fujitsubo
Full Access Member
Does anyone know if there is a rev limiter on the Liberty? I noticed that my KJ goes up to 4,000 rpm and that's it. Even when it's in neutral gear, the highest rpm that i can get is 4- 4 1/2 thousand rpm's.
Rev limiter
- Thread starter fujitsubo
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2003KJ
Member
yes it does. Mine kicks in right before redline, so thats about 5600rpm's roughly. If yours is stopping at 4000, ya might wanna have that checked..lol.
fujitsubo said:
I think automatics have a separate rev limiter on them when they're in park or neutral that won't let them over-rev like crazy. When in "drive" you'll likely find that it revs much higher (still limited though). Although there's many ways to test what your rev limiter the safest ways are on a dyno, or at the drag strip, the other ways are likely all illegal or reckless. [-X
MoladoGuy
Full Access Member
Bennett said:
HAha 7K!! Drive it like you own it!!
fujitsubo
Full Access Member
2003KJ said:
is yours a manual transmission or auto?
fuji
JeepJeepster
Full Access Member
wow, if u got it to 7k then thats not good, it has a red line for a reason, and thats means the engine is not made to over that!
2003KJ
Member
fujitsubo said:
42RLE automatic, 3.7L, 2003
leadfoot
New Member
I just thought it may be useful(for those like myself not familiar with Jeeps) to bump this thread along, as prior to searching I had no idea there was a rev limiter. Not knowing so earlier today almost made me pick up a hammer and start swinging.
I finished doing my first plug change(at 41,250 miles) on the supposedly fastidiously maintained KJ V6(25,000 miles when purchased) that my brother purchased last year, with receipts showing spark plugs changed regularly blah blah. When pulling them out the gaps were all at least 80 thou, and they were NGK ZFR6F-11G(original spec). When I went to purchase these yesterday I was given a set without the "G", and was told the "G" has not been listed in Australia for some time. I think the workshop supposedly doing the work had not been doing so.
To cut a long story short, after finishing the plug change and starting, no check engine light but a definite misfire at 4000rpm in neutral, which what prompted me to want to start swinging hammers. Driving showed no other problems.
Luckily, I have access to this forum and much useful info.
Thanks Jeep KJ Country.com
I finished doing my first plug change(at 41,250 miles) on the supposedly fastidiously maintained KJ V6(25,000 miles when purchased) that my brother purchased last year, with receipts showing spark plugs changed regularly blah blah. When pulling them out the gaps were all at least 80 thou, and they were NGK ZFR6F-11G(original spec). When I went to purchase these yesterday I was given a set without the "G", and was told the "G" has not been listed in Australia for some time. I think the workshop supposedly doing the work had not been doing so.
To cut a long story short, after finishing the plug change and starting, no check engine light but a definite misfire at 4000rpm in neutral, which what prompted me to want to start swinging hammers. Driving showed no other problems.
Luckily, I have access to this forum and much useful info.
Thanks Jeep KJ Country.com
JeepJeepster
Full Access Member
Everyone realizes thats its not good to rev an engine with no load on it, correct?
bmrrwolfe
Full Access Member
Yeah don't try to get over 4k in park or neutral, it will limit you
Take it merging onto the highway and gun it
You can legally accelerate as quickly as you want, and keep the overdrive button off so it will stay in gear.
Take it merging onto the highway and gun it
You can legally accelerate as quickly as you want, and keep the overdrive button off so it will stay in gear.
ptsb5a
Full Access Member
3.7 and auto. Won't see the high side of 4 grand in park or neutral. No problem spinning to 6ish when stomping on it to pass.
I've gone over 6k before...off road...
rockymountain
Full Access Member
Most don't but... oh well. I used to watch NASCAR a lot and whenever they blow an engine it is usually when they lift off the throttle going into the turn.
WTH are you revving it up for in neutral anyway?
Midgear
New Member
Keep in mind that I do take care of my vehicles, I don't constantly nail redline and rev my engine just for cause, and when I DO, it's only for very short periods of time for experimental purposes and/or because I actually need those revs.
for those that are afraid of revving..
