3 replies to this topic

[elgarra]

I'm in the process of sorting out my 1275 spi. The tickover is high and moves between 1500 and 2000rpm...(Seems to be a common problem.)

The previous owner had problems with the battery going flat, part of which i believe to be due to it running the wrong alternator (45 amp rather than 70(?)...............But i'm suspicious of the fact that he also replaced the stereo around the time the battery started giving him trouble.


Am i right in thinking that the high tickover may be partly due to the ECU upping the tickover to try and suck some juice from the crappy alternator?.................and that i'll also need to index the stepper motor when i re-connect the freshly charged battery?

by the way, I've replaced the alternator with a lovely fresh 70 amp jobby from Mini spares.


Thanks in advance.




(If i could edit this thread title so it doesn't say steeper motor, i would, but i can't.)

Edited by elgarra, 23 September 2009 - 02:05 PM.

[elgarra]

I have been reading the replies to similar queries and will certainly be trying those too.

[xrocketengineer]

Hi,
High idle speed is usually caused by a vacuum leak. The first to check are the lines from ECU (MAP sensor) to the fuel trap and from their to the back of the intake manifold. Also the line from the Thermac valve on the air cleaner intake to the back of the manifold next to the other connection. They need to be in next to perfect condition.
If the battery discharge happens over several days, it could be caused by a bad ECU. The first symptom of this battery draining is a the warm relay module after sitting overnight. It is a smart failure, meaning that it is not there all the time. It shows up the first time you start the car and will not go away until, the battery is disconnected, battery dies or one of the connectors on the the relay module is disconnected.
What remains active after the engine is turned off is the main relay. The relay coil gets 12V from the battery through pin 6 of the larger connector on the relay module (hot all the time, brown wire). The ground for the coil is provided by pin 3 (white and purple wire and and same as pin 4 on the ECU) of the smaller connector when the engine starts activating the relay. However, when the engine is turned off, the ECU continues to provide a ground path through the above mentioned pins causing the the main relay to stay active. If either connector on the relay module is disconnected and reconnected, the failure resets and goes away. But it will come back with the next engine start.
So it looks like pin 4 on the ECU is acting up (single connector ECU). I measured the voltages on the connectors by inserting a pin/needle in between the wire(s) insulation and the external weather seals on the back of the connector. The pin was pushed in until it made contact with the pin inside.

I hope this helps,

Ivan

[elgarra]

Excellent reply.

I've printed it for my manual.