fluctuating oil pressure and check engine light

[onesojourner]

this is on our 97 tj 4.0. the check engine light started coming and going last week. it still does this a bit but it is on most of the time. the oil pressure is fluctuating between 20 and 60. any one have any thoughts on where I should start trouble shooting?

[TanYJ]

Turn the key on, off, on, off, on, and leave it on for a fw minutes, all without starting the engine, and it should show a fault code on the odometer.  I'm not sure the '97s will have the ability to do that, but it's a good place to begin.

[xj42]

I think that 96+ has OBDII, so I'm not sure the key on/off will work, give it a shot though.  Just hook up a scanner to the OBDII port and see what you get.  I've got a scanner that should work.  PM me if you're interested.  Otherwise try a dealership they may scan it for free and would be more help than me.

[OJTV8CJ]

I do the key deal on my wife's 96 ZJ all the time.  Well - maybe not ALL the time but.....

[onesojourner]

ok the odometer said 12, 43, 11, 55

does that mean anything to anyone?

[OJTV8CJ]

12 = ky cycled code
43 = misfire code
11 = no crank signal
55 = end diagnostic mode

I would unplug and replug the crank sender.  What is probably happening is the Jeep is idling low enough that it is fluctuating the oil pump.  Or the sender is going bad.  My wife's would drop to 0 then go to like 20 but never over that.  I replaced the oil sender and it popped back up to 20 and 40.  But, I also replaced the crank sender about a year later.  If the crank sender goes it won't start.

[YJ_Aaron]

List of codes for TJ's


http://www.jeepforum.com/forum/showthread.php?s=&threadid=23788

11 No crank reference signal detected during engine cranking. Intermittent loss of either camshaft or crankshaft position sensor. CKP sensor target windows have too much variation.

12 Direct battery input to PCM was disconnected within the last 50 Key-on cycles.

43 Peak primary circuit current not achieved with maximum dwell time. Misfire detected in one or more cylinders 1 thru 6. (4 and 6 cyls.)

[YJ_Aaron]

Oh I see how it is Brad.  You go back and edit yours after I find him some answers.  I'm on to your game.   :afightee:

[OJTV8CJ]

I was typing when you posted.

[YJ_Aaron]

Sorry for HIJACKING.

ya that's why it says EDITED BY OJTV8XJ RIGHT?

[onesojourner]

ok where is the crank sender for me to unplug. I have actually never even heard of that one.

[onesojourner]

is it going to hurt anything driving it this way?

[YJ_Aaron]

Is the jeep running rough or dying?  Does it have a miss at idle?

[onesojourner]

its never died. it sounds like it is idling really rough.

[onesojourner]

ok I have driven this thing about 5 times and the check engine light has been off and it seems to be running smoother.... why... I did nothing to it.