PhilisDiller

Dunno about cruise control. I need some interior bits and was planning on grabbing all the sensors/solenoids. Also need the window seal for both front sides. I'll snag the mirrors too and maybe drop the towing mirrors. Dunno which route I want to go there yet. I'll keep my eyes peeled for axles too. What's the reason for the throttle body? I thought people upgraded to the HO TB?

A 88 renix XJ just popped up at my junkyard with the same blue color interior. I’m going to grab anything that looks good and am wondering if anyone had recommendations for things that I need to grab while I have access to a renix?

There were a few on eBay for $91 so I grabbed 2. I have a feeling I’ll be owning an 2 door renix XJ in the future. 😈 there’s 2 more on eBay but they are $121. Ouch

Good stuff! I think you're right. I did a test today and can tell you with certainty that idling does not "teach" the ECU. The LT stayed at 126 after 30 minutes of idling with an ST around 30. I took her for a 25 minute drive on the freeway and before I even got halfway, my LT was at 105. While cruising, my ST is almost perfect! Pretty much floats at 100-110 the whole time. The ONLY time my ST doesn't look great is at idle. Everywhere else is just beautiful. I haven't done any long term mpg testing yet, but looking at my speed and GPH, I was getting around 22mpg on flat highway and even 16-17 going up hills. And she could mostly maintain her speed in 5th gear going up hill. The only last thing i'll do is get exhaust fume smog testing done for my own personal knowledge of her polution levels. I'm really happy and will probably leave the engine as-is for now and will start focusing on the windshield leak, detailing the interior, replacing ripped seats, fixing rust, getting my keys working (I don't need a key for my ignition and I don't have doorlock keys). Thanks a million for all the help. It's been a bumpy ride but I'm a happy camper

Thanks for all the info there. It looks like manual is a simpler ecm relearn process. I still need to take it for a long drive, but it looks like I've developed some sort of parasitic draw on my battery because it's been dead when i go to start it the last two times. Never had this issue before the last week. I'm thinking that my ECM was reset when i had to jump her to get her started because my LT was back at 128. It was down at 120 last week, but like I said I don't drive her much. I'll spend some time pulling fuses to find where the power draw is coming from. I'll make an effort to take her for a daily highway run. I have only taken her for two 40 minute drives in the last month, but the battery was reset after that I believe. I had always assumed that the ST and LT were related but not dependent on each other. If you're constantly running with an ST at 50, I assumed that LT would slowly start dropping down to 50 but I guess I was thinking that the LT only impacts Open loop? If ST is at 50 when LT is at 128, Would it be expected for ST to change if LT dropped down to 50 as well? Like is the ST +-128 from whatever the LT point is? Example: After an ECM reset, ST was at 50 and LT was at 128. If I take it for many long drives and the LT drops down to 50, what should the ST be at? Would it still be around 50 or would it be closer to 128? Does it function like this? Assuming LT sets the base fuel usage and when in CL, ST adjusts fuel usage from the LT point? That would be awesome if that was the case... Open loop - LT = Fuel usage Closed loop - LT+ST = Fuel usage

Alright I closed off my EGR and I also managed to snag a Mopar 4713639 oxygen sensor. I can’t really tell a difference in performance after doing the EGR. I also replaced the new vacuum connector line that was on my FPR because it was split. the oxygen sensor swings a lot faster and is more responsive. Before putting in the Mopar sensor it would struggle to keep closed loop when I let off the throttle because the ST would go to 0 before the O2 sensor is able to respond in time. Watching it, I could see it was slow to respond. The new Mopar sensor is a much better and almost never fails out of Closed loop because it’s so much faster and catch the O2 swing before ST fails. Buuut, she still idles around 20 ST. I checked my butterfly valve and can fit a piece of paper between the valve on throttle body. I was concerned she was getting choked for oxygen, hence the low O2 numbers. I don’t think that’s the case though. after changing in the 746 injectors my idle has been around 1050. Before it was 750. My tps is 16 so I’m a bit stumped with the idle. Seems like a vacuum leak, but I can’t find ANYTHING. I did another propane test today and realized that even if I put it into the intake, I don’t hear the idle change. What I do see is the O2 readings stop swinging and read low. So I was watching the REM while doing propane tests and didn’t see anything indicating a leak.

You're a good man

Thanks a million for listing the NOS O2 part number in your build thread. I used the parts catalog to get the O2 number - 53004245, but can only find crappy Crown ones. I hadn't seen the part number 4713639 used anywhere. Even searching Comanche club for "4713639" your build thread is the ONLY post that has that number. I got SUPER lucky and found some on ebay. I picked up two so I don't have to worry in the future when it's even more difficult to find. They'll be here next week! There's one more available on ebay. I paid an arm and a leg at $92 each though

Hehe, I’m on the hunt now! I’m thinking of swapping my old o2 sensor in to see if it was never bad in the first place. Damn these rare renix era jeeps. Every parts car in my area is 90+ and all junkyards within 3 hours haven’t had a renix Jeep come through in the last 4 months.

