Jump to content


Photo

Mpi Cooling Fan Not Working - Really Stuck And Need Some Desperate Help!


  • Please log in to reply
53 replies to this topic

#16 M700FGT

M700FGT

    Mini Mad

  • Noobies
  • PipPipPipPip
  • 135 posts
  • Location: Kent
  • Local Club: LSMOC

Posted 16 June 2018 - 08:34 PM

Thanks Carlos,

 

Nope, not the relay, I switched them all around. I also tested it with a 9v battery and it clicks to open perfectly. 

 

This is driving me crazy!!

 

I do have local garages, but really want to do this one myself



#17 M700FGT

M700FGT

    Mini Mad

  • Noobies
  • PipPipPipPip
  • 135 posts
  • Location: Kent
  • Local Club: LSMOC

Posted 16 June 2018 - 08:57 PM

 

 

Have you tested the fan by connecting the wires together on the temp sensor. I have an spi which has the sensor in the bottom of the rad at the front, not sure where it is on the mpi.

If the fan runs with wires shorted then it is the sensor faulty or an air lock in the system.

 
That was number 5 - bridge with a split pin. It didn't work.

Haynes manual section 12.43 diagram 25 shows the wiring diagram for all injection models. There are two fuses to check numbered 93 and 94. 93 supplies 12v to the coil ofthe relay. The other side of the coil goes to the temperature switch then to earth. 94 supplies the relay switch contact. When the relay is energised by the temperature switch closing the contacts on the relay close and provide a supply to the fan motor.

 

Hi Milton,

 

I can now see thats in my Haynes, but I can't work out which fuses are 93 and 94. The fuse box on the mpi only holds 24 fuses. 

 

I cant see any other reference on the Hayes manual to their location. 



#18 M700FGT

M700FGT

    Mini Mad

  • Noobies
  • PipPipPipPip
  • 135 posts
  • Location: Kent
  • Local Club: LSMOC

Posted 16 June 2018 - 09:23 PM

Just read the engine management wiring diagram - actually understood it!

 

The two fuses are B9 15a which is in the fuse box under the steering wheel, and slot 1 30a fuse which is in the engine compartment fuser box. checked both boxes and they seem fine.

 

So not s fuse, relay, fan or rad. There is voltage in the loom that connects to the temperature sensor in the thermostat housing. Thats really the only thing left replace (I think) 



#19 Wiggy

Wiggy

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 1,036 posts
  • Location: Hampshire

Posted 17 June 2018 - 08:37 AM

The only thing you don't seem to have checked is the actual power feed to the fan itself.

If the loom to temp sensor was damaged, the fan would run constantly. Wiring to the sensor is not directly connected to power to the fan.

First, check the fan connector doesn't have rusty pins.

You need a multimeter. I would disconnect the temp sensor, then probe the Black/Green wire going to the fan. One probe on that, one probe on a good earth. NOT the other wire in the fan connector. If you see 12V, then it sounds like an earth issue.

If you don't see 12V, we'll go backwards to the relay and check the wires there.

#20 Bat

Bat

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 903 posts
  • Location: Bermingum

Posted 17 June 2018 - 10:25 AM

Hi,

Thing to keep in mind with the mpi is the fan is controlled by the injection ecu.

It uses the one and only temp sensor on the engine measures the temperature and switches on the relay which the powers the fan.

Much the same as the temperature gauge is connected to the ECU and not the temperature sensor.

Cheers  :proud:



#21 M700FGT

M700FGT

    Mini Mad

  • Noobies
  • PipPipPipPip
  • 135 posts
  • Location: Kent
  • Local Club: LSMOC

Posted 19 June 2018 - 08:31 PM

Hi all,

 

So im still battling on!

 

My new temp sensor arrived today, so I've just fitted it. As good measure I also replaced the thermostat as it was only £5. The original sensor did look messy, but the thermostat looked ok. The previous owner did say Croydon Mini's had relaxed it, but if they did they didn't remove all of the previous gasket, which was a bit of a mess. Go I gave it a good clean up and replaced the gaskets. 

