90 wrangler yj horsepower

[agentrhodes81]

I just bought a 1990 jeep wrangler 6cyl. However, i feel I dont have the HP i need. Im missing something somewhere. anyone know what i can tune up to fix this? the person just put a weber carborator high performance on it. im getting all tha gas i need, just no power is comming out. i replaced the sparkplugs already and that helped a little. i seem not able to go up hill in 4Low either without it cutting off. thank you

[lah2420]

If the motor was weak to begin with, the Weber won't help. Others might suggest the TFI or HEI ignition upgrades, but I didn't get a noticable gain with the TFI. I'd try a good tune-up first and put a gauge on to check your gas pressure. The Weber doesn't work well with over 2.5 to 3 lbs of pressure. I also had a brand new fuel pump that delivered enough for low RPMs but not for higher RPMs or under a load. Another thing to check would be your compression.

[dingus]

the 4.0 liter HIGH OUTPUT motors (which started in 91 or 92, i forget...) came with an additional 15 horsepower out of the box due to a higher compression cylinder head. you could try swapping heads and some simple bolt ons will get you +30 hp for less than 500 bucks.

[lah2420]

I'm pretty sure the HO 4.0 started in 92. Unless they came earlier in the Cherokees.

[Junkpile]

The problem you are having going up hills in low-range is common with carbs. The float system, for one, just doesn't like severe angles. Either get really good at tuning/modding a carb, live with the problem, or convert to fuel injection.

There are lots of power mods available for your engine, and alot of crap parts that claim to be power mods. Of course you need to open up the air intake and exhaust, but don't get bogged down with fancy overpriced ricer type mods......like $250 air cleaner setups. It's not only a waste, it makes you look silly to have $1000 worth of "speed parts" and still only have 220hp. They help a little and allow the real mods to work better, but they aren't going to make much difference by themselves. The HO head is the key to making the I6 produce horsepower and breath in the upper rpm range. The raised-port High Output cylinder head came out in 91.