84 CJ 7: Cold Start Great/Hot Start Not So Much

CJM1971

Member
Joined
Jan 24, 2017
Location
Raleigh, NC
Any older model CJ drivers run into an issue of having a good cold start but after driving for a while it doesnt seem to want ro turn over? I have teated the battery and alternator, new plug wires and distributor. Runs fine when it fires, but when the Jeep is hot and I go to start it I get a wont-wont-wont, for 2-3 seconds then it fires. Gave it too much gas last week and it backfired, smelled like gas, sounded horrible, so I backed off. I checked the oil thinking I just seized it up, and it has been making a knocking noise for a second or two when I fire it cold as if its taking a second for the oil to circulate around in their. Going to try a 5W/30 oil and an anti-drain back plugged filter. Nice to have a vehicle with all the 'stuff' in front if you but I do wish I could plug into the auto-zone computer and have a diagnostics run.
 
Vapor lock?
 
It started back up once it cooled down, a little rough running, but as always, it started up cold. If I could pull codes it would help, may run it to AutoZone, but the temp guage wasnt pegged last week, and 250-300 maybe, but Im going to check timing, etc, this week if I get a chance. My first fear was a full motor rebuild, hope that isnt the case!!
 
Calm down. Nothing posted indicates a new motor.

Now 300 degree temps..yikes that's bad.

Have you messed with the timing?

Timing advanced too far, will cause overheating and hot hard starts.
 
Also not mentioned is the starter. and even possibly the cables.
BTW what happened that it got so hot on you?
 
Thanks Ron, didnt want to have that conversation with the wife! I was actually just driving it home from work, it was a nice day and wanted to take the jeep. I havent messed with the timing at all, but it could probably use it. My first thought was the starter, maybe it gets too hot after I drive it. Thought the thermostat also since it was showing a high temp. I recently looped the heating core hoses since the core under the dash leaked a little but I didnt think that would have anything to do with it since the heat doesnt work anyway, its just a weekend driver, and I dont plan on messing witht the heater stuff anytime soon. Previous owner put in a new temp and oil guage so Im not sure I trust them 100%, both tend to bounce a bit so I deff want to get those in check since both are very important. It had a nice new Edelbrock Carb but I wont touch that, need to leave that tweak to an expert.
 
And you can't pull codes on an 84 CJ unless you have put a modern engine in it. Just thought I would throw that out there. Autozone will be useless for your diagnosis.
 
Thank you all once again for the help, Im going to start with the timing and go from there, may be throw on a new tarter and check the overall motor compression.
 
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