No Start. Fixed distributor was cause

[daking]

So for a few weeks my MJ has been randomly stalling. Be driving, and engine will die. Sometimes it'll restart, but usually I have to let it set. MJ would drive awesome, except when it would stall. 

 

I thought it was fuel delivery. Cause, after the engine would stop, if I put gas down the TB, it would start.  

 

Well, finally it stopped and would not start. After checking the usual, I was kinda stuck.

 

I decided to take a look at the Distributor. I had installed it a few months back, new from AutoZone. As looking inside, I found my problem.   

 

The "pulse ring" is pressed on to the shaft. It is NOT supposed to rotate independently of the shaft. On my New Autozone Distributor, that pulse ring is loose. It rotates a few degrees on the shaft, just enough to mess up the timing. 

 

 

 

I was able to force it on the the shaft to lock it. It's advanced the timing now, I think. I need to put a timing light and see. It will come loose again, I need to find a way to actually lock it. like a tac weld. If it advances the timing, like the CPS mod, I may keep it. 

 

 

Anyone else see this issue before?

[HOrnbrod]

From your diagram it looks like you have an early 91-93 HO distributor - it's a poor design. The pulse ring in your diagram is not pressed on; it's a separate part you can get - p/n 33004254. A better solution is to junk the distributor and stick in a 94 and up distributor - it's PnP. Then if your sync sensor (pulse ring) goes out again, you can change it from the top w/o yanking the dizzy out. And no, you are not changing ignition timing with it moving around the shaft, you are changing injector timing - not good. From one of my earlier posts:
 

Good to hear. :cheers: The early HO distributors are tricky to get in right. Awhile back the sync sensor on my 91 distributor went out (fault code). To change the sync sensor (pulse ring) on the 91-93 distributors you have to pull it out, remove the gear and shaft, and tear it completely down. It's a PITA. The 94 and up distributors do not require removal to change the sync sensor, it's all done from the top. I found a reasonably priced NOS 95 distributor and stuck it in and it runs great. So when you can, grab a newer distributor for a spare from a 94 and up at the yard for easy replacement when (not if) your sync sensor goes out again.

Also just to verify it's right, you can stick a timing light on #1 and look at the timing marks on the timing chain cover at about 2K RPM. It'll jump around a bit, but the light should be fairly steady @ 14* - 18* BTDC. You can't adjust timing, but at least you can see if the advance signal from the ECU is proper.

94 - 99 distributor

 

[daking]

ah, good info. I was not too sure if it was moving the timing or not. But fuel makes sense, It seemed like a fuel problem when it would fail.  

[schardein]

Got my XJ for $400 because that sensor was bad.  Discovered the different later model distributor while searching parts at the junkyard.  Grabbed it and a spare late model sensor just in case.  Took me a while to diagnose because PO had pulled the bulb from the check engine light.  When I finally discovered that and replaced it, got the code and did the fix.  Been meaning to grab one for the MJ.

[daking]

 

From your diagram it looks like you have an early 91-93 HO distributor - it's a poor design. The pulse ring in your diagram is not pressed on; it's a separate part you can get - p/n 33004254. A better solution is to junk the distributor and stick in a 94 and up distributor - it's PnP. Then if your sync sensor (pulse ring) goes out again, you can change it from the top w/o yanking the dizzy out. And no, you are not changing ignition timing with it moving around the shaft, you are changing injector timing - not good. From one of my earlier posts:

 

Good to hear. :cheers: The early HO distributors are tricky to get in right. Awhile back the sync sensor on my 91 distributor went out (fault code). To change the sync sensor (pulse ring) on the 91-93 distributors you have to pull it out, remove the gear and shaft, and tear it completely down. It's a PITA. The 94 and up distributors do not require removal to change the sync sensor, it's all done from the top. I found a reasonably priced NOS 95 distributor and stuck it in and it runs great. So when you can, grab a newer distributor for a spare from a 94 and up at the yard for easy replacement when (not if) your sync sensor goes out again.

 

Also just to verify it's right, you can stick a timing light on #1 and look at the timing marks on the timing chain cover at about 2K RPM. It'll jump around a bit, but the light should be fairly steady @ 14* - 18* BTDC. You can't adjust timing, but at least you can see if the advance signal from the ECU is proper.

 

94 - 99 distributor

 

 

Well, 3 distributors later, and I'm still not working. 

 

1st, I agree the 94 n up is a better design. But it is NOT PNP. The electrical connector is different. How do I know?, cause I bought one, installed it, and went to plug it in.... You what I discovered? I discovered I just spent ~1.5hr (includes buying part) to find out the connectors are different.  

 

2nd, You are correct the actual Pulse Ring is not pressed on, however the flat part under the ring, that is pressed on. And that is what failed. The Rotor is keyed by the pulse ring, not the shaft. So, because the mount for the pulse ring came un pressed, it not only caused the pulse ring to go off, but also caused the rotor to be off alignment.         I'll post a video shortly. 

 

3rd, turns out most part stores only keep ONE distributor in stock.  

[HOrnbrod]

Odd, the connectors on the old and new dizzys were the same for me.

[daking]

[gogmorgo]

What's the part number on the late '95 dizzy? I've also swapped one into my '91 and the connectors were the same. 100% plug and play. Only thing I had to do was rotate all the spark plug wires one position on the distributor cap to get the timing correct to the housing position forced by the newer style hold-down. Don't remember which direction it was, but I remember finding it in a forum post saying the firing order in the Haynes manual is wrong. I'll see if I can find it.

 

Edit: Don't know if this is the same one, but a quick search showed a whole bunch of folks got mislead by the Haynes manual. http://www.cherokeeforum.com/f2/distributor-cap-rotor-78168/

[HOrnbrod]

56027028, Distributor, 94-99. PnP replacement for the 91-93 53006150.

[rocketwheels]

I shared your woes.... recently I replaced my dizzy because of that pulse ring.....seems mine had been going bad forever, causing a miss that got ever worse. Had the guys here walk me thru anything i didn't already think of on timing and tuneup / ignition.....only to find the hold down tab on the dizzy was cracked , allowing the shaft to wobble around, causing errant firing of the fuel injectors. Been like this for 5 years, until I couldn't drive it anymore because of the miss.