 

This has made no difference at all.

 

The reason I haven't done much with the power side is purely as im not very good in that area and this is the first time I have done anything like this before.

 

I do however have a meter, not that I ever normally use it. I checked the connector to the fan - no rust or visual damage, and no voltage. 

 

The next thing along is the big green fuses. Didn't try for  a reading here, but visually there are no breakages in the fuses. 

 

Followed the loom back to the relay which I have already swapped over and tested with a 9v battery. I removed the relay and checked the connector. Green/black wires have no voltage, but one of the purple wires was up to 17v with the engine running. 

 

As I mentioned before, im new to all of this, so not really sure where to go from here.



#22 Wiggy

Wiggy

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 1,036 posts
  • Location: Hampshire

Posted 19 June 2018 - 10:56 PM

What were you using as an earth for the multimeter? You must use something other than the pins on the relay/connector.

17V is odd. Check across the battery with the engine running and see what voltage you get.

Both the purple wires at the relay should be receiving 12V. The light green/black wire should be receiving 0V ish if the ECU is trying to turn the fan on. The Black/Green wire should be transmitting 12V to the fan connector.

If all of that checks out, then test for continuity between the Black/Green wire at the relay and fan connector.

Edited by Wiggy, 19 June 2018 - 11:10 PM.


#23 Wiggy

Wiggy

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 1,036 posts
  • Location: Hampshire

Posted 19 June 2018 - 11:12 PM

Oh, all of these tests would be done with the temp sensor disconnected.

#24 Bat

Bat

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 903 posts
  • Location: Bermingum

Posted 20 June 2018 - 10:29 AM

Hi,

Right let's break this down to power system and control system.

First remove the fan relay and bridge the pins in the socket, with a piece of wire between the purple and the black/green, these will be opposite each other.

If the power system is ok the fan will run.

Let us know how you get on...

Cheers  :proud:



#25 M700FGT

M700FGT

    Mini Mad

  • Noobies
  • PipPipPipPip
  • 135 posts
  • Location: Kent
  • Local Club: LSMOC

Posted 20 June 2018 - 07:00 PM



Attached File  IMG_1871.jpg   43.23K   2 downloadsAttached File  IMG_1872.jpg   39.98K   3 downloadsAttached File  IMG_1875.jpg   38.65K   2 downloadsAttached File  IMG_1876.jpg   47.55K   0 downloadsAttached File  IMG_1877.jpg   38.86K   0 downloadsHi all,

 

So im still battling on!

 

My new temp sensor arrived today, so I've just fitted it. As good measure I also replaced the thermostat as it was only £5. The original sensor did look messy, but the thermostat looked ok. The previous owner did say Croydon Mini's had relaxed it, but if they did they didn't remove all of the previous gasket, which was a bit of a mess. Go I gave it a good clean up and replaced the gaskets. 

 

This has made no difference at all.

 

The reason I haven't done much with the power side is purely as im not very good in that area and this is the first time I have done anything like this before.

 

I do however have a meter, not that I ever normally use it. I checked the connector to the fan - no rust or visual damage, and no voltage. 

 

The next thing along is the big green fuses. Didn't try for  a reading here, but visually there are no breakages in the fuses. 

 

Followed the loom back to the relay which I have already swapped over and tested with a 9v battery. I removed the relay and checked the connector. Green/black wires have no voltage, but one of the purple wires was up to 17v with the engine running. 

 

As I mentioned before, im new to all of this, so not really sure where to go from here.

Thanks guys, this is getting interesting now!

 

So I removed the relay and bridged as you said. Got a meter of 17.46 with the engine running. Tried with and without sensor installed - no change.

 

Stuck the meter in the 30a fuse that is also used for the fan (According to the Haynes manual) and I got 17.69 with the engine running. 

 

As I had to cut the connector of the new fan (Mini spares spacial supplied with wrong plug), I cut the connector on the other side just encase there was an issue with the connector. Still nothing.