I love to experiment with things, namely mah vehicles. I like to find out as much about it as possible.. including where it redlines at and where the rev limiter is set, how quickly it revs, how quickly it winds down after revs, ect ect.
I can tell you that my 2002 Liberty Sport 4x4 (with the 3.7) will rev to 5800 RPM's while in park or neutral at any speed, where it cuts fuel to prevent over revving.. which gives you that "bouncing off the rev limiter" situation, will shift at just under 5800 RPM's under WOT, if left in first gear on a loose / slick surface, the rev's will creep up to just before 6k RPM before it cuts fuel to prevent over revs, giving that rev limiter bounce-
and, in 4LO, (needs further experimenting), attempting to pass 25 MPH results in a rev limit of about 4k RPM in second gear. this only happened once and I need to go out and tinker with it again and see what it does, it took place over one mabey two seconds of rev limit and I didn't really think much of it, but this thread makes me want to go give it a test and see what happens. I could be wrong- it was one of those things that just happened and you don't really remember much of the details.
anyhow. as far as rev's, that's what I know from my own tests. you newer model Liberty's probly have the 4k rev limiter just to keep the rev's to a minimum while in park or neutral, my Oldsmobile Alero did this.
for those that are afraid of revving..
I love to experiment with things, namely mah vehicles. I like to find out as much about it as possible.. including where it redlines at and where the rev limiter is set, how quickly it revs, how quickly it winds down after revs, ect ect.
I can tell you that my 2002 Liberty Sport 4x4 (with the 3.7) will rev to 5800 RPM's while in park or neutral at any speed, where it cuts fuel to prevent over revving.. which gives you that "bouncing off the rev limiter" situation, will shift at just under 5800 RPM's under WOT, if left in first gear on a loose / slick surface, the rev's will creep up to just before 6k RPM before it cuts fuel to prevent over revs, giving that rev limiter bounce-
and, in 4LO, (needs further experimenting), attempting to pass 25 MPH results in a rev limit of about 4k RPM in second gear. this only happened once and I need to go out and tinker with it again and see what it does, it took place over one mabey two seconds of rev limit and I didn't really think much of it, but this thread makes me want to go give it a test and see what happens. I could be wrong- it was one of those things that just happened and you don't really remember much of the details.
anyhow. as far as rev's, that's what I know from my own tests. you newer model Liberty's probly have the 4k rev limiter just to keep the rev's to a minimum while in park or neutral, my Oldsmobile Alero did this.
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Why in the world would you sit and rev to 5800 RPMs no common sense at all
Same reason that you'd run an engine with no oil....
tjkj2002
Full Access Member
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For some diagnostic tests
,seriously.You can hold it at redline and do no damage(well at least for 200 hours,wouldn't want to go much past that continuously without a oil change) ,why it's there.If damage does occur you had a underlying issue already.
J-Thompson
Full Access Member
I have more than once hit the revlimter in both the TJ and the KJ
more so in the TJ ,muddy hill = find the revlimter
I call BS to any one who claims over 5500 in a 3.7 auto KJ ,45rfe
I NEVER got over that ,limited out at 5750
the TJ limit is 5500 and I have seen guys "bounce" off of it for 3+ minutes trying to climb muddy hils
the new VW with the 2.0T engine mad for RPM's in the 7K+ range is hard pressed to break 6K even floored
I know trying to "see what happens" 30-90 takes less than 8 seconds and then you are passing cars in the merge lane
more so in the TJ ,muddy hill = find the revlimter
I call BS to any one who claims over 5500 in a 3.7 auto KJ ,45rfe
I NEVER got over that ,limited out at 5750
the TJ limit is 5500 and I have seen guys "bounce" off of it for 3+ minutes trying to climb muddy hils
the new VW with the 2.0T engine mad for RPM's in the 7K+ range is hard pressed to break 6K even floored
I know trying to "see what happens" 30-90 takes less than 8 seconds and then you are passing cars in the merge lane
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