16 replies to this topic

[Bluemini]

IMPORTANT NOTE: An engine mod like this may consitute a notifiable modification to the insurers and licencing bod(ies).


A friend of mine has an M reg Single Point Injection mini. Since he’s had the car, he’s had nothing but trouble with one thing or another. The final straw was when it kept staling for no apparent reason. After asking a number of people for their advice, it seemed that the general opinion was that the ECU must be faulty, and the best cure would be to take it out and replace it with a carb instead (much more tuneable).


This is where I come into it, I was asked to help solve the problem. After an initial inspection I made a list of the parts required (at this point I’ll point out that we had a donor mini to cannibalise).


1 x Metro 1 3/4” carb
1 x K&N filter
1 x Metro/aftermarket inlet manifold
1 x Metro electronic dizzy
Male & female spade connectors
We also decided to change the plugs, leads, dizzy cap and arm too.


The carb, filter, manifold and dizzy were sourced from a local breakers for £35, while we bought the connectors and plugs, etc from a motor factors for around £30.


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 on the single point, unlike the standard carb engines where it is all one cast unit, we decided to keep the existing exhaust set-up for ease and to keep costs down. 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. At this point I’d like to point out that it is a good idea to remove the cover off the bottom of the carb and check the internals are all ok and clean before bolting everything down. (We didn’t and had to take it back off later to clean it)


Next was the distributor, the one for the single point 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. The new dizzy was put in and the new cap and arm put on, along with the new plugs and leads too.


That was all we were hoping we’d have to do, other that a small amount of modification to the wiring, but after sitting scratching our heads for a while trying to figure out how to modify it, we went for a second option - take the front loom from the donor mini which had the same clocks and switch’s as the mini we were working on, so wiring it up was relatively easy. The loom from the SPI was a mass of wiring and took a bit of doing to get out, but looking back, we should have just cut it to bits instead of trying to save it. The only part of it we had to leave in was the exhaust sensor located in the manifold, this was only left behind to keep it’s hole blocked in the exhaust, though with the wires just cut off. While we were at it we replaced all the connectors that looked dubious so as to save any aggravation in the future.


Next was to 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 wire 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.


Next was the fuelling problem, we hadn’t realised that the SPI used an electric pump, but this was easily overcome by using the mechanical pump form the donor mini. But the SPI also has 3 fuel pipes too (2 large braided pipes, one with orange marking and one with green and a smaller black plastic pipe). We opted for the one with the green marking on it, so connected it to the fuel pump and the pump to the carb in the usual way, leaving the other 2 pipes free.


This was it, it was time to try it. Turning the key, it fired up first time! I was very relieved because I was unsure what the cam would be like with it being for an SPI, but it all seem ok. It was then taken for a test drive and after about going about 20’ cut out. “poo! it aint gonna work, the cam must be all wrong” were my thoughts at the time, so we tried it again and the same happened. Every time it cut out there was a strange hissing noise, as if there was a build up of pressure escaping but we couldn’t find where. Desperation was setting in now, so I rang a couple of people I know who might be able to help. They suggested checking the fuel lines and filters that are in the tank and also that the exhaust was clear. We thought the best bet would be to change the fuel tank for the one out of the donor mini, but after trying to go for a test drive, once again it died with the hissing noise. Then we unbolted the exhaust at the cat to make sure it was ok. While dragging it out from under the car we noticed bits off black stuff falling out of it, this black stuff was the remains of the inside of the cat, which had broken down into bits and been blown back, blocking the rest of the exhaust solid! Back to the motor factors for a new rear section of exhaust, we decided to re-use the cat even though it was empty of it’s cat material because the motor factors wanted £140 for a new one!!


This seemed to cure it, it ran like a dream once I tweaked the ignition timing slightly, so off for another test drive. This time we got as for as the hill out of the car park, and it started coughing and farting again and cut out, but without the hiss. By now I was beginning to wonder if it was really going to work at all, or whether we should have left it as a single point. I messed with the timing and got a bit of an improvement, but it was still gutless on the hill and under load. I was running out of ideas by now big time. After about an hour of fiddling, I decided to take the carb back off and check that it was working ok wasn’t getting blocked. When I removed the bottom cover, I found it full of gunk and bits of dirt. Once cleaned and washed out, it was put back on and fired up and taken for a spin once again. FINALLY!! it worked it ran like a dream, didn’t cough, didn’t fart, didn’t cut out, perfect....


So, if anyone else has problems like this, hopefully I might have given you some ideas as to what the cause/cure might be and if your thinking about swapping from the SPI to carb, then maybe it’ll give you the incentive to go and do it - it's cheaper than a repliacemant ECU. In all it took 2 of us 2 days to do, but a day of it was spent trying to find out why it didn’t work, so 2 people should be able to do the conversion in one day if they’ve got a good idea of what they’re doing.

