R33 GTST/M Speed Signal from Cluster to ECU

[schalachi]

Hello guys. I am new to this website today. I have searched everywhere on the internet. I am good with car wiring, and I have 1 last issue I need to resolve on my ECR33 1994. I have used NDS I and the cable to find and repair an issue successfully. Everything in the car works (except for HICAS; it is being deleted today using GKtech parts). I have noticed when I unplug the HICAS ECU that steering gets hard, so I left it plugged in. Anyway, that's not my issue. My speed reading in NDS I does NOT work (reads 0 kph) however it works on my cluster. I have read that there is a signal from the cluster to ECU. I want to short test this wire to make sure it is not broken but I don't have the means of identification (diagram). Can someone help me identifying the wire from cluster to ECU? Maybe previous owner cut this wire to remove speed cut or something. Thanks

[Duncan]

It was extremely common to cut the wire from the dash to pin 53 at the ECU to remove the speed limit, and it doesn't affect how the car runs.

The R33 pin outs should be available by searching on these forums if you want to check

Edited March 22 by Duncan
Corrected incorrect pin #

[MBS206]

15 hours ago, Duncan said:

It was extremely common to cut the wire from the dash to pin 52 at the ECU to remove the speed limit, and it doesn't affect how the car runs.

The R33 pin outs should be available by searching on these forums if you want to check

Oh man, Id forgotten about the old cut the wire to beat the 180kmh speed limiter, ha ha ha!

[schalachi]

18 hours ago, Duncan said:

It was extremely common to cut the wire from the dash to pin 52 at the ECU to remove the speed limit, and it doesn't affect how the car runs.

The R33 pin outs should be available by searching on these forums if you want to check

Hi. Thanks but I have seartched and dont know how to find diagrame here. Can you link it here?

[schalachi]

18 hours ago, Duncan said:

It was extremely common to cut the wire from the dash to pin 52 at the ECU to remove the speed limit, and it doesn't affect how the car runs.

The R33 pin outs should be available by searching on these forums if you want to check

Duncan, I am looking at ECU Pinout and its says 53 is VSS not 52. but I havent found a good copy of cluster diagram so I can start tracing 

[schalachi]

Let me first look at the ECU connector and see if that wire is simply cut right there. Thanks. Will report soon

[Duncan]

Sorry to mislead you, I said 52 from memory (because this came up earlier this week).

As you said, the correct wire is 53, and I've edited my post above as well

[GTSBoy]

9 hours ago, schalachi said:

Hi. Thanks but I have seartched and dont know how to find diagrame here. Can you link it here?

I posted this on March 10

 

 

[joshuaho96]

On 3/21/2024 at 12:57 PM, Duncan said:

It was extremely common to cut the wire from the dash to pin 53 at the ECU to remove the speed limit, and it doesn't affect how the car runs.

The R33 pin outs should be available by searching on these forums if you want to check

In my experience it affects idle, it definitely uses the VSS signal to raise the idle target and adjust the open loop AAC duty cycle or something like that. If you push the clutch in while moving it will idle closer to 1200 rpm before very slowly dropping down to 950 rpm. More often than not you need to get it into neutral and make sure the neutral switch actually triggers by wiggling the shifter in neutral before it'll finally decide to drop the idle down.

[GTSBoy]

^^ All true, except that RB25s idle at 650.