97 TJ tune-up questions

Wajeep

TJ Enthusiast
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Jan 27, 2021
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125
Location
Wa State
Hey all...thanks again for all the help lately. Since I just acquired a 97 wrangler sport (4.0 manual) I’m pretty confident it could use some tune up love. What do you think a fairly handy guy like me should do? Plugs, distributor cap, etc. Oil has been changed and the transfer case fluid was replaced when a minor repair was done before picking it up to buy?

If the coolant looks good, can I just replace it? I would like to replace the upper and lower hoses. I’m slightly above average in the handy department. Thanks for suggestions on things I can and should do.
Matt
 
I see your profile pic, but not sure what your jeep is equipped with. I would go to your profile and at least put the basics in to include mileage.

Off hand the basics: plugs, wires, cap, rotor, I would do at least your upper 2 o2 sensors but all 4 would be best. use nothing but NTK or NGK. Get one of those cheap coolant gages to test your fluid, since you asked about it.
Use Redline in your transmission if you are going to change that fluid
Search on this forum "how to's" to flush your heater core.
keep driving it and let it speak to you! They have a way of communicating with a true Jeep owner.

enjoy and welcome to your new hobby
 
I would do everything suggested above, but would flush the cooling system and replace the coolant, as well as change the axle lube and the transmission fluid. This way, you know all the fluids are fresh.

Check and/or replace the radiator hoses and heater hose.
 
When you do the transmission/differential fluids, make sure you are using the correct fluids. There are specific oils for the early years of TJs.

Coolant, don't forget a new cap. Also, while you are doing new coolant, disconnect the heater hoses at the engine (not the firewall) and reverse flush the heater coil (put your garden hose on the smaller of the two heater hoses, and have a bucket on the larger heater hose to catch the garbage).
 
So far as the ignition system goes... I'd replace the distributor cap and rotor and make sure the new cap and rotor have brass contacts, not aluminum which doesn't last. Better caps and rotors like that are not as easy to find but they're worth a bit of extra searching.

It probably needs new ignition wires too. Avoid the so-called performance ignition wiring sets claiming "low-resistance". Low resistance sounds good to the uninitiated but where the ignition wiring is concerned, the resistance is a good thing and is added to the wiring at extra cost. Its job is to curtail the ignition wires from radiating static/RF which can affect the computer not to mention adding noise to your AM radio as well as a CB radio. Mopar is actually the best quality if you can find it. Also, due to the extremely low current in ignition wires, the resistance added to the wiring does not significantly reduce the voltage provided to the spark.

For spark plugs, Autolite's iridium XP-985 will be great choice and last at least 200k miles. Champion 3034 or Autolite AP-985, both are platinum, would perform as well as the XP-985 but they would last around 100K miles.
 
So far as the ignition system goes... I'd replace the distributor cap and rotor and make sure the new cap and rotor have brass contacts, not aluminum which doesn't last. Better caps and rotors like that are not as easy to find but they're worth a bit of extra searching.

It probably needs new ignition wires too. Avoid the so-called performance ignition wiring sets claiming "low-resistance". Low resistance sounds good to the uninitiated but where the ignition wiring is concerned, the resistance is a good thing and is added to the wiring at extra cost. Its job is to curtail the ignition wires from radiating static/RF which can affect the computer not to mention adding noise to your AM radio as well as a CB radio. Mopar is actually the best quality if you can find it.

For spark plugs, Autolite's iridium XP-985 will be great choice and last at least 200k miles. Champion 3034 or Autolite AP-985, both are platinum, would perform as well as the XP-985 but they would last around 100K miles.
Thanks Jerry!
 
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ZFR5N (NGK)plugs are what the MFG recommends using.

I've always found it best when starting anew with a vehicle to try and get everything back to base level. Meaning using OEM parts.

This way should you have a lingering problem it can help eliminate second guessing things like a certain ignition component.

If we were doing a tune up on a 97 jeep (i own a facility) I'd round up all oem recommended parts and install.
Call your local Jeep dealer and ask for cap and wires/plugs...(I just know the plugs ZFR5N number)
Even if you don't wish to buy from them they'll give you part numbers and you can source them a different way.

Good luck and congrats on the score👍
 
ZFR5N (NGK)plugs are what the MFG recommends using.

I've always found it best when starting anew with a vehicle to try and get everything back to base level. Meaning using OEM parts.

This way should you have a lingering problem it can help eliminate second guessing things like a certain ignition component.

If we were doing a tune up on a 97 jeep (i own a facility) I'd round up all oem recommended parts and install.
Call your local Jeep dealer and ask for cap and wires/plugs...(I just know the plugs ZFR5N number)
Even if you don't wish to buy from them they'll give you part numbers and you can source them a different way.

Good luck and congrats on the score👍
Thanks for the great advice! Much appreciated.