NA Motor Discussions regarding N/A KA24E, KA24DE, and SR20DE

tops out at 112?!?

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Old 03-16-2004, 08:59 PM
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Unhappy tops out at 112?!?

hey i did some research threwout the whole site as to not make any one mad for having to repost a thread...buti cant find anything on how to fix the limiter on my '89 240sx.
i have taken it a few times up over and hundred and as soon as it get to 112 it just konks out and goes down to about 108 or so.
i dont think it is the cars max cuz its no where near red line..prob aruond 4500-5000 if that...
thanks for any help
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Old 03-16-2004, 09:26 PM
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There is a fuel cut at 112-117mph on a 240sx and most nissans. Search to find ways to get around it.

Moved to NA
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Old 03-16-2004, 10:44 PM
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ive gotten my 89 coupe to 120.
does my car not have the limiter or what? the cars stock.
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Old 03-17-2004, 12:04 AM
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All of them have them stock, no matter what. Were you on a flat road, down hill? If your going downhill you will obvisouly go faster, and if you were going uphill your top speed will be slower
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Old 03-17-2004, 09:00 AM
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Originally posted by -HyJynX-
All of them have them stock, no matter what. Were you on a flat road, down hill? If your going downhill you will obvisouly go faster, and if you were going uphill your top speed will be slower
Then, I bet his car is an automatic. Automatics do NOT have a speed governor.
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Old 03-17-2004, 03:57 PM
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You sure? I swear they do!
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Old 03-17-2004, 03:59 PM
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Originally posted by -HyJynX-
You sure? I swear they do!
I'm positive. I use to have an automatic S13 coupe. I had it well above 120, and no hesitation what so ever...
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Old 03-18-2004, 02:02 AM
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I have an AUTO SR ECU and it still has the cut...
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Old 03-18-2004, 02:06 AM
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Oh and keep in mind that your speedo can be WAY off easily. Bigger rims/tires, even tire pressure. Not to mention that on older cars they just slightly get out of calibration... WELL over 120 could be like 127... well the fuel cut is at 115, so that's only 12 MPH... If you had gone 140 I'd say you're right.

Either way, I don't know, I've always been told the auto's dont have fuel cut, even on the SR ECU's, but then mine did, so I'm skeptical about what people actually know based upon experience/what they've read.
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Old 03-18-2004, 04:04 AM
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I have no experience with the SR ECU. But, I'm 100% sure that the KA auto ECU does not have a speed cut.

Think about it.... If the ECU has a cut off at a certain speed, what tells it that certain speed? The speed sensor. Even if its out of calibration and your speedo says 127 MPH, the ECU sees 127 MPH. So, it should have cut off already. Even if it is off by 20 mph.

Last edited by JeromeS13; 03-18-2004 at 04:06 AM.
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Old 03-18-2004, 10:04 AM
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I was searching around and supposedly autos dont have speed limiters, but I dont know...
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Old 03-18-2004, 10:31 AM
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Speed Govenor/Rev Limiter
Removing Top Speed Limiter

As for removing the speed limiter, I highly doubt the dealer is willing to help you out with this one. I actually just completed the task last week.It's not too difficult to do yourself as long as you have the ability toramp or lift the front of your car up enough to get to the transmission. Here's the procedure. First you must disconnect two sensors (presumably RPM limiters?) from the tranny. One is the fourth gear sensor, while the other is the fifth gear sensor. If you look at the transmission under the car there are supposedly four (4) sensors (I only saw three, but the fourth one is somewhere under there), the ones that need to be disconnected are the middle two (2). The electrical connections are simple snap lock configured so not cutting is required. Once the two connections are disconnected, I recommend you thoroughly tape over the ends of the connectors to prevent moisture from entering within.

By doing this step the ECU doesn't know your 4th or 5th gear RPMs, therefore it won't limit you. Note: If you have faith in placing your car on jack stands (some members have done this) you can test the limiter for each gear before and after each step. What you'll find is that the ECU limits the top end RPM for 4th and 5th gear before you disconnect anything. Afterwards, the skies the limit.

The last step is to disconnect a control wire that comes from the tranny area and passes by the passenger side of the starter in the engine compartment. You'll find another simple electrical connection (looks like a tube style fuse holder) with small gauge wire. Unhook this connection and then drive your car and you'll notice the speedometer doesn't work, nor do the number onyour odometer change. What you've disconnected is the sensor that transmits the speed to the ECU and the display. Now the computer tries to watch your speed to make sure you don't go past 115mph (S13 model, S14 may vary higher), but never cuts off your fuel since it doesn't have a clue how fast you're traveling.

Since most of us don't cruise over 115mph you may want to wire a switch into the speedo connection just mentioned. I used a simple red rocker switch and installed it into the blank Nissan console plate located to the right of my
rear window washer/wiper control buttons.

