OneOverZero

Valve noise has continued, seemingly becoming much louder about 10min after the coolant reaches operating temp - I'm guessing it's due to oil heatsoak. Still haven't pulled the VC (possibly the head), but it has ~820mi on it now. Seems to be coming from #5 or 6, if my listening horn (a reversed vuvuzela) is any indication. Has anyone succeeded in replacing the front, driver's-side freeze plug with the engine in the truck? Mine appears to have been pressed it properly, but it still weeps from the top. Hoping that's the source of my coolant loss. Turn signals are intermittant and tend not to work once it's more than 65F outside. This is... not reassuring for someone who fears electrical fires. I'm going to start pulling & cleaning all the grounds I can track down. At times, I can hear the relay but have no dash indicators or signals, though the hazard lights all work (aside from, at times, the front passenger side). Truck died on me about a mile from home earlier in the week (thankfully, I had a nice pulloff and was a mile from home...). It stumbled from a stop a few times prior (AFR always going very lean, then briefly overcompensating to very rich), but AFR pegged at max lean and it stuttered off the road before stalling. Wouldn't restart for a while, even after I threw a few gallons of gas in it. Still not certain what's going on - when it was stumbling off the line, I assumed the TPS was rotating on its mount, but it pretty clearly had fuelling issue. I'm guessing rail pressure was close to zero. It started up and drove away just fine after about a half hour. Probably time to replace the Airtex pump the PO installed, and I might try swapping out the FP ballast resistor with a spare just in case. Will also pull the taillight to clean the FP ground.

Ran into a puzzler with my newly-running '90 MJ with a rebuilt '94 HO. Engine currently has 32 miles on it after cam break-in, and aside from a lifter rattle, all appears to be good aside from a stubborn unsteady idle. It often lopes along at 400RPM, consistently surging to 600 or so every couple seconds when hot, and will nearly stall when the clutch is disengaged suddenly (approaching stop sign, etc). I didn't have any idle issues when I pulled the old driveline in late 2012, though basically everything in this truck is new, so I'm starting with a massive list of unproven components. Renix TPS (on HO throttle body with Hesco adapter) is adjusted perfectly at 17% of FSO, air/fuel ratio is steady at ~14.6-14.7 at all times (immediately jumping to 22.4, max gauge range, when off-throttle), and all sensors aside from MAP are new and test properly. Fuel pressure is perfect with a new FPR and lines. Grounds are all clean with no detectable electrical issues (though my turn signals did stop working on the way home today, hmm). I'm going to test the MAP sensor (though I don't see where I can cleanly probe it) and throw a vacuum gauge on the intake tomorrow to ensure that I don't have a massive leak. I also have a Mopar-reflashed ECU in the garage, though I'm holding off on installing that until I'm confident that all else is stable - my understanding is that the reflash only helped with cold idle issues. EGR solenoid has been removed since I'm running the '94 intake, though all evap lines, canister, rollover valves, etc have been replaced. I'm hoping that the lifter rattle isn't indicative of something that could result in vacuum fluctuations, though I'm probably going to end up pulling the head to investigate sometime next week. That said, I'm using the donor XJ's HO IAC valve in the HO throttle body. I'm willing to bet the valve is at fault, though is the HO IAC valve compatible with the Renix ECU? I know the HO valve mounts to the block adapter, but I believe the valves themselves have the same bolt spacing and are visually identical - should I be using a Renix valve in the HO adapter? I see different PNs for '87-'90 and '91-'97 valves, so I'm tempted to dig out and clean off a Renix IAC. Thoughts? Thanks! Bob

I'd like to know myself! Haven't started it since I made that post. Time to get a 10-day transportation permit, get it inspected, and transfer the AMC6 plates from my XJ to my MJ. :) The answer is yes! For the first time since August 2012, the truck has moved under its own power. Put all of twenty miles on it. The valve clatter I heard during cam break-in isn't getting any better - if anything, it's a good bit louder when moving since I can pull more vacuum off-throttle. Haven't narrowed it down to a certain cylinder yet (probably #3 or 4), but it sounds exactly like a collapsed lifter or poor oiling. Oil pressure says at 45-50psi at cruise and dips to ~25 at idle, so unless I'm completely misremembering the filter adapter circuit and bypass, it should be good at the top end (especially since it's much quieter under load). Fresh oil and filter before I left the house, at any rate. I'm not losing any sleep over the clatter for the time being, so I'll drive it by the machine shop this week. I doubt it's going to do anything that would tear up the lifter bore, and it's making good power. AFR says within 14.4-14.7 under load, so it's right at where I'd expect stoichiometry to be with E10, and it immediately blips to 22.4 off-throttle. IAC might be acting up, as a quick snap of the throttle results in a near-stall before bumping back up to a proper clip. It's an HO IAC in a Renix truck, so that may be to blame - don't know what the differences are, so I'll clean and swap in one of the Renix ones I have around (pretty sure the mounting is identical). If nothing else, the pieced-together and resealed junkyard AX15 is one of the nicest-shifting transmissions I've felt. The only real knock I have against the Dart/Abarth C635/535 trans is the marginal shifter feel and numb clutch paired to an electronic throttle, so I may just have forgotten how crisp this direct mechanical link really is. The LUK clutch does chatter slightly if I'm sloppy, but that's not too surprising given the new bits and a flywheel with the concavity machined off of it.

