Woe_is_Jeep

Hey gang,

I've been back on the forums mining for info, trying to avoid starting a new thread because I get it... the questions I'm asking have been answered before, somehow, somewhere. I am looking and searching everywhere, in every spare minute I have...But I'm still struggling to find threads and answers that don't dead-end or end up with a 3.4L swap (LOL, I still want to do that one day, but not today). If you don't want another thread like this, I won't take it personally if you lock it up.

1986 v6 2.8L, manual transmission, 4x4, all stock (I know, it's foolish, I know)
drove it from Albuquerque, NM to College Station, TX a few years ago when it was still my daily driver. it did great, as usual. I've made that drive dozens of times in this car, and plenty of other really long road trips. got the car from my parents when I started driving in 2004, they're the original owners since '86. anyway.

it was running fine, being started occasionally and left to idle
stopped running during one of these idle runs, and now it will crank all day but no spark. ive read lots of threads that start this way but I'm still getting nowhere. the car has been sitting for a few months since it died, and now I'm back. my old man was starting the car up for me.

no reverse lights, no blinkers, no hazards, and no lights on the dash. the key buzzer works, and I've got headlights, brights, running lights and brake lights. dome light working too. just replaced the ignition switch atop the steering column to see if that was the issue here. no change. all fuses in fuse box look good with the exception of the silver relay for intermittent wipers at bottom of fuse box. that one is so corroded I can't actually remove it without fear of breaking the leads off in there. I'm bad with electronics, but I feel like that can't be the problem so I'm continuing with other diagnostics. I won't get my feelings hurt if you tell me it's crazy to continue before I figure out the blinkers and reverse lights and instrument panel lights... that's why I replaced that ignition switch but they're still not working and I can't figure out what else to chase. trying not to throw parts ***** nilly and that's exactly what I did with the ignition switch. dream: a car with the least amount of wiring and electronics possible. someday.

no spark from plug when I pull one from the block
I have 12 v constant at the negative terminal to ignition coil. no flashing when using test light from other connection to the coil.
no spark from the coil-to-distributor cap wire when I put a spark plug in the wire and ground it to the engine block. also tested this with a new coil I have, also no spark.
rotor turns freely. was somewhat dirty, same with dist cap, cleaned 'em up.
so...
Ignition control module? I have it pulled off of the distributor as of 5 minutes ago, and I'll try to test it but I think I'll ultimately just replace that part. i've seen some ways to test these ICMs so I'll try to find the right method for this part/this vehicle/this engine. (now's when I wonder about the gremlin in my hazard/blinker/reverse lights)

the car's been sitting, and it was my daily driver before that, so before the trip I have upcoming I think I'll just go ahead and do dist. cap, rotor, distributor pickup coil, and new plugs and wires in addition to the ICM. but...buying a complete distributor assembly is not much more than the sum of above parts, but then I've gotta worry about the distributor coming out easily and maybe have to deal with lots more issues resulting from removal and installation of an aftermarket distributor... and I know that throwing money at this turd is the last thing anyone on here would recommend, but I have serious history with this car and I want to get it back to where I'm living in FL so I can actually consider things like a 3.4 swap since I now have a daily driver out there and don't have to depend on this daily.

my pipe-dream goal is to get this turd started, and drive it from TX to FL, maybe in as little as two weeks. HOPEFULLY. (hope in one hand, crap in the other, I know) I have lots planned, and it's obviously going to be lots of "fun" and I'm just getting started! As soon as I got back I ripped out the interior to make sure it wasn't a total rusted out nightmare. there's obviously some rust in the front floor pans, and lots of surface rust elsewhere, but only two small areas in the front and right corners that would actually merit a patch. so I think the body of the car is good, and that makes it worth it to me to keep pursuing. the frame looks perfect, still got factory paint visible in most areas.

thoughts?

P.S. seriously, I know, you think this is dumb to keep this engine in there. I'm just working with what I've got, and trying to stay within my means and capabilities for the time being. I really am trying to do my research here, but if someone feels like throwing me a bone I'd really appreciate it.

