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Unread 08-25-2009, 08:28 PM   #1
PlazJ
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Crankshaft Position Sensor - Found! With Pictures.

You old pro's will have to excuse my enthusiasm, but I spent quite a bit of time trying to figure out where this sensor was located because mine might be bad. For the benifit of others and to give back a bit for the help I've received here, I've grabbed some pictures that seem to be as rare as photos of the locness monster. (at least from a google or yahoo search)

First let me clear up where this is located for a 5.2L V8 like mine. I've found conflicting information.... it's on the left, right, passenger, driver side. I think this because the location is different for the V8 opposed to the 6 and 4 cylinder and when some one asks, they don't always get the answer that matches their engine. And even if the info given is correct, the description of the location is a bit vague.

So... for the 1994 V8 5.2L 318 it is located on the passenger side, behind and just below the head and below the steel EGR tube going from the exhaust manifold to the EGR valve. The two bolts that hold it on are hex heads that actually face upward, not towards the rear as I might have suspected. It takes an allen wrench to remove them. (Not sure what size yet)

This is my first Jeep project. What gets me is that when I had the manifold and the heads off, I could have just about reached over and had a new one installed in a few minutes. Unfortunately I didn't go looking for it untill the engine was back together and running. Now it's a major pain. If you have a meater arm than I do, it will be darn near impossible to get to.

What I did to reach it was to remove the kick down cable, pull the heater hose out of the way, move the fat wiring harness up and forward out of the way and move the other plug wires, vacuum lines and the EGR valve out of the way. Several parts I tied back with wire or zip ties to make room to reach back there. Becareful not to knock around the oil pressure sensor back there, you might break it. The manual suggest totally removing the EGR valve and oil sensor.

Now the good part... with serveral tries I managed to get my camera down there and get some pics to share. The angle changes as I tried manuvering for better shots. Here's what it looks like hiding back there...










Any body know what that spring is sitting on top of the transmission? Never know what you find in the nooks and crannies.

Also here are photos of the signals coming out of the Crankshaft sensor and the Camshaft sensor at about 1000 rpms. Question for the pros.. the peak voltage is about 2.4 volts. The signals look good, but is that level correct? (back to manual reading to find out) I don't wan't to spend hundreds on sensors I don't need so I'm trying to test all of them before replacing.


** Crankshaft position sensor. Probed at the Red wire with black stipe in the wiring harness running above the driver side valve cover.



** Camshaft position sensor. Probed at the Grey wire with black stipe in the wiring harness running above the driver side valve cover.



I hope this is helpful

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Unread 09-05-2009, 09:58 PM   #2
jcnash001
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PlazJ, thanks for the post. I'm glad to know that I'm not the only one reading conflicting information with the crankshaft position sensor. Your information and pictures are excatly what I found in my "95 JGC V8 5.2 liter.
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Unread 09-08-2009, 02:29 PM   #3
jcnash001
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Those two hex bolts are 1/4 and a pain to get out. The one closest to the distrubutor can be gotten out with an allen wrench attached to the small hole in a tire tool that comes with small cars. The one closest to the passenger fire wall can be gotten out by grapping hold of allen wrench with vice grips. Didn't fix my stalling problem though, but at least I know that I can add yet another new sensor to my list of new parts that didn't fix my problem (idle air valve, throttle postions sensor, o2 sensor, fuel pump relay, fuel pump, fuel filter)
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Unread 01-17-2010, 10:47 PM   #4
ZJ5point2GCL
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just to clarify, the too chunks of metal that you see meeting in the pics, are the head and the block?
also is there a cam and a crank sensor?
thanks
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Unread 01-18-2010, 12:26 AM   #5
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Quote:
Originally Posted by ZJ5point2GCL View Post
just to clarify, the too chunks of metal that you see meeting in the pics, are the head and the block?
also is there a cam and a crank sensor?
thanks
Cam sensor is under the distributor cap beneath the rotor.

crank shaft sensor, That was a pain on the 5.9 Too
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Unread 01-18-2010, 12:29 AM   #6
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That is a good Picture of the sensor mount. that had to be take with motor and trans out of the vehicle. Or not! Wait you took that? nice, my bad
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Unread 01-18-2010, 02:47 AM   #7
baxy
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that spring looks like it might be the spring out from under the carbon button inside the distributor cap
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Unread 01-18-2010, 04:53 AM   #8
ratmonkey
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the crank sensor on later models used hex head screws instead of the socket head cap screws seen in those pictures.
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'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

