Mini flat spot

[Bearded-lada-man]

Hello, this is a minor technical query on behalf of an associate of mine. The car in question is a Rover Mini Cooper (Mini 40 ltd edition) and it develops a nasty flat spot around 25-30 mph in third gear, not sure of revs as I haven't been out in it yet. Has anyone had this phenomenon? If so what is the remedy, the garage want it for 2 days which seems a bit excessive and quite frankly you could strip it to components and rebuild it in that time. They seem to think it is a common fault.

Thank you in advance for any thoughts,

Phil

[Fatboy]

Don't know how to help, but my mini has a flat spot at about 2500-3000 rpm (MG Metro engine) so I'd be intrigued to see what they need 2 days to do to fix it - I'd always asumed an hour or so on a rolling road to get it set up right would do the job?

[ccharlie6]

well as it's a late mini its going to be an injection engine and i'm guessing because of the age its going to be a multipoint system. so flatspots normally i would think fuelling around that point if all basics have been covered (ignition system etc) the easiest thing to do is to take it to a rolling road (that specialises in minis preferably and so what they say)

[Matt_T16]

ccharlie6 said:

well as it's a late mini its going to be an injection engine and i'm guessing because of the age its going to be a multipoint system.

Not on an A-Series chap. Pair of injectors for the 4 cyls with some clever timing trickery in the ECU to get em firing at the right point.

Matt

[Bearded-lada-man]

I thought the early 1.3i's were SPI and the later ones (like this) were MPI? Have previously looked into cooper racing where only SPI's were allowed.....

[Pigeon]

The A-series has siamesed inlet ports, so it'd be a bit tricky to fit more than 2 injectors.

[Fatboy]

Bearded-lada-man said:

I thought the early 1.3i's were SPI and the later ones (like this) were MPI? Have previously looked into cooper racing where only SPI's were allowed.....

As pigeon says, A series has siamesed inlet ports (cylinders 1&2 and 3&4 share an inlet port) therefore you can't fit an injector per cylinder without going to direct injection into the cylinders themselves

The later cars are more correctly referred to as Twin Point Injection (TPi) rather then the less accurate MPi.

[Bearded-lada-man]

OK, OK, so how do I fix it already?

[annodomini2]

Check the ecu for faults?

May be a sensor out? could be increased impedance on a sensor? (wiring fault, sensor fault)

Checked, cleaned the plugs?? changed them, leads

The Twin point minis have full electronic ignition so it can't be dizzy cap.

[Mr2Mike]

Fatboy said:

The later cars are more correctly referred to as Twin Point Injection (TPi) rather then the less accurate MPi.

I think "multi" covers any number greater than one quite well!

Check the pipe that runs from the manifold to the MAP sensor, they can get a signficant amount of oil built up in them that causes hesitation.

[Bearded-lada-man]

Many thanks folks, will investigate further.

[Fatboy]

Mr2Mike said:

Fatboy said: The later cars are more correctly referred to as Twin Point Injection (TPi) rather then the less accurate MPi. I think "multi" covers any number greater than one quite well!

Technically yes it does But I tend to think of multi point being 1 injector per cylinder, hence my distinction between the two in this case