I too am an SPi guy and it is VERY helpful to have a scan tool handy, just to rule out some of the obvious. I actually built my own cable that connects to the factory diagnostic port plug and terminates in a USB. There are a couple pieces of software that have been designed for our cars from enthusiasts for your PC. Unfortunately for me, I am a Mac/iphone guy. I took my fathers older Samsung S whatever and download the mobile version of one and keep the entire setup in my car just in case. Great to have and all the info can be found on the Injection-specific portion of theminiforum.

//www.theminiforum.co.uk/forums/forum/140-injection-mini-specific-spimpi/

They are not complicated systems really if the water temperature is reading lower than usual and the car is running rich chances are there is a coolant temp sender problem.
The good thing is they always seem to go to rich mode a so at least you can make it home with no long term engine damage as too rich is always better than too lean.
As Jim pointed out the scanner is only a limited look at things and a bit vague and archaic compared to today's scanners but at least it is something to work with and you can clear the codes with it.

Glad it worked out and you found the tool to be useful!

On the Mini Forum other people have had similar symptoms, but the coolant passages in the intake manifold have been blocked with coolant crud. I guess a regular flush out takes care of the these, ounce of prevention sort of thing.
Terry

Thanks ,  kinda why i wanted to toot my own horn !
   Someone might read this in the future and need to investigate the same.

Came down to = Testing the coolant temp seperately from a running engine...  I used the 2nd spare sensor= plugged in + ignition on, applied direct heat and watched the coolant temp on the scanner rise. That also corresponded to the gauge rising appopriately too.

While still researching i found the Ohm Resistance of the coolant temp sensor  = Ohms drop as the Temp warms.

So somewhere between 300 - 200 Ohms  the temp should be at operating; Temp.  ~88C
  I ordered some resistors and also tested this way to =   300 Ohm.. NOT QUITE to mid gauge  0 70degrees Celcius.
   ~200 Ohm =  89 Degrees Cel.. by the computer scanner.   SO  proving the Wiring + Computer WOULD calculate temp if the sensor was seeing temp.

 
 

C	F
Degrees	Degrees	Ohm
0	32	6000
20	68	2400-2600
40	104	1100-1300
60	140	~500
80	176	~300
88	190	225??
100	212	~100

This blockage actually came down to a Manufacturing defect in the hose.( A NEW HOSE- not the factory radiator hose)  2 years ago i installed new Rad + Hose for general maintainance. From there this issue started to occur = Customer advised this came on Slowly.   Sure enough =  a rubber blob inside the hose connection was blocking flow + letting a little gunk antifreeze coolant also block up = No flow.   Enough other water was flowing to keep the engine fine, just not enough to the Intake + ECT Sensor.

I liked learning this SPI stuff and the ACR tool is VERY Useful when leading to a diagnosis like this.

Wow that's a new one for the books.
The majority of spi faults can be covered with vacuum line ends, coolant temp sensor, O2 sensor, crank sensor, and fuel trap and also setting everything to spec. A lot of people do not know the codes presented (if any) are stored forever and have to be cleared with the spi reader.
The biggest issues i have found seem to be when someone who has no knowledge has been into the system and screwed everything up.

Glad you got it sorted.

Resolution :

SPI was running  on ' choke" or ecu thought to run the car rich becasue the Temp sender was not getting warm.
  In this case there was a blockage in the rubber radiator hose preventing water flow to the intake.

 No water flow no temp seen by ECU.
Remove blockage = flow returns. Temp Returns.

Having ACR Tester was very resourceful to showing the Temp values not being seen by the computer.. First fault check the electricts.. then the Operation.

DONE!

All of this is for the SPi only. The only problem I see with some of these tools is that they are not SPi specific, alot of perceived data is presented that is not used in the MEMS Mini implementations.

Probably for the cost of shipping, you can make the connection required for one of these:

MEMS Gauge for Windows Colin Bourassa
MEMSGauge is a graphical display and diagnostic tool that reads runtime data
from the ECU in the Rover Modular Engine Management System (MEMS). Currently,
only MEMS 1.6 is supported.