Got all the brake lines squared away and successfully bled the entire system (didn't bench bleed the master this time - installed speed bleeders at all four corners since I'm lazy and hate brake fluid). It's ready to go... apart from one problem. I could've sworn the hefty swaybar and poly mounts were in place, but they're not. I sheared both swaybar endlinks in half when pulling the OE pieces the start of this whole project, and the bolts holding them to the axle are corroded all to hell and back. After countless PB Blaster soaks, I've only managed to move the nuts a few threads. They're not going anywhere, and I can't find a way to hold the links out of the way of tierod/tires since they're shorn in half. No luck cutting through the bolts. From installing the JKS Quicker Disconnects on my XJ, I thought I remembered these bolts being keyed, but these appear to spin freely. I'd like to know myself! Haven't started it since I made that post. Time to get a 10-day transportation permit, get it inspected, and transfer the AMC6 plates from my XJ to my MJ. :)

I've converted my '90 MJ to an open cooling system when I rebuilt a '94 HO, and ran this universal coolant bottle for engine break-in: However, that's just janky. I picked up a repro 2.5L XJ/MJ coolant bottle, and noticed that the wiring harness (headlights, fan switch, etc.) can't easily be pushed aside to drop the bottle in place. I can shift the fuel pump ballast resistor, now-unused EGR solenoid, and ground, but the bottle can't squeeze between the airbox and the sheetmetal. (Overflow fitting on the radiator is also 180deg out from where it should be for the new bottle... oh well.) What have other 4.0L folks done to accommodate the 2.5L bottle?

Success on one front! E2 is the error code for "no sensor detected" - it promptly calibrated and read 22.4 once connected. Beautiful! It's wired to key on at accessory and run (through a tie into an unused live wire off the horn relay, as 1987Comanche found in my electrical manual). For the time being, wiring is run down the side of the dash, though I'd like to route it properly once I get everything running and have the time. Also need to tap from a headlight power wire to allow the gauge to dim with lights on. It's mounted in an Autometer pod, as the brackets I made for the dash proved to be useless once I realized they dash support interferes with the deep gauge. Oops. At this point, I just need to... redo all the brake lines I made, as I don't trust a single one of 'em. Also need to grab a coolant temp switch with ~215-220F activation temp for the HO thermostat housing.

Huh, a means of determining AFR without waiting for the plugs to season and the pistons to hole: Going to make a sheetmetal gauge panel to replace the OE clock. I haven't even tried with the vacuum bleeder yet - so far I've just tried the speed bleeders. The new screws that came with the calipers were so bad that I put them in the trash where they belonged, so I can't go that route, unfortunately. That said, even with the speed bleeders locked down, I can't build pressure at the rear... hmm. I think I'm just going to tow it over to Presley Automotive and have them pull fluid through. At least that will narrow it down to an MC issue if it's not an improvement! Thanks! I'm ready for the build thread to be over, to be honest. :rotf:

I've got a Bosch wideband with an Innovate AFR gauge - just need to weld in the extra bung in the crossover! Think I'll bend a sheetmetal bracket that will fit in place of the OE clock block. If it's running funky in closed-loop operation, I'll know soon enough. Ran into a braking mystery. Went to bleed the new brake setup (for reference - '04 WJ master/booster, XJ proportioning valve since my balance assembly was shot, Wagner calipers, Wagner wheel cylinders, Bendix hoses, nickel-copper lines, speed bleeders) and it won't build pressure at all when attempting to bleed either caliper. I noticed a pool of fluid under the rear hose after I pumped the pedal about fifty times to no avail, though I need to narrow that down to the inlet or axle block. That said, no clue why the calipers won't pressurize. No leaks whatsoever in the front system and I bled the MC in the truck (bent some extra line up into the reservoir, primed everything, and swapped over the lines quickly). Either I completely misunderstand the inner workings of a dual-circuit MC or my junkyard WJ MC is shot, I suppose. :dunno: Also, 1987Comanche raised a good point regarding the Renix/HO IAC interchange - I'm using a '94 throttle body (IAC included) with a Hesco TPS adapter. Are Renix and early HO IACs functionally identical or do I need to revert to '90 unit I pulled with the old drivetrain?

