Jeeps dont seem to like high RPM's

oh yeah, run that baby into the red and try some tire chirpin' hard shifts (5spd) that one distinct clunk is your driveshaft hitting the freeway.
 
120mph huh? that sounds like fun, except...

1. Aren't they governed? A 93 dakota is governed at 95mph and i thought Chrysler would have followed suit for its other light trucks and SUV's.

2. How do you know? Last I checked the speedo in my xj only goes up to 85(and it annoys the hell out of me :) ).
 
91Limited said:
120mph huh? that sounds like fun, except...

1. Aren't they governed? A 93 dakota is governed at 95mph and i thought Chrysler would have followed suit for its other light trucks and SUV's.

2. How do you know? Last I checked the speedo in my xj only goes up to 85(and it annoys the hell out of me :) ).
Click to expand...


I was gonna say, my speedo max's out at like 100, but the governor kicks in at about 95mph....only had it there once on the freeway cause A) the rest of the traffic was doing faster than that.....I was even in the right lane and getting passed by little old ladies in Buicks like I was standing still... and B) I kinda wanted to see how it handled at that speed....and like I figured, like crap. Havent been back up that high since......and I still managed to get 21mpg even runnin maxed out for a good 4-5 miles.

That being said, i hardly ever go above 2500rpm around town. About once or twice a month i'll go out onto this deserted, long, flat strip of pavement that used to be some sort of road and just nail it, and let the tranny wind out in as many gears as possible(automatic). I do it mainly because I want to know if I ever need to get out of somethings way in a hurry it can still do that with out any problems. Plus, it seems to run a little bit better after a good run like that.
 
Well, governors aside...the police-package clusters go to 120 (or 125, can't remember).

-Rich
 
99XJSPORT06 said:
I was gonna say, my speedo max's out at like 100, but the governor kicks in at about 95mph
Click to expand...

Hmm... I've had mine out to "h" before it hit the speed limiter. (Yeah, like the "h" in km/h at the bottom of the speedo) I'd have to guess it was around 120 or so. I was on a nice, long, slightly downhill, straight stretch of road messing with a coworker on the way home one day. It felt fairly steady, though I wouldn't want to be going around even the slightest curve at that speed.
 
98JeepXJ said:
Hmm... I've had mine out to "h" before it hit the speed limiter. (Yeah, like the "h" in km/h at the bottom of the speedo) I'd have to guess it was around 120 or so. I was on a nice, long, slightly downhill, straight stretch of road messing with a coworker on the way home one day. It felt fairly steady, though I wouldn't want to be going around even the slightest curve at that speed.
Click to expand...

Didn't feel like putting the jeep into repair position that day?
 
My '91 MJ with auto trans shifts at 5k with the throttle on the floor in drive.

Be careful, the engine can outrun the tach with light load. Last week a kid broke the crank in a 4.0 at the mud hole....it was spectacular...blew a hole in the pan you could put a fist through. The crank broke at the first rod journal. It was screaming for mercy at the moment of failure.

The harmonic that 5-90 is talking about causes the crank to try to "whip" around...this can cause premature main bearing failure or broken crank. It should not be confused with "valve float".

If you have a "shuddering miss" at 4 k...check your distributor indexing.
 
GHeez!!! Yikes!!! Unbelievable!!! This puts me directly into the chicken-shit category. With 150K on my original clutch and having NEVER felt the need to be over 3500 rpm's on the highway, maybe I WILL make it to 300K without a rebuild!!! :yelclap:
 
My Jeep starts shaking at about 60 on the highway, but I'm only doing about 2000rpms. I don't think it's the engine, though. Probably just the car rattling in the wind. It is, after all, a giant rectangle on wheels (and then a smaller rectangle in front of that).
 
