Kyle Bertrand

My jeep is my daily has 220000 miles and still runs pretty good but it is starting to get a little sluggish at times. I want to get it running good this winter since I'll have some free time. Other then general maintenance what are some things I could check into or replace to make her running nice and smooth?

Saudade

Define "sluggish"?

By "general maintenance" I assume you mean oil/filter change, air filter, check other fluids (trans, brake), check belt tension. I would pull and check plugs (change if needed). While the plugs are out, check compression. Run some fuel/injector cleaner. Remove and check cap and rotor (clean/change if needed). Check plug wires and connectors (change if needed). Clean your throttle body. Look for any oil leaks, coolant leaks and correct as needed. Check and adjust tire pressures as needed.

Even if your CEL is off, connect a scanner and look for any pending codes.

robsjeep

Check for intake leaks, inspect spark plugs, run some cleaner through the gas tank, check fuel pressure, assure throttle is fully opening, clean air filter, a new O2 sensor if your is high miles, check timing, new spark wires cap and rotor if applicable, is exhaust restricted (busted catalyst? )

I had an intermittant miss once, it was a cracked spark plug ceramic, in the dark you could see the spark from it going to the head!

make sure you sensors are good, for instance the temperature sensor, the manifold pressure sensor etc.. make sure all the vacuum fittings and hose are leak tite.

you can do an engine vacuum test, quick and easy, just buy a vacuum gage and hook it with a tee to one of the vacuum hoses, that can tell you a lot.

of course a compression or leak down test can also tell you if mechanically things are good or not.

Id consider the vacuum test after checking the basic tune up stuff.

remember O2 sensors are are comsumable, 30k to 60 k mikes is typical life of them.

An engine analyzer can help. I got a snap on analyzer, it helped me find some issues, if you got a fancy obd late model then there are other brands of anaylzers, but I got a pre obd 1990 jeep.

tech

If you have 220000 miles and never done the timing chain the I would change it , on top of doing all the things that was suggested ,

Lake00XJ

4 hole injectors is a nice upgrade

vroomvroom

4 hole, 12 hole, 36 hole, 100 hole, etc... injectors aren't an upgrade unless your injectors are currently shot. But if your injectors are currently shot, any new or reman injectors including stock 1 hole would be an upgrade.

There's been dyno reports on here and the "performance" difference is negligible at best.

Lake00XJ

Fair enough, mine definitely ran better after new (4 hole) injectors. But you are right, anything newer than 20 year old injectors are an upgrade

Roler

Convinced by the youtubes showing an impressive atomisation of the multihole injectors vs the single injector 'stream', I did the swap. Negligible difference, not even on fuel economy, against all logic. Just my n=1 experience..

Randy Bobani

The Jeep engine is port injected and the combustion chamber features a swirl inducing ridge on the plug side. This ridge will atomize fuel even if you blast it in with a fire hose. Multi-hole injectors were introduced to atomize fuel in OHC engines where inducing swirl is impossible. They are also required for 4 valve chambers where the injector is positioned directly in the center of the chamber. AFR being the same, Injector flow rate being the same, there will be zero difference in performance between a Jeep engine with OE injectors v the Chinese 4 or 12 hole injectors.

Roler

Good info there!

mskam355

After I get the car parts sorted out, I usually take the time to tune the car. First the interior, then the exterior. I was recently given a car to pimp it out. First I took care of all the internal parts. Then I started to tune the inside and put in mercedes benz car mats and other stuff like that. So I think at your stage tuning might work.

mervebitanem

I would pull and check plugs (change if needed). While the plugs are out, check compression. Run some fuel/injector cleaner. Remove and check cap and rotor (clean/change if needed).

cruiser54

Beware!!

There are many horrible "new" injectors out of china.
Best to get reman injectors from Trevor here on CF. They come with the flow chart!!
trevor.skankfootracing@gmail.com

vroomvroom

Thanks for advising, I'll keep that in mind. Does he also offer pigtails for injector connections. Mine are all brittle and are somewhat broken. They are hanging on for now but will need to be replaced. At least for my piece of mind.

agreen

They're just EV1 style injector clips. They're readily available if Trevor doesn't carry them.