Troubles starting and keeping 4L running

[specialk]

We are some fun with this 4.0L out of a 95 Cherokee that is in the MJ.  Does a lot of sputtering and does catch, but you have to hold the throttle wide open...

We are getting 2 codes:
- 54 - Distributor Sync Pickup
- 76 - Fuel pump bypass relay circuit

We have:
- tested fuel pressure.  Holds at 44psi when running
- changed plugs
- changed dist rotor
- changed to new dist cap
- changed new wires
- swapped complete distributors
 - checked vacuum lines.

Dana and I are now thinking CPS.  I would like to be sure on this though as it is $115 for a new one.    Any other thoughts?   
 

[jkrubi]

When did you start gettin the codes before or after changing the dist?  You've made sure that the timing is correct?

[BUKI]

When did you start gettin the codes before or after changing the dist?  You've made sure that the timing is correct?

X2.  maybe 1 tooth out on distro gear??

[specialk]

Codes happened before the dist swap.  Not much you can do with timing, right?  The distributor just fits in one way.     The timing appears to off about 15 degrees.... I think that's  what we measured...

[JENSSEN]

I have spare CPS`s if you want to borrow one to test.

[jkrubi]

If I remember correctly if the timing belt skipped a tooth it's about 15 deg. When was the last time the belt was changed? If the timing is out by 15 it will start hard and run like a bag of sh#t.

[xjpete]

sounds like its off by a tooth on the distributor ... timing chain should be ok !

[specialk]

I will play with moving the dist a tooth and see what happens. Jenssen... I will let you know if I need to borrow the CPS - thanks guys.

[BUKI]

I might be off my rocker, BUT in theory a cps works or doesn't work, and has nothing to do with throwing your timing out by 15*.  15* is a long way out.  Could be a timing chain but when they do stretch to the point of skipping dont they make a clattering sound inside the t chain cover (ie tensioner hooped)??  CPS is supposed to send signal for fuel and spark??? so CPS bad = no fuel or spark?  I have worked on tons of v8s similar symptoms AFTER changing Distro (forgot to mark rotor to distro relation).  AGAIN this is only theoretical as I have never changed one on a jeep before.  Although pulling the distro again (after marking rotor relation) and going one tooth back and forward is free.  I would do this prior to purchasing a CPS.

[The Machinist]

Did you do this when installing the new distributor?

"The distributor needs to be set up properly, then the ECU handles the rest of the timing, but the initial setup is very important. In my opinion, the easiest thing to do at this point would be to pull the distributor out and to set it up properly, then at least, you've got a fighting chance of getting the engine to run right. Here are the pertinent two pages from the factory service manual that describe how to set up the 4 liter distributor. You need to pay attention to where the rotor needs to be when the engine is rotated to TDC, so the "scribe mark" described on the first page is very important."

Make sure the engine is at tdc on the compression stroke when doing this. 



 

[Pookapotamus]

yes we have installed the distributor correctly, (although this does not mean we did not screw up  )

we have tried other distributor positions with no luck and yes it definitely sounds like a timing issue. although it did run really rough then all of a sudden run good, only to stall out on idle. then we could never get it to run nice again. 

my questions are thus:

is the flywheel the same for a 89 renix and a 95 high output? if it is different could this be throwing the timing out by 15 to 20 degrees? is it possible that Kevin put the flywheel on in the wrong position?  also is the cps the same from a standard to an automatic? as the cps we have is from an auto.

Confused Pook.

[specialk]

The CPS is the same for both manual and auto... checked that out

[XJHERO]

did you have the timing chain off or did the PO have it off?

[Gearhead]

yes we have installed the distributor correctly, (although this does not mean we did not screw up  )

we have tried other distributor positions with no luck and yes it definitely sounds like a timing issue. although it did run really rough then all of a sudden run good, only to stall out on idle. then we could never get it to run nice again. 

my questions are thus:

is the flywheel the same for a 89 renix and a 95 high output? if it is different could this be throwing the timing out by 15 to 20 degrees? is it possible that Kevin put the flywheel on in the wrong position?  also is the cps the same from a standard to an automatic? as the cps we have is from an auto.

Confused Pook.

The flywheel will only go on one way  .

I can't confirm  ,  as I'm not sure , but  you may be correct in thinking the fly wheel from the 89 renix is not the right flywheel .


Somebody should know this ? 

[XJHERO]

well the trans that kevins 4.0l is mounted to is a 97 i do belive and that same trans was on the renix 4.0.
if that info helps at all