1987Comanche and I had a heck of a time breaking in the engine tonight. Got started a little after sundown and ran into some questions: 1. APN header (316 stainless steel) uniformly glows a dull red (ports to collector) when varying RPM between 2000-2500 or so. We only noticed this once after shutting off spotlights (it's dark out!) after about five minutes of runtime, so I killed the engine. Confirmed static timing and swapped out the original Renix injectors for freshly-balanced Bosch units from a Volvo 850 Turbo. Glow appeared to be less pronounced at this point (nothing visible if under ~2000RPM for a few seconds) and I ran it for another 20 minutes with no issues, but I'd really like to know what kind of AFR it's producing. No cat yet, so I don't have the benefit of checking temps on that - I'd expect considerable glow there if rich. O2 sensor is new (unproven), and since the header appears to be a uniform temp across all six ports, I'm thinking this may just be normal for a stainless header under no-load conditions. Thoughts? 2. Temps rise to ~215-220F after ten minutes or so of the above conditions. That said, I don't know how effective the electric fan is when the engine isn't idling, and I probably should've installed a new clutch on the mechanical fan. Again, I don't know whether or not this is typical behavior given the circumstances - just have to drive it on the street and see how it behaves. Thermostat opens and cooling system appears to have bled out nicely. (Radiator doesn't have a sensor bung for the electric fan, so we just jumped the harness to kick it on. How did I not notice this?) 3. There's definitely an audible lifter clatter once hot, though oil pressure is good. It's unnerving, but as before, I don't typically sit in my 4.0 Jeeps at highway RPM when parked in the driveway with the hood up, so I'm trying not to overanalyse this until it proves to be sustained and pronounced under "normal" conditions. Perhaps it'll go away with engine time or perhaps it's just a 4.0. My concern is that the OE-length pushrods may be too long, though my machinist pointed out that head & block were decked maybe ten thou total for cleanup. 4. Front galley freeze plug has begun to weep very rapidly. I have a feeling that I'll have to run some block sealant through the lovely all-new cooling system, as pulling the engine to replace the plug isn't on the agenda. JB Weld (or my current "solution", ultra copper RTV) isn't up for the task, I'd say. That said, it ran very nicely with only a couple hiccups - need to adjust idle stop on the throttle body, and the thermostat housing gasket apparently didn't seat. Oil on the dipstick looks perfect and smells gas-free, though damn does CompCams ZDDP additive ever smell funky. I'm on ChumpCar junkyard duty tomorrow (need a Kia Sportage R&P for an '85 RX7 GSL-SE), but hopefully the truck can move under its own power with fresh oil on Monday.

At this point, I got my brake calipers figured out (the above is correct) and ran into a fueling issue. I haven't yet diagnosed the fueling issue, but ran into something that may be worse. What smells sweet, is approximately 23% denser than 10W30, and shouldn't be leaking from your drain plug? :dunno: Drove home from Ohio to discover that the plug leaked a little under a quart of Rotella onto the garage floor over the past three days. Not only that, but the puddle contained a circle of coolant/water that may or may not be related. I replaced the plug & washer that came in the new Spectra pan, letting a couple cups of oil drain into a clean container (lowest point in the system, etc), only to discover that a few drops of coolant pooled in the periphery. Unless the leak is coming from somewhere else and I didn't clean out the drain pan sufficiently, fueling (and a new drain pan with a curved sealing surface) is the least of this truck's concerns. The #11 head bolt would leak down the other way from what I can tell, the block was Magnafluxed (prior to assembly in June 2012, granted), and the head gasket is a new Fel-Pro unit that was incrementally torqued down under new ARP bolts (in January). I'll put an easily-monitored glass cup under the leakpath tomorrow to see if coolant shows up in that. I don't even know anymore. :peek:

Thanks folks! NAPA should have my pressure gauge tomorrow, but I'll be out of town this weekend so this'll have to wait until Tuesday. Definitely have some things to discuss with 1987Comanche over lunch tomorrow... Yup - the only old components in my fuel system are the tank (cleaned inside, painted outside), '94 rail, and the ~2yr-old fuel pump. Hoses, fittings, filter, seals, etc are all new. I've more than once second-guessed myself on this. :yes: The return is in-line with the FPR and the feed is connected to the second fitting (just behind the return on the '94/95 rail). I checked this again tonight just in case, since confusing an identical pair of braided hoses isn't hard... fuel supply surges forth from the feed nicely. Here's what they looked like last month before I buttoned up all my lines, hoses, wiring and such: This is something I should've been doing right off the bat before even attempting to fire it - should've done it when I checked the other sensors. I'll have new information Tuesday. Thanks again!

