CaffeineTripp

Not that I'm so much worried about spraying TB cleaner on anything inside the engine bay, just that it's a bit hard to find any leaks on vacuum hoses and lines with it, along with carb cleaner and soapy water. So I'm under the assumption that no matter the year or engine, all Comanches had the C101 connector that was just plain ol' junk?

Seems the going assessment. Eventually I'll end up taking off the intake manifold and the exhaust manifold and rebuilding the throttle body with all new gaskets and seals, cleaning up everything on that side and getting rid of useless vacuum hoses and lines to keep it simple and straight forward. Only the things that are necessary for the engine to run and run well will I keep hooked up. Be nice to get rid of all the rats nest of vac lines/hoses. In any case, to a question that I had above, this C101 connector, is this also a problem on the '86s, or did Jeep for some reason get it right for the first two years of production and then get lazy thereafter? As to checking for vacuum leaks, besides using carb cleaner, soapy water, propane, or something else like that, I've heard that if you use a fog machine that can work as well, but then there's the risk of harming an internal sensors; MAP, O2, IAT. It's something that I've looked into purchasing so I can have the capability to find every single leak that the 2.5 has rather than going through all the hoses with carb cleaner in hopes that I can hear/see anything going on with the truck as the engine's loud as hell.

Checked out the sensors today before work. The MAP sensor is reading at A-C: 5.02, B-C: 5.0. A-C: 1.479 Ohms constant. The TPS, which I believe to be on the backside of the TB closest to the firewall: A-C: 4.97, B-C: 5.02. All of the voltage readings were taken at KOEO. The front sensor, which I thought housed the IAC valve, apparently isn't much of a valve whatsoever, more or less filled with gears, a stator much like that of the , and not nearly as much of a pain to disassemble as the TPS is on the back of the throttle body. There is also a sensor, what I believe to be a sensor, at the back of the head on the driver's side. Can't for the life of me remember what color wire that was leading to it was, was unplugged. Coolant temperature of some sort? Driver's side left, at the very rear. Also, possibly fixed a massive vacuum leak near the throttle body itself; an L shaped vacuum hose which connected directly to the intake manifold and a small, black vacuum line. Needed to be removed to access the TPS. As of now, she runs brilliantly, though it's still a bit of a trouble since I didn't really do anything.

I've done that part alway when I was going through cleaning many of the grounds I could find. Got the main battery ground cleaned on the block, head to firewall ground, and a few others. The ground strap is still in quite goos condition with no fraying.

I'll start off with the problem; the Jeep won't idle at all. Stalls. Takes a bit to start and will only start when throttle is held down. Throttle must be held down to keep the Jeep idling. Seems to have a miss until you hit ~1800 RPM. Smooth from 1800 RPM +. Cap, rotor, plugs, wires are within a year old, checked gap on plugs and it's fine. Checked for some vacuum leaks at obvious points, but a bit hard to do without a fogger machine. I've searched and came across a few options; clean the IAC, check TPS voltage on positive and sending, test MAP voltage, solder C101 connector (if it is a problem for the 1986 as well as the 1987 2.5s). Problem is, most of everything I've found is for a 1987 and above engine, not sure how much readings and connection points differ between the '86 and '87+ model years. What I've found for the sensor readings is this: MAP: 4.5-5.0 volts with KOEO TPS: ~4.82 V Positive, 17% for Output to ECU Fuel Pressure: 9-13 lbs (though I've also seen 6-9 for TBI equipped)

Manual trans. So, no very worried about any of them of course, just wondering what they all went to considering I don't have the correct manual for the vehicle. Got the '88 wiring manual in PDF. Thanks for the info!

