flint54

Well, things have gone from bad to worse. Truck will no longer idle, and can no longer be driven either. The latest changes: 1) I swapped back in the original distributor, after dismantling and cleaning/polishing the shaft. No improvement, so I put back in the new distributor. The old dist had several degrees rotational freeplay of the rotor mounting plate anyways. Have strong blue spark at all plugs. Absolutely certain that rotor is aligned with #1 at TDC compression. 2) I swapped in the correct (396) ECU pulled from a running motor, and no improvement. No fault codes either (other than 12 & 55). 3) I installed a new, OEM, CPS. Motor runs long enough to call this good. 4) I installed a new, OEM, coil. Have strong blue spark. I can start it at half throttle, and it will rev between 3K and 4K (with some sputtering) but as soon as I let off it dies. I can start at closed throttle, and it will limp at about 200 rpm for a couple minutes. Compression good, vacuum good, fuel pressure good. There are no "smilies" to convey my status, but this one scratches the surface: :wall:

My 21 year old starter bought the farm a couple months ago, and I got a new OEM starter from the dealer same day. Cost me $180, but works like a champ, and I have some confidence it may last the next 21 years, possibly longer than I will.

"the old school solid copper core Champion plugs, Champion RC12LYC" are exactly the plugs I'm using, and they're new (like damn near everything else), of course. The auto parts guy tried really hard to sell me the fancy platinum XYZ miracle plugs for $16 each, but these $2 Champions are all that anyone really needs. I'm going to be jeepless for the next month working in DC, but when I get back I'm seriously considering limping this thing to Hesco. I doubt their dyno goes low enough for the current condition. ;)

http://www.mecum.com/auctions/lot_detai ... ryRow=1710

("that's where the factory roll bar support goes. :thumbsup:") YaaaHooo, I've been highly curious about those mounts for years!

To Don, Yes I knew it was a long shot on the ECU swap, but it cost very little. I looked at the FSM schematic beforehand, there's only one pinout chart for both manual and auto, and for MJ they differ by only one pin. The auto has a neutral sense input (pin 30) that the manual does not. There are two other differences (pins 26 and 46) but they're XJ with security module only. I figured it was worth a try. I've got an Ebay 396 ECU on the way here now. To Exgrayxj, All recommendations are most welcome. I'm not sure how the distributor could be a player in this issue, but it would be a simple enough test. I'm going to soak it in penetrant for a good long while and I think the chirping will resolve. The innards are gummed up (like an old carburetor bowl) and solvent should undo. Yesterday I looked at an OEM intake gasket, and it appeared to me a lot more substantial than the Felpro I used during the intake swap. So, I replaced the intake gasket to rule out an undetected leak. (BTW I asked the dealer, just for grins, what they would charge. They said $90 for parts plus 5.5 hours labor. I got the OEM gasket for $20 and completed the job in less than 3 hours). The removed Felpro gasket is unusual in that it appears as if some fluid (fuel??) has soaked around, and outward, past the sealing region of each intake port. After a 24 hour retorque, plus an engine hot/cool second retorque, there are no changes of symptoms. My local Jeep shop (Jeeper's Den in Orlando - great folks), suggested I monitor fuel pressure through the RPM range and look for dropout. They're thinking starvation at higher RPM's. I did that today, and fuel pressure remains steady at ~32 with increasing RPM, up to, and beyond, engine getting ratty. If I blip the throttle quickly, fuel press spikes high (~40) corresponding to the momentary vacuum drop. All seems well here. If things don't improve after the next ECU swap, I'm tempted to just drive this thing up to the folks in B-ham and let them sort it out. My bag of tricks is nearly empty.

Didn't see that one, was there a solution? I'm really doubtful the distributor could be the culprit since it only has one correct position, and since the motor will rev when sitting still, up to around 4K rpm before getting ratty. I swapped back in my known good OEM CPS, to rule out a faulty replacement CPS, and no change. I also found a connector under the ECU that plays in this circuit, opened it up and found a bit of green,.Cleaned it well, but that wasn't the problem either. There's an outfit I found online that offers an ECU testing/rebuilding service, but it's pricey and I'm curious if anyone has used this service: http://www.directauto.com/product-exec/ ... ng_Service The want $100 to test, and $228 to repair if damaged. The ECU for automatic (488) doesn't play nice in the manual, and I had no JY luck locating a 396 ECU to try. Over on stroker forum there's some discussion about stumble @4200rpm due to valve float, but those folks are running cams with rapid rise. My cam is, and shall forever remain, stock.