Woe_is_Jeep

okay, just tested the ICM, with some promising results although now I'm totally skeptical about everything:

re-confirmed 12V going to the ICM
just confirmed that the pickup coil beneath the rotor is giving 0.4 volt signal, within the range of 0.3 to 1.8 that I read in the diagnostic here: https://easyautodiagnostics.com/gm/2...dule-tests-2#1
so even though that 0.4 is on the lower end of the range, I believe this indicates my ICM is bad... so I guess I'll replace that instead of getting the full distributor assembly, although since the car has been sitting it's awful tempting to replace most all of these ignition components outright to avoid a problem between here and Florida.

still wondering why the heck my blinkers and reverse lights, and the dashboard lights/instrument panel, are not working. every other electrical piece of the car that I have checked so far is in fair condition.

Woe_is_Jeep

is there some reason why non-functional reverse, dash, and hazard lights would keep the thing from getting spark and running? power seems to be making it to all the right parts in the ignition system, and now I suspect the ICM (skeptical on this, but I did the tests so it might be...) but when I install the new ICM after it arrives tomorrow morning, the only other thing I'll have to go on is this electrical gremlin affecting the dash, hazard, and reverse lights.

4.3L XJ

OK, verify you have power to the coil. Then if you don't fix that. If you do then the problem is in the distributor with the distributor pickup.

Woe_is_Jeep

hey man, thanks for the reply.

i did already verify that I have power to the ignition coil, but I will re-verify I get 12v constant to the coil.
also verified that the distributor pickup coil is kicking out power within the range indicated on this how-to:https://easyautodiagnostics.com/gm/2...dule-tests-2#1 it was putting out on the lower end of the range specified in that tutorial, at 0.4 with my multimeter on the lowest AC voltage setting (the 200 setting) it kicked out 0.4 V and that tutorial specifies 0.3-1.8

Woe_is_Jeep

i also humbly admit that I cannot verify the voltage from dist pickup coil was jumping higher than 0.4, so I see what you're saying 4.3LXJ.

I'm going to do the tests again in a few minutes.
will reconfirm 12v constant at the coil going to the ICM
will re-test the wires coming off of the dist. pickup coil, and make sure it's fluctuating higher than 0.4 (wondering if my multimeter has low enough "resolution")


i've been researching other electrical issues and can't seem to figure out best way to tackle my lack of reverse, blinker, hazard, and instrument panel lights. I was able to pull ALL fuses (including the horrible wiper relay) and cleaned them all up and replaced burned ones. but I'm not focusing on this too much right now because it seems like anything going on in the fuse box right now isn't stopping power from getting to the ignition coil.

Woe_is_Jeep

okie dokie

confirmed: 12-12.34 volts constant at the ignition coil, tested at the positive wire that attaches directly to the ICM
confirmed: using the multimeter on the AC 200 V setting (the lowest resolution available on my multimeter for AC voltage), the wires coming from the distributor pickup coil remain constant and read at 0.4 V and i believe that's a fail. should fluctuate between 0.3 and 1.8 according to the link posted above.

so I'll replace the dist. pickup coil as well, but I'll have to wait to get that part by tomorrow at the earliest I think. and I'm putting the new ICM in there anyway, although after looking at its guts it seems fine at a glance. tonight I'll pull it off and see if I get a different test result after some cleaning.

LOL, as hard as I tried I'm ending up throwing some parts at it, but so far it's just the new ICM that's definitely going on there. I have a new coil that i'll return if this works out.

still wondering about the lack of reverse, blinker, hazard, and instrument panel lights... i feel like the lack of these lights shouldn't affect my ability to get spark and run the motor based on the checks I've done, so I don't want to focus on them currently until I have the peace of mind of running engine. but if that's totally incorrect, I would happily admit that and accept the shame as long as I can get this POS running and closer to the road to FL. pretty determined.

4.3L XJ

On that 2.8L rig, you have four fusible links on the starter relay that power everything. One of them may be shot. Also do you know how to ohm those coils to check them?

Woe_is_Jeep

again, 4.3L xj: you're a saint, thank you for replying.