i chased a porsche in my 95XJ down to indiana once. not sure how fast i was going but my speedo was pegged on the bottom. from driving my corvette i would guess i was going +/- 120. i thought it did really good for such a small SUV. the thing that bothered me the most was that i had just filled up my tank at the previous exit and while following the porsche i could actually watch my fuel gauge go down. after about 20 minutes i was down to half a tank. it was fun though. but ever since than it sounds like i have rod knock. LOL i wish i would have been running amsoil back then. might have held up just a little better. it's amazing to see the difference between regular oil and amsoil when frying bearings in a lab.

i took to corvette up to greenbay once and hit about 140+/-. with police scanner, radar detector and calling all truckers ahead i stayed on that for about 15 minutes.

other than those 2 incidents i usually do the speed limit.
 
Got the tach cluster put in and it looks like I'm with a lot of the others, making the first two shifts usually no higher than 2500 and the rest closer to 2K. Maybe not to peak torque but they do have a very good rise from just about zero up to 2500 and just can't see any point in "normal" driving to ever go higher. I don't think I have ever spun it over 4500, that's where it starts sounding like it's not really wanting to be there, and since there's no torque there isn't much point in arguing.

Had an old 4-banger S-10 and it was just the opposite. While it sounded just as bad as the Jeep at 4500 (maybe worse), that was where the torque peak was and there was no hill climbing at anything less (3rd gear flat out 60MPH up a 6% grade). The dealer said yeah they sound like crap up there but that's where they work, don't be scared. Had the truck from when it was brand new til just a few months ago (that's 22 years and 150K) and the most major thing I ever had to do to the engine was change a head gasket at about 100 grand.
 
Dr. Dyno said:
The 4.0 is a torquer, not a revver, and the rev-limiter usually cuts in between 5000-5300rpm depending on which year you have.
Click to expand...

So even my 89 has a rev limiter?

Me thinks me should go out and fire her up and answer me own question.....
 
I have an 89 with an auto, with around 209k on the clock and every so often I'll bring it up to 5k RPM in first, just to give it a good ol' "Italian Tune-up." The 4.0 doesn't like it too much, I have a sticky lifter that really likes to rattle like hell when it shifts out of 1st at 5k. Sounds like an old diesel, which is essentially what you have to treat the 4.0 as, a big slow revving torque beast that has the tendancy to sound like a diesel.
 
high RPMs ...high speed...don't think I've had mine over 80 mph or 3200 RPM. Just gets to noisey and scary in that range, I think about what I'm in, a rusting 16 year old piece of sheet metal with more holes in the floor than a piece of swiss cheese......lol....gotta fix that someday...maybe get 'er up to 85 mph then.

"Cap'n I'm givin' her all I can....I "canna" nay give her anymore.....she's gonna blow!!!!
 
scorpio_vette said:
i took to corvette up to greenbay once and hit about 140+/-. with police scanner, radar detector and calling all truckers ahead i stayed on that for about 15 minutes.
Click to expand...

I'd pay money to see a corvette wizz past me at 140 with a 4' whip CB antenna... :D
 
I'd pay money to see a corvette wizz past me at 140 with a 4' whip CB antenna
Click to expand...

actually it was the really long metal one from radio shack. what's that like 6' or longer??? i don't remember. i did think it looked weird at first, but being able to talk to truckers 6 miles ahead makes for a ticket free trip. LOL

i'll try and see if i can find some of the pics.

PS: believe it or not, but in the 70's and 80's you could get corvettes with optional CB's from the factory.
 
You must log in or register to reply here.

Similar threads

T
High Idle Issue
Replies
1
Views
206
Tim_MN
Tim_MN
A
6/1996 Fuel pump & Regulator replacement
Replies
2
Views
173
Anak
Anak
R
Random Hard Start, Low Power
Replies
0
Views
107
rtd16
R
V
1997 4.0 XJ behaves like running out of fuel
2
Replies
29
Views
913
vaco
V
J
Down to a few electrical issues.
Replies
3
Views
342
Jay Ratliff
J
Back
Top