coolwind57

Me too.

Isn't all caps "COMANCHE" 86-87 Renix?

Took 6 times to read it, but I think its sinking in. So, the search continues since NSS circuit appears good.

No quite tracking you here. What exactly am I checking by doing this? It will not start in D, by the way. There were times in traffic that it did not start in N, but then again I was quite stressed to get the dang thing running quickly. I know it starts in P, but sometimes after a few seconds.

Sounds good, fellas. I'll give this a shot just as soon as my flu symptoms go away. Sucks.

I've had the truck only for 6-Months. No real parts cannon for this particular problem, other that what I noted above that you read: a different cleaned and indexed TB with a different set of IAC/TPS. Once possible clue: I had to replace my fuel tank. When I took my truck bed off, I discovered that that tank was badly corroded. Upon reassembly, I did have to FOREVER crank the engine to get it to fire for the first time with the new tank and new fuel filter. I did drizzle a little fuel into my TB intake hose to assist. I initially figured that I may had fouled the TB and that's why I concentrated my efforts on it and it's components. Two cleaned and indexed TBs and little results so far. It's improved but still the low rpm and sporadic dying is there. Typical "tune up" items replaced since ownership: wires, AC plugs, Dist cap, etc. Had future plans on upgrading to 4-hole injectors, but not in the budget yet. That sounds like a parts cannon response, but again, I had plans on doing it anyway. Sure would like to know what's up with this and to see if I can correct it before I dump funds in injectors. Besides IAC, what negatively affects rpm and bogging upon acceleration? Can I correctly boost rpm in some way just to see if this corrects the stalling?

I thought I had this issue resolved like 3 times now. Still reoccurs. This last time, it took 2-days for the symptoms to reappear. I thought I had it. Nope. I'm now on my second thoroughly cleaned throttle body (TB) to try to correct this. I had broken some TPS/IAC studs on the first one and just wanted to replace the whole TB anyway. Also, I've used a different (used) TPS and AIC on the second TB. I indexed the butterfly plate inside the TB (set-screw) as recommended and I've properly set the TPS with my multimeter per well documented instructions. Here's the symptoms: Seems to be too low rpm, at least to my ears. Both TBs that were installed seemed to be low rpm as a matter of fact. Engine often dies once acceleration begins, say at a stop light for instance. When it dies, I have to quickly shift into park and start again, of course. Sometimes, I have to wait a second before restarting, as the starter system appears completely dead when I turn the key. It has always started back up when this odd event happens. I often get a surge of rpm when it restarts. Idle seems a bit better with this second throttle body, but again seems like rpm seems to be too low by my ears. By better, I mean is sounds more consistent and not missing so much. But I do slightly detect that it doesn't seem perfect. I've performed Cruiser54's tips 1, 18, 28, 29. Automatic/column shift transmission, by the way. Based on what I'm reading about the CPS here on the forum, it appears to not be associated with my symptoms. As soon as I get some time, I plan on continuing with Cruiser's electrical cleaning tips. I have a third used IAC that I haven't yet tried, so perhaps I just have two bad IACs, though probably unlikely. Am I missing a critical troubleshooting tip?

I put in a junkyard 3-pane easily myself. It wasn't bad. Remove your rubber trim molding, clean and sit it aside. Clean the heck out of that metal window channel. Both mating surfaces need to be quite clean -- I used lacquer thinner. I'd go for any heavy non-film-leaving solvent if possible. You may need a heat gun to help you along. It was a God-send for me, as my job would had taken a lot longer without one. Do any rust repairs. I had quite a clean truck, but still found a couple of rust spots in that channel area. I psanded them down and shot some primer/paint over them. Go to Advance Auto and pay $25.99 for this: Have yourself a warm garage. Dry fit to ensure you're not getting ready to do something dumb. I then placed the ribbon sealer in the window channel surface, then brought my glass to it. Mate the two surfaces. All at the same time, use good duct tape (Monster tape is awesome for this) to attach to glass and wrap along the roof of your truck. I used three equally spaced pieces of tape. That'll help you keep it good as you install glass and as you apply pressure to sealer areas. You'll be leaving an open channel around the perimeter so that you rubber trim goes back in. That trim is essentially cosmetic, you know...doesn't really do anything as far as mechanically holding the glass in. Shove it into place. I shot a little black silicone in the upper corners and secured with tape till dry just to kind of seal it down a bit. My had very minor curling with age. I've got several Months on my truck using this product/method and I'm good. No leaks. Looks good. Quite inexpensive. Go for it, man. I've heard that the four-pane rear windows don't fit quite perfectly but we probably ought to hear input first from others.

Totally groovy. Nice touch.

Got it fixed and she's blowing out hot air like a champion. I did two things: 1. Disconnected heater hoses at valve cover, drained heater core then blew it out via my lungs. 2. Poured CLR into lower heater core port until I began to spill out of upper hose 3. Waited about a half hour and drained. 4. Flushed with water by pouring it in, then blowing it out. Did this like 4 times, alternating ports and thus direction of flush. I also bought a spill-proof funnel system and totally burped my new open system the way it should be done. I'm digging this new funnel. Worth the 20 bucks spent. No leaks and it totally worked like a charm. I'm loving this new heat.

