Crankshaft Position Sensor.....?

[rocketwheels]

Hey guys, haven't been too active lately, but gotta ask a question........Sgt Rock has had an ignition miss since I drug it out of the chicken shed several years ago. Have never been able to nail it down. Over time (and sometimes twice) I have replaced everything in the ignition system along with everything in the fuel system (including TPS and CPS ) and still this infernal  miss is there.....all of a sudden got much worse. Occasional stutter, thuds and occasional pops thru exhaust....all happening when trying to hold constant speeds between 45 and 70. Purrs like a kitten at idle and until just now runs like a whipped dog at full throttle.

 

   The question is about the distributor and the CPS which is apparently inside of it.  Are these prone to slow failure or what?  What is the best solution....1 rebuild the dizzy with the new cps.....2 replace with new/reman stock unit....3 replace with the GM HEI style replacement ?

 

Any insight would be helpful. Thanks guys !!

[Eagle]

Are you asking about the crankshaft position sensor (which is what "CPS" usually indicates, or the camshaft position sensor (which is the one that's inside the distributor)?

[cruiser54]

Are you asking about the crankshaft position sensor (which is what "CPS" usually indicates, or the camshaft position sensor (which is the one that's inside the distributor)?

And on a Renix, it's not really a cam position sensor. It's a sync generator for the fuel injectors. 

 

Year of the truck? 

 

I would click on the link in my signature and do Tips 1 through 5 if an 87 or 88 and all but Tip 2 if it's 89 to 90. 

[rocketwheels]

my bad.....I meant Camshaft sensor or whatever it is called inside the dizzy. This is an '88 model.

[cruiser54]

my bad.....I meant Camshaft sensor or whatever it is called inside the dizzy. This is an '88 model.

Unplug the little plug at the dizzy and see what happens. 

[rocketwheels]

cruiser54......just unplugged and test drove, no difference, exact same actions

 

....PS, I followed most of the "cleaning the connections and grounds" tips ,I think I'm good there.

[cruiser54]

cruiser54......just unplugged and test drove, no difference, exact same actions

 

....PS, I followed most of the "cleaning the connections and grounds" tips ,I think I'm good there.

I'm not surprised.

"Most"? Why not all?

[rocketwheels]

...all of the first ones except tip #2, haven't devoted enough time for that yet.

 

anyways, if there was no change by unplugging the dizzy, then that means the items in the dizzy is.....A - not working at all.....OR.......B - not getting current or signal when it is plugged in ?

[rocketwheels]

update....had more time to work with it this weekend, seems the entire dizzy is worn out....the lock down ears/ring is cracked and even when secured the whole dizzy is sloppy side to side and up and down in the bore. Guess I'll go buy a new one that has a new sync sensor in it.....p.s.  where is the timing mark on the crank harmonic balancer?....on the face/lip of the outer ring, or under the belt on the grooves, or even behind that?

[HOrnbrod]

[rocketwheels]

thanks hornbrod !

[cruiser54]

See tips 12 and 13 to get this done correctly. 

 

And, Tip 2 is not one to ignore. 

[rocketwheels]

....alright !!  Good to go.  saved up and bought a new dizzy, complete with cap and Sync sensor inside.  old Sgt. Rock purrs like a kitten.  Amazing to have to chase this problem all this time. I bought this truck many years ago and this "misfire" began shortly after starting to drive it.....progressively got worse over time.  Threw parts at it one at a time, figures it was the last possible item that could be replaced.  The dizzy was just plum worn out, had play in 3 different directions....and I'm not sure if that sync sensor was the problem or just another factor.

 

  Anyways, thanks for all the info and insight !

 

BTW.....my harmonic balancer /pulley does not have any timing marks of any kind (on the rim , the face or anywhere), so I just brought the 1st piston to the top and made marks on the old dizzy so i could duplicate the re-install.

[HOrnbrod]

BTW.....my harmonic balancer /pulley does not have any timing marks of any kind (on the rim , the face or anywhere), so I just brought the 1st piston to the top and made marks on the old dizzy so i could duplicate the re-install.

 

Odd, I've never seen a harmonic balancer w/o the timing mark. Maybe they don't scribe timing marks on the ones made in China.    :peek:

[rocketwheels]

I kinda thought it was odd , too.  Do later engines not have timing marks? 

 

It is possible this is not the original , the truck has 237K on it and I have no idea of the history other than purchased new by a chrysler employee, left to sit for 7 years in a chicken shed, and then I got it.   It may have a later model engine , I wouldn't know. All of my local jeep friends were very impressed by the power and acceleration this truck has....maybe it has a later motor in it.

[HOrnbrod]

I had timing marks on the 01 XJ I used to have.

 

Check your engine block casting number. For an 88 it should be 53005535 and it's located on the left side under the front freeze plug.

[gogmorgo]

The timing mark on the Dorman HB can be hard to spot. Just a little nick in the rim.