jamespwsullivan

Pete-later reply but we appreciate your checking. We replaced the mismatched bolts with 4 of the type you described. Thanks!

A bit of an update with more to follow on another thread when I get a minute. The fan installation was not trouble free but with some creative thoughts about spacing on the mount points the finished product is pretty good. And as expected, it did not resolve the overheating issue. The KSuspensionfab kit optionally provides a sensor and Tee for the thermostat housing. After reinstalling the factory sensor (for the supplied fan controller) in one side of that Tee, the dash temp gauge isn't registering properly - actually is isn't registering anything. We just installed that instrument cluster but the gauge was working before we moved the sensor.

So we're going to replace the fans with a setup that has a higher air movement output (cfm.) That's going to happen whether it is the real issue or not because I am now convinced that the two aux fans do not out put the same amount of air as a mechanical fan plus one aux fan. I can't find a part number on the Delco-Remy (stamped) alternator but I have a strong suspicion that it came with the TJ block. In any event I think I'll put a new alternator on the list. Need a known quantity... Last but not least, someone on FB asked about reverse rotation water pumps. The pump on this TJ block (2003) does run CCW as opposed to the crank which runs CW. However, a guy I really respect on the wranglertjforum.com says that a reverse direction pump cannot be installed on a 1999 and older block, so it make sense that you can't go the other way either. That doesn't mean that the water pump isn't a suspect though. It isn't leaking but almost everything I haven't touched on the cooling system is still a suspect. LOL

Good suggestion and I have heard similar before but without the detail. As long as the thermostat housing is the high point the burping should work as needed. I alrday have a thermostat housing with a sensor in it and will try that procedure. Thanks

Going to try a different efan next. I'm looking around to see if I have a spare / known-good IAT sensor. Thanks

Here's what I found from the last time I dumped a log from the REM. STFT range between 133 and 158 LTFT steady at 128 CLOSED LOOP - seeing it switch to closed shortly after starting INJ Pulse Width (PW) - range between 6.9 and 7.4 Intake Air Temperature (FIA) - The header in the data log file form the REM shows this as "IAT" rather than "FIA" but that's not the interesting find. It is stuck at 68 degrees which surely means something about the sensor. It sure is not hotter than the outside ambient temperature although I will test again since the daytime temps have dropped since the last time the truck was run. LEAN versus RICH - Sure it swaps back and forth but is not stuck in a LEAN state for any big amount of time.

@ Ωhm - Double checked before I responded... No it's not running lean and yes it is running in closed loop as would be expected.

@m2bandit I don't see mention of burping here. I like to first fill from the top rad hose. Then remove the temp sensor on the back of the head, park the jeep nose down and fill it while at operating temp until it comes out of the sensor hole. Reinstall sensor, place cap on. Take a couple short drives getting up to operating temp (210 I think) and check fluid each time. If you don't have to top off you're good. The head is from the 2003 TJ so does not have a sensor at the firewall end. We did burp the coolant the best we could without the access and did this---> You can see one of many discussions here: https://www.naxja.org/forum/showthread.php?t=939188 about a procedure we used that involves tiny holes in the thermostat. What I can say is that the coolant level is stable over 200 miles of driving. Your comment about putting a mechanical fan back in use is interesting. The spec'ed air flow from the electric fans seems adequate but I'm about out of ideas so I'll see if I can source a fan and clutch from the JY. Thanks for the ideas.

Thanks for the early feedback. Lower radiator hose seems fine. Not ancient but not brand new either. I'll report back on the REM/ECU info the middle of next week when I can physically get back to the truck.

My brother and I have been chasing a hot running problem on my MJ 4.0 I6. The block and head are from a 2003 TJ, the intake is ‘87 Renix, and the cooling system is closed. I just read pizzaman09's post and don't see anything that fits that we haven't addressed already. Here’s the question: Is the next right step is to pull the head off? If/when we pull the head, we’re going to look for blocked cooling passages and/or a failed head gasket that is allowing early coolant return (h/t to Ryan Aumiller in the Jeep Renix group on FB in response to my post from August 2021): https://www.facebook.com/groups/391733537829621/permalink/1505664613103169/ There is no visible sign of coolant and oil mixing in the crankcase. A couple of things that could be tried before pulling the head: (1) pull spark plugs and look inside cylinders with a boroscope to see if one or more cylinders is/are “too clean”, suggesting coolant intrusion (2) test for combustion leaks (using this detector from HF): https://www.harborfreight.com/combustion-leak-detector-64814.html The current sitch is that the things we have done (listed below) have helped but we are still seeing temps of 225 F - 230 F on the Renix Engine Monitor (REM) under load. We have heard from many REM owners members of this group that temps at or below 210 F on the REM are to be expected. (We don’t currently have a factory temp gauge so the REM is our only coolant temp source at the moment.) https://nickintimedesign.com/product/renix-engine-monitor-ii/ Also: This is a road vehicle—we’re not talking about trail use but it does have 35” tires on a 5” lift with an AW-4 transmission, 4:10 gearing. Unless there’s something else obvious that we’re missing, you’ll probably agree that this is a head-scratcher. Other than the two things mentioned at the top is there anything missing from what we’ve addressed that might impact the efficiency of the cooling? Already done: (1) all applicable Cruiser54 tips (2) IR thermometer check (no particular hot or cold spots found) (3) tested and replaced all sensors that were out of spec or believed to be janky (4) new water pump (5) new 195 F thermostat (6) new coolant pressure bottle and cap (7) new full-width aluminum radiator (Spectra CU78) (8) replaced single crank-driven radiator fan with two factory-style aux electric fans—1 controlled by sensor mounted in radiator fins (203 F on) and other by REM (210 F on) (9) Bleepin’ Jeep style 3-part cooling system flush (done 9x [yes, really] – until coolant retained green color) (10) bypassed heater core (temporarily) to eliminate it as a possible problem source.