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Unread 01-18-2010, 07:10 AM   #9
KJK
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Here's a pic (not mine) showing the location of the CPS on a V-8 with the trans removed:

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Unread 01-19-2010, 12:10 PM   #10
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PlazJ
The amplitude of the square wave is not important, as it will change slightly with engine rpm. However the frequency of the wave is important. Which I do not know what it is suppose to be.
When the voltage drops to zero the PCM fires the coil.
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Unread 08-15-2010, 07:35 PM   #11
PlazJ
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Just thought I'd mention that I finally replaced my crank sensor. I had a stall problem recently that screamed "bad CPS" so I went a head and installed a new one. It was much pain just as anticipated. It took 3 hours, 2 different length allen wrenches and a small closed end wrench used as leverage to get the old bolts out. Couldn't hardly see a thing during the whole job. Getting the bolts back in with out dropping them was just as much fun. I bruised and scraped up my arm pretty good too. It looked like I had arm wrestled an angry cat by the time I was done.

However, after all that my problem still remained. In the end the culprit was a new coil that I'd installed only about 11 months earlier. I had a good spark at the coil but it seemed weaker at the plug. Putting in a new coil solved my problem. I think the old coil is even still under warranty. But anyway I feel good about having a new CPS installed instead of waiting for the 16 year old one to go bad. Best of luck to anyone else who has to change their CPS.
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Unread 03-16-2011, 08:21 PM   #12
bobkat2
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Thanks for that information Plazj. I just obtained a 94 GC that I just got running pretty good and it just died. Would not start no mater what I tried. I'm going to replace the crank sensor and see what happens. I could not figure out the mounting hardware involved, I was looking for a bolt on that bracket. Thanks for the heads up on the hex wrench.

I'll let you know how it turns out.
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Unread 03-16-2011, 08:55 PM   #13
PlazJ
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Quote:
Originally Posted by bobkat2 View Post
Thanks for that information Plazj. I just obtained a 94 GC that I just got running pretty good and it just died. Would not start no mater what I tried. I'm going to replace the crank sensor and see what happens. I could not figure out the mounting hardware involved, I was looking for a bolt on that bracket. Thanks for the heads up on the hex wrench.

I'll let you know how it turns out.
I've found out the hard way there's a lot of parts that can all lead to the same trouble. You may have to go through more that one to get to the solution. CPS has been one of the root causes, but here's others that gave me and others trouble too...

Did you try out a new selonoid yet? An extra $65, but maybe an easy fix if you're lucky. Also the computer modules go bad. About $100 for a used one, make sure to get the right model number that matches the one you have. (You have an I6 or a V8?) Also search this site on how some are doing their own module repairs by replacing worn out capacitors. The fuel pump can give out. That's a bear to change since you have to drop the tank. Might also go ahead and replace the fuel filter while you're at it, cheap and easy. The plenum and intake gaskets can give out on the V8's causing your fuel/air mixture to crash along with letting water mix with oil if the intake gasket fails.

My old 94 GC is running as strong and great as ever now, but I had to replace a bunch of worn out parts to get it there. Good luck to you.

PlazJ
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Unread 03-18-2011, 03:42 AM   #14
bobkat2
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Originally Posted by PlazJ View Post
Did you try out a new selonoid yet? An extra $65
Do you mean the CPS? I did install the CPS with no luck. I have an extra computer but it has the same symptoms. I brought the jeep home installed a new battery set the neutral safety switch so it would start in park and it fired up and was running. The only thing that comes up on the display is "check oil level" but I don't think would cause it to not start. I'm going to change out the cam sensor next. I guess it's just a process of elimination at this point.
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Unread 03-18-2011, 09:41 PM   #15
PlazJ
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Quote:
Originally Posted by bobkat2 View Post
Do you mean the CPS?
No not CPS, but I did make a mistake. I meant to say the coil. I had two go bad in less than a year. The first wasn't a surprise because of it's age. The new replacement died in less that 11 months.

Drove to work fine that morning. Started fine when it was time to leave. Put it in gear, moved 10 feet out of the parking space and it died completely. Wouldn't start again and would only occasionally cough as if to fire.

I checked for spark and it looked ok. Besides... the coil was practically new. "That couldn't be the problem. Must be the CPS..... "

Nope, after checking everything including putting in the new CPS, I put in a new coil and it's been running like new for the past 8 months. I now always carry a spare coil.
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