 

So power is getting as far as the 30a fuse, but the wires to the fan are dead!


Edited by M700FGT, 20 June 2018 - 07:04 PM.


#26 Wiggy

Wiggy

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 1,036 posts
  • Location: Hampshire

Posted 20 June 2018 - 09:43 PM

We're trying to help you systematicialy, but you're ploughing on rather haphazardly. I'm sorry, but take a step back for a second.

Ignore the fuses. They're before the relay.

By the look of it, you've bridged the wrong pins on the relay.

Bridge a Purple wire (preferably pin 30; is may say on the relay) to pin 87 Black/Green wire. Your currently bridging to light green/black.

This should then feed power to the fan connector. Check the continuity between these two points. If its open circuit, there's the problem.


Also you should not have 17V. It's too high. Like I said, check across the battery with the engine running. If you get 17V there (you probably will), you have an alternator problem, and you'll blow something if you keep running it.

#27 M700FGT

M700FGT

    Mini Mad

  • Noobies
  • PipPipPipPip
  • 135 posts
  • Location: Kent
  • Local Club: LSMOC

Posted 20 June 2018 - 10:53 PM

We're trying to help you systematicialy, but you're ploughing on rather haphazardly. I'm sorry, but take a step back for a second.

Ignore the fuses. They're before the relay.

By the look of it, you've bridged the wrong pins on the relay.

Bridge a Purple wire (preferably pin 30; is may say on the relay) to pin 87 Black/Green wire. Your currently bridging to light green/black.

This should then feed power to the fan connector. Check the continuity between these two points. If its open circuit, there's the problem.


Also you should not have 17V. It's too high. Like I said, check across the battery with the engine running. If you get 17V there (you probably will), you have an alternator problem, and you'll blow something if you keep running it.


Ok so I clearly didn’t connect to the pins I thought, as with the engine off I connected 30 and 87 which got the fan going!!

At this point the temperature sensor is plugged in. I connected the meter into those two pins, which started at around 13.3v and then crept up to 15.7v.

I do genuinely appreciate the help and I am trying to follow instructions and advice as best I can while still being a novice. But hey, we all have to start somewhere.

#28 M700FGT

M700FGT

    Mini Mad

  • Noobies
  • PipPipPipPip
  • 135 posts
  • Location: Kent
  • Local Club: LSMOC

Posted 20 June 2018 - 10:59 PM

I forgot to mention, the battery metered was giving out 15.45v.

Not sure if it had any bearing, but it was charged at the weekend by a plug in trickle charger.

#29 Bat

Bat

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 903 posts
  • Location: Bermingum

Posted 20 June 2018 - 11:05 PM

Hi,

Right so you had the fan running that's one part out of the way.

Next get a marker pen and write the letter F on the fan relay and pull it out and put it to one side.

Next get another yellow relay from somewhere else under the bonnet. If you can find the horn relay put the fan relay in there and press the horn to test the fan relay. If not just stick the relay in the fan socket and see if the fan runs when the engine gets hot.

Again let us know how you get on...

By the way I'm assuming your temp gauge works ok?

Cheers  :proud:

PS I think your multimeter is wildly inaccurate, try a new battery in it, failing that a new meter!  O_O


Edited by Bat, 20 June 2018 - 11:07 PM.


#30 Wiggy

Wiggy

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 1,036 posts
  • Location: Hampshire

Posted 21 June 2018 - 09:52 AM


I do genuinely appreciate the help and I am trying to follow instructions and advice as best I can while still being a novice. But hey, we all have to start somewhere.


I know you do, mate. I just don't want you to break something, or have to shell out for new parts that are unnecessary. ??

I'm no expert, I've just learnt to read wiring diagrams. If you have a Haynes, take a look at Diagram 4 on Page 12B. You'll be surprised at how simple the fan circuit is. If you need any explanation, I'm happy to.

Give the contacts in the relay socket a good clean too. I'm glad we're getting there!

I hope Bat is right with the dodgy multimeter. Something is a bit screwy.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users