Thanks for your comments. Mobile version it is then!

Years ago I used Tapatalk to view and respond to this site, but then I got a different job, they gave me an iPhone, and the app didn't work the same way so I dumped it. back to Android for me now... So I installed Tapatalk (not Pro) and I can't even find this site. What's up?

Definitel planning on practicing a lot with both new and old line.

The Titan got a couple of recommendations so I think that's the way I'm gong to go. The bar type tools are really common so there must be something that works in that design too, but I won't have uses for a kit that supports multiple sizes I'm going for the space savings. LimeyJeeper's recommendation is no doubt a quality tool but probably a bit of overkill and outside my budget.

Thank Eagle.Lots of good info on this thread. I'm sourcing some "Cunifer" line.

Thanks for the offer, but the truck is in Kirkland, WA so I'm planning to purchase a set and leave it for my nephew when we're done. I'm also thinking that I might have to do some of the work with lines in place so a handheld could be easier. It sure looks like a bench mounted type could be more consistent. Can you tell me how you know about 37 versus 45 degrees? I love to know sources!

I am in the process of replacing some brake lines and other brake components. I have some questions. I have read several places that the preferred inverted flare for brake lines is a double rather than a single flare. Thoughts on this? I am looking at flaring tool kits and see that many offer both 37 degree and 45 degree tools. Which one is correct for the MJ? Does anyone have any recommendations for flaring tools sets? I want a tool that makes good flares and has a decent lifetime but see no reason to spend the money an a hydraulic tool. Thanks

Results of our science experiment. Full disclosure--both of my parents were teachers so my brother and I are all about one step at a time, and we are also about getting to the bottom of something so that we understand it. So, don't take this as any distrust of anything that people contributed. i love it when things work out. Picture #1 is another shot of the original distributor with a cut off cap and #1 at TDC. Sorry the shot isn't lined up so it's easy to see the line of the side of the cylinder head. Next picture is the new distributor (NAPA NND ST4692) installed. Engine is still #1 at TDC. So, we didn't measure the gap to get the .020" shown in the earlier diagram, but the new distributor installation sure looks a lot more like that diagram - which confirms (probably for the umpteenth time) that the original distributor in the vehicle was not manufactured properly and needed to be indexed. Working on the rear brakes right now so I can't do a test drive, but I'm optimistic that this change may have an impact on the smoothness of acceleration under load.

Yes it has a ballast resistor. Haven’t tried the bypass but did test fuel pressure and it’s well within spec.

@Ohm I think I understand that, the pic I posted wasn't oriented well enough for all to see that my cap, rotor, etc. is very close to what Cruiser's picture shows. Looking at the number of teeth on the distributor shaft I suspect that a full tooth would be too much change. That's why I'm suggesting that I tweak the position after cutting off the tab. Am I missing something you're telling me? And BTW, why is it that MJs got shipped from the factory with the distributor (incorrectly located? Does it have to do with the location of the tab on the distributor? Is it the location/nub that the tab locks into? Thanks to all who have contributed so far. I'll keep this updated with status.

So if I do the indexing procedure described by Cruiser54, I can adjust it that way rather than lifting up the dizzy and dropping it back down one tooth later? If I am seeing the drawing right, it's very helpful. The rotor tip must be completely past the #1 post.

Tenth character is "H"

Here is a picture of the rotor location when #1 is at TDC. Reading Cruiser54's tip I think that the rotor tip is in fact slightly trailing the #1 location. I'm just looking for some feedback or confirmation. thoughts?

@cruiser54 Yes I understand. I should have said that I have a 1987 and it's verified by the VIN.

@Cruiser54 sorry to take so long to post an update. I didn't mention that my MJ is in Kirkland WA and I live in Indianapolis, IN. I'm (sort of) retired so I come out to visit my truck (and my brother) about once a month and now I'm back. I just got here and this morning I observed something that I can't explain. My top priority for the day is to delete the C101 connector. There isn't one! I thought that the C101 was the connector through the bulkhead behind the fuse box, bot looking at your video and some other threads make it clear that I am wrong about that. There is a bracket still in place but no connector, and frankly there is no evidence of any splicing in the vicinity of the bracket. There has been an engine swap in the past, but it's still Renix 4.0 and I'm not sure what to do next. I'm looking for advice about next steps. I have considered creating a new wiring harness but that seems to be a lot of work. the truck spent a lot of time sitting in the humidity and heat of south Florida without being started and I have refreshed a bunch of connections - lights and such - so is it time to re-do all of the wiring? I still have occasional issues with bucking and sputtering under load and have done a fair amount of work replacing sensors, working through Cruiser5 tips, etc.