8 replies to this topic

[minimowta]

Hi everyone,

I've been struggling with my 2000 1.3 MPi for a while now. It used to have a missfire and the fan runs when engine is cold/normal.

The missfire is pretty much fixed now, my garage have done a lot of tweeking and changed the air and water temp sensors. They say the momentery missfire when I put my foot down is due to a sooted up head which is momenterily soaking up the fuel on injection. I can check this when I fix an oil leak from the back of the gasket.

The fan issue still remains. I've had a new water sensor fitted and that hasn't fixed it. The fan stays off for a few days and then comes on unexpectedly while driving (engine is not overheating) and stays on until I switch the engine off. When I switch on again sometimes it stays off, sometimes it comes on again.

I can make the fan come on by pulling the plug off the sensor and putting it back on while the engine is running. The fan keeps running but the engine note changes - I think this is some sort of "limp home" mode. When I switch off and on again the fan stays off. When I pull the plug off the temp gauge stays at normal until I switch off and on again then it stays low until I plug the sensor back in, then it goes up to normal again.

It seems that a momentery break in the circuit is all that is required so I thought it might be a loose connection. I have tried tapping the wiring loom and connectors to try and simulate a bumpy road or the constant vibration the engine undergoes but cannot make the fan come on! The wiring seems OK! Sometimes the fan comes on normally as the temp increases (as a result of the stationary running with muggins under the bonnet) and goes off as normal as temp drops so the sensor and fan seem to be doing their jobs properly when required.

I am really at a loss as to what to try next and wondered if anyone had had a similar problem and can give me an idea of what to try next.

Thanks in anticipation!

Mike

[L400RAS]

Please see the attached pdf document from Rover.

This. is the part from minispares as mentioned

HTH
Ryan

Edited by L400RAS, 30 October 2009 - 05:33 PM.

[minimowta]

Please see the attached pdf document from Rover.

This. is the part from minispares as mentioned

HTH
Ryan

Thanks for the reply Ryan.
That plug looks very similar to the one I have, same colour and the terminals look very similar - like the business end of a clothes peg I did suspect this connection and slightly bent the spades on the temp sensor once to make sure that there was a connection. Might have fixed it for a bit but the fan eventually started again, I'll try twisting them slightly tommorrow to see if that helps. It's interesting to see that this is a recognised problem. by the way the minispares price for a plug seems a bit high!

Cheers, Mike

[minimowta]

Following Ryan's pointer I had another look at the plug yesterday and mine is actually slightly different to the one in the photo he posted. The moulded in manufacture date is "96" so I'm sure it is a pre-mod version. I pushed a scalple blade inbetween the connector on the plug and the spring tension of the connector is very light which makes me think that the engine vibration could bounce the connector apart and make an open circuit thus starting the fan.

To test this I made some small plastic springs and pushed these behind both sides of the plug connectors and was pleased to feel a reassuring resistance when I pushed the plug back on. The plastic springs appear to have tightened the grip on the spades on the sensor. I'll see how it goes and report back.

Cheers

[L400RAS]

Hi Mike,

a good idea with the springs, however i believe many people say its the actual wires that fracture, at hte point they exit the plastic plug. This is because the loom was too short originally, and if the engine stabilisers allow the engine to move, the wires stretch and break internally; its not just a problem with the connector. With the new connector, you are meant to leave a good few inces of spare wire.

On one of my MPis that had a fan problem, what i did was to re-route the loom from underneath the coolant tank to along the top of it, thus "lengthening" the wire, and it stopped the wiring being pulled when the engine rocked slightly (i also did the stabiliser bushes after this). THhis fixed the same problem you are having.

Ryan.

[minimowta]

Hi Ryan,

Thanks for your help on this, mate. The lead to the plug is quite long on my mini. I knew about the workhardened of wires to the MAP sensor so gave the lead to my water sensor a good wiggle in the early days, and since, to try and make the fan come on but it hasn't done yet. I have looked at the wires as well and there is no sign of any stress. I'm going to try my botch for a while to see if it works, if not I'll shell out for a new plug and lead as you suggest. Must say it will grate a bit paying 30 odd quid for it...... heres hoping the plastic springs made from a milk container will work! Who ever said good British improvised engineering was dead!
I'll let you know.

Cheers, Mike

[L400RAS]

Hi Mike,
if your plug is still at fault, you could try this. you will also need the correct "F type" crimping tool. The plug is also common on fords and vauxhalls (thanks to Ethel for that info), so you could search a scrappy, remember to leave a few inches of wire to splice into your loom with.

these could make a cheaper option,

HTH
Ryan.

[davecrook1]

so what is the actual improvement in this harness?? could you not just put some spade connectors on the end and try it?? cause im having the same probs.. where the fan comes in when semi warm and runs then constantly..

[davecrook1]

does anyone if that solves the problem??