Carbureted YJ sputters only when heat or radio are on

GOIRISH

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Just getting used to my carbureted 1990 yj. She sputters bad when the heat or radio are on (worse in mornings or evenings when it’s slightly cooler). Original Carter carb w stepper motor. Not nuttered…yet although I did unplug stepper and adjust pins and it runs way better in normal circumstances. It does still stall out a lot. Planning on nutterimg and also maybe getting a motorcraft 2150. Any thoughts?
 
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GOIRISH

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Tested that theory out. Lights radio wipers heat - each alone seem ok. Two or more at once engine starts to misfire especially when accelerating in Third and fourth.
 
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GOIRISH

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I finally got around to testing the alternator and battery voltage with a multimeter. Not sure if I did it right (watched Chris Fix on You tube). Without engine on battery read 12.85. Fired up the engine and jumps to 14.5. Turned it off and it drops to 13.30 and continues dropping so must be charging. Tested alternator with car on read 14.6 which is supposed to be correct from what Ive read. Turned on headlights, beams, radio and heat. Jeep immediately dies. Fired it back up and it runs with it all on but seems to struggle. Batter reads 13.2 (as opposed to 14.5 when it was on without all the accessories). Still seems within the correct range. Not sure where to look next but seems like my alternator is not bad. I still haven't nuttered her yet and I have a 2150 carb and rebuild kit. A little nervous to do all this stuff though b/c I dont know what Im doing and want to get this stalling problem fixed first. Any ideas? I have more time now as my job eases up this time of year.
 

Piratesailor

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Sounds like alternator is working fine. My guess is you have a bad ground or a short somewhere. The issue is… where. Electrical is a pain to trace.
 

Piratesailor

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Fyi… ran across a post on another forum that is similar to yours. He turned on the headlights and the engine died. Turns out it was a bad ground. Seems there are multiple grounds on the YJ and they go bad on occasion.
 
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GOIRISH

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Yeah sort of a good news bad news situation. Alternator is more expensive but grounds and shorts hard to find. The lights and the heater seem to be the two that set it off more so than the radio. So I guess I’ll start there. But I don’t know much about electrical. Im guessing all the grounds in this sucker could use to be replaced. If I had the know how I’d rewrite her and be done.
 
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GOIRISH

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I may have figured it out. More like stumbled upon a solution by accident as I barely know what I am doing based on YouTube. Anyways hope this helps the next guy.

Unrelated but I just did the butter bypass. I had to adjust the carb screws. Anyways - when I did I tightened the sol vac which for those who don’t know has a little “Turkey timer” arm that pops out when your idle would normally drop with something like AC. In my case lights and heat too maybe???? Anyway that and i advanced the distributor a few nudges. No timing light. Both seemed to help. Finally ran w no sputter or backfire with lights radio and heat on!!!! It stopped stalling constantly although it did stall once at a stop sign. But prior it would stall every second.
 

jpjeep26uk

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Oh I did clean up my grounds too.!
You may be able to help me too with this one. Developed a bad backfire recently out of the blue and have tried everything with new ignition pack, plugs, pcv valves, overhauled the rocker cover, new distributor, compression test passed fine, new pipes here and there, thorough wire scrub of relays etc... and it seemed to go away, hurrah! No so fast. I tool her out for a good drive today and although she didn't backfire she did seem rough in low revs and didn't want to pull away in second without gas, got home and she's making farting noises and seems to be on the edge of stalling or backfiring. Gets worse if I n the fogs or spots on whislt shes idling. If I didn't know any better I'd say she needs her idling increased as she sits at 700rpm and thats when she farts/ pfaffs etc. Where were the grounds ?? I only know one. Thanks from the UK. 2.5l 1988.
 
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GOIRISH

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There’s one big one on the firewall behind the engine. Maybe another one on the drivers side firewall too. A few by the head lights. I’m a total newbie on all this stuff watching you tube and trial and error basically so I don’t really know where all of them are but follow around the body and you’ll find them. Easy to pop off and clean up and relax attach. Advancing the timing a bit at a time by hand eliminated the main issue I was having. Had to adjust idle again after though.
 
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jpjeep26uk

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There’s one big one on the firewall behind the engine. Maybe another one on the drivers side firewall too. A few by the head lights. I’m a total newbie on all this stuff watching you tube and trial and error basically so I don’t really know where all of them are but follow around the body and you’ll find them. Easy to pop off and clean up and relax attach. Advancing the timing a bit at a time by hand eliminated the main issue I was having. Had to adjust idle again after though.
Great stuff, I'll do this today and clean up the grounds. By the way, mine is a 2.5l 1988 with a TBT and you mention advancing the timing etc, is this the TDC process? I was told I didn't have that kind of engine last week but after your post I had a really good look and waaaay down on the right hand side from standing in front of the jeep are the little markings. Plus the belt wheel thing has a tiny notch on it so I'm assuming I can perform the TDC work and get her firing right? Thanks.
 

Piratesailor

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I’d agree that this Sounds like a timing issue. I believe the 2.5l is computer controlled timing. The only questions I’d have is the procedure to install a new distributor… is it specifically and could it cause the issues. also the order of the plug wires. Lord knows I’ve messed that up before. They there is the computer and also the timing chain. The rest is way above my pay grade.
 
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jpjeep26uk

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There’s one big one on the firewall behind the engine. Maybe another one on the drivers side firewall too. A few by the head lights. I’m a total newbie on all this stuff watching you tube and trial and error basically so I don’t really know where all of them are but follow around the body and you’ll find them. Easy to pop off and clean up and relax attach. Advancing the timing a bit at a time by hand eliminated the main issue I was having. Had to adjust idle again after though.
I cleaned all my grounds and boy did they need it. How did you adjust the idle?