6 replies to this topic

[200dl]

I have a weird problem with my fan. It starts running before the engine have even gotten hot. Once it have started running it wont stop. This problem have increased gradually and now it's always there.
However it appears to be temperature related because if I stop the engine after driving for 30 min. or so, leave it for a minute and then start again the fan acts normal.

Somehow the temp. meter seems to have the same decease. If I start the engine it takes normal time for the meter to go up to the "normal temp line". If I then after 5 min (the fan is running all the time so the engine should be cold if I'm not totally wrong) stop/start the engine the meter goes down to the bottom line but still the fan is running.
Now I now stop/start again after a minute the meter goes up to normal temp and still the fan is running.
The automatic choke however seems to work independently. When I suspect that the engine is cold I normally get it confirmed by the idle at 1200 rpm. If I run it on higher revs for a while to get the temp up the idle goes down to 800 rpm just like it should.

I changed the temp sensor a while back and it didn't really help. I doubt that it is the relay since that would probably cause the fan to not start at all if it was busted.

I'm clueless now. Does anyone have any experience of something like this? Any good ideas?

Thanks!
/Dave

Edited by 200dl, 18 August 2009 - 04:04 PM.

[andatche]

Is this an MPI or an SPI? If it's an SPI then the aux electric fan is controlled by a seperate temp sensor that mounts in the bottom front of the radiator and not the coolant temp sensor. I had exactly the same problem with my SPI (electric fan kicking in all the time), replacing this sensor solved the problem. IIRC the electric fan in the MPI is controlled by the ECU based on the CTS reading.

[200dl]

Is this an MPI or an SPI? If it's an SPI then the aux electric fan is controlled by a seperate temp sensor that mounts in the bottom front of the radiator and not the coolant temp sensor. I had exactly the same problem with my SPI (electric fan kicking in all the time), replacing this sensor solved the problem. IIRC the electric fan in the MPI is controlled by the ECU based on the CTS reading.

I suppose it is an MPI. It is a -99 Sports pack.
So if I get you right it can only be the sensor, ECU or the connection between those two?

[mykweb]

this is a very common mpi issue, My car suffers from it.... nearly all the bloody time.

Its usually down to the wire that connects to the temp sensor. If you pop the bonnet and have a look its on the Thermostat Housing just behind the alternator. Brown plug - takes a 19mm socket or spanner.

Uusally what happens is that wire gets put in place and when you drive or rev the mini the engine rocks. Over time this causes the wire to strech. And in turn causes issues. Also check the connection itself, over time people removing the plugs incorrectly they get damaged and broken, and when the engine runs it can cause a intermittent connection.

I have extended my wire when I rebuilt my loom to avoid this issue.

However another common problem is the temp sensor failing. They cost about £15 from a local motor factor, and its the same sensor that is on a Land Rover and the MG TF, and a metro I think.

If I remember correctly a good way to check the temp sensor to see if the wire is ok or the ECU is working, is start the car from cold. As soon as you start it go around to the front and pull the connector off. By default the ECU will kick the fan in. If this does not happen I would say its wiring related. If the fan does not kick in, its the temp sensor

[200dl]

this is a very common mpi issue, My car suffers from it.... nearly all the bloody time.

Its usually down to the wire that connects to the temp sensor. If you pop the bonnet and have a look its on the Thermostat Housing just behind the alternator. Brown plug - takes a 19mm socket or spanner.

Uusally what happens is that wire gets put in place and when you drive or rev the mini the engine rocks. Over time this causes the wire to strech. And in turn causes issues. Also check the connection itself, over time people removing the plugs incorrectly they get damaged and broken, and when the engine runs it can cause a intermittent connection.

I have extended my wire when I rebuilt my loom to avoid this issue.

However another common problem is the temp sensor failing. They cost about £15 from a local motor factor, and its the same sensor that is on a Land Rover and the MG TF, and a metro I think.

If I remember correctly a good way to check the temp sensor to see if the wire is ok or the ECU is working, is start the car from cold. As soon as you start it go around to the front and pull the connector off. By default the ECU will kick the fan in. If this does not happen I would say its wiring related. If the fan does not kick in, its the temp sensor

Problem solved! Thanks!

It seems like it was a connection failure. The wire was good in place on the temp sensor but I simply took it off and soaked the connector in electronic cleaner, left it for a while and rinsed a bit with compressed air. When I put the parts back together it worked perfectly.

What I still don't understand is how the temp meter can go up when the engine is obviously cold. But I suppose that is more of an academic question as long as everything work.

[chrisking2021]

Problem solved! Thanks!

It seems like it was a connection failure. The wire was good in place on the temp sensor but I simply took it off and soaked the connector in electronic cleaner, left it for a while and rinsed a bit with compressed air. When I put the parts back together it worked perfectly.

What I still don't understand is how the temp meter can go up when the engine is obviously cold. But I suppose that is more of an academic question as long as everything work.
[/quote]

Just for info the ecu tells the fan and guage what to do. if the sensor fails the ecu goes into "safe mode" putting the fan on and showing a normal reading on the guage

chris

[greg.harvey]

Related question - if the temp sensor is failing, will the temp gauge still function? My temp gauge seems fine, but the fan comes on very easily. Should I buy a new sensor?