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Black smoke

jeepster96

NAXJA Forum User
Location
Port townsend,WA
I have a 96 with a 4.0 and today i just noticed that when i step on the gas then let off some black smoke comes out and also when its idling theres a little bit of water or condensation comeing out too. and also when im out wheeling the temp goes up and over 210 i have a 180 stat in it for the jet chip. any ideas what my problem is?
 
Black smoke means your running rich. Running rich could explain why your engine s running hot too. Water condensate is normal.
 
When did you purchase your xj and how many miles on it then and now? That could be your culprit im guessing. But then again, a bad enough o2 sensor would throw a check engine light.
 
Dave4.0 said:
Black smoke means your running rich. Running rich could explain why your engine s running hot too. Water condensate is normal.
Running LEAN would cause the engine to run hot, rich should not cause it to run to hot. I'm almost wondering if the cooler thermostat isnt letting the engine to heat up enough and the computer is trying to correct for this. The lower temp. thermostat also may be opening to soon and not allowing the antifreeze in the radiator to cool down when driving at low speeds in the trails
 
Last edited:
bfred said:
Running LEAN would cause the engine to run hot, rich should not cause it to run to hot. I'm almost wondering if the cooler thermostat isnt letting the engine to heat up enough and the computer is trying to correct for this. The lower temp. thermostat also may be opening to soon and not allowing the antifreeze in the radiator to cool down when driving at low speeds in the trails


I agree change to a higher temp thermostat and while you are at it change those O2 sensors. If you change the sensors don't for get to disconnect the battery for at least 10 minutes so that when you re-connect it the computer will reset itself.
 
bfred said:
Running LEAN would cause the engine to run hot, rich should not cause it to run to hot. I'm almost wondering if the cooler thermostat isnt letting the engine to heat up enough and the computer is trying to correct for this. The lower temp. thermostat also may be opening to soon and not allowing the antifreeze in the radiator to cool down when driving at low speeds in the trails

Then why do vehicles run rich when they are cold? I thought it made the engine hotter, faster? Not so?
 
why are you yelling?

take out that chip, run the stock 195 thermostat and test your O2s to see how fast they switch voltage.
 
jeepster96 said:
I HAVE THE JET CHIP STAGE 2 AND IT SAYS TO RUN WITH A 180 IN IT.
Call JET and dicuss this problem with them. Ask them WHY you need a lower temp thermostat. The factory computer is designed to run with a 195 so unless the chip modifies the parameters to account for this, its not going to let it warm up properly. You didn't state how long its been acting like this, is it something just recent? Has it ever run right with that chip? Maybe the chip is fryed?
 
I ran a Jet S2 chip for a short time. F'ed all type of stuff up. Then it shorted and cooked my main wire harness and computer. Jet would not even offer me a replacement more or less the damage that was caused by the chip itself.
MY ADVICE
Take that thing out before you F up anything else. Replace the t-state with a 195*, Test the 02 sensors and replace as needed
 
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