7 replies to this topic

[ksymo]

I’m hoping someone can help me on this!

I have a 1993 Mini Cooper 1.3i (1275 cc). When run from cold for around half an hour, it regularly (but not always) displays a fault where it revs itself. The revs can go up to the 5000 mark on occasion, with my foot being nowhere near the accelerator pedal. When it is having one of its revving episodes, dipping the clutch can cause it to rev even faster. When I get it back home on the drive, it can rev between 900 and 1500 idling in neutral, swinging between the two. When it’s been revving madly, switching off and on again will sometimes partially correct the fault – taking the revs down to around 1500 idling.

I’ve taken it to a garage who couldn’t put their finger on the problem but suggested the following:

1) A wiring fault
2) A problem with the ECU

I’ve also spoken to a Mini dealer who suggests the problem may lie in the rubber tube connecting the ECU with the engine – which may be cracked/split.

If anyone’s had similar problems and fixed them I’d really appreciate any pointers. I love my Mini (as does my girlfriend – who won’t drive it in its current state!), and although I am a bit of a novice (it’s my first Mini) I’m not afraid of getting stuck in to fix it.

Please let me know if you have any advice.

Thanks.

[Sacaasi]

I’ve taken it to a garage who couldn’t put their finger on the problem but suggested the following:

1) A wiring fault
2) A problem with the ECU

lol i bet this helped loads.

what about a rolling road diagnostic run?

sorry i dont really know much about ECU engines so cant help alot - i just found the garage bit quite funny and typical of a garage who cant be arsed fixing your car.

[haz]

i dunno how much help this is either seeing as i know nothing about the SPI or MPI systems on a mini

but i had a civic a while ago with the same problem, it was an ECU controlled carburettor, and it was an ECU fault but i 'fixed' by by playing with the choke on the carb... this gave me another problem when the car wasnt reving madly being that there wasnt enough choke to start the thing!! a bit of right foot in the morning when this happened did the trick, i dunno if you can do the same with a mini or not

[Its A Real Mini Adventure]

I would sugest a split or collaped rubber hose around the manifold area, or the start of a engine tempriture sensor going down?
Id start with a collaped rubber hose thou ... youl have to forgive me, ime not familar with spi injection system setups..

[DaveRob]

This is HIGHLY unlikly to be an ECU fault IMHO. if you look under the Air filter to the right as you look into the engine bay you will see the throttle cable link to the actuating arm.... further on in the linkage is whats called the lost motion gap. when its reving up and down does any of this linkage move ?..... if most of this is stationary then this sounds like its a leak in one of the tubes off the manifold. If any of its moving enough to cause 5000 revs to come up id suspect a mouse under the dashboad pulling your cable mate. If you do a search in the injection specific section then you will find all sorts of posts where this is explained in detail, (except about the mouse stuff). These fine tubes can easilly become loose or kinked or leak.... check every one from end to end including the elbows... if in doubt repair or replace.... no leaks whatsoever. take the air filter off completly and investigate for leaks around the throttle body and along the pipes. Make sure that the red pipe going to the bottom of the ecu is clear of fuel or liquid..... blow dont suck.... and make sure that the small box it connects to mid way between the throttle body and the ECU is clear of fuel or liquid also. Their are many here more experienced than me who will comment on the switch on the accelerator because given the year of yours I think mine will work differently. A wiring fault I also would guess isnt probable.... unless the accelerator switch is something to do with it. Hope this helps while your waiting for a guru to come along...... expect this to be moved to Injection specific.... as if by majic.... or as if by Dan

Edited by DaveRob, 10 February 2008 - 06:16 PM.

[ksymo]

Thanks to everyone for their comments so far. I'm happy for any other comments made while I'm working my way through the suggestions so far.

Thanks again.

K

[Dynamodoug]

I had the exact same problem, to the point that it scared children when i stopped at pedestrian crossings... I dont know exactly why pushing the clutch down makes the engine rev higher (although mine did too) but i replaced the accelerator cable and the problem stopped. I used to get this a lot in the summer when its hot.

[slicksimon]

i would change the coolant temp sensor.
i had a vw in my garage a while back an i did so much fault finding on it but cudnt put my finger on what it was.
all the clues i had got eg.... revs up on its own from cold ect led to the temp sensor which when i changed it it fixed the problem.
jus a thought