I may share my thoughts on this issue if I may. I once had a metal building that had no roof insulation. We operated a kiln oven, and in the wintertime, that non-insulated metal roof literally rained on us. Frost developing overnight would become heated once we fired up the oven. The resulting thawing caused raining inside the building. It was an odd site, man. The solution was in insulating the roof. I replaced the roof (it was getting pretty rough anyways) and used that vinyl bat type insulation for metal roofs. Condensation is not allowed to form once insulated. If I had your issue, I'd likely run to Lowes or Home Depot and buy a roll of that self-sticking duct insulation stuff. It is a thin, like 1/4" foam with adhesive on one side and aluminum backing on the other. Its form fitting and I'd apply it then reinstall my headliner. It would probably give you a good, noticeable difference in the Summer too from the direct hot sun.

Just recently replace my negative battery cable. It looked bad but once I removed it and could see the whole thing, it looked REALLY BAD. Replace those suckers a.s.a.p., brother.

What I used was actually a Carburetor AND throttle body cleaner, in one.

No valve any longer.

Yes, was planning on adding an old coolant jug. Keeps engine bay cleaner, plus I want to see what the heck might had been in there. Absolutely. My plan is to use the compressed air only at low pressure...basically as a different, non-liquid medium to help better clear out old coolant so that my vinegar and/or CLR can do it's thing. More like call it a weekend with my schedule. I never seem to have more than 2 hours to work on any one thing. Probably do it in a day if all the star line up just right. Thank you. I sure appreciate your comments, fellas.

Napa runs about $60 in my neck of the woods. Ebay often sells for 10-15 bucks. I think a MOPAR unit is on ebay for like $145. Crazy differences. It's all a toss up on how one makes a decision on buying IACs it seems.

Yea, I don't think I'd bother testing that thermostat. Might be better to just replace it. haha! Feeling your pain on this project, my brother. But you have to admit: This stuff is kind of fun!

Just saw a video of a guy that blew out heater core with compressed air then used CLR and allowed it to soak for 20 minutes or so. Flushed the heck out of it with water afterwards. May be my last ditch effort.

I had rebuilt a heater box in a 99 Cherokee about 6-7 years ago. Agreed, PITA but doable.

Decided to relocate the vacuum canister today. I kept reading about how prone those two vacuum lines are to breakage/leaks that run to the bottle's original location . Easy-peasy, man. My 1989 model has the "ball" type and not the football type that I hear are on earlier MJs. I found the ideal place is up under the old pressure bottle bracket that I had recently modified to hold my new open-system coolant recovery bottle. I feel a bit better now.

Blower motor/squirrel cage is clear. I have good blower strength. Cowl area had been cleared a while back. no junk in there when I took out my wiper assembly a couple of weeks ago. Yes, I'll try a chemical flush....or a vinegar flush or both. Anything other than pulling that dash and core.

I dig the idea. I'd also love to see a simplified Troubleshooting Guide that lays out the most common issues we experience (Vacuum system, IAC/TPS diagnosing, etc). Can be separate from Mods. Just factory fixes and repairs. Searching seems to get mixed results from each individuals and it might help prevent some from being annoyed at answering the most common questions. I usually always get answers by searching, but it can become quite time consuming.

No, at the time I chose not to use any of these products. I had heard others say it was the beginning of the end of their components afterwards (water pump, heater core, etc). I figured that I'd better not expose my 28 year old system to anything that might weaken it. Perhaps I should reconsider. I may try a flush product and circulate just the heater core loop. I'm thinking the heater core is not providing enough surface area to provide the heat exchange, possibly due to some sludge that flushing alone is not fixing. Also, I'm wondering if my water pump may be weak.... I am getting heated hoses throughout, so some is obviously circulating. Perhaps its just strong and adequate enough to prevent overall system overheating but a bit too weak to shove much coolant to the heater core..... Just thinking out loud.

I spoke too soon. My problem is back. Wife and I nearly froze on the way to work this morning. As previously mentioned, adding coolant helped a bit. But.... I proceeded with my conversion to an open cooling system. All went well, new 195-deg thermostat, new coolant, flushed entire system. This is the 2nd time I THOROUGHLY flushed the heater core as well as the entire engine/radiator. I had previously removed the HCV, so no issues there. So, I'm having the same symptoms as before: VENT puts out a tiny bit of heat. HEAT puts out nearly nothing but cold air. DEFROST puts out same as VENT...not much to write home about. 1. I checked the blend door cable and it works beautifully, extending all the way to warmest setting--and it pushes the flap to it's limits, which is the black plastic stop you can see on HornBrod's picture above. 2. After my frigid trek this morning, I checked both heater hoses and they were hot to the touch, as was the top radiator hose. 3. Air volume coming out is adequate--just not hot. 4. As I toggle through the VENT, HEAT, and DEFROST sections of the controller, actuators seem to be quickly doing their job. Air toggles like it's suppose to. 5. Pushed open and peeked through the blend door and I see the squirrel cage and all looks clear. Before I diagnose this as a bad heater core, is there any way there might be another actuator inside the air box that may be faulty/disconnected or something that would cause these symptoms? Anything I can look for under there that might be obvious? I've looked at some heater box pics, but I'm really not familiar with the inner workings of this beast. i really hate the thought of pulling my dash, evacuating my original refrigerant and replacing both heater and AC cores if there might be one more thing that I can check or try.