[GCarpJeep]

I've noticed since i've been in wyoming that my YJ feels weak on the uphill mountain passes here (coming out of Laramie towards Cheyenne, if anyone is familiar). I've had to put it in 3rd and jam the gas pedal to get up the hills and stay at a reasonable speed (which is still 20 under!!!). it has a Howell Fuel injection system and the manual doesnt say anything about adjusting to elevation. I'm going to check my plugs to see if any are fouled up 2moro since i drove it from Pennsylvania.

Does anyone else have any suggestions, or are these just the woes of owning a YJ? i hate having to be on the highway in 3rd gear to stay at 55-60 mph up hill when the speed limit is 75. seems like a 4.2 ltr engine should be stronger... (btw, i'm only running 30" tires)

[GCarpJeep]

also, i was reading in another post about "bad gas". the fuel tank was changed about two months ago and the Howell came with a new sending unit.

i have a feeling i'm goinna be told to regear or deal with it...

[provinT13]

Fuel filter? Cat?

[buckshot500]

If you haven't done the Nutter Bypass yet, & you are still running through the on-board computer your in luck!




Click the view key at the top of your screen & then zoom in a few times.







.

[FarmBoy]

You lose something like 5% of your HP for every 1000 feet you are up in elevation. If you're ay say 3-5000 feet you could have lost 20% of your HP compared to what it was at sea level.

-jeff b.

[Mean Max]

I'll bet you're running a bit "lean" on the jetting now that you're at a higher elevation.

Almost all carbed motorcycles must re-jet for higher elevations.

Max

[Louie4]

Originally Posted by Mean Max

I'll bet you're running a bit "lean" on the jetting now that you're at a higher elevation.

Almost all carbed motorcycles must re-jet for higher elevations.

Max

I think he's running the Howell Fuel Injection kit.

[Mean Max]

Originally Posted by louie4

I think he's running the Howell Fuel Injection kit.

DOH!

As I just said in another post, I need more "idiot-proof" things around me.....like maybe some threads that read themselves to me.....

Max

[Louie4]

Originally Posted by jacylin

http://www.jeepforum.com/forum/showthread.php?t=826316

I think you're spamming. I don't need new kicks.

I'm sure you'll be banned soon.

[xxxflhrci]

I have owned more than one 4.2 Jeeps nd would guess that your mountain performance is pretty much normal. Sure, they have plenty of torque, but only 112 or so hp. You can't expect steep grade pulling peformance out of them when it comes to speed.

[UnFocused]

You probably should adjust your timing as well for high altitude. The factory spec calls for 16* as follows:

http://home.sprynet.com/~dale02/ignition.htm

from this site:

http://home.sprynet.com/~dale02/list.htm

You may get a better set on the timing by tuning it by vacuum rather than the timing marks. It’s worked for me over many decades and altitudes and accounts for both engine wear and altitude. I operate with the same engine at 8500 feet and my timing is at 19* BTDC with no problems, plenty of power, and 18.5 to 21.6 mpg.. Here’s how you do it:

http://home.sprynet.com/~dale02/wiretrik.htm

also from the second link above. You might want to cycle the distributor 2 or 3 times to find the max vacuum and lock it down on the final cycle. Last make sure your air intake is really free flowing; the major problem is lack of air at altitude. If there’s a low restriction air filter available for your air cleaner by all means get one.

Good luck!

[jeeepguy]

Originally Posted by xxxflhrci

I have owned more than one 4.2 Jeeps nd would guess that your mountain performance is pretty much normal. Sure, they have plenty of torque, but only 112 or so hp. You can't expect steep grade pulling peformance out of them when it comes to speed.

This is more than correct. I have two 4.2L YJs right now and they both run the same as yours. My stroked YJ roars over the passes and my XJ with a stock 4.0L with 200000+ miles runs over the passes easily at 70+.

If you have an original 4.2L engine with typical year miles (200000+), you will have probably 40-50bhp, even with the Howell FI. Also, you didn't mention if the head was replaced or is it the original 4.2 head? Makes a HUGE difference.

Put it on a dyno and you will see.

Conclusion... you have a tired 4.2 and you will not be able to do anything about the climbing power until you replace the engine. Period.

Good luck...

[1998zj]

I have climbed that pass many times. You are at 8400' by the time you see Lincoln. I had a 3.0 liter Ford Ranger that used to struggle up there too. I think you are doing ok to be going 60 up the hill. The 4.2 doesn't make much more horsepower than my 2.5.

[GCarpJeep]

thanks for the responses. it is the stock head on the engine. would i replace it with a 4.0 head. also, my engine has about 135,000 miles on it. i'd love to replace the engine, but i have to do it as economical as possible. nothing fancy, i'm on a college budget. maybe something where i can retain the transmission, axles, etc...

guess its gonna take some saving and i doubt i'll be driving fast in the winter anyway.

[buckshot500]

In post number 4, I was trying to refer you to info concerning the "high altitude jumper wire" that is located under your dash near the glovebox. Try it, it might help!