12 replies to this topic

[cooperdan]

Hi guys

im getting seriously peeved off with my spi...i believe you can actually take the ecu *fruit and fibre* out (excuse my language) bad week..am i right is it allowed? might consider it not sure..can you point me in the right direction

[Ethel]

Emissions testing is based on the engine, if you do go to carb swapping the whole engine will make MoT's a lot easier. Be sure you have a valid engine number for the new one though.

Apart from the carb and assosciated plumbing, you'll need to sort the ignition as it's also controlled by the injection ECU.

[cooperdan]

is there anything on the forum like a how to guide on doing this or books etits really tempting me

[mab01uk]

MiniMania do an SPI to Carb Conversion kit which replaces the ECU with a simple relay (Bosch AR201 or similar) which you could copy using secondhand parts...................

http://www.minimania...4/InvDetail.cfm

http://www.minimania.....RB CONVERSION

http://www.minimania.....RB CONVERSION

https://www.bmw-mani...68/ArticleV.cfm

Quote:-
SPI FUEL INJECTION TO HIF SU REBUILT CARB CONVERSION

In the history of the Mini the drive to keep the product alive and marketable meant the factory decided to modernize the fuel system of the Mini from Carb to Fuel Injection. Thus in 1991 the first FI was installed on the Mini. Know as Single Point Injected or SPi for short, the system also incorporated its first ECU into the car. This version of the Mini was produced until late '96 when it was changed to the Twin Point or Multi Point injected version also know as a MPI Mini. The MPI model is a completely different set of problems and thus will not be addressed by this review.The SPi Mini might have achieved the objective of better fuel economy and emissions control, but the loss of performance and reliability still plagues the life of the SPi Mini. In addition the SPi Mini is very difficult at best to upgrade to get any significant performance enhancements.

Thankfully the best solution is still very practical: convert the car back to a single 1 3/4" SU carb and eliminate the ECU. This opens up the entire universe of performance enhancements and upgrades that have been developed so successfully over the years.

The basic elements of the conversion process are simple enough: Remove the entire FI assembly and ECU, install a conventional 1 3/4" HIF series carb and manifold, replace the ECU with a simple relay, install a fuel pressure regulator and replace the distributor. Wire and plumb all of this together and you have it! Wiring and plumbing diagrams are provided in the kit.
Included in the kit are: 12-803 - Fuel Pressure Regulator A+ - Distributor 12B561 - Carb Spacer 22A152 - Stud, carb to manifold 2A3005 - carb abutment bracket 88g429 - carb gasket AJM601 - intake/exhaust manifold gasket AR201 - Relay C-AHT771 - Intake manifold CZK6491 - choke cable clip Fitting01 - 3/8X3/8 brass fittings Fitting02 - 5/16X3/8 brass fittings Fitting03 - 5/16X3/8 fitting with .100" hole FZX1280/rebuilt- HIF6/44 Carb SBB10126 - throttle cable SD40 - K&N Air Filter

Included in this kit are all the basics you will need:

1 x Mini 1 3/4” carb
1 x K&N filter
1 x Mini/aftermarket inlet manifold
1 x Mini A+ Distributor
1x Fuel Regulator
1x Relay
3X Brass fittings

Not included in this kit are various sundry items that you will need for this conversion. They include wire, fuel hose, misc. electrical connectors, hose clamps, etc.

The first job was to remove the injection unit, which unbolts like any normal carb manifold. Because the inlet and exhaust manifolds are 2 separate units you can retain your stock exhaust manifold. Further gains in performance can be expected if the exhaust manifold and muffler system are also upgraded. On removal of the inlet, the mating face on the head needed cleaning to remove the traces of old gasket, after which, a new manifold gasket was put on. Next we bolted on the new carb and manifold.

Next was the distributor, the one for the SPI is no good for a carb mini because it doesn’t have the little box on the side for the coil connections; it uses a control box which is linked to the ECU. For this application we will simply have a later model distributor with the “little black box” already mounted on the side of the distributor. Figure 1, below, shows how it is wired. Make 2 new wires to go from the coil to the dizzy, there are ways to do it using the existing coil wires, but my way is easier! Firstly, use the original wire that supplies power to the coil from the loom, then find 2 pieces of wire around 8” long and put the relative connections on the end for one to go from the “ + “ coil terminal to the dizzy, and one to go from the “ - ” coil terminal to the dizzy. On the dizzy we used, it had a 3 spade connection on the little box on the side; one of the wires went to the top one and one to the bottom one. If the engine won’t spark when you turn it over try changing the connections over, so the top one is on the bottom and vice versa.
Ignition (distributor) timing should be such that total advance should be in the 28 degree range when at 3,500rpm.

