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Need help with CPS

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Old 12-23-2011, 03:00 PM
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Default Need help with CPS

So the other day I was driving and after a light the jeep seemed to die like it was out of gas, which it was not. After doing some reading everyone seems to be saying that it is time to replace the CPS. Now is this something that is easy to do?? Some places I have read say the engine needs to be in top dead center...what ever that means and some other places dont say it at all. Can someone help me out alittle and give me some direction on how to do this. Thank you.
Old 12-23-2011, 03:11 PM
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The motor can be anywhere, it is on one of the engine to bell housing bolts on the drivers side towards the top. You can see it from under the hood but it can be a real ***** to reach. I removed the tranny cross member to drop the back of the engine down about 3" and used a long extension. You may be able to do it with out if you have long skinny arms.
Old 12-23-2011, 03:27 PM
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Originally Posted by douglasstorm
So the other day I was driving and after a light the jeep seemed to die like it was out of gas, which it was not. After doing some reading everyone seems to be saying that it is time to replace the CPS. Now is this something that is easy to do?? Some places I have read say the engine needs to be in top dead center...what ever that means and some other places dont say it at all. Can someone help me out alittle and give me some direction on how to do this. Thank you.
Do you mean the crankshaft pos. sensor? I think the top-dead-center part is for when aligning the distributor rotor. There is also a camshaft pos. sensor underneath the ignition distributor cap.

The crankshaft sensor is a pain to get to but can be done in about 30 mins.

Here's some info on the sensors:
http://www.lunghd.com/Tech_Articles/...iagnostics.htm

Last edited by McHank; 12-23-2011 at 03:30 PM.
Old 12-23-2011, 09:27 PM
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No I already changed the Crank sensor. Im talking about the Cam position sensor
Old 12-23-2011, 10:32 PM
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Originally Posted by douglasstorm
So the other day I was driving and after a light the jeep seemed to die like it was out of gas, which it was not. After doing some reading everyone seems to be saying that it is time to replace the CPS. Now is this something that is easy to do?? Some places I have read say the engine needs to be in top dead center...what ever that means and some other places dont say it at all. Can someone help me out alittle and give me some direction on how to do this. Thank you.
To replace cam sensor/pick up plate remove distributor cap and rotor pick up sensor and unplug. Only goes on one way just like the distributor cap.
Old 12-24-2011, 12:10 AM
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Originally Posted by bsmith97xj
To replace cam sensor/pick up plate remove distributor cap and rotor pick up sensor and unplug. Only goes on one way just like the distributor cap.
So do I need to be concerned with the engine being at TDC??
Old 12-24-2011, 12:49 AM
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i have coils but i still have the sensor... i just took it out and dropped the new in... tahdah. google it and they will show exploded pics.
Old 12-24-2011, 02:58 AM
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Originally Posted by douglasstorm
So do I need to be concerned with the engine being at TDC??
I think it depends if you have a HO or a Renix? Mine's a HO and you just drop it in under the cap, but Renix is a bit more involved.

http://www.lunghd.com/Tech_Articles/...lse_Stator.htm
Old 12-24-2011, 10:37 AM
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Originally Posted by McHank
I think it depends if you have a HO or a Renix? Mine's a HO and you just drop it in under the cap, but Renix is a bit more involved.

http://www.lunghd.com/Tech_Articles/...lse_Stator.htm
Yeah I was reading this article and just got alittle confused. Gonna try it here in a few.
Old 12-24-2011, 12:22 PM
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Doug you really should post what you have. Makes it easier for people to help.
Old 12-28-2011, 07:53 PM
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I have a 93 xj with 4.0L with 210k. Bought the jeep about 2 months ago and it ran fine. One night it died like it ran out of gas. It restarted with no problems. About a week later it started fine and died again at a light. About 10 min later it started right back up.
Thinking that it was fuel filter I replaced that. When I pored out the old one it all came out brown. So thought this was the end of it as jeep ran great. Then later that night it died...again. After about 30 min it started right up.
After doing some research everyone was saying Crankshaft Sensor or Cam Position sensor. I decided to replace both. Drove it all day today with no problems till almost home and check light came on with code 34...Speed control vacuum or vent solenoid circuits open or shorted,... Had the code before I replaced Cam Sensor but went off. Oh and also seems to true off when I take the vac off the heater control valve. Then cleaned the Throttle body and it started right up. Drove it around the block and turned it off then tried to restart it and it just cranks and wont turn over. Any help would be AWESOME!! Thank you!
Old 12-28-2011, 08:53 PM
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What are you missing? Spark, fuel, fuel volume, compression.....
Old 12-28-2011, 09:02 PM
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I'm not much help, trying to learn...up in info threads there was this;

34 Cruise control circuit. Fault in circuit.

I would think you might want to check for spark some time when it won't fire.
Me, if it had spark I'd try a shot of starting fluid then, you'd know for sure if it was fuel or spark. It does sound a little like spark, and maybe a bad new CPS, but I don't know. You might try unplugging it and plugging it back when you have a problem, guess that connector could do that.

Cruse has a fuse, and probably a relay I think...

Grounds? Connector at PCM?
Old 12-28-2011, 09:20 PM
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BSMITH...just checked spark and have that. Also checked fuel and it shoots out the fuel rail so I know that i have that. Still at a loss.
Old 12-28-2011, 09:22 PM
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DF...if it was a bad CPS then wouldnt it not start ever??


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