Passenger's side connector Passenger's side connectors Driver's side connector

Besides the poor Jeep idling horribly, missing at low RPMs, and having some vacuum leak somewhere, I've got some questions about some random connectors and what they should have connected to. Also, I assume that the wiring harness for the 2.5 would be for the 4.0. I've got a random connector on the driver's side of Purple/White White/Black And on the passenger's side Connector 1 Red Yellow Black Connector 2 Red Connector 3 Orange As for the idle issue, I believe it to be ignition/sensor related as it only misses, and has a hard time starting and idling. From 1,500+ RPM she runs just fine, below that not so great. I believe that I'm going to take the TB off, give everything a good cleaning, especially the Idle Speed Control sensor as it appears that's a big problem. The vacuum leak will require replacing all of the vacuum hoses. Is there a kit? or do I have to measure the diameter of each hose along with its length to figure out all the vacuum lines. The brake booster is rusted below the master cylinder, however, I've sprayed soapy water and carb cleaner on it and there are no bubbles forming or idle changing (when the engine does idle properly). As a side note, there might be a fuel leak, though where I'm not certain. Near/on the gas tank. The engine will probably need a rebuild soon, as she's sucking down some coolant, which in all probability could affect the idle.

Way too expensive for a $100 truck. Was thinking more along the lines of my old A'Pexi SAFC knobby-style that I've already got if I'm going fuel management. I'll goof around with it and see if it's possible.

I think for the major part of it would be rebuilding the engine/swapping out for a later model longblock. Not that it needs it, but once it's done, it'll last another 150,000 easy...and have it's power back, if it had it at all. Secondly, put in a 5 speed transmission instead of the 4 speed. Minor stuff. New windshield as it's all cracked to hell, door latch for the driver's side because it doesn't close fully, and tires. That'd about do it. Body's too far gone to worry about it anymore. :dunno:

Topic as it says. What are two major things, and three minor things you would change about your Comanche? I.E. Major: Engine, aspiration, transmission, body, etc. I.E. Minor: Headlights, interior, exterior (paint, bumpers, etc.), wheels. Ready and go!

There was a guy on a forum that I was avid at, DSM1Eights.org, who changed the 4G37 engine from a distributor setup, to a coil pack set up using the Ford EDIS system, running spark timing off of the crank wheel. Turned out to work darn well, surprisingly. I think I could possibly go that route, but maybe using the stock location of the distributor and weld on a ring gear to that, or something like it, and use that for the spark timing. Can't remember exactly how he had set his up, been quite a while since I've visited his build thread. More of just a curiosity. If that doesn't seem to be the case going that route, what would be a good coil upgrade? MSD/Accel/Other?

I've been toying around with the idea, just to see if it can be done. I've got an extra coil pack from a '90 Eagle Talon 2.0 Turbo, in good condition. I haven't done much checking on any of the service manuals for either the Comanche or the Talon in terms of wiring, voltage output, and all that sort. Just curious to see if anyone has converted a 2.5 to a DIS.

Have you given changing the thermostat a shot, flushing the heater core? What's the problem that you're having? Did not have to plug that vacuum line at all. Blows 'hot-ish' heat, probably needs a flush of the heater core. Works on all the settings; panel, heat, bi level, floor, etc.

Did a little digging around the positive battery wire's loom. Found this. :doh: Gotta love previous owners and their 'fixes'. Be a while before I can get a new battery wire to supply power, so for the time being I cleaned as much of the corrosion off as I could, loaded it with solder, put heat shrink around it, and some new wire loom. Should hold for quite some time at least. I still don't know if that was the exact problem, but it sure is a big red flag.

Just got done starting her up again. Fired right up the first time. Turned on the heater, wipers, blinkers, head lights, parking lights, stepped on the brake, put it in reverse. Did just fine. Turned on the hazards and she started to die. Turned them off, ran correctly. Turned them back on, ran just fine. What kind of weird electrical gremlin is this? As a side note, I believe I read a while back that the blinkers/hazards will make the fuel gauge needle jump back and forth when the lights are blinking because the relay is wired into the fuel gauge?