Disclaimer: This method may vary for automatics and S14 models. Drive safely and responsibly.

Mike Lee
Turbo240sx@hotmail.com

WARNING

Super page! I have owned a 1991 240sx and an 1989. My latest venture is an 89 SCCA ITA racer. I just recently got the car built and its first test day and race. I did not have time to get a chip (also not legal, :-o) to remove the speed limiter. I missed pole in my class by .233 of a second and I was losing more than that on the straight because of the limiter. Therefore I took Turbo240sx@hotmail.com advise under Speed Govenor/Rev Limiter in your FAQ section to remove my speedo and limiter. Well.... ....at the start of the race, in third gear, I pass two cars and go to fourth, NOTHING!, I try fifth, NOTHING!, I go back to third and redline! Try 4 & 5 again, NOTHING! After almost getting rear ended I packed it up after one lap. Apparently the computer could not read 4th & 5th, after disconnecting the harnesses!? I know your are not directly responsible for the info on your page and I am ultimately the one responsible for what I do to my car. I emailed Turbo240, (nicely) and no response. The main reason I write to you is to remove or at least fix the incorrect info that cost me my first DNF in four years. And I was bragging to all my Rotary friends that my 240 would be just as dependable as our RX-7's. :-p... Well, enough rambling, I was still wired from this weekend. Again nice page! I hope to contribute soon.

Thanks!
Juan D. (Racer X)
Gainesville, Florida
tkht@atlantic.net

Another

How do you remove the speed limiter?

After reading the first solution I looked into finding a simpler solution. Best of all, everything can be done at the computer. My car is a 89 with a 96 ka24de, but all the wiring and computer is 92. On my computer, there is a yellow wire with green stripe, 8th one over from right on harness. This is the vehicle speed sensor signal. Cut that wire. That is it. If you have a California car I think it will trigger a code, but for the rest of us, it is an easy trick. Your speedometer will still work because the signal comes from the tranny, goes to the gauges, THEN feeds the computer. I had to find a solution because my car comes very close to the speed limiter at the end of the 1/4. If anyone can beat the revlimiter let me know. I'm working on it.

Name: Steve Kovacs
Email: ddrew@caverns.com

How do I remove the speed limiter from the 240?

If your willing to spend the extra cash head over to http://www.superchips.com/240.htm and take a look at a super chip. They claim that it brings your HP and torque up 10-15% in mid revs. Price as of late 1999 - 395.00 american.

The Dixie Flatline
Email: staring@yerass.com

Rev Limiter

I don't know how many people have run into a problem with your rev limiter, but I've noticed the 240's rev limiter is quite harsh. It is bad emough to stall the engine sometimes, especially if you hit it in the middle of a speedshift. Although I have no solution for the rev limiter aside from getting a reprogrammed computer, If your engine dies because of the speedlimiter, it won't start right back up. I don't know how many times I had to pull over and try to figure out what to do. I used to just wait 10 minutes and start it up again with no probs, but I did find an easier way. I did hit the rev limiter on the freeway in morning rush hour and stalled the engine. Frantically I tried to get the engine restarted while I was still rolling to a stop. I then found out by turning the key back to at least the acc. position(I wouldn't recommend turning it back all the way as your steering wheel may lock), you can then start the car right back up! It took me 1.5 years to find this out, and it probably the best discovery I have made about this car. Saved me from getting flipped off and yelled at from passers-by. I thought this might be helpful, if not at least interesting.

Chano
91 240
C-Kwik@ix.netcom.com

A Verification

Hi Shawn I am a longtime fan of you website. I own a black1992 240sx five speed coupe. I read something on the faq part of the web site about the speed limiter. I was wondering if you have tried any of the solutions on your car or gotten any feedback on them. The one I speak of in particular, is cutting the green and yellow wire on the computer. I would very much appreciate it if you would give me the heads up on this. Thank you in advance for your assistance in this matter.

Thanks for responding Shawn, I researched this at the dealer and I had one of the techs verify it in on the schematic. It works like a charm. It is the 8 wire down on the left #32 in the computer (yellow/green strip) the rev limiter can be by passed by removing the tachometer cable from the tranny.(although I haven't tried that one yet). Thanks again.

Ray
Raymond.Augustine@mt.com


http://www.**********/faq/index.html
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Old 03-18-2004, 11:17 AM
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thanx mucho
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Old 09-09-2004, 04:17 PM
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i got a question is the yellow/green wire also on the 89 Single cam ka24E computer. I would love to remove my speed limiter, but am not too sure if I can do it the same way as the duel cam. Thanks...
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Old 09-09-2004, 06:21 PM
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Originally posted by Nunook
i got a question is the yellow/green wire also on the 89 Single cam ka24E computer. I would love to remove my speed limiter, but am not too sure if I can do it the same way as the duel cam. Thanks...
IIRC it's still the same
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