weird rev limiter problem

[Drifterxl]

first of all, yes i searched, and i may have found a solution to my problem, but my problems a bit weird and am unsure of a couple things....

i just recently replaced the clutch in my 90 240sx and sense, i have had a couple of problems to kink out. i finally got thru the breakin period and so i was havin a bit of fun with the clutch and what i've noticed is my rev limiter is messed up. before my clutch swap there was no limit to any gear except 5th when i hit the speed limiter at 180km/hr. now, after the clutch swap, i have a rev limiter in 4th gear that comes on between 3800-4200 rpm and a limiter in 5th that comes on at 3500 rpm. as well, and even stranger, very rarely, but every once in a while a rev limiter will kick in in 3rd gear at around 4500 rpm (give or take). due to this i am unable to take my car much past 130-140 km/hr...... not that i really need to, or should, but its a pain in the a$$ none the less. though when in nuetral shes rev happy all the way to 6800 rpm. i did some searching and found a thread that said if you unplug the middle 2 sensors on the transmission your 4th and 5th gear limiters will be gone, do you think that this would fix my new problem? and what about that 3rd gear limiter? i've never heard of anyone having a limiter in 3rd, any ideas???

on a side note (i posted about this a few days ago), after my clutch swap my odometer and trip odometer stopped working, and also, in the year and a bit i've owned my 240, the speedo has never worked right either. could either of these problems have any connection with my rev limiter problem? i was informed these problems were most likely a faulty cluster, however, because my odometer stopped just after my clutch swap, i am suspicious as to whether or not something happened during my clutch swap. so what do you guys think?

[ArticDragon192]

Maybe some messed up sensors? Usually there is a fuel cut off once you reach 115 mph, dunno how much that is in kph.

[Drifterxl]

the 115 mph cut off is the 180 kmph i was talking about, that part i was fine with, but i am not even close to reaching that, this rev limiter kicks in way before, my top speed right now is about 80-90 mph. the rev limiter won't let me go faster.

and one correction to my first post which i just realized tonight. that 3rd gear limiter is constantly there at 5000 rpm. i've never heard of anyone having a rev limiter anywhere on there 3rd gear. whats up with my car?

[Gold Digger]

I had that exact same problem with my 90 240 hatch...turned out the speed sensor gear in the transmission was stripped. If you have no speedo, the computer has no idea how fast you are going, so it cuts you out at 3500 in 5th. Go to a Nissan dealer and get a new speed sensor. If I remember, they are a little price. I think somewhere near $120...but that was 7 years ago. They are easy to swap. Two 8mm (I think) bolts, unplug the wiring harnes about 6 inches down from the sensor, and put in the new unit. You will loost transmission fluid from the hole when you take the sensor out, so be sure to refill it when you are done. After that, your speedo, trip and regular odomiters will work. Hope that helps.

[Drifterxl]

killer. thanx for the info C33. ill go look into that. the only thing is that my speedo has never worked ( i know i should have got that fixed, i'm workin on it) and this limiter problem only just started. why would that be?

[Drifterxl]

i have one other thing to add that i found out the other day. i figured out that if I tap the clutch a little just before I know it will cut out (giving my car a few little bursts), that it will go past the rev limiter and I can then redline. its a little tricky, and i'm sure harder on my clutch, but i got around the speed limiter (if that makes any sense). anyways, has anyone ever heard of something like this? i'm gonna look into this speed sensor gear, but in the mean time, can anyone figure this out? thanks!

[Gold Digger]

Never heard of anything like what you are talking about with you limiter. Also, I am not sure if Nissan sells that gear now. You actually might be able to get the whole unit from a junk yard for cheap...I did mine when I was still a noob to the the 240 scene in 97. Only had the car for four months when the speedo went out. Drove it like that while I was stationed in San Diego, then when I took the car back to Illinois was when I chaged the sensor. If you have any mechanical knowledge, it will be easy...if you don't it will be a little difficult. Not to hard though, you should be ok...and if you can get the car up on jack stands, thats even better. I did mine on the side of the street with just my car jack...that was freaky...good luck though.

[Drifterxl]

ya, i thought it was a little odd about how i got past the limiter. but in any case, i'll fix this gear. if ya don't mind C33, could you give me a rundown on the procedure. i've just recently replaced my clutch and the entire rear sub-frame and suspension assembly, so i figure i can tackle this. and a little heads up would certainly be appreciated. thank you.

PS. i just wanted to ask again (because this didn't get touched on yet) would unplugging the 2 middle sensors on the transmission fix this problem at all? i've heard of people doing that, so i was curios. thanx again.

[Gold Digger]

Not sure if unplugging the sensors will do anything or not. Last I read, which was quite some time ago, when 240sx.org was still a full website, if you did something like that, there were problems on some, and no problems on the others.

As for doing the speed sensor swap.

First go to Nissan and buy or order the sensor or gear. This was a part you could only buy from the dealer when I did mine. Make sure you have your VIN handy so they can get you the right gear. I have heard that some trannys had different gears for the sensor.

Get the car up high enough on jack stands to get under and have enough room to move. Get a pan or something to catch the transmission fluid that will drain out. Find the sensor...should be about 1ft up from the end of the transmission on the drivers side. Look for a cylindrical object abut 1.5-2 inches in diameter with wiring coming off of it. Follow the wiring to a plug about 6-8 inches up from the sensor and unplug the harness. Next take your wrench or socket...whatever you have, and unbolt the sensor. Should be two 8mm bolts. Could be 10's, cant remember...did mine in 98. There might also be a paper thin gasket between the sensor and transmission....but like I said...been a real long time. When you get the sensor out, it should have a red plastic gear on the end. If there are broken or no teeth, well, you found your problem. If the newly purchased sensor has the gear already on it, just go opposite of the removal. In my case, I had to buy the sensor and the gear, so if this is your situation, you will need the C-clip that holds the gear to the sensor shaft. Take that off, put new gear on new sensor, lock it in place with C-clip and re-install. Plug the harness back in, fill the transmission back up with fluid and take for a test drive. After that, you should have your odometer, trip odometer and speedo. And if you have cruise controll, that should work now too.

Hope that helps out, and let me know how it goes.

[Gold Digger]

bump

hey man, have you done anything with this yet. Just curious to know if you fixed the problem or not.