The next step involves getting the correct fuel pressure to the carb and getting a return line back to the fuel tank. When you removed the ECU you removed the means to activate the fuel pump, etc. The pressure put out by the stock pump is way too much for any carb set-up. Thus we have to plump the regulator in line from the tank before the carb. But as the pressure is very high and the car was already set-up with a return line to the tank, the best method short of replacing the gas tank and fuel pump is to simply install the regulator with a second output that is returns the unwanted pressure back to the gas tank. It is also important to not vent too much pressure and thus we use a .001 mechanical restriction in this line. Connect the line from the tank to the input side of the regulator; one of the outputs goes directly to the carb, while the second out goes through the restrictor to the rear. Provided in this kit are 3 brass adapters for the regulator. A visual check will tell you that one of the small one has a restrictor inserted into it and thus should be used on the line returning to the fuel tank. The largest of the three should be used to connect the input line from the tank to the regulator. The third one is used to connect the regulator output to the input of the carb.

Next comes the process to activate the fuel pump and the rest of the primary electrical system now that the ECU has been removed. While it might sound simplistic, we are going to use the single relay included in this kit to replace the ECU. Find a suitable place to securely mount the relay. The wiring diagram included in this kit shows connecting from the ECU plug terminal 11 to terminal 85 of the new relay. From Terminal 20 &4 of the ECU plug to terminal 87 of the relay and then take terminals 30 & 86 of the relay and go to ground.

E.C.U. connector #5 to coolant temperature sensor on cylinder head.

The car should now be ready to go!

Article Date: Apr 15, 2005

Attached Files

•  RelayAR201_lg.jpg   18.1K   21 downloads

Edited by mab01uk, 04 March 2009 - 07:22 PM.

[Darkscamp]

whats up with your spi to make you want to do this?

i know theres a lot of injection haters out there but i enjoyed many years of happy motoring in a spi. i must admit there were a few issues i had to sort but i've had more from the carb setup in the scamp, thats been the annoying pain in the butt for the last few years.

[cooperdan]

Dont get me wrong i have enjoyed the spi its been very good alot of fun..but i just had few problems with it recently and its annoyed me a bit and opening that bonnet to aload of relays and wiring is pain in the arse..i like the simplicity of a carb and the vast amount of upgradable parts..its easier to work on aswell..

P.S. mab01uk top man thanks

[Bungle]

mab01uk

can you now give some info of how to make a carb fitted injection engine pass a injection MOT test

[mab01uk]

mab01uk

can you now give some info of how to make a carb fitted injection engine pass a injection MOT test

http://www.motuk.co.uk/manual_730.htm
Vehicles fitted with a different engine:-
"Test according to which is older, engine or vehicle.
e.g. A 1995 car fitted with a 1991 engine (of whatever make), test to 1991 standards for emission purposes."

"Note: The onus is on the vehicle presenter to prove engine age."

Here is the official VOSA Government MOT website with the relevant page of the manual.
Link:-
http://www.motinfo.g...m3s07000301.htm

Personally, for future originality reasons, I would always try to stick with the SPI/MPI system on any Mini factory fitted with it, as long as most spare parts are still easily available.

Edited by mab01uk, 05 March 2009 - 07:26 PM.

[taffy1967]

mab01uk

can you now give some info of how to make a carb fitted injection engine pass a injection MOT test

Yes that is the problem, unless you simply fit an older carb equipped engine so they have to test it going by the age of the engine at the not so strict emissions test level.

[Bungle]

that was my point you can't just rip off the injection and fit a carb

you need to change the whole engine

[maph2]

i'd get the plug and play programmable ecu kit. more expense than going to carb but will release more power and economy. there are better options now than just "slap a SU on it" for Mems injection owners

[Sprocket]

i'd get the plug and play programmable ecu kit. more expense than going to carb but will release more power and economy.

Thats a misnomer

[minijoey]

Hi there,
I'm new here on the forum, rebuilding a '93 sprite spi. Since I'll put on older engine in I would like to run a hif44.
I've already got one second handed and it is in great shape. The problem I think with the conversion kit is and wich also is one of the reasons I would like to do this conversion is that I would like to tidy up the engine bay.
I don't like the look of the ecu and all of it's wiring including the extra hoses and electrical parts. (I prefer K&N breathers on my engine)
So the few questions i've got left is: Will I be able to run a carb engine with my fuel tank and it's pump. If so how? I need to do new plumbing so new fuel lines won't be a problem.
MOT is no issue since I live in the Netherlands and we've got other rules.
Hope you can help me out. Regards