Rev limiter issues

[Gcurlz]

I need to know where to start because this is bugging me. The rev limit is set to 5500-6k and I want to lift it to stock. The car has a key driver chip in it I swapped in my ecmlink chip and it was fine revving to 7k but my question is there anyway around it with the key driver chip due to I don't have my ecmlink cable?

 

[mitsuturbo]

Are you sure you don't need to do something with a clutch switch/wire? This sounds like a launch RPM. Maybe the system doesn't know the clutch pedal status and is locking you at launch limit.

 

[JCorbo25]

Could definitely be the launch control system kicking on, I'd check the clutch wire first.

I think you can re-program the keydriver chips with the proper software/cable.

 

[ktmrider]

Gents the KeyDIVER ( not driver ) chip is an EEPROM setup, an ECMLink cable won't work.

OP you have some type of Launch/Stutter Box setting on your chip. Plenty of threads on here about it.

 

[tektic]

If you have a chip read/writer you can do whatever you want with it. Although There is a steep learning curve this way. Just stick with the ecm link since you already have it

 

[desant78]

EDIT: This will only help if the clutch switch is failing. If the Keydiver chip is worried improperly, this will not help. See below post for why.

First, with the car not moving, what is the rev limit set to? Mine was 4500.

Second, when moving, what was the rev limit set to? Mine was 6k.

And I have a keydiver stage 3 chip. The reason this happened was because the "launch control" was 4500 and the "no-lift to shift" was at 6k. This was acting ALL THE TIME so when driving, the 6k limit occured. A lot.

The cause of the problem was the wiring to the clutch switch was wrong, so the ecu always thought the clutch was pressed down. So with 0 mph, the ecu attempts a launch control. and at any speed, a 6k limit kicked in.

I fixed this by unplugging the safety clutch swithc, which is right above the clutch pedal. Disconnect it, and see if you can rev properly. If you can rev properly, then it is definately a wiring issue due to the keydiver settings. If it is not doesn't change, then you have another, crazy wiring problems. If the wiring is correct, you should be able to rev to 7k+ but if you keep your foot on the throttle, and hit the clutch, the RPM with be limited to 6k for hte "no lift to shift"

I personally left the switch unplugged, because I don't much drag racing, and prefer to start the car without the 2600 ACT PP engage stressing the thrust bearing. Also, my rev-limit on the keydiver stage 3 was set to 7.8K /ubbthreads/images/graemlins/devil.gif

Good luck!

 

[Gcurlz]

My clutch switch is already disconnected and still 5500 6k rev limit I put in my ecmlink ecu and it goes right to redline 7200. I don't know with this chip lol

 

[tektic]

The chip expects to see the clutch switch. So if the upper switch is not connected and functioning property that is your problem.

 

[desant78]

Quoting Gcurlz:
My clutch switch is already disconnected and still 5500 6k rev limit I put in my ecmlink ecu and it goes right to redline 7200. I don't know with this chip lol



Oh my I made a error! My keydiver started working not when I disconnected my switch, but removed the line from where the ECU taps into the switch! What I suggested before will only help if you clutch switch had failed.

When the clutch switch is pressed, it opens a switch. This means, one side is grounded, and the other side is not longer connected, and there fore not grounded. When the ECU loses this ground because it is attached to the "other side" it allows the car to start, because it thinks the clutch pedal is pressed all the way. Now when you are driving, both sides are "grounded" and "connected"

This is the same way the keydiver 2-step and no lift to shift works. When a ground is present AKA "clutch pedal is not pressed" you can rev to 7k. When the ground is not present, aka "clutch pedal is PRESSED DOWN" the ecu assuems you are starting in first gear, or shifting, and adds a much lower rev limit using the keydiver.

That being said, one side of the plug is ALWAYS grounded. the other side of the switches changes from "GROUNDED" to "NOT GROUNDED" based on pedal position. If the ECU signal for rev limit (which needs to be added for keydiver) is hooked up side that changes from "GROUNDED" to "NOT GROUNDED" it will work.

VERY IMPORTANT: If the signal (wire) for rev limit is attached to the other side of the plug for the clutch switch, the side that is "ALWAYS GROUNDED", the ECU will think you always have the clutch down and will ALWAYS have the rev limit enabled at lower revs.

Hope that helps, and very sorry i left out that detail last time. It was two years ago I did this, and had to read my old thread to remember what I did.

So find the clutch wire, and trace both sides. See if any wires are spliced into it that does not look like it was factory. Remove one at a time (if you have numerous) and test rev limit. See if that helps! This might require removing the lower parts of the trim, to expose wiring right under the steering wheel. that is where mine was.


p.s. I'm not sure your technical background, so I tried explaining things with easy to understand terms vs. the proper electrical-wizardy ones, incase anyone else (including OP) reads this and wonders why I explained it like I did. Feel free to PM to get my number and discuss this if you have any more problems. I did a lot of research into this way back when I was first on the road.
Maybe this helps, good luck!

 

[belize1334]

If your vehicle speed sensor is not getting a signal to the ECU it will put it in launch mode because the ECU thinks you're sitting still. A simple test for the VSS is your wipers. They're speed sensitive. Do the wipers go faster as you speed up?

I had this problem about 7 years back. Turned out to be a short in the wiring harness. I ran a new wire from the VSS (which is in the speedo cluster) to the ECU and voila. Launch control works correctly again, though my wipers are still stuck in slow mode. meh