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Oh okay right on! Thanks again man!

Hahaha dude I told myself when I was troubleshooting this months ago “I’m not gonna fall victim to the ol oh it’s just a fuel pump”. Thanks for all your help over the year man, I greatly appreciate it! Now to get this thing road worthy! By chance would you happen to know how I could bypass that rear adjusting brake system? I have axles out of my XJ that I’m throwing under this thing for a 4wd swap and need to ditch that.

I’ll be damned, it’s running!!! I can’t believe it took me damn near a year to figure that out, I thought to myself I’d never fall victim to “it needs a fuel pump”😂

So upon further investigation, I don’t think anyone’s messed with it. All of it looks oe and it appears that rubber isolator at the bottom of the pump rotted away and the sock fell off. It won’t stay on since there’s nothing holding it

Well…..I found the sock, and the rest of those gaskets😂

Just what I needed to hear haha, if this doesn’t work I’m debating going down and buying an inline and throwing it in there. I’m not sure if it’s just the hose that’s the problem just based off the general condition of the gaskets and what not and it looks like the pick up could be partially clogged. Is there supposed to be a sock or anything at the bottom that fell off? I found it exactly how it is in the pictures.

I just pulled the fuel pump and needless to say, I may have found my issue or least this isn’t helping me any haha. Do you know if there’s anyway I could rob parts off the 89 XJ pump?

So I went ahead and just for $#!&s n gigs made sure that it was in time and it is, piston 1 TDC, oil pump pointed alight past 3:00 and rotor sits in at 6:00. I pulled the IAC for another look and it is still connected to the sensor but man it’s rough haha, I’ll attach a picture. I’m not seeing a CTS where I thought it would be, I know 4.0’s have one at the back of the head and one on the tstat housing. Any idea of where there on these? EGR seems to be okay, I can manually move the diaphragm in it and one of the things I did months ago was clean it up and put a new gasket on it as the old seemed a lil shot. Looking at the o2 sensor now, that thing looks burn but I don’t know if an o2 sensor would cause this thing to run so bad, I also know they are internally heated. Will attach a picture as well.

Haha thanks for coming back after a few months and merry early Christmas to you! I abandoned this thing to work on my XJ but I’m getting tired of DDing my CCLB 7.3 but I never lost hope, just got tired of fiddling with the Comanche with no progress. I'm hoping after work today I can spend some time with it. From what I recall, the bulb is intact but cracked, I believe it’s still connected to the sensor itself just a little worse for wear. As stated before, ofc being almost 40 years old, the vac liked are pretty dry rotted and also worse for wear but I do know that it is getting good vacuum but I do wanna try and replace some lines if I can get some hose. I haven’t bothered with the o2 sensor or the CTS other than trying to see if unplugging the o2 would make any difference and it did not. I haven’t looked at the injector while the Jeep is running but I assumed(I know I know, never assume) it was doing what it needed to do just based off the incredible richness when the map is unplugged. In the event that I need to replace the injector and these few sensors, would you have any recommendations for brand? I know how these things are picky for their sensors and unfortunately I do not have a REM. The PO for this unit was kind of spotty but and didn’t own the Jeep for very long before I got it but I do know that the original owner did a bunch of shade tree mechanic repairs ie: wire nuts, shelving for speakers, missing fuses, shotty taillight wiring etc. So the history of when it last ran and drove is pretty vague.

Hey guys, finally worked up some courage and motivation to jump back into my Comanche project. 1986 2.5, 4 speed and long story short I’ve been chasing an issue where the Jeep will start and run(horribly at that, incredibly rich, sputters etc) only with the MAP vacuum line unplugged. Verified voltages on all sensors in and around the throttle body, rebuilt the throttle body, cleaned all grounds front to back, replaced MAP 3 times,replaced 4 small vac lines going to the throttle body, adjusted new TPS, new gasket on EGR, good vacuum coming from the MAP vac line, ECU appears to be fine visually and I’m getting 5v to the sensors tested. I'm now wanting to maybe replace the IAT, CTS, and maybe the o2 sensor. I haven’t really checked the latter but I know the IAT is smoked as I remember pulling it out and the end of it being busted to $#!&. Anyone have a line on a new sensor and if not, a conversion? It’s my understanding that these sensors no longer exist but I cannot for the life of me find a conversion thread. TIA!