My ECU is 56027396 (for 1992 manual 6 cyl). Today I scoured the JY, and grabbed an ECU from a 92 XJ, auto (all I could find) #56027488, hoping for good interchange. Well I put it in and truck runs like crap, even worse than before. Plus triggers maint light. Stumble, miss, cough, sputter, and stall unless I keep my foot on it.

And the outcome is...no joy. No fault codes, other than 55. I pulled the ECU plug, and found very little oxidation. I treated both plug and all pins to a liberal dose of "deoxit", and scrubbed all. I verified all pins are correctly positioned, other than the 10 of 60 not applicable to me (per FSM schematic). I also verified continuity, and no resistance, of the conductor (#19) between ECU and coil. I even swapped in yet another, this time OEM, coil. I still have a dramatic, and intermittent, miss under load. When the miss happens the tach also blips, suggesting to me this is electrical (since tach feeds from ECU). The miss happens now at 2K(sometimes), 3K (nearly always), and 4K (sometimes) RPM. Feels as if I momentarily unplugged the coil. Yes, installing the "upgrade" intake manifold was the genesis of my troubles. I am sorely regretting my inability to resist the temptation. Could not leave well enough alone. Lot's of new power, but a totally unacceptable downside. One interesting observation, the build of my truck is 11/91, but the sticker on the ECU is 01/93, suggesting that it was replaced (warranty job?) during the first year of operation. I cannot imagine the ECU being the source of this issue, particularly since it was initiated by a completely unrelated (manifold) exchange, but I am rapidly running out of things to suspect. Also, not sure I mentioned this before, when I suddenly let off the throttle while in motion the motor will nearly, and sometimes actually, stall out. Idle is no longer reliable. I used to count on my ability to diagnose/resolve stuff like this, but not this time. Totally stumped. :hmm: :hmm:

Pete, How I wish that's what it was, but that also is new, replaced while I had intake off, taking advantage of the extra room opportunity.

Ok, I've tested both coils, and both are within FSM spec. Primary at 1.1 ohms and secondary at 11.5K ohms. I keep reminding myself that my intent was improvement, by updating to the newer intake and replacing a troublesome distributor. It's been all downhill since then. Intermittent miss, with all new ignition components, reworked head, and newer intake. Also, when I suddenly release the throttle the idle drops to near zero. The IAC is new and the TB is new and clean. Idle vacuum symptom: Steady at 18-19, then slowly (15 seconds) climbs to 20, the idle speed drops a couple hundred and the vacuum drops quickly back to 18. Will do this pattern all day long, all by itself. Will rev to redline smoothly (without load), but with load it sometimes sputters first. No, I don't have AF meter yet, but plugs indicate reasonable mix (lt brown). (unlike the black I got before backing off the AFPR). I've checked and rechecked for intake leak with propane and no indication, but I'm about ready to pull intake again just to look at the (new) gasket for any sign of bypass. Any other suggestions (not involving explosives) are most welcome!

Will check that when I get back to FL, but it's a brand new coil, from NAPA. Did same thing with the old coil, so, if it's the coil, it's both coils doing the same thing.

FYI, in the El Paso Mega-U-Pull is an 86 long bed with a Very nice bed, including the heavy mat. No tailgate. One of the soundest JY beds I've ever seen.

Well it's not over quite yet. Now after ~600 miles, still have an intermittent miss that's vexing me sorely. Only happens between 2000 and 2500 RPM, moving down the road. It's as if I turned off the key for `1/4 second, like a quick cough. It happens about once every few miles, whether or whether not under load. All the following are new: coil, distributor, cap, rotor (button), wires, and plugs. All connections to dist and to coil are clean and firmly tight. Sitting still, I can rev it to redline repeatedly without a miss. Have good fuel pressure and delivery, injectors nearly new. Any ideas where the heck to go next? :hmm:

Thanks for the replies, and for posting the dist. alignment process. I had already worked through that via FSM, but those visuals are better. So here's the rest of the story. After a bit of prayer, and a few hours sleep, clearer thinking returned and I was led to look for really dumb simple stuff (those are usually the gotcha's right?). Ive been messing with "button"s for many years but never knew that term. I have a couple new, but unprintable, terms. Turns out the metal tab that rides on the contact inside the cap had very poor, and intermittent, contact. That's why I was able to see spark at plugs but no run. Wasn't getting spark at every plug every time, but only every plug once in a while. Didn't realize that when testing individually. Once I bent that thing higher up, voila - running truck. I love simple solutions, but I love them a lot more when they don't take all night. About the old distributor, I may be able to resolve it by soaking in penetrant. There's a lot of gummed up fluid inside, as if oil had found it's way all the way up the shaft over time and then congealed. BTW this dist is a newer flavor with notched shaft so the button can only go in one position. The older style has potential to install more than one position.

