5 replies to this topic

[tallperson]

Hi. New to the forum and had a quick look round but couldn't find this discusses anywhere.
I was just wondering what rpm your mini sits at when idling?
I bought my first mini yesterday and it seems to bit slightly higher than id expect (About 1150 rpm) which I guess isn't too high but just wondering how it compares to others?

Is a 1994 1275 mini Mayfair.

[sledgehammer]

Hi

 

1150 is high for normal idle -

 

Does the car have a carb ? or is it fuel injection (MPI - SPI)

 

if it has a carb - the idle should be easy to lower with the idle adjustment screw (but first check for leaks)

 

also check the choke mech is fully working & not sticking - throttle cable is returning to the stop & return spring is good

 

http://sucarb.co.uk/...r-tuning-single

 

http://sucarb.co.uk/...r-tuning-single

 

 

another possibility is an air leak - so check pipes & gaskets are good

 

If it is SPI / MPI it's more complicated - & there are others on here better qualified on the injection models than me

 

but if SPI / MPI - it could still be manifold / pipe leaks -

 

the elbows / connectors on the small manifold pipes can crack giving all sorts of problems

 

welcome to the forum

Edited by sledgehammer, 29 August 2014 - 10:56 PM.

[minisilverbullet]

Hi. New to the forum and had a quick look round but couldn't find this discusses anywhere.
I was just wondering what rpm your mini sits at when idling?
I bought my first mini yesterday and it seems to bit slightly higher than id expect (About 1150 rpm) which I guess isn't too high but just wondering how it compares to others?
Is a 1994 1275 mini Mayfair.

I would check that the throttle cable is adjusted correctly. You could try and google the procedure or buy a haynes ( you will need it again anyway).

Next up I would check all if the vacuum lines.

Do not be tempted to adjust the so called "idle screw" this needs the correct diagnostic equipment.

[Guess-Works.com]

I would be wary of raised idles on a recently purchased car, in fact I would have checked it before buying....

 

Raised idles are caused by one of two things, incorrect adjustment or an air leak... the former is usually done to disguise something else, which could be rough running at idle, caused by either poor compression or a high lift long duration cam, the latter of these I'm sure you would have been made aware of. It could also be done to disguise low oil pressure and a flicking oil light...

 

Lets hope it's just an inept previous owner or an air leak.

 

A standard 1275 should idle comfortably at 800 rpm. 

[tallperson]

Thanks for getting back to me do quickly.

My car is SPI so looks like a more complicated fix?

I bought it off a friend who has looked after it pretty well so I know he's not concealing anything deliberately.

So you'd suggest the first things to check are the throttle cable (presumably to check it's not too tight and therefore keeping revs high), and also to check for air leaks. What pipes do I need to check for air leaks?

One other point of interest is looking back through the MOT logs it sends that it has been over 1000 rpm when idling most years since '97!

[minisilverbullet]

Regarding the throttle cable. If you follow the cable towards the throttle body, you will see the "lost motion linkage". This is basically 3 prongs the middle prong should sit right in the middle of the outer two.

Regarding the vacuum pipes the car shoul have 4: a long black one running from the ecu to the fuel trap ( which is a small matchbox sieve box). From the fuel trap you will have a shorter line which connects 2 the back of the throttle body. To check these you really need to take them of. This is easy as they are just push fitted on. The other two lines ( assuming you have the original air box) are red and yellow.