SoCalManche

Today was the big day after tireless working to get emissions ready to go; Smog Check Day. I sit there in waiting area trying to listen in on their conversation to hear how poorly she is probably doing on the test, and then I'm met with this: Hell yeah, baby! The satisfaction of seeing how low those numbers are makes the work well worth it. Suck it, California!

Reviving this thread for a question that also deals with calibration. I have an '86 2.5L and I bought the truck with a busted tachometer, where idle would read 4,500-5,500 RPMs, and when you're cruising down the highway, the need is pointing direction at 6 o'clock. I like the red clusters anyways, so I snagged a full cluster to swap in and be done with it. Well, the tachometer is playing silly again, and now I'm reading 0 RPMs, even though it is calibrated to 4 cyl. And I'm very sure it is calibrated to the 4 cyl because if the adjuster is rotated the other way entirely, idle reads below the 0 RPM mark, even though it responds quickly anytime I open the throttle; the other tachometer also responded appropriately when throttle opened up. So my question is whether or not I'm extremely unlucky and both tachometers are just botched? I tested for voltage at the ICM and the dash harness, and got battery voltage both times, as well as 0 ohms as well. Any thoughts?

I replaced the 02 sensor within the two weeks ago with a Bosch one before the cat started rattling. Ohm'd out both the previous 02 sensor and the new one, and the old one actually has less resistance. That video is at operational temp, or at least what it can get up to, which looks like it reads out at 175-ish degrees maybe? I'm swapping a new Motorad thermostat in today as we speak to see what change may occur.

1986 Jeep Comanche 2.5L seems to be running rich. I've scoured CC on other running rich scenarios, and it seems like the culprit 9/10 times is the 02 sensor. I have a bit of a different scenario for you folks. When she starts up, she evens out on her idle and sounds good; sounds really good actually. However, I have what I feel may be an excessive amount of water with some discoloration. Here's a quick video of said tail pipe action: https://drive.google.com/file/d/1BrjBtLbsyfzmVeayyzdZG3ll8TpFgoj1/view?usp=sharing You'll hear some rattle, and that's the cat; she just up and recently started rattling like crazy, and my muffler guy said the core is shot (not the shield around it), so one is coming Friday to get thrown in. Spark plugs are also under a month old, and are already fouling. My question is whether or not that is a normal looking symptom for a cat being shot, or if that is excessive? Definitely have rich fumes coming out, however I've tested every sensor on the TBI, and everything seems to ohm out how it is supposed to. The other thing I need to mention though is that she doesn't seem to get fully up to temp, so I've read on here to just get a thermostat from a dealership and be done with it, and that should alleviate the issue to a degree as well. Just looking for some peace of mind with this rich running condition because I've been racking my head around the sensors seemingly being in functional order. Does having a bad cat AND possibly a bad thermostat cause this kind of exhaust as seen in the video above? Thanks guys.

On the look out for those rare goodies that everyone else is looking for it seems...: Factory roll bar (LWB) (Lucked out with someone posting one on an offroading FB group) Factory bed mat (Thanks @CoastChief!) Factory rear mudflaps (Snagged a NOS pair of fronts thanks to @MJCARENA)

Yeah, I already did the valve cover mod for the baffles. I was just curious as to if the air filter on the valve cover itself had any real upside/downside. My system is setup in factory style. Thanks for the info!

I went back and looked at the valve cover mod tip, and it seemed much simpler than initially looked over. Knocked it out pretty quick and oil stopped coming out of the metered orifice. Now I believe hissing is coming from the exhaust manifold...an MJs work is never done!

So I got the metered orifice for the valve cover. Hooked a line up super professionally as you can see, and now of course, I run into the problem of oil getting through the orifice a bit and into the line to the throttle body. Do I need to do the top Cruiser has listed on the aluminum valve cover?

To christen my MJ's recent revival, I'm finally starting a build thread for my 1986 Jeep Comanche 2.5L / AX-5 / 4x4 / D30 & D35 / Long bed. To kick it off, I decided I was sick of smelling oil, so I've gone about doing the aluminum valve cover swap. The parts list I used is as follows: - '96 2.5L valve cover - Fel-Pro valve cover gasket (#VS50502R) - 1/2" x 6' heater hose (Prestone #HH0102) - Universal assorted rubber vacuum caps (Dorman #47396) - PCV elbow (Dorman #47079) - PCV grommet (Dorman #42344) - 1/2" hose clamps (MasterPro #MP5512V) - Metered orifice for PCV connection to throttle body (NOT CURRENTLY SET UP) So the swap is 99% done, I am unable to find a metered orifice to put in the valve cover, since mine did not have one on it when I got it. If anyone knows where I can snag one, please let me know! Anyways, had some fun with the paint, and man was it a pain to scrub and prep. But, overall fun experience, and the valve cover, air box cover, and TBI cover spruce up the engine bay a bit. Installing the PCV grommet and elbow in the rear of the valve cover was quick, and I wanted to explicitly make a note to other '86 2.5L out there that may get confused when people are discussing how you must change your PCV/CCV lines when you do the valve cover swap; we are the rare ones that do not need to do this. This photo shows why: F For starters, we have a solid vacuum harness (can't tell if metal or hard plastic) where all our lines hook up that plugs directly into the throttle body, as pictures above. There is a port on this harness not shown that pops up next to the front of the valve cover for the old PCV valve to connect to, going directly into the throttle body, while the rear elbow was connected to the vacuum harness, shooting off to the air box. As you can see in the picture, I plugged that connection on the vac harness (on both ends), and did a direct line to the air box. Hose is a bit big for those ports which is why I am bypassing it, and if you just throw a hose clamp and crank it down on the airbox port, you'll be fine. Whenever I get the brass metered fitting to pop into the valve cover, I will probably use the vac line already there, as I think the diameter will be relatively close enough to also lock down with another hose clamp. My TJ is setup the same way with this valve cover, but I'm under the assumption that all you 4.0-ers out there have it reversed, hence needed to swap it back? Bottom line, my '86 seems to be stock with the front PCV valve shooting directly into the throttle body, while the rear PCV elbow goes directly to the air box. I will update once I get that fitting popped in the valve cover, and start her up. And yes, it seems I don't have a picture of my engine bay pre-upgrade which sucks because would have been nice to have a side-by-side comparison. Oh well, if I missed anything, feel free to ask me to clarify; cheers guys!