We got the engine rolling road tuned and it reached a max bhp of 45, which I feel is a little low for a 1300, but we didn't take it to our usual tuners, so variances in roller callibration have to be taken into account. Another factor that might play a part in this is the fact that all the gause or whatever it is inside the CAT has been taken out, so it is now hollow which could be effecting the back preasure in the exhaust. The stuffing broke down leaving the CAT empty, but we decided to leave the empty box on, just in case Mr MOT tester said it needed to be there.

[bikemark]

Next was the fuelling problem, we hadn’t realised that the SPI used an electric pump, but this was easily overcome by using the mechanical pump form the donor mini. But the SPI also has 3 fuel pipes too (2 large braided pipes, one with orange marking and one with green and a smaller black plastic pipe). We opted for the one with the green marking on it, so connected it to the fuel pump and the pump to the carb in the usual way, leaving the other 2 pipes free.



hi, what do you do with the orange and the third (is it the one to the charcoal filter??) fuel pipes?

also is it really nessesary to change the fuel tanks over? whats wrong with the spi one?!

what do you do about the coolant sensor!?

will this fuel pump be ok to use?

http://cgi.ebay.co.u...1QQcmdZViewItem

[Pavel]

One of the pipes should be a return pipe to the tank. Basically you can keep the entire fuel system (tank and pump etc.) from an injection mini, but you will need a pressure regulator I believe.

Another thing you want to keep in mind is that you WILL destroy the cat if you run a carb on the engine. To avoid yourself the trouble, replace it with a cat link pipe (something like 20 quid from MWS?). Then sell the cat on ebay if you want.

[Sprocket]

Then try and get a carb equipped engine in an injection car through the 0.3%co emissions test.

Youll be very lucky

[miniboo]

pmsl was waiting for that Sprocket.

Nice one for doing the conversion and getting it running but really and truely you haven't really solved the problem as such just got rid of all the injection stuff.

[Guess-Works.com]

you wont necesarily destroy the cat,I believe some of the carbed coopers have cats... but what you may have problems with is the MOT and emissions depending upon the age, M is 94/95 ? Think 95 is the cut

[miniboo]

1 August 1992 is the time when a cat test is used in an MOT

[Guess-Works.com]

* I was a bit late then *

[miniboo]

I posted this in the removing CAT thread aswell.

http://www.motuk.co.uk/manual_730.htm

[Bungle]

Another thing you want to keep in mind is that you WILL destroy the cat if you run a carb on the engine

my cooper carb came with a car and the only thing that destroyed it was speed ramps

Then try and get a carb equipped engine in an injection car through the 0.3%co emissions test.

Youll be very lucky

this first post is from nearly 3 years ago

blue must be able to tell us how MOT's have gone since

[miniboo]

hah only just noticed that. blimey search must be getting used a fair bit!!!

[Sprocket]

As said in the other topic posted above, it all depends on the tester, fact is if an injection engine in an injection car with a carb and no cat it would not stand a chance of passing the emissions test. FACT!

The emissions test is designed in such a way that it shows up one or the other, both if your real unlucky.

Leaving the cat on at least it should pass that part of the emissions test, you may well get the natural idle test within limits, but it will idle pants with no idle control. detuning the engine to get it through emissions then retuning it to get the performance back is not strictly above board. Like wise niether is the tester changing the test criteria from a cat test to a non cat test because 'Its a Mini' when it wont pass the correct one in the first place. I know it happens, you know it happens, they know it happens. If you drive up to your test center with the emissions control systems as described above, and you notice a VOSSA van parked outside, turn around and go home.

Frankly im happy with my £200 high performance cat and fully operational injection system, at least i know im doing my bit for the environment, however small, and it WILL pass emissions test every time. Oh and the non cat fumes stink the place out.

Edited by Mini Sprocket, 05 December 2006 - 11:40 PM.

[bikemark]

One of the pipes should be a return pipe to the tank. Basically you can keep the entire fuel system (tank and pump etc.) from an injection mini, but you will need a pressure regulator I believe.

Another thing you want to keep in mind is that you WILL destroy the cat if you run a carb on the engine. To avoid yourself the trouble, replace it with a cat link pipe (something like 20 quid from MWS?). Then sell the cat on ebay if you want.

could you not just run a mechanical pump and disconnect the wires from electric fuel pump? pressure regulators are very expensive arn't they? and what pressure do they need to be?

Edited by bikemark, 06 December 2006 - 09:15 PM.

[fikus01]

pressure regulators are very expensive arn't they? and what pressure do they need to be?

i think a turbo regulator(this is what you'll need) costs £30 - £40 max it uses the fuel and return and the standard in tank pump!! and you can get them with a gauge that will show pressure.

http://www.minispare....aspx?pid=37056

thats the kitty!!

then there is my favourite 3 words, ROLLING ROAD SETUP

[bikemark]

how about this one? will this work?!

http://cgi.ebay.co.u...1QQcmdZViewItem