What button? What three holes? Not sure what you mean. I don't think the old dist was bent, just galled up fiercely.

Well this has turned out to be a much greater debacle than I envisioned! Got the new distributor today (Morris 4x4 - great folks - rocket fast shipment). The swap was uneventful, but it ran like a dog for a couple minutes and quit. I'm very confident I got it positioned correctly, but I rotated one spline in either direction just to double check. Nothing. Want back to basics, pulled #1 plug, rotated to TDC on compression stroke, and verified rotor pointing to #1 plug wire. Triple checked wire firing order, 153624. Tested coil and shows strong spark. Tested each plug wire and getting spark to each plug. I have ~40 psi fuel pressure at the rail. No spit, no sputter, no nothing. CPS is nearly new. Only fault codes are 12 (recently disconnected battery) and 52 (running rich) What the Heck is going on here?!? :headpop: BTW, the old distributor was so bound up internally I could hardly even rotate the shaft by hand.

Try this source for PN 83502639: http://www.factorychryslerparts.com/pro ... 02639.html

Replacement dist on the way, will post results when done. Very surprised, given the low mileage and easy life, but stuff does wear. I know this dist has never been removed so will be interesting to see if anything is missing. I'm not sure how far (if at all) oil comes up the shaft, but my hunch is a worn bushing that gets quiet after a minute of lubrication.

Yeah, the A/F meter is in the near pipeline, I need the data. My thinking was that the AFPR adjustment, set at only 2-3 psi over original, was compensating for all the other things I've done to improve airflow. (no cat, better intake, FIPK, porting, 63mm TB, etc) I don't think I've ever had a vacuum leak, at least not one that shows up on the gauge. I'll swap back the old IAC to see if that makes any change also. On the plus side, as long as the RPM is above 2500, this motor now moves this truck like a scalded dog, especially in the dirt. :rotfl2:

As a followup, I installed the Hesco AFPR and adjusted the setting to 34psi (vac on)/42psi (vac off). Drove 800 miles and pulled plugs. They're much darker now, nearly sooty. No more too lean. Once I modify the downpipe to receive a 2nd O2 sensor I'll put in the A/F meter and have real data. Now then, the new development is unsteady idle. When driving, sudden release of pedal and motor will nearly stall. Sometimes it will really stall. When sitting still, the idle is smooth, but an occasional downward (~200 rpm) momentary drop. This new development is only after reworking the head (valve job and shave). Double checked manifold bolt torque - all good (gasket is new) Checked compression - 165-170 psi on all cylinders and full on 3 strokes Looked for intake leak using propane - none found Vacuum is steady at 18, and responds correctly when throttle is blipped IAC is new and OEM IAC and TPS connectors verified clean :hmm: :hmm: :hmm: ?? Any ideas?

Yes, I do. As it turns out, it wasn't the AFPR after all, it was the connection between gauge ant shrader valve. Intermittent. Pulled and cleaned the core, and all is well. Holds 40 psi with motor off for about an hour, then drops to 30. Good enough for me, for now.

To the OP, let's keep in touch. I'm getting ready to begin that swap myself within the next month or so. I'm also going to switch to the external slave bell housing, will probably refresh the clutch parts, and also add the Novak cable shifter while I have it all apart, plus a new rear rubber mount. While I can, I'm also thinking of seeing whether I can take out some if the shifter freeplay. It's not a lot, but would like less. The first headache I forsee is dealing with those lousy "nutserts" where the crossbar mounts to the frame. I know they can be replaced but I'm going to think about whether there's a more substantial solution, like welding in real nuts. Also a new CPS and grommet while it's free access.

Symptom: "ert" - "ert" - "ert" loud chirping when first starting the motor It goes away completely after a minute or so. I thought it was the tensioner pulley at first, so I pulled it and replaced it as it felt a little rough. No joy. Got out the old shade tree stethescope (a 24" 3/8" drive extension) and probed all the logical places. No joy. Then I noticed the sound was well aft of the belt plane, and discovered it is the distributor. I know they're not really rebuildable (based on parts manual not listing any bushings/bearings). My question is, before I just go buy a new one, are there any upgrade options, given the opportunity? Thanks!

Supposed to be ~40psi at the rail. And there was, right up until installing the Hesco adjustable regulator. Now there's no residual pressure. Shut off the motor and pressure goes to zero. Not a calamity, but makes for longer cranking. Put the old reg back in and system holds pressure just fine, so it's not a check valve issue. Somehow the AFPR is permitting pressure loss when pump is not running. Exchanged the regulators twice to reproduce the problem. The O-rings are fine, no damage. Anyone else with the AFPR have this issue??