81 cj8 258 randomly dies

81 cj8 258 randomly dies
S

scrambler

Jeeper
Posts
65
Thanks
0
Location
southeast, idaho
Vehicle(s)
1981 cj-8 258 4-speed bone stock
I have a 1981 scrambler w/ the AMC 258 i6 / 4.2l 2bbl carter that will start and run great and then will die at random times. It will act like there's no spark but it will turn over with the key and almost start but die off immediately after letting off the key. I have rebuilt the carb and adjusted the vaccum hoses so it runs good... when running, also I just replaced the plugs, wires, cap and rotor. Any ideas on what the problem is?
 
Id be looking at the solenoid under the hood on your fender. Check for the two small wires being loose. Alot of times the boot style plugs that are on them loosen and dont provide good contact. They can be crimped to get them tighter with a needle nose. One of them should be marked "I" for ignition. If this is the problem thats the most likely one.
 
I just cleaned the coil connections and made sure they were secure. I'll see if that solenoid is the problem tho. Weird thing is that I've driven and hit big bumps to see if that would kill it (loose wires) and it wouldn't. Just yesterday I had it in my driveway, started it and let it run for bout ten minutes then it died just sitting there. :confused:
 
When is the last time you replaced the Ignition Control Module (ICM)? What you are describing sounds like what happens when the ICM goes bad. The Motorcraft dura-spark module is known to just give up like that with no forwarning.
 
Yup thatd be the next place Id go. I have one that I no longer need if youd like to try swapping it out without grabbing a new one.
elwood blues said:
When is the last time you replaced the Ignition Control Module (ICM)? What you are describing sounds like what happens when the ICM goes bad. The Motorcraft dura-spark module is known to just give up like that with no forwarning.
Click to expand...
 
elwood blues said:
When is the last time you replaced the Ignition Control Module (ICM)? What you are describing sounds like what happens when the ICM goes bad. The Motorcraft dura-spark module is known to just give up like that with no forwarning.
Click to expand...


what elwood said.:cool:
 
if the module is the problem you can do what is called a stealth gm module. i did it to mine and it is alot more reliable than a after market ford one.
 
First thing you need to do is determine if you have a fuel problem or a spark problem, using a flashlight look down throat of the carburetor and have someone push on the accelerator or move it by hand. If you are getting fuel you will see it spray into the carburetor, if you do not see this check your fuel pressure, fuel filter, fuel line, in tank filter, fuel pump and carburetor.

If when it dies it seems like you just shut the key off then it is most likely spark, the Motorola ignition module is terrible and is always the first thing I will test. However many times I find a bad pick up coil located inside the distributor. Anytime you’re testing electrical devices it’s best to use a hair dryer to heat them up, many times of electrical device will work when cold, but not work when hot.
 
I have looked down the carb and I am getting fuel. My next move was the module but didn't wanna fork over the cash for it if its not the problem. Would it be the module if its going down the road fine and just looses spark then a few minutes later starts like nothing was wrong? Also it doesn't sputter it just seems like it looses spark, the engine still turns over but doesn't combust.... I think. Petescj that'd be great if you have one just lying around I could use?
 
I have seen coil, pick up coil, and module cause this. You can gut the Motorcraft module and install a GM module in its case, stealth.

O.K. I am going to start controversy here, I don’t like the stealth module, there are two ways the module cools down, one is through the mounting and the other is from the air moving around in the distributor. To be safe on a trail you are going to take a spare module anyway, so you are right back at square one.

I will always install a HEI distributor in a AMC 258 i6 / 4.2l , they are around $100, bolt in, and the module is small enough to fit in the CJ glove box. You would need to change the plug wires and run a new wire to the battery terminal of the distributor. My thoughts are do it that way or leave it stock, either way carry a spare.
 
Thanks I'll have to swap some things out and see if it works. Gives me somewhere to start though. I really appreciate it. :)
 
pm me an address and you can have it for the cost to ship. :)
scrambler said:
I have looked down the carb and I am getting fuel. My next move was the module but didn't wanna fork over the cash for it if its not the problem. Would it be the module if its going down the road fine and just looses spark then a few minutes later starts like nothing was wrong? Also it doesn't sputter it just seems like it looses spark, the engine still turns over but doesn't combust.... I think. Petescj that'd be great if you have one just lying around I could use?
Click to expand...
 
scrambler said:
Thanks I'll have to swap some things out and see if it works. Gives me somewhere to start though. I really appreciate it. :)
Click to expand...


i work at advance auto and we have a tester that can check your module.
 
Alright my bro in law had a gm hei spare that he gave me so I think i'll try that first see where it gets me. Thanks Petescj I'll let ya know if I still need it after swapping the hei.
 
Not trying to take over here but when I installed my hei I used one of the wires that went to the old oil filled canister coil. My top end seems to leave something to be desired. Could this be it? It was fine before the conversion.
rushpowersystems said:
Keep in mind the coil wire is a resistance wire, best way to do this is with a relay, the HEI will not run well with under 10 volts. Here is a link on how to wire a relay if you need it, I would just pull power off the alternator battery post with a 12 gauge

Rush Power Systems tech tips: Relays, Switches, & Diodes | The National Voltage Star
Click to expand...
 
You must log in or register to reply here.

Jeep-CJ Donation Drive

Help support Jeep-CJ.com by making a donation.

Help support Jeep-CJ.com by making a donation.
Goal
$200.00
Earned
$85.00
This donation drive ends in
Donate
Back
Top Bottom