Whoa, just realized I never replied back with the results and it's been a whole month. All of you folks are right, of course. :cheers: I again swapped on the calipers shown above, and although the machined ears on the calipers don't appear to match the casting, it's correct. I just overthought it and second-guessed everything when the machining (particularly that inboard ear) sat so far out. I did receive at least one set of calipers that were mislabeled, but hey, the above ones were correct anyway. The fact that machining on left and right calipers isn't mirror still strikes me as odd, though. Good thing calipers slides aren't put under shear because these things sure have a good bit of angular slop. :rotf: Thanks again!

I’ve just finished reassembling my MJ after a solid year of partial restoration and am ready to get it inspected. When cranking, all I get is – no fuel is being injected. After probably a minute total of cranking over several hours, the cylinders and spark plugs have no traces of fuel. It provided a healthy pop when starting fluid was sprayed. First thing I did was pull the feed hose (feed and return are -6AN Aeroquip) from the ’94 rail and verify that it was providing sufficient supply when priming at key-on. All seems good. The CPS (new, so untested) appears to be functional as the spark plugs fire consistently. Injectors are reman/matched Bosch units, though I’ve also tried the old Bendix units since they’re handy. When checked, all of both sets provided impedances that should be accepted by the ECU. Although my multimeter can’t get a reading from the short pulse width provided by the ECU, it does display quick nonzero voltages when probing the injector pigtails while cranking. Fuel pump seems to be functional – previous owner installed it in September 2011 (~1500mi) and all I did was pull it to replace O-ring and lock ring when I installed the new rollover valves/grommets and new injection hose & clamps. It primes the system nicely at key-on. All underhood electrical grounds are new and I cleaned/regreased all just in case. I also cleaned out the bulkhead connector. All electrical systems work apart from the interior lights (may need to finish some underdash wiring) and the radio (which illuminates but doesn’t turn on – probably also a minor issue). All exterior lights, chimes/buzzers, and non-mechanical gauges function correctly. All sensors are new (though I wish I'd left the old ones in for the time being). This leaves me completely puzzled, but with a few possibilities. Bad injector ground(s). I can’t imagine that all of the signal wires have failed, though (if I remember correctly) the 1990 electrical manual refers to each injector grounding independently to the ECU. The 1987 diagrams show a common ground – I thought these were identical systems, but I guess the transition away from the C101 connector changed things. Zero/insufficient fuel pressure, possibly due to failed FPR (also new/untested), though I thought it would simply fail at the 31psi under-vacuum position. When bleeding the Schrader valve on the rail, it always has an air pocket that reappears very quickly and the valve never produces a strong spray, so I'm suspicious that the FPR is just looping fuel back through to the tank. But wouldn't the injectors do something, even under low rail pressure? Fried ECU. I originally had the battery ground going to the block, though this changed when we noticed that the ’87 Renix troubleshooting manual clearly shows the battery grounded to the starter. Doing this resulted in a very hot ground and a clicking starter (why it’s different from the manual and why the starter isn’t grounding through the block is beyond me). Returning the ground to the block fixed the issue and it cranks smoothly, but would the ECU be susceptible to damage with the bad ground? My next step is to put a gauge on the fuel rail and confirm that it’s pressurized properly. If that isn’t the case, I’ll swap out the Renix ECU for the Mopar-flashed TSB ECU, but is there anything else I’m missing? Any well-known Renix issues that could be behind this? Thanks! Bob a pre-disassembly shot...

If it's kosher for me to crosspost from my project thread, I've run into an issue that has reassembly at a standstill and hope it can get some more visibility in Tech. I can't find the correct calipers for my '90 2WD Pioneer, but I foolishly returned the pieces on the truck as cores before checking the replacements. At this point, I've exhausted local supplies (listed below) and am going to start ordering online. RockAuto lists Wagner L123602 and L123603 as correct for a '90 2WD, so it's my next option, though not one easily (or cheaply) returned. I can't find an image of them anywhere, though the other calipers they list for my application appear to be the same incorrect casting as the SE4892 shown below. Does anyone have experience with this setup? Tracking down the correct calipers is the last big step to getting my truck out of the garage for the first time in over a year.

MJ now has rear brakes! What an odd setup on the Dana axles. Still no luck tracking down calipers. Calipers shown in 1990 microfiche are 05252985, 05252984 (oddly enough, appear to be shared with my Dart): And boy howdy, does that ever look like the SE4892 from NAPA: Not even close. See also: why I'm replacing the rotors and wheel bearings, and why I shouldn't apply grease in the dark. Based on a few trips back and forth, here's a group of NAPA calipers that don't appear to be correct, along with their respective applications (according to NAPA interchange, at least): SE4892, SE4893 ('90-'92 XJ/MJ, 2WD, pictured above) SE4890, SE4891 ('90-'92 XJ/MJ, 4WD) SE4732, SE4733 (pre-'90 XJ/MJ) What exactly do I have here? And what am I doing so horribly wrong? I wish these had the same unit bearing & hat rotor setup I'm familiar with from later XJs.