So I've seen a few guys on here throw on a mini air filter on their aluminum valve covers after doing that swap. Can someone give me a little more info on why you would install one? Which filters are you using?

Yeah, I'm just trying to get it to shine enough near original color so that it doesn't look as wonky, ha. A bit of an eye sore when it's the only part that's dull. A full Colorado Red repaint will be in order much farther down the line.

Wow, it's pretty amazing what a little bit of love will do with that Ultimate Compound. Sun is out in full force today so you can't tell how much of a difference there really is, but this is one light coat thrown on.

Thanks for the info, guys. I'll check this stuff out.

For those of you that are rather knowledgeable about how paint works and what can and cannot be restored, I was wondering if there was something I could do to get this panel back to sheer beautiful color the rest of the truck is. For whatever reason, this panel is the only part of the truck that is extremely faded, and I'm just looking for tips on how I would go about bring some life back to this side. I'll be doing a full re-paint of her factory color far down the line, but until then, I'd love to remedy this. Side note: you can see where I rubbed some of it with my finger and it seemed to return to normal, but that is merely temporary. Same occurs when she gets a bath once in a blue moon.

No wonder she was a pain when people were trying to help get her back on the road! Haha

I definitely owe both of you guys a round!

To celebrate ending her 1 year hiatus from the road, I'm here to register her to the forums! 1986 Jeep Comanche Custom / 2.5L / 5-speed AX-5 with NP207/ 4x4 / Long Bed / 4.5" Long Arm / 33" BFG KO2 / No sway bar... Don't have build sheet unfortunately as it has disintegrated on the driver's side door. All I know is she has 4.10 gears (for now) and a fifth gear that doesn't want to synchronize in the tranny, ha. She turns a lot of heads in San Diego though! Those hills are just a tad rough at times with the 2.5...

Final Update.... https://drive.google.com/open?id=171kmLh5nhzj53nDfmLT6q-ZzMMQfw96G She runs! It's almost enough to make a grown man cry. But it wasn't without a fight. Threw the new (to me) injector in the throttle body, and then attempted to put the fuel pump back in the tank, only for the the (positive) wire on the assembly to break off one end. No worries, fashioned a new one, hooked it up, and she started up! It's been a long year constantly staring at her in the backyard, and now I'm ready to build her into the Unicorn she is. Pardon the video to those that watch it; forgot to connect the down pipe to the manifold...ha; loud and proud! For those having issues currently with a no-start condition, I hope this massively long thread can help. Lots of learning thanks to Ωhm and eaglescout526; seriously, without them powering through with me, it would have been all for naught. I am extremely gracious for the time and knowledge they gave me within these last two weeks, and hope it helps anyone else in the future. Big takeaways: the '86 doesn't have a C101 connector, however it does have the C100 which is a smaller in size, but full of just as much tar; a great thing to learn and to scrap out, and I'm confident it helped with the voltage raising back up to battery voltage at the fuel pump. Also, triple checking the dipstick grounds is always a good thing to do, as well as adding all the grounds that Cruiser says to add in his tips, regardless if 2.5/4.0. Other than that, this was a great learning experience, and stoked to see what the future has in store for her! Cheers guys!

UPDATE: For those of you still following this docu-series on the Unicorn, found out the injector is shot even though it seemed to test okay in the ohms department. Will report back when a working injector is acquired to hopefully seal this thread once and for all.

Yessir. I'll report back whenever I make a move and either have a new (to me) injector in my hands or if I borrow someone else's to test it out. Until then, I appreciate all the willingness to help get this ol' girl back on the road, as well as teaching me even more ins and outs of the RENIX system! I'll hit this thread back up as soon as I snag a new injector one way or the other!

Actually, I've got one better. I'm going to see if anyone in the local Jeep club that runs a RENIX 2.5L would be comfortable to come over and let me test their injector in Ol' Unicorn.

I agree! I just asked the local Jeep cemetery if they had any RENIX 2.5L TBI injectors, and anytime they get them in, they sell like hotcakes. So SOL on that call. I'm calling a local fuel injector shop on Monday when they open to see what the turn around time is to service my injector. It would be the most cost-effective move at this point.

Well I tried the different orientation, and it was same start-up, so I agree with that.

Yeah, hindsight seems to really get me on here. Once I posted (yet again), i realized you were trying to figure out a bench test for me. Ha!

Why not just throw it in your MJ?