AnotherOldJeepGuy

OK I finished my homework before the heat come back outside. Pulled 3 lugs at the block ground point, plus the primary ground cable. The primary ground cable is relatively new and still looked clean, the other three were not terrible but for sure have been improved now. I scuffed them clean with sandpaper, also the point of contact with the block. Then gave them a bath of contact cleaner. After the cleaner dried I put it back together. I cycled about 6 times turning key to RUN and OFF, checking codes at each RUN position. I saw I3 no ground detected the first time, then every time after that I saw "No Injector 12V” + “KO Tests Not Run”. I did try wiggling the connection at I3 and the harness, that didn't change anything. I never saw any complaints other that I3 during this limited test. I started up and watched the Knock count, first letting it idle for a minute or so. I did see it toggle to 1 and back to 0 occasionally at idle. Then I bumped it up to around 2500 RPM, +/`100 I guess and I saw the knock counter report from mid-20 to mid-40. According to the REM doc, 10-100 is normal at that RPM so based on that I assume my results are OK, and also I am assuming without any way to know otherwise, the knock sensor is reading correctly. After this just for grins I disconnected the battery for about 30m for an ECU reset then repeated everything above after the ground cleaning. After the ECU reset, switch between OFF and RUN (not starting) about 6 times. Never saw the Injector ground open reported, but I did still see "No Injector 12V” + “KO Tests Not Run”. Once I saw “KO Tests Not Run” by itself and once or twice I saw ECU report No Errors. Then I started up and looked for knocks. Results very similar although the knock count seemed to be a little lower hitting upper 30s. But I realize this is a sampling of knock counts so I don't know that "a little less" means much especially since it is still in the range noted as normal by the REM docs. For future reference, how long is really needed for an ECU reset? When I disconnect battery I have been disconnecting both cables and shorting them together help bleed off everything.

Gotcha. So at locations 1-3 I have 1 old and 2 new injectors. There is one thing unique with 1-3, the ones that have from time to time thrown the fault, they are probably the ones farthest from the ground lug based on how the wires are routed. I'll try the knock test above then clean up that ground connection, and see what happens. Probably be tomorrow morning cause here in Texas it's already too dang hot by about noon for me to do a lot of work out in my driveway!

How are the injector numbers assigned? Is it 1 through 6 from back to front, or front to back, or an assignment related to firing order? Across the multiple readings I have gotten when I did see the INJ error, I saw I1 the first time, then I saw I2&I3 a couple times after that. I installed 1 new injector in Feb '25 to replace one that was leaking even after new o-rings. 2 others were replaced by a shop maybe a year earlier. So I have 3 relatively new and 3 original as best I can recall all apparently working fine until my maneuver. From back to front, if that numbering is 1 through 6, then I1, I2 and I4 would be where the original ones are, and the other 3 are new over the last 2-3 years. If I knew how the numbers are assigned I could relate the failures to all old, or all new, or a mix.

Here is what I saw for those readings. I am not expert enough to know if these meet the criteria of falsely reporting lean or not. or what would cause that to happen... It is interesting that LT says the ECU is "using the Base Fuel Curve (I think that means Open Loop) while ST says it is not. I have no idea what that means, but it seems like it can't be both. I ran the engine for a while and watched the readings that indicates Closed, to see if they changed, I didn't see them ever change from reporting closed.

Got a new one good through July 3... 340611031172570460

Continued with the soap bubble test. This time I soaped up the connections at the Oxygen sensor and the pipe between the exhaust and intake manifolds. And as much of the rest of the exhaust manifold I could get the soap sprayed on. Still no bubbles. I have probably gone as far as I can go with the soap bubble test, I don't think I can get to any other spots. If there is a crack, it either can't blow a bubble or it's where I can't get to. I studied the REM documentation a bit more and found that it says when the sensor is operating properly the reading should constantly swing between a high and low value, and mine is doing exactly that (1.7-4.8). And it seems so unlikely to me that the 'maneuver incident" could have caused my relatively new sensor to go bad, but it is another test case I can try since @Gojira94 generously lent me a oxygen sensor for the test. I did go back and check my Rock Auto order and the sensor I installed in Feb '25 was NTK 23553 Oxygen Sensor.

Rain Stopped so I collected the engine running dataset and added to PDF. Note that since TSP was showing low I adjusted it to 17 before collecting the additional information. My expertise doesn't let me identify good/bad but I don't see much that is obviously way out of line based on the REM documented expectations. I guess I am most curious about the readings that kept moving around, because the movements coincide with the engine revving up and down during idle, and it didn't use to do that (IIRC). REM Gauge Readouts Engine Off-On.pdf

Thanks for that confirmation, I figured but the warning was not clear!

I collected everything I could find that lined up with the "REM Gauge Readouts Summary" with engine OFF before I got chased in by rain. I got the reading through the menu HOME->DIAG->READINGS and noted them in a copy of that list which I have attached here. I got an error when I attached it, or at least a message, telling me that pdf was not supported? I am guessing with no knowledge that the error means it calling be displayed in the thread, but I am assuming the attachment can be opened by anyone that can open a PDF. Can someone confirm it can be opened so I know posting a PDF works or does not please? Looks like there are other sub-menus but I don't have any REM for Dummys book to follow to know what other buttons I might need to push or in what order, so I am hoping this gets me where I need to do. I'll update and repost with a version annotated with the same reading with the engine running after the rain. REM Gauge Readouts Engine Off.pdf