 

• Overview
  //www.bearinghead.com/rover-mems-16-diagnostic-protocol.html
  
• Download releases:
  //github.com/colinbourassa/memsgauge/releases/latest
• Discussion group:
  https://groups.google.com/forum/#!forum/mems-diagnostics
• MEMSGauge depends on another piece of software that Colin wrote, librosco.
  Each of these two projects has its own GitHub repository:
  https://github.com/colinbourassa/memsgauge
  https://github.com/colinbourassa/librosco
  
  MEMS Rosco for Windows LeopoldG
• Analyzing tool based on Colin Bourassa‘s MEMS Gauge
• Download
  https://github.com/LeopoldG
• MEMS Rosco Presentation
  https://docs.google.com/viewer?a=v&pid=forums&srcid=MDE0OTMwMzE1Mzg1ODI0NjE0MzMBMTAyODY1ODUzMjc1NDYwNjk0NzcBZGZ6UGpKYWtCd0FKATAuMQEBdjI&authuser=0
  
  MEMS Analyser for Windows RMRSoft Alan Richey
• MEMSAnalyser is a program to analyse the Rover MEMS 1.6 as fitted to Rover cars in the early to mid 90s, and also in the Robin Hood Superspec Kit car. It uses a logging program called MEMSLogger to produce a data log file while driving and then post-drive it analyses up to 50 parameters from the data file and displays them in a graphical format.
• Acknowledgement: MEMSLogger uses a program called readmems.exe written by Colin Bourassa as part of his program called MEMSGauge, which provides a real-time display of the ECU parameters (see //www.bearinghead.com/rover-mems-16-diagnostic-protocol.html for details). My thanks for his help and allowing me to use the program.
• Download
  //www.rmrsoft.com/mems/index.htm
  
  MEMS Diag for Android Pawel Wozniczka
• MEMS_Diag is an android application designed to communicate with pre-OBD Rover engine management systems (ECU). Modular Engine Management System (MEMS 1.6 / 1.9) was used on many cars in the 1990s built by the Rover group (models equipped with different variants of K16 petrol engine)
• Free Lite version
  https://play.google.com/store/apps/details?id=com.rovermemslite&hl=en
• Information
  //memsdiag.blogspot.com/

Not sure the links will still work after cutting and pasting.

It looks like some of the links work and some don't. I should have mentioned this stuff in the email.
Terry

I have a factory SPI test diagnostic kit that I've never used and am ever likely to - open to sensible offers...

when doing the o2 sensor, you don't have to disconnect anything. just unbolt and move it out of the way to get access to the o2 sensor.

Thanks for the directions.. I Have a 'tool' En Route... 

Will be searching out the O2 sensor.. AFTER I put the manifold back together. THEN I Can run the car again and Scan with tool to see the sensor inputs..  

Will be funny if  it is the O2 Sensor... have to pull the manifold Again to access + replace.

 Owner has said this has been a Slowly occuring up coming issue.. over time the RPM's would increase more and more.. COULD be a sign of dying Oxygen sensor so computer is compensating.. 

In my plight to find a tool for these SPI cars I ordered a Cable  + pLug from UK for these Systems   then to download the software for a modern off the shelf 'tool' to see sensor inputs.  Will see how that tool works when it arrives too.

I have a crypton model. I had a sykes pickervant model, but sold that one. These readers are very limited in their functions. The must for these units is to set the rpm. They will tell you the water temp, O2, rpm. Not much else. You said that you have an ohm reading at the water temp sensor which is good. But I suspect it's your O2 sensor. Have you replaced that? My email is [email protected] Jim

Just a simpleton thought but could something be blocking the throttle so it sits open just a touch more than normal idle?  I don't know if SPI has a position adjustment for the throttle pedal, throttle cable, or the throttle itself.

jedduh..  the last time I had to use one. I rented one  from the UK..    cost more to ship than the cost of renting.. which was 120 quid..  maybe jim fai.. might have one in MN. or Malsal in Fla..??. later bc

Greetings.

 Working with an SPI. 
   Physically car runs great...  however.. when 'warm"    Temp gauge does not move  also runs at High idle  about ~ 12-1500 RPM
 
Have replaced Water temp sensor in Manifold.
Have Tested current temp sensor (ohms drop as heat is applied)  appears working.
Have traced contunity of wires back to ECU for connectivity from Sensor to ECU.  All signals present into ECU per wire diagrams.

Looking to rent / Borrow a SPI (late model) ECU MEMS scan tool. I want to see if the ECU is seeing 'temp's from respective sensors.
Specifically this is a 94 - German market mini.
 

Next to trace signal back to Dash for the temp gauge. = IS that connected properly?

Trying to solve...   IS the computer telling this to run at High idle? and why?


Vacc lines all replaced and under checking in great condition.

If anyone has access please let me know . Would rent + ship = deposit etc.. 
  Shipping for use in Charlotte NC.

Thank you.