Kind of thinking that same way as well with the load tester. I may still bring it to Advanced Auto and get that checked out, but it's still having a hard time driving under load as well at points. I believe the fuel pump to be in good condition, though I don't have a pressure tester, it is sending fuel, in increasing amounts (visually), through the throttle body. I'm at a loss as to what the exact problem to be, and since this is my DD, I've got to come up with a solution quick. Tomorrow's going to be a lot of testing. Fun in this 10* weather we're having in MN.

Tested the battery at standing and charging, came to 12.8 standing and 14.7 charging. The alternator relay clicks, though that doesn't necessarily mean it's in good working order. Any electrical load applied; headlights, taillights, hazards, blinkers, etc. kill the engine. The clutch master cylinder is leaking onto the fuse box, though I moved it as best I could as I don't have the funds for a new master cylinder right now and I'm not sure which fuses, capacitors, and relays do what on the fuse box as the writing is barely noticeable. Any thoughts?

Heater Control Valve Fix Cost: $9.70 for on-sale antifreeze Time Required: 45 Minutes Tools: Flathead screwdriver Needle nose vice grip x2 Equipment: Upper Heater Hose/PVC Piping Worm Clamps Coolant, 50/50 Antifreeze Drain bucket Rags Step 1: Drain 1 quart of antifreeze from the cooling system via the drain C#*@ at the bottom of the radiator. Step 2: Un-clip the 4WD vacuum actuator. Clamp the coolant hoses leading to the heater control valve, then remove the hoses from the heater control valve. Place a drain bucket underneath the firewall to catch coolant that will drain out of the heater core and heater hoses. Step 3: Remove the heater control valve from the heater core hoses. Step 4: Attach the heater hose that runs from near the thermostat housing to the top heater core line. Attach the heater hose that runs from the intake manifold to the bottom heater core line. As you can see, my heater hose that ran from the intake manifold was too short so I had to connect a 45* piece of plastic running from the chunk of heater hose on the bottom of the heater core line to the heater hose. Nearly long enough, but not quite. Step 5: Add coolant to the radiator, start the engine and let run for 15 minutes to burp the cooling system of air. Enjoy having heat when you want it instead of being frigid during the winter! Suggestions: I didn't have the money to pick up a fail safe thermostat or a gasket that matched, let alone the time to completely flush the cooling system, but it is something that could be done while you're in there fooling around with the heater control valve.

Like a lot of us, as it seems, the heat vacuum actuator that's just before the firewall which allows hot coolant to travel to the heater core is broken/clogged with junk/just plain old. Aside from removing it as I don't have the funds necessary for more coolant and longer cooling lines, just to make sure that there's enough wiggle room for the movement of the engine, has anyone figured out a way to keep the plunger in the open position for the time being? I suppose zip-tying the actuator arm might be doable, but who knows how long that will last. Eventually, I'm just going to remove the entire thing and not worry about the longer warm up times, not that it would take that long anyway.

I'm not so much worried about the gasoline smell as I can always just cap off the line(s) that lead to the tank. I've removed the EVAP/charcoal canisters from several of my vehicles with no ill effects, save some of the gasoline smell in one. Not a big deal to me though. Just trying to eliminate as many of the lines that aren't truly needed. The less vacuum lines = the less likely a leak. Easier to diagnose and so on. Heh, sorry about putting all of these in one topic, just trying to keep the forum from getting a bit cluttered up.

I was all set to do the front brakes, but apparently I don't have the correct hex socket; standard, not metric. I feels around the lines of a 10 MM hex, but I want to make sure before I go and pick up a set. Also noticed that when I took the wheels off to check the brakes, that the brake hoses are cracked, down to the fabric even. Obviously, it's more economical to replace the hoses with the OE style rather than the stainless braided, but I might just replace them both with the SS braided. More or less to ensure that they'll last a lot longer and I'll get a bit better feel out of the brakes themselves. As for the rear drums, are there different sizes, as I noticed on www.RockAuto.com, or just the standard size for the early trucks pre-4.0? On a side note, got a tach installed. SunPro Super Tach 2. Common tach, but it sure is helpful.