I replaced the starter relay some time ago, so I'm foolishly thinking that's not my issue here. probably foolish because it's "old" but it's not as old as the other ignition components i'm diagnosing. i recognize that's probably incorrect logic as far as electronics work. the starter relay to my recollection is this piece, or something that looks similar, and is mounted inside the

the only similar component I've found that is suspect is another relay (i think its a relay) but it has a wiring harness attachment and sits closer to the firewall than the starter relay
regardless of my aforementioned uncertainty, if the starter relay, or another relay or some other electronic piece im overlooking is not functioning properly:
would I still get my 12v constant to the ignition coil? if im getting 12 to the coil could the issues with other lights prevent the engine from firing? it cranks all day.
if the starter relay does control ignition coil then I'll replace the relay ASAP to see if that gives me my spark.
years ago I chased around an electrical problem with this car, and thanks to this forum I replaced the starter relay and that fixed it. this was before i even created a user profile for this forum. the information was already here and it saved my A$$. the information in this forum kept me and my family turd on the road for years. still true today.

my thought process (which is likely wrong) is as follows:

i have a good battery
the car was running fine until it suddenly died, and now:
no reverse lights; no instrument panel/dash lights; no reverse lights (there was an aftermarket stereo installed, and I'm open to that being a possibility and plan to yank it and insulate all wire ends). I replaced the ignition switch atop steering column because I got an indication that switch could be culprit for non-functioning blinkers/hazards and reverse lights. I replaced, installed correctly, have functioning ignition that cranks the engine all day, and the headlight brights switch that's attached also works perfectly.

fuse box is old, but i've cleaned it and pulled all fuses, cleaned corrosion, replaced blown fuses. still no power to dash/reverse/hazard and blinker lights. there's a possibility one of the buzzers or larger relay/fuses in the fuse box are bad (because theres no visual indicator if they blew or not), but i'm not chasing that because I seem to have power to the ignition system at this time. that might be a mistake. I can rig up a buzzer test system like I learned in this forum to check the harnesses etc, but I have power to my ignition system so I'm trying to save myself some headache. in these times it's not so easy to justify multiple trips outside of my "quarantine bubble." it's a whole thing, but I'm still determined and I'm still going to the parts store(s) when I'm confident the part is worth it.

i currently have no spark at the plugs;
no spark at the wire coming from the ignition coil;
12v confirmed are getting to the coil;
and a constant but not fluctuating voltage from the distributor pickup coil.

tomorrow I have the new ICM coming, and a new dist pickup coil. I'm just going to put them on, because why not at this point, I need to get this thing running to meet my goals. but I'm skeptical, because I really feel like I'm doing my due diligence.

I know my posts are long... but I'm putting all the information in here. I'm really trying to do my due diligence. i sincerely appreciate the help. any tip that I get on here can help me get "unstuck" from the mental rut and try another check to see why this [relatively basic] car won't start

Woe_is_Jeep

holy schnykies i should've known better than to paste that image in there. here is my reply without the URL for the picture of the starter relay that I tried to include in my previous reply: (all other links in this reply were auto-populated by the forum)

again, 4.3L xj: you're a saint, thank you for replying.

I replaced the starter relay some time ago, so I'm foolishly thinking that's not my issue here. probably foolish because it's "old" but it's not as old as the other ignition components i'm diagnosing. i recognize that's probably incorrect logic as far as electronics work. the starter relay to my recollection is this piece, or something that looks similar, and is mounted inside the
engine compartment on the passenger side just rear of the battery:

the only similar component I've found that is suspect is another relay (i think its a relay) but it has a wiring harness attachment and sits closer to the firewall than the starter relay
regardless of my aforementioned uncertainty, if the starter relay, or another relay or some other electronic piece im overlooking is not functioning properly:
would I still get my 12v constant to the ignition coil? if im getting 12 to the coil could the issues with other lights prevent the engine from firing? it cranks all day.
if the starter relay does control ignition coil then I'll replace the relay ASAP to see if that gives me my spark.
years ago I chased around an electrical problem with this car, and thanks to this forum I replaced the starter relay and that fixed it. this was before i even created a user profile for this forum. the information was already here and it saved my A$$. the information in this forum kept me and my family turd on the road for years. still true today.

