stumble @5500

[poneyrunner]

i was out messing with the timing and also finally got a working tach in my car.. i have an 89 s13 that i swapped in a ka24de.. timming is set at 20tdc car runs good and pulls pretty descent to 5500 rpm.. doesnt matter what gear.. but it seems as soon as it gets to 5500rpm the car kind of stumbles and then has absolutely no power after 5500... what is this all about. what could cause this to do this?

[Matina210]

Did you ever find an answer? I have a similar problem. At 5500rpm my car bucks like I've tripped the rev limiter, and I absolutely can't rev past that.

I found on another thread that it may have to do with a ground wire coming loose. Or, it might have to do with a transmission sensor. At the moment, I can't find that thread again.

[compactfean]

There Is a few things it could be. Disconnect all the sensors from the trans (4th, 5th gear switches, and speed sensor) and see if that fixes it. If it does, than connect them back one at a time till you find which one is causing it. Also make sure your coil is working top notch. There are other things that can cause that, but are more in depth problems.

[compactfean]

There Is a few things it could be. Disconnect all the sensors from the trans (4th, 5th gear switches, and speed sensor) and see if that fixes it. If it does, than connect them back one at a time till you find which one is causing it. Also make sure your coil is working top notch. There are other things that can cause that, but are more in depth problems.

[Matina210]

Thanks! I'll check the transmission sensors next. I found this thread, where they say it could be a loose ground wire:
rev-limit-perfect-till-5500-rpm-t358449.html
I checked all the ground wires I can find, and they're good.

I found a thread where they say it can be caused by a dirty MAF sensor, and to try cleaning it. I sprayed it with MAF cleaner, and still have the "rev limit" at (indicated) 5500rpm.

The transmission thing seems very likely at this point...at least for my particular symptoms.
rev-limiter-on-a-93-240sx-5500-rpm-true ... 38389.html
http://zilvia.net/f/tech-talk/331215-s1 ... 00rpm.html

Thanks!

[Matina210]

Maybe it's not a transmission sensor, or maybe I need to try something else with the transmission.

A friend drove it and said it seemed less like the spark cut for the rev limiter, and more like the fuel cut, which he associated with the speed limiter. I thought that fit theory of the bad transmission sensor.

I found 3 sensors on the passenger side of the transmission, and unplugged them all. (First the middle one, took it for a test drive. Then the rear one, took it for a test drive...) I still have the "rev limit" effect at 5500rpm.

I'm guessing none of those was connected to a speed sensor, since my speedometer still works normally.

I was really sure it was a transmission issue when I realized the last shop to have the car had the transmission out. It's real easy to imagine them messing up a wire.

What else can I try?

[compactfean]

Try the speed sensor. Its the sensor all the easy in the back of the trans. Other than that id still ohm out your ign coil. after that you start getting into disconnecting ecu wires.

[Matina210]

This was 4 years ago, but I'm having the problem again.
I'm going to post the solution here, so the next time I it comes up I can look it up again.

I went to the right side of my transmission and unplugged things to see if one solved the problem. Unplug one, drive it. Unplug another, plug the previous back in, drive it.

The problem was the "neutral switch", at the very back of the transmission.

Unplugging that one solved the problem. I zip-tied it up and out of the way, and life was good. I could rev it all the way to 7000rpm!

This is a recurring problem because when I go to a mechanic - like, for an inspection, or something - mother f*** keep plugging it back in.

I'm tempted to just cut the damn wire.

Anyway, I found this thread with helpful pictures on Zilvia.net:
http://zilvia.net/f/showthread.php?t=413901