Certainly possible given the fuel maps can change with what the ECU is seeing. Suppose that those throttle bodies are pretty much a dime a dozen, just wiring everything up and making sure that the TPS and IAC can interact with the ECU properly would be the hard part. Worth a shot!

Here's mine. An '86 with the 2.5. I've got plans for the truck, some extraordinary, though most not so much. All depends on how much spare money I've got laying around to actually complete the job. For the time being though, she'll be a daily driver through the winter and we'll see how she goes through the summer, after all, I'm a tuner at heart, not a rockcrawler. :nuts: She's not pretty, and has her fair share of rust due to Minnesota and Wisconsin living (FO salt!) In any case, I've got her planned for a 5 speed swap, intake, intake heat shield, wideband O2 sensor and gauge, A'Pexi SAFC, larger injector (TB swap?), swap out the steelies for '88 Dakota Sport aluminum wheels (trashed the truck, now gotta find it again), port match the intake if it needs it, 2.5" header back exhaust into a generic high flow muffler/Dynomax, Brembo discs, EBC pads if available other wise ceramics will do, install a tach, water temp., oil pressure/temp., vacuum gauges, electric fan. All in all, not too much in the conservative build. Not really anything for horsepower whatsoever, more or less just bringing to the standards that I have for it. But, if I were to go a little nuts to the truck... Rebuild it from bottom up with 8.8:1-9.0:1 forged pistons, 264/272 cam, 3 angle valve job, 1MM oversized valves nitride coated, ACL bearings, MegaSquirt, bigger injector(s), throttle body, extrude honed intake manifold, RPFabrications exhaust manifold, 2.5" side dump exhaust with Dynomax muffler, Garrett T28 turbocharger, 2G DSM intercooler, custom intercooler piping, GReddy Type S BOV, manual boost controller, dropped 2", aluminum driveshaft, 235/60R16 Pirellis, ACT/Centerforce clutch, custom dampener...but that's all just some dreaming.

Adding a secondary injector might screw with the mixture of course, especially if they run in parallel with one another. Along the lines of what I'm trying to do; get a wideband O2 sensor and gauge along with using the A'Pexi SAFC to give some control over the amount of fuel is going into the engine, though I don't know if the piggy-back will work until I give it a shot, but that's for a later date. WBO2 gauges are super expensive. Besides, all the drivetrain fluids need to be changed out before winter really sets in. Going 2bbl would certainly help the high end if it's not controlled at all, super rich at the low end. Though I'm wondering if the intake mani, even if it's a Clifford, would be able to handle that much more fuel going in it. I'm assuming, since I don't know the flow rate of the OE injector, nor the flow rates of the Chev injectors, that it would need a hell of a lot of air and flow to be able to compensate nicely without much tuning being done. Anyone happen to know the volumetric efficiency of the engine? I know there's a way to calculate everything, but, well, I had to take algebra many times, so that says something about my math skills. Also, I'm looking at the vacuum diagram and am thinking about removing the following lines and components: Vacuum Hoses: EGR Valve to EGR Solenoid Hose EGR Solenoid to TAC Sensor Hoses (On Throttle Body) TAC Sensor to Air Cleaner Box Hose Components to Remove: Charcoal Canister EGR Valve EGR Solenoid Components to Block Off: EGR Valve (if applicable) TAC Sensor EGR Solenoid (if applicable) PCV Air In (Large PCV) - Add Breather The only problem I can conceive that would happen when removing the vacuum lines is a little bit of a hard start during cold weather and some rough idle during the same temperatures given the manifold heater tube would be basically useless. Though I could build an 'air box' heat shield type of thing around the air filter with a port for the tube itself to help out with the initial start and idle before warm up. I believe that I read in one of the manuals (Hayne's? FSM?) that the Renix ECU is EEPROM. Of course, this means that some of the parameters are adjustable and can be saved via hooking up a computer and essentially programming the ECU that way via a piggy back/stand alone like ECMLink. I highly doubt there are any EMS out there like that, but who knows? :typing: