9 replies to this topic

[jerrydt]

Hi all,

I'm having issues with the coolant temperature readings on my 1993 SPI. I've ruled the gauge out, ruled the sensor out....so the only real thing is the cable. It was pretty mangled when I bought the mini. The wire coating had melted and taped up instead (and a bad job at that).

 

How does one go about replacing that wire? I understand that it goes to the ECU, is that right?

Any help much appreciated!

Thanks all

Edited by jerrydt, 19 July 2018 - 08:15 PM.

[Bat]

Hi,

The wire does go to the ECU then that sends a signal to the guage.

There's a repair loom available from mini Spares part number YMQ105690

Cheers 

Edited by Bat, 17 July 2018 - 10:18 AM.

[jerrydt]

Hi,

The wire does go to the ECU then that sends a signal to the guage.

There's a repair loom available from mini Spares part number YMQ105690

Cheers 

Thanks for the reply! That part number says its for a twin point. Will it work on my single too?

[Bat]

Hi,

Sorry thought yours was an MPI.

Still it's 2 wires with a plug on the end so I can't see why not.

You'll need an SPI owner to confirm though!

Cheers 

[jerrydt]

Hi,

Sorry thought yours was an MPI.

Still it's 2 wires with a plug on the end so I can't see why not.

You'll need an SPI owner to confirm though!

Cheers 

Normally I'd just cut the damaged bit and splice a new one onto it. But as it relies on resistance, I don't want to alter resistance by splicing it and/or using a different gauge wire. Any idea where/how I can figure out the current gauge?

[Sprocket]

 

Hi,

Sorry thought yours was an MPI.

Still it's 2 wires with a plug on the end so I can't see why not.

You'll need an SPI owner to confirm though!

Cheers 

Normally I'd just cut the damaged bit and splice a new one onto it. But as it relies on resistance, I don't want to alter resistance by splicing it and/or using a different gauge wire. Any idea where/how I can figure out the current gauge?

 

 

In the grand scheme of things, 1 or 2 ohms resistance in a wire carrying no current over less than 1 meter distance is not going to make much difference to the readings. The gauge is fed by the green/blue wire from the ECU, up through the 13 way connector on the bulkhead near the inertia switch, then direct to the gauge cluster. The coolant temp sensor wires, the pink/green wire from the ECU goes direct to the temp sensor connector, the pink/black is terminated in the loom down near the ECU  to the common sensor ground (which is a failure point in its own right). 0.5mm2 wire should be more than adequate for the task.

The green/ blue wire that feeds the gauge only carries a pulsed ground signal from the ECU, not resistance like the old sender fitted on carb engines.

Edited by Sprocket, 19 July 2018 - 10:05 PM.

[jerrydt]

Thanks Sprocket! So if I order some 0.5mm2 wire and splice it myself I should be golden?

[Bat]

Hi,

Anything thing 0.5mm2 or above, 0.75 or 1.0 will do too. It's only going too small that you need to worry about. To be honest there's so little power involved you could use a bit of damp string! 

Cheers 

[Kevdee]

Hi hope you don’t mind me jumping in here just got a spi on Monday and the temp guage isn’t working but seems to run ok , I have a spare clock cluster so changed that over to see if it was the clocks , nope , then I removed the sender wire and shorted that out to watch it go to full but no movement after reading this it goes to the computer first so shorting the cable won’t work I guess so can still be the sender that is broken? Treat me as a idiot here with spi as only had carb before this one , thanks guys :)

[Sprocket]

Best way to check is to unplug the ECU. Remove the white plastic shield from the large 36 way connector and with a tiny watchmakers screwdriver, ease back the little retaining clip holding the pin on the green/blue wire, and gently pull out the pin from the connector housing. No need to tug on it, it will come free quite easily so long as you've released the retaining clip.

 

Ground this pin on the green/blue wire. with the ignition on, the gauge should go full hot. If not, repeat this procedure, but now on the body loom side of the thirteen way connector up on the bulkhead next two the inertia switch and the two yellow relays., if the gauge goes full hot, then you have a break in the wire in the engine loom between the ECU and the thirteen way connector (could be the connection at the thirteen way connector its self).

 

You could probe these pins with the ignition on, as they should have 12v on them

Edited by Sprocket, 22 July 2018 - 07:52 PM.