my thought process (which is likely wrong) is as follows:

i have a good battery
the car was running fine until it suddenly died, and now:
no reverse lights; no instrument panel/dash lights; no reverse lights (there was an aftermarket stereo installed, and I'm open to that being a possibility and plan to yank it and insulate all wire ends). I replaced the ignition switch atop steering column because I got an indication that switch could be culprit for non-functioning blinkers/hazards and reverse lights. I replaced, installed correctly, have functioning ignition that cranks the engine all day, and the headlight brights switch that's attached also works perfectly.

fuse box is old, but i've cleaned it and pulled all fuses, cleaned corrosion, replaced blown fuses. still no power to dash/reverse/hazard and blinker lights. there's a possibility one of the buzzers or larger relay/fuses in the fuse box are bad (because theres no visual indicator if they blew or not), but i'm not chasing that because I seem to have power to the ignition system at this time. that might be a mistake. I can rig up a buzzer test system like I learned in this forum to check the harnesses etc, but I have power to my ignition system so I'm trying to save myself some headache. in these times it's not so easy to justify multiple trips outside of my "quarantine bubble." it's a whole thing, but I'm still determined and I'm still going to the parts store(s) when I'm confident the part is worth it.

i currently have no spark at the plugs;
no spark at the wire coming from the ignition coil;
12v confirmed are getting to the coil;
and a constant but not fluctuating voltage from the distributor pickup coil.

tomorrow I have the new ICM coming, and a new dist pickup coil. I'm just going to put them on, because why not at this point, I need to get this thing running to meet my goals. but I'm skeptical, because I really feel like I'm doing my due diligence.

I know my posts are long... but I'm putting all the information in here. I'm really trying to do my due diligence. i sincerely appreciate the help. any tip that I get on here can help me get "unstuck" from the mental rut and try another check to see why this [relatively basic] car won't start

Woe_is_Jeep

thanks again for the insight. Im confirming that we're talking about the same starter relay. posting link to image of similar part below.
https://images.app.goo.gl/UJFuDX2PviMhDXWy8

i think I know about the starter relay like i mention in previous post, but admittedly don't understand the fusible links therein.
and I guess I don't know how to "ohm the coils to check them" like you said, unless you're talking about doing the tests for voltage on the ignition coil(12V DC constant) and dizzy pickup coil (AC 0.3-1.8)?

i truly don't know what I'm talking about, i'm feeling in the dark and grasping at straws that i find in the forums and youtube videos.

4.3L XJ

That is the correct starter relay. There should be some fat wires on the large positive post that are colored green or orange. I don't remember which is which since mine have been deleted, but one is 20 amp and one is 30 amp. Stick a pin in the wire past the fat parts and check for voltage in the wire. No voltage means the fusible link has blown. Never liked those things. Here is how you check the coil

https://itstillruns.com/test-gm-igni...l-5931701.html

Woe_is_Jeep

Thanks man.
Checked the resistance on the coil, and I have a new one here so I'm able to cross reference what comes in the box, what's likely been on the cherokee since 1986, and the instructions you sent.
All tests between the side terminals on new and old coil are identical and pass the specs, reaing at 1 Ohm
Fresh out the box reading from side terminal to high tension terminal = 7.47 (7470 ohms, pretty much spot on for the specs in the tutorial)
resisting since 1986, reading from side terminal to high tension terminal =12.59 (well outside the specs in the tutorial, too much resistance)
BUT: A couple days ago I hooked up (did not fully install in case I can return) that new coil to see if I would get spark from the high tension wire to the block with a spark plug, and there was no spark.

I'm gonna check the relay today like you recommend. Mine has some bundles of three green wires, and the only fat wire is the feed coming right off the +battery terminal.
original wires don't tend to hold their color haha. red wire is what I installed when I replaced this relay a while back. Red wire comes right off + battery terminal. I suppose the other fat wire you're talking about is the one coming right off the top, or the bottom most wire coming off that post. The middle wire is a group of two coming off that post.

4.3L XJ

By fat wire, they are just a little thicker than normal and will have some type of factory connector. The four in the upper left are the ones I am talking about. Those are the fusible links

dave1123

A fusible link generally looks like a heavy rubber covered short section in the middle of the wire. Basically it's a non-serviceable fuse molded directly into the wire. It's had to tell if it's blown visually, but if you've got power on one end and no power on the other end, it's busted.