@JMO413 Do you remember what band Oxygen Sensor you are running? Ahhh reading through your build thread I see you have a NOS O2 sensor. Lucky bastard!

Wow great video. what injectors are you running? here's the things I noticed right off the bat. - your O2 sensor is muuch faster mine and tighter range than mine. - your gph usage is lower than mine, even though my pulse width is shorter than yours. I’m assuming that’s because my rpm is higher 1000 vs 800 - your duty cycle is lower than mine even though the pulse width is higher. you - 6ms 3.1% duty cycle Me - 5.1ms 4.2% duty cycle. Jeeze, as soon as I type this out I realize it’s also due to my higher RPMs. here's a video after shes been warmed up for comparison! This was right after I installed my injectors and my idle increased from 750 to 1050 from the install

For some context, my jeep seems to be running a bit rich still. I've gone through and done all of Cruiser54s tips 1-6, except the Coil/ICM fix. I have no issues with starting her and she ALWAYS starts after 1 sec of cranking, not 4-6 seconds like I've seen reported from other Renix owners. Here's everything that I've done since I got her. Eliminate C101 connection - verified ground sensor resistance below 0.5 Ohm for all sensors New FPR - verified fuel pressure at rail 31/39PSI Rebuilt 746 injectors New exhaust to fix bad exhaust leak New O2 sensor(NTK23553) Adjusted TPS to 16% (unable to get 17%) New IAC Verified MAP sensor is reading correct and not leaking against a vacuum gauge Blocked off my EGR because my EGR was faulty New spark plugs NGK ZFR5N New wires Indexed the Dizzy and new cap n rotor new 195f thermostat because my running temps were low New IAT sensor because the one that was in there was wrong resistance range reading 60f colder Cleaned Throttle Body Everything I've done has helped a little bit but never as much as I'd expected. For example, when my FPR was bust and I was getting 40PSI at the rail, I was convinced I had found the source of my running rich issue. Injectors are the thing that FINALLY allowed it to maintain Closed Loop at idle, but even then it's at the limits of the ECU. The only thing I can think of that could still be causing issues would be the ECU or possibly bad O2 sensor. Although it does swing, it's slow. When running in OL, my O2 sensor reading is basically STUCK floating around 0.5-0.6V. I know it reads lean conditions just fine because when decelerating above 2500RPM I know fuel is cut and the O2 is reading 4.8V or something. It's only after it has trimmed 30% of the fuel that the O2 sensor even begins to start registering readings that aren't just "Rich". That leads me to believe it's just running stupid rich.

I have it set to ludicrous. I was able to find a video of a jeep that was "running rough" and his O2 was swinging about 5x faster than mine at least

Hey all, The MJ I picked up was the first Jeep i've ever driven (besides renting a new wrangler) and I don't have a good point of reference for what a health Renix 4.0 should drive like. I'm hoping to actually go test drive one in my area, however they are far and few between and the closest ones for sale are about 1.5 hours away. Too busy for that right now. I'm hoping someone with a healthy running Renix 4.0 that owns the REM unit can show me a video of what outputs they are getting at idle. Readings I'm extremely interested in O2 output reading and swing rate at idle -I'm trying to get a better gauge for what the O2 swing should look like - I feel like mine is a slow swing and it takes on average roughly 2 seconds to complete one full Low -> High -> Low cycle. I've heard it's supposed to swing "lightning fast". I've been trying to source a Mopar 53004245 O2 sensor but those are nearly impossible to find. The O2 sensor I have now is a NTK 23553 but it's the newer 4 wire sensor. Vacuum - On NickInTimes website, he says healthy vacuum should be above 15Hg. Mine floats between 16 and 17Hg, but I've heard it should be closer to 18+ ST In Close Loop - Would like to see what range a health 4.0 ST should be at. I know in theory, it should be 128, but just want to see real world feedback. Also, bonus points if someone has 746 injectors installed. I've heard ST drops to around 70 with those injectors. However I'm bouncing between 0-20ST at idle. When cruising most of the time I'm able to maintain around 40-60ish, but idle is a bit concerning for me. Pulse width/Duty Cycle at Idle in OL and CL - Going from OL to CL, my jeep leans out the the fuel by around 30% down. In OL pulse width is 6.9mS, but when it's able to hold CL, I have around 5ms pulse width at idle. I do have the 746 injectors. I just want to see what a normal Renix jeep pulse width is. In advance, I really appreciate it!

What do you mean by this? Are you saying there is no benefit to the egr?