OK, I got some info. I am far from an expert at using this tool yet and I am trying to figure out the button driven menu system, but my first attempt I get the following: REM installed, Key ON, engine not yet started. CODES: -REM CODES --No REM Codes -ECU CODES --Injector 1 Open (this was not consistent, I later read instead I2 and I3 Open, but not I1) According to the documentation on the website, "ECU does not detect Injector # wire has a ground path" -TCU CODES --No TCU Codes. -ABS CODES --Not Available. Then with engine started. CODES: -REM CODES --Loop Fault Lean According to the documentation on the website, Possibly faulty o2 sensor, weak fuel pressure, other fuel system imbalance. – TIP: This code is more common during cold weather starts as the first Closed Loop attempt may fail due to the Cold Fuel Enrichment value still being too high. This code can be ignored if the 2nd closed loop attempt succeeds -ECU CODES --No Injector 12V** (This was consistent, but is to be ignored**) --KO Tests Not Run **According to the documentation on the website, if "No Injector 12V" is received along with "KO Tests Not Run" it can be ignored. -TCU CODES --No TCU Codes. -ABS CODES --Not Available. Once I can get more familiar with the menu I'll try to grab the other items listed by @Gojira94.

Great Find!

When I first switched from r12 I was not impressed. That was quite a while back. It never seemed to have the same bite. Over the years I have gotten maybe 3 new compressors and sometimes they worked great, sometimes they were just OK. So I guess to answer your question, if your replacement is done right, and the components are all good, you should expect your AC to be almost as good as the r12 was as far as I can tell. If it isn't, you have an issue with parts or the install, or both. I have a spike thermometer stuck in my center vent because it was feeling a little less effective last summer. I added just a little Freon and it got back to normal or a least close to it. When outside is in the 80s or less it probably hits low 40s, as the temp goes up as we are quite familiar with both living in TX, it can't keep 40, but the delta from outside is still around 35 or so.

Awesome, I'll be watching the mail! Thanks again!

I just did soap test #2, I suds-ed up all along the top of the area where the manifolds connect and again saw no signs of any bubbles being blown, or soap being sucked in, and also no sign of RPM changes with the soap and then as I rinsed it off. This is not too surprising since the water testing has already proven to not show anything, but it was another place to try the soap that was easy enough to get to. Now I need to let it completely cool again and see if there are other places I can soap up and try again. I am not loosing track that everything was great until the "maneuver incident" so although I cannot yet find any crack, a physical issue still seems more likely (at least to me) rather than some control that failed coincidentally at that same instant. I have read over the distributor index posting at least 4 times at this point, and have not come to a sufficient understanding of that task to pursue it. It may be beyond the extent of my mechanical grasp, time will tell.

I got my last ones at Advance Auto Parts in Jan '25 when my local store was closing, sorry I don't have the PN. I don't remember them being anything different than OEM, so however many holes the OEMs have, these have, and they work fine.

Good info thanks. But luckily I don't believe I need a replacement, at around mid-80 degrees the resistance was around 2k, which I now know is an accurate reading. BTW I did try starting up with it disconnected just to see if I noticed anything different, I didn't. Then I reconnected it.

I just typed the ohm number even though I realize now I specified I used used the k-ohm scale. The correct statement would have been ~2.06 k-ohm. Sorry for the misleading post....

Looks like I might need to replace this, so it would be helpful if you could note back if you were able to get to this without removing other things, or, what other things you had to remove to get to it!

@M.T.Hands posted back in 2024 that he fixed his regulators. I followed the post so I went back and looked at it, but I don't see any info on how in that post. I remember someone talking about swapping the spline end to end and getting the bad part moved to where it didn't count, but I don't remember where that information is. The first time mine started doing this I was able to clean in good in place and oil it up, and that fixed it for maybe a couple years, so that might work for you depending on the amount of wear. The last time mine started to act up the only thing I managed to do was to literally block the window from going all the way down, which was where the failure was. Not a great fix but a functional band-aid that kept me or a passenger from accidentally lowering it to a point I could not get it raised back up. Good luck and if you find a source of good replacements please post it!

I went back through reading about the EGR because I am still curious about the EGR movement not being consistent. Reading back through I realized I didn't answer this post questions. I don't know that anything smells any different, if so it's not obvious to me. I don't have anyone handy to rev for me, but I'll see if I can get my neighbor to do it when he gets home from work. I'm still curious why my EGR moves only sometime when I rev up, and when it does move is when I get the backfire and the delay to accel, and want to stall, when neither happen when it doesn't move.

I measure ~2060. It's been roughly 2 hours since I had the engine on for about 4 minutes, and the exhaust feels cool, so I'm assuming that is cool enough. I don't have a 10k scale choice, all I have is ohm, k-ohm, m-ohm, so I used k-ohm setting. I remeasured on auto-scale and got the same value. So for sure not open or 30k+, but perhaps low. I guess maybe I should watch temp with the REM and see if ECU is getting reasonable values before I replace this sensor, especially since I don't know how much stuff is in the way for replacing it. I started up with sensor disconnected just to see what it did, it ran just the same at start up as with it connected. I only let it run about a minute not knowing what damage I might do.

Wow, talk about redundancy! 3 Fluid Temp sensors! Overheating if it happens could for sure be a big deal so other than 3 failure opportunities, having 3 sounds fine with me!

Did soap test #1 at the donut. Didn't see any bubbles on first test. But I can only test a little at a time since I have to catch it on my phone. Got about 2 minutes max before it was hot enough to evap the soap. https://drive.google.com/file/d/1UWBtZNOYjkVmAVcxKzix_9CgiTkAnvvP/view?usp=sharing Wasn't a 100% test, I don't think I got soap all the way around so I'll try again, after it cools off. This is the CTS correct? Looks like a single wire so I measure between the connector and chassis?

Understood. Good to know. This one has been working from Feb 2025 though. But I wish I still had to old one to swap back in, since the issue back then didn't turn out to be the sensor, just to rule out it has not failed.