R33 gtst Cluster gauges not working at all

[Manuel Miguel]

Hello everybody, i’m new here 😀.
Straight to the point, i bought a r33 gtst. The car was originally with the rb20 and then someone did the swap to rb25det and put a Vems v3 ECM.
The problem is, the cluster is not working at all (no lights, no gauges etc). But if i conect the computer to the ecm i can see the speed, rpm, boost, temps , everything. 
I took out the cluster and checked the conectors and looks fine. I also checked the fuses and all were fine. 

Can be that installing the aftermaket ecm they didn’t conect the cables to the cluster and plug them directly to the ecm or something like that? How can i check that? Any other idea? 
 

Thanks🤗🤗

[Duncan]

So, the dash has about 40 connections through the pins in the back. If you are getting absolutely nothing then it is almost certainly power or earth that is missing. Suggest you get hold of the dash pin out and use a mulitmeter to check for those pins

[GTSBoy]

The dash doesn't get ANYTHING from the ECU except the tacho signal and the check engine lamp. Everything else, being fuel, oil pressure, boost, water temperature, speed, etc, all come direct from the various sensors/devices scattered around the car.

So the ECU change is not at fault. You have some serious problem with all the wiring. Follow Duncan's advice.

[Manuel Miguel]

On 4/9/2022 at 10:45 PM, Duncan said:

So, the dash has about 40 connections through the pins in the back. If you are getting absolutely nothing then it is almost certainly power or earth that is missing. Suggest you get hold of the dash pin out and use a mulitmeter to check for those pins

Okay, so i just checked the ignition-12v and grounds and it is good.
What i found is that the illumination cables(+ and -) are not good. Bouth pairs are bad. They are shorted to ground because i can’t get 12v between them, i get 12v touchin the ignition-12v with ill+ and also with ill-,  ill+ and ill- have continuity between them. 
 

so for sure theres something wrong, i will check the cables later. But this is for illumination sistem, can that provoke that the gauges are not working?

And what the VSS means? Can i check that pins also?

Thanks a lot 😊

[GTSBoy]

On 9/5/2022 at 1:16 PM, Manuel Miguel said:

ill+ and ill- have continuity between them. 

Um. back up a second. The illumination + and - terminals on the dash itself should have continuity between them. They are either side of the lamps.

The illumination works by a switch, somewhere else (well, actually, it's obvious where it is, it's the headlight switch), provides either power or earth, depending on which way it is switched. I'm not going to go find an R33 wiring diagram to check. You can do that.

VSS is the vehicle speed sensor. You can't really check that. It's one wire up from the speed sensor and then the VSS signal out to the ECU and other CUs that use it. The speed sensor on the gearbox produces a +/-1V AC (sawtooth) waveform that varies frequency (and magnitude) with vehicle speed, and the speedo in the dash converts that to a 0-5V square wave (PWM) signal (the VSS) that varies pulsewidth with speed.

The illumination should not interfere with the gauges. But, my experience on these forums is that these faults are always caused by something completely stupid and unexpected.

[Manuel Miguel]

On 5/9/2022 at 7:54 AM, GTSBoy said:

Um. back up a second. The illumination + and - terminals on the dash itself should have continuity between them. They are either side of the lamps.

The illumination works by a switch, somewhere else (well, actually, it's obvious where it is, it's the headlight switch), provides either power or earth, depending on which way it is switched. I'm not going to go find an R33 wiring diagram to check. You can do that.

VSS is the vehicle speed sensor. You can't really check that. It's one wire up from the speed sensor and then the VSS signal out to the ECU and other CUs that use it. The speed sensor on the gearbox produces a +/-1V AC (sawtooth) waveform that varies frequency (and magnitude) with vehicle speed, and the speedo in the dash converts that to a 0-5V square wave (PWM) signal (the VSS) that varies pulsewidth with speed.

The illumination should not interfere with the gauges. But, my experience on these forums is that these faults are always caused by something completely stupid and unexpected.

Okay i see. Thanks a lot! I will do more investigation job. 
So i think that all the sensors are just conected directly to de ECM an not to the cluster. Can i put a parallel cable that goes from the sensor to the ecm and to the cluster? Is not gona affect the meassurements?

[Duncan]

Even if all the new sensors (or even old) were wired to the ECU, you would still have plenty of action in the dash. Night illumination, all lights coming on for a few seconds when the key is at IGN, etc etc. Plus, things like the tacho tap into the same signal that the ECU uses. Your problem is a dash or dash wiring issue.

I forgot to ask, are you sure the dash fuse is not blown?

When the dash is out of the car, can you apply 12v to pin A9 and ground at A4, B10, eg by touching terminals on a battery.  Then, if you apply 12v to any of the warning lights (eg A1, A2, A7, A8 etc), they should light up.

If that is all good check the car side where the harness is, check the grounds all have good continuity to ground and A9 has battery voltage with the key at IGN. 

[GTSBoy]

On 9/5/2022 at 3:44 PM, Manuel Miguel said:

So i think that all the sensors are just conected directly to de ECM an not to the cluster.

No. That is the exact opposite of what I told you in my first reply. The ECU knows almost nothing about what is on the dash. The only stuff that comes from the ECU to the dash is the tacho, and the engine warning light.

[Manuel Miguel]

On 5/9/2022 at 10:44 AM, Duncan said:

Even if all the new sensors (or even old) were wired to the ECU, you would still have plenty of action in the dash. Night illumination, all lights coming on for a few seconds when the key is at IGN, etc etc. Plus, things like the tacho tap into the same signal that the ECU uses. Your problem is a dash or dash wiring issue.

I forgot to ask, are you sure the dash fuse is not blown?

When the dash is out of the car, can you apply 12v to pin A9 and ground at A4, B10, eg by touching terminals on a battery.  Then, if you apply 12v to any of the warning lights (eg A1, A2, A7, A8 etc), they should light up.

If that is all good check the car side where the harness is, check the grounds all have good continuity to ground and A9 has battery voltage with the key at IGN. 

Yes,all the fuses were ok

[Manuel Miguel]

On 5/9/2022 at 11:02 AM, GTSBoy said:

No. That is the exact opposite of what I told you in my first reply. The ECU knows almost nothing about what is on the dash. The only stuff that comes from the ECU to the dash is the tacho, and the engine warning light.

What I mean is that I think everything is directly connected to the ecm (because when connecting the pc I can see all the info) and nothing to the cluster and that is why the cluster does not work.  That is why I ask that if I have it like this, if it is possible to put a cable from the pin where each sensor is connected on the ECM to the cluster to have the signal divided into 2 and be able to see it in both. Except for the tacho and engine light tha is diferent

[Ben C34]

There are 2 temp sensors. One for ecu, one for gauge.

By " all the info " you mean coolant temp and revs right?

 

 

 

Ask yourself this. Can you see the oil pressure or fuel level on the ecu?

[Ben C34]

On 9/5/2022 at 6:32 PM, GTSBoy said:

The only stuff that comes from the ECU to the dash is the tacho, and the engine warning light.

Facts

[GTSBoy]

Germaine Greer quote of the day.gif