crank sensor, turn the key to RUN, see if the gas gauge reads normally.

 

It read normal for a second and then slowly went back down to empty

 

You have a basket case. LOL


I think the PCM is working (in this respect) otherwise you wouldn't get the low fuel advisory light.


Your fuel quantity sender may be buggered up.


BTW, have you checked the fuel pressure at the rail with the engine running? Sound be 49.2 psi +/- .5 psi at idle. Advance the throttle from idle to a higher RPM and watch the fuel pressure.


If you want you can check some sensor voltages at the crank sensor connector, using a digital voltmeter.


Unplug the crank sensor.


Connect the voltmeter negative probe to the battery negative post.


Turn the key to RUN.


Touch the pin cavity in the crank sensor harness connector with the Orange wire.


You should see 5.0 volts +/- .5 volts.


Next, touch the pin cavity with the Brown/Yellow tracer wire.


You should see .015-.020 volts.


With key to LOCK, both of these test should read .000 volts.

 

Well, the spare cam sensor didn't make a difference. The distributor looks good and has no excessive play. Cap and rotor are fairly new and look good as well. What's interesting though, I tried the test you told me to do on the crank sensor and I get 0.00 volts with the key off AND with the key on. What I don't understand is, wouldn't that cause the motor to not start?

 

WTF...


Are you sure you hard your meter set to 20 Volts DC , on the Orange wire, meter negative probe to the battery negative post?


If you had 0.00 volts on the 5 volt supply circuit nothing would work.


Repeat the test on the TPS and/or the MAP sensor and see what you get.

 

Tps and map tested fine again. Crank sensor still reads zero.

 

 

If the TPS and MAP Orange wire are getting 5 volts with key RUN, then there's an open in the 5 volt feed wire going to the Crank Sensor.


The 5 volt (Orange) wire is a spliced circuit, feeding the PCM, Cam Sensor, Oil Pressure Sensor, Crank Sensor, MAP Sensor, and the TPS. The Orange volt supply wire originates at the PCM, connector C1, pin A17.


The splice is in the wire loom that goes in to the fuel rail wiring manifold, near the throttle body. The TPS, Crank Sensor, MAP Sensor, and IAC wiring group up and go in to the rail manifold there. Wiggle this loom when taking the 5 volt reading at the Crank Sensor and see if the 5 volts appears. If not, unwrap the loom to access the splice. If it does, unwrap the loom and fix the splice.