Please post some pix! Maybe even a video of it running and at full chat! I bet it sounds awesome.

Actually it really doesn't whine.  It sounds really good.  and yes its a tight squeeze.

 

Good for you. Isn't it more like a whine, whine. Has to be a tight squeeze. Any pics?

Once I got the switch sorted it started running great.  That little switch is a bugger.

 

Since then I now have a supercharger, EFI and water/methanol injection.  It runs REALLY REALLY good now.  vroom vroom

Is the mini running good now?

yep.  2 plug ECU.  

That pesky switch has caused many people problems over the years. VERY important to list the year of your car in the question as these SPis went through a few tweaks along their journey. Your car has a 2-plug ECU as well, correct? 

SPI's don't have a MAF.  What I posted yesterday was the solution to the issue that I had

lots of ideas being thrown out so here is one more.
My mini is carbed but..........

if your SPI is like other FI engines:
it has a mass airflow (MAF) sensor
The MAF measures air mass to allow the computer to regulate how much gas is needed.
MAFs can go bad and cause erratic, unpredictable running and throw a lot of inexplicable codes. 

If you simply disconnect the wiring to the MAF, the engine will run on default codes.
When you do this and if it runs fine, you have proven the MAF is bad.

MAF operates usually by seeing cooling effect of airflow on a hot wire or screen in the intake duct between the air filter and engine. 
The wire/screen alters voltage depending on temp, then sending this signal to the computer.
Some people have removed, then gentle cleaned the wire/screen, thinking dirt on the wire was a problem, then reinstalled.
I have always just replaced them
 

Thanks for the update. Never knew about the input switch. you learn something new everyday.

I was going through some old posts and i thought i would give an update as to what the issue was.  

After lots of trial and error with the car I found this out.  On early SPI's there is a small little micro switch just about the gas peddle.  You have to be on your back under the dash to see it.
Basically if there is an issue with the switch one of 2 things will happen.  

1) it will run great from 1 - 2000 RPM and like crap over 2000 RPM
0r
2) It will run like crap from 1 - 2000 RPM and great over 2000 RPM

My car used to have a really bad water just above the gas peddle.  The car was outside during a really bad rain storm.  My guess is that the switch got wet inside and was shorting causing the car to run poorly over 2000 RPM.  Once the switch dried out everything was fine.

FYI Mini Spares does have the part if anyone needs it

//www.minispares.com/product/Classic/Electrics/Switches,%20stalks/NNS10001.aspx?0912&ReturnUrl=/search/classic/throttle%20switch.aspx|Back%20to%20search

Ok so I was going to post a video so you could see what the car is doing. Its working now. Go figure. I hate intermittent issues. Gotta love Lucas wiring.   I'm going to monitor for a bit.  Does this narrow it down for anybody?

Chris is going to do some more troubleshooting and we will see what we can find.

With the FI engines using feedback for management, it is sometimes difficult to separate symptoms from causes.

All the readings looked within range and all the actuators engaged on first look with the ACR.

I was reviewing the Mini Forum thread early this morning:

//www.theminiforum.co.uk/forums/topic/20533-having-problems-with-spi-single-point-injection/

looking for some hints

It could be the potentiometer. The Mini forum uk has a good thread on SPI problems.

I believe the MPI's had the switch Terry.

I don't think the crank sensor would cause surging it would seem more like a fuel problem.

This is not a minor surge or mildly mis-running engine.

The RPM surge is about 1500-2000 starting at about 2K. Up to 2 K it seems fine at first.

Starts quickly and easily.

This is an early SPi I beleive(92). Does it have the accelerator pedal switch? What does it look like? I did not see anything, but I was not sure where to look exactly.

It seems like it could be the stepper motor or throttle pot that would cause such wide fluctuations, but this is no minor stumble.

I wish I had more time yesterday. I have MPi spares, but no SPi unless they are common with the MPi.

For the MPi the ACR verifies the crank signal, but on the SPi checklist menu I did not see this. Is that correct?

Terry

No cat on the car.  Straight pipe down the middle to the muffler.

The car came with a stainless exaust from Moss Motors.

Unusual but maybe a blocked catalytic converter, should be easy enough to check just unbolt it from the system.

Terry came over today and we hooked up the ACR.  There were some old codes around water and ambient temp.  We cleared them.  After that - nothing.  No codes at all.  

With the ACR we also ran through all of the relays, stepper motor, etc.  They are all functioning.  

We also thought that it might be a dirty or bad crankshaft sensor.  Swapped that out with no change.  Cleaned up the original (it had a lot of shavings on it) put it back in - no change.
I tried running the car w/o it.  The car would not start.  I also tried unpluging it with the car idling and it died.  So I am assuming that the sensor and the wiring is good.

Here are all of the component readings at idle:

RPM - 920 to 940 (very smooth)
Idle Switch - OFF
P/N Switch - ON
MAP - 27
ECT - 79
IAT - 31
Ambient Temp - 19 (assuming that is in celsius)
Volt - 14.1
Throttle Pot .50
Lambda - was jumping between 30 and 785
I think this was all of them

At about 2,000 RPM (where the trouble starts) everything was about the same except:
MAP - Jumping between 50 and 70 (changed with the surging of the motor)
Lambda - About the same as idle.  Except I saw it hit zero twice.

I have also changed the fuel filter (cut open the old one nothing clogging it up).  I have also checked the fuel pressure.  About 10psi when the ignition is turned on.  15psi when the car is running.  At idle and at 2,000 RPM's the pressure is steady.  The book says it should be between 1 - 1.5 bar so I believe that we are in range there.

Any other thoughts?

 

 

Chris and I will get together this weekend. We will see what information the ACR provides.

I have more experience with the MPi than SPi, anyone with suggestions on what else to look for please reply.

Terry

I have heard there are a couple of ways to do it one way is leaving the ecu in the system and the other way is getting rid of everything and going with an electronic dizzy. Doing the conversion leaving the ecu should only eliminate the coolant temp sensor and the air flow sensor on the airbox i think.