Cj7 stalling

Garrett Benson

New member
Hey guys, I'm new here, but over the past week I've had problems with my jeep, it'd run phenomenal when it'd first start up for the day but after it runs for a bit and I shut it off to do whatever I'm doing, when I go back it runs just awfully, I'm not sure because my temp gauge doesn't work, but it feels like it's running REALLY hot, any of y'all have suggestions of what to check?

I have a 304 with a motorcraft 2100 carb and an HEI distributor, my jeep is entirely stock aside from the 4" lift kit
 
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Hello and welcome to jeepz.com. Since your temp gauge isn't working was just wondering if your fuel gauge was . They work as a pair on the CJ and should be replaced as a pair as well. That sometimes presents problems with the fuel tank sending unit in terms of compatability for accurate ( or close at best) readings . But you'll want to know engine temp at all times regardless of any issues . You'll have to determine if the engine is running too hot for obvious reasons . Be sure the usual,items like radiator hoses not collapsing , water pump circulation , thermostat operation , heater core circulation or any restrictions are a cause.
Of you find the cooling system is in order or get it in to shape and it's all good then it's time to check the fuel and emissions system. Check if the fuel line from the tank isn't getting neat soaked from being to close to exhaust or the fuel line from fuel pump which may have been rerouted to accommodate the motorcraft carb isn't suffering the same. Check that all vacuum lines are correctly routed since the carb has been fitted to this engine , especially evap.lines . If a canister purge line is feeding the engine cold with no thermal switch for example it will run rich and continue to do so when engine is warm and idle will suffer over rich condition. Cold engine on fast idle will be less noticed . A thermal,vacuum switch ( TVS) or coolant temperature override ( CTO) are supposed to prevent things like this. It's possible that items such as these have been installed incorrectly since the carb may differ from the original configuration so it's best to sort this out and be sure. Float bowl vents vent TO the canister purge and fuel vapor should be introduced to the engine when warm via the vacuum switches previously mentioned usually to a throttle plate port and the switch controlled by engine vacuum ABOVE idle . That vacuum signal comes from the float bowl ( upper) part of the carb . Usually a signal port on the rear of the carb operates this bit sort this out with a manual that best illustrates the model carb to correctly route all vacuum lines that exist .
Another possibility that may be likely is the carburetor itself. The motorcraft has a power valve just as a Holley carb has but of different design but does,the same job. Of this valve fails , the result is an over rich condition , flooding , stalling whether idling or accelerating . youll want to check your spark plugs to see if there are tell tale signs . Of the porcelain is whitish or burned looking ( running hot or too lean ) wet or carbonated ( over rich condition) . You may want to be sure the choke is working right and not sticking partially closed with fast idle off. Does the exhaust have a heat riser valve ? Is it opening fully when warm ? Hopefully you don't have a sinking carburetor float causing a over rich condition cold or warm .
How about the ignition system ? You'll want to be sure the ignition wires are primo as well the cap and rotor.
These are some items of the top of my head but even items such as a fuel filter shouldn't be overlooked. A fuel restriction can be troublesome and cause similar symptoms . Usually fuel,restrictions are noticeable cold or hot engine but good to be sure .
Hope this helps but at least is a good start . Check these items and let us know what you find . Post back when you can . Thank you for your membership .
 
Some after thoughts are is the distributor vacuum advance receiving the correct signal from the float bowl port and not a throttle plate port ? Are the centrifical weights hung up or the return springs loose ? Base gasket vacuum leak ? Any vacuum leaks ? A vacuum gauge reading must be sought on a warm engine to be sure the engine is pulling healthy vacuum and not low or erratic. Hope the idle mixture is set right . After the engine is shit down , is there a puddle of raw fuel in the intake below the carb ? You can check this with the choke valve fully open and the throttle blades open to see if there is puddling. That would indicate if fuel well plugs leak or float is stuck open or float is saturated with fuel and causing a rich condition.
 
Just to add: Is this jeep new to you? what core radiator do you have?? how many blades are on your engine cooling fan? reason I ask is if the jeep was a 6cyl originally and someone swapped the 304 in and used the 6cyl radiator and fan, you are getting minimal cooling. some times the 6cyl system will be enough to keep it cool and sometimes not. I recommend a 3core or large 2core radiator, and the full size jeep pickups had cooling blades with 6 or 8 blades on them (cant remember) and provide much better cooling. They are a direct bolt on swap. I don't think this has anything to do with the emissions charcoal canisters as I have always taken that stuff off anyway with no problems except some fumes.
 
Your radiator sounds ok, but the fan blades would concern me. The 4 blade fan is what I have had to replace in the past for a fan with more blades when going from the 6cyl to 304 , it cools so much better and ended my heating up problems. I think I would open up your radiator and flush it out with a water hose, make sure your thermostat isn't sticking. if that don't help, Id look for a bigger fan..
 
Thanks! I put a bigger fan on and flushed out my radiator yesterday. Haven't driven it enough to see if it's gonna overheat or not yet. I lost a bolt for one of my body mounts when I hit a speed bump, anybody know what size the bolt is?
 
the mention of a body lift could affect the cooling as well. The body lift, lifts the hood, fenders, grill and RADIATOR up higher away from the engine, making cooling more difficult.
 
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