Sorry man my day was busy as hell yesterday and I didn’t even get a chance to look at the forums! Do you have any pictures of said diagram or anything of that sort? I may double check it this weekend if I can find the time. How important is the vacuum lines “if that’s what they are” in the Airbox? I mean I know most vacuum lines are important obviously but there’s 2 if I remember correctly in the Airbox that some unwelcome guests chewed up. I managed to kinda rig them back together but obviously the problem I’m having is still there.

No unfortunately the sticker faded away…

Yes, the ISA does work as far as I know. I can audibly hear it tap the throttle everytime it dies and I have seen it spin open/closed when I was messing with the diaphragm in the EGR. And the vacuum line for that connects to one of the metal tubes that in turn connects to the TB where the 4 collect if I remember correctly but yes, it is obvious haha. As far as touring goes, everything looks right. I thought about replacing every hose as it wouldn’t hurt but I can’t seem to get a straight answer in which diagram is accurate for an 86 with the 2.5. I’ve seen multiple diagrams out there but I’ve heard people say multiple were wrong, 0 help to me lol. I also do not know what size of hose was used for everything, I just haven’t looked.

Oh sheesh hahaha, I’ve tried the spare parts game but I can’t do it, the only things I’ve been holding onto are random BS things such as visors, mudflaps, etc. I have a Lund moon visor on my one ton XJ as well as 2 non lighted visors sitting on the shelf, an aluminum rear visor, fiberglass rear visor for new body style, and a plastic rear visor for old body style. I have a set of OE Cherokee mudflaps and now a set of OE Comanche mudlflaps. I essentially collect all the non important stuff haha.

I appreciate it but I’m willing to take your word that it’s more than likely not an ECU issue, you have a much better idea than I do haha and I wouldn’t wanna burden ya with your extra parts! I need to spend more time with it but I’ve been wrapped up in my Cherokee as of recently when I’m not at work 😒

Sounds like a heap of fun haha. Well at this point I’m at the verdict of gut it and new body style swap it, which was always the plan, but I was really hoping I could figure something out to be able to at least drive it around a bit while I finish up my one ton project.

Ah okay gotcha, I wanna say yes when I did test them. If I remember correctly the only concerning one might’ve been the MAP connector but I don’t remember what its values were, I do know for sure that CPS/TPS are good. I did actually see the date code, it’s a little faded haha and you’re correct, 85. I’m still at a loss, I can’t believe I’m this stumped haha, i have the ECU cracked right now and don’t see anything alarming.

It just seems ridiculously clean to be from ‘86 to me, the connector pins on the harness side are in the exact same condition.

Before I get to testing all the sensors again, I went ahead and dropped the ECU down. I’ve heard that the reman/USA/Mexico made ones are crap or something? Or like the good OEM ones were made of France or Mexico? I might’ve misheard but my ECU has made in USA on it, so I’m thinking it’s been replaced before?

Well not very, I went ahead and adjusted it considerably going both ways. No real noticeable difference it just won’t stay running with the vac plugged in. Right now I have it running with the plunger showing maybe 2-3 threads and the vac unplugged.

Here’s some pics, this is as of right now, no adjustments made and turned off.

Oh okay gotcha, I should be getting off here in about an hour or so. I'll give it a shot and report back along with pictures of the ISA. Thanks man!

Okay, so you think I should unscrew it a bit and see if that does anything? About how sensitive are the adjustments on it?

Yea, I'm gonna go mess with it a bit after work but unfortunately I can't find the picture I had of the engine bay. From what I can remember everything looked in decent shape but I don't remember how far the adjuster was pushed out but it is indeed still there. Yes, if the vacuum line is plugged in I can force it to start by holding it to the floor haha.

Okay! Now since the Jeep will not start with the MAP vac plugged in, assuming the ISA needs adjusting, should I start it with the vac unplugged and adjust it from there and see if it starts up or runs with it plugged back in? I wouldnt have any other way to do it hence it will not run with that vac line plugged in.