I have a 92 cherokee, 4L auto, 320,000km. I can feel it has more horse power in sunny days. In wet days it's lack of power. I changed plugs, ignitions wires, cap and roters 30,000km before. Anything I need to look into?
thank you in advance.
Herb
Snow...
93 XJ 371,000 km's
How is the air filter? When they get older humidity can affect the air flow through the dust.
I don't know what plugs you used, but I have seen a pile of those expensive bosch platinum plugs burn out fast in the 4.0 and 4.2 engines. They last for 6 month or a year, then the engine power up and dies. The best is a Champion in my opinion.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'sHerb wrote:
They also ran better on cloudy days / rainy days due to the high humidity that contributes to the 'octane number'. The humidity helps to slow the flame front propagation in the combustion chamber .... just like adding extra octane. Should be the same with EFI as that doesnt sense the change in mass flow rate due to the less dense 'wet' air intake. Air saturated with water vapor is less dense than dry air, etc.
So just WHERE in hell can I buy some metering rods (Rochestier Vari-Jet Carb) of varying thickness and taper ... so I dont have to machine new ones? .... and I dont have a jewelers lathe.
thank you everyone for the input. I don't believe it's my imagination. I drive it everyday, I know in dry day, it gets more power.
Mike, I bought the plugs, cap, roter, and wires from the dealership. the air filter was changed 10,000km before.
Is it possible the wires cracked(which I did not check) not insulated, or the end of the wires not fully pushed into the plugs.
I find the air filter can be sneaky on 4.0's with high mileage because the engine sometimes will spit an oil film onto it. Even my CJ's just messed up catching me by surprise. I went camping a couple weeks back and used a full tank of gas for 210 miles! 70 freaking liters! I haven't driven the CJ much in the last year so have very little miles on that filter, but it was blocked with dust anyway.
It would be worth checking the wires too. They can back off a plug or work out of the distributor cap sometimes.
Have you changed fuel brands recently? I do find a difference in performance and mileage between brands.
Mike
Herb wrote:
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