|
||
|
21st November 2019, 05:18 | #61 |
Posted a thing or two
Rover 75 2001 Club Sedan V6 2.5 Join Date: Mar 2007
Location: Sydney
Posts: 1,458
Thanks: 18
Thanked 9 Times in 6 Posts
|
Took for a run today, seems ok, just want to say a thanks to Arctic and Simon for their help.
|
21st November 2019, 07:46 | #62 | |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,374
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
Quote:
Your case was a strange one and I still don't understand it but I'm glad that your repair worked! Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
|
21st November 2019, 09:42 | #63 | |
Give to Learn
Freelander 2 Join Date: Aug 2010
Location: West Midlands
Posts: 18,714
Thanks: 1,155
Thanked 6,407 Times in 3,874 Posts
|
Quote:
Great to hear you got it running as it should be, do a few runs with the OBC set at 19 then 7 noting the temperature on the screen, park up and let the car tick over while watching the temp when it reaches 100 -101 see if the fan kicks in on slow speed to bring down the temp to about 95-96 It may well have been one of the relays you changed, let us know if you try the above.
__________________
Arctic Givology Learn to Give Everything is Achievable ad altiora tendo. Check out our Nano meet dates http://www.midlandsnanomeets.co.uk/ http://www.the75andztclub.co.uk/index.php?thepage=howto " You do the work , we supply the expertise " |
|
21st November 2019, 10:25 | #64 | ||||
This is my second home
Rover75 and Mreg Corsa. Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,753
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
|
I'd suggest the first clue to the connumdrum is in the Demist Test when this question was asked (post 41):
Quote:
Quote:
Quote:
Quote:
What happened here is the trinary tripped on the emergency aircon over-pressure fan speed (speed 2) because the refrigerant had already gotten too hot from the earlier test. This overheating/over-pressure was probably exacerbated by the very high ambient temperatures currently plaguing Australia and a failing/failed condenser matrix. So I'd suggest Joe also checks the condition of the aircon condenser, which if poor will need replacing. It would be informative if Joe would report on his aircon performance now that speed 1 operates correctly. From what's reported in the news, he'll certainly need it. TC Last edited by T-Cut; 21st November 2019 at 10:27.. |
||||
21st November 2019, 12:16 | #65 | |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,374
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
Quote:
In another thread MarinaBrian said that ECM coding can be changed to suit a 2 speed fan, the implication being that the 105 degrees switching is then applied to the fast speed relay. When I asked whether he had proved this by practical means, no reply was forthcoming. I therefore conclude that he hasn't. There is an MGR technical bulletin which warns dealers that T4 can indicate a fault with a 2 speed fan system and that fault is that medium speed has failed. That implies that the switching points are the same whether a 2 or 3 speed fan is fitted so we're back to why Joe's fan started running at 105 degrees. We really need to wait for a KV6 owner with a mildly overheating engine and a 2 speed fan with the instrument pack diagnostics activated to tell us at what displayed temperature the fast speed cuts in. Up until now, I'm sure that we've had many reports of the temperature gauge shooting to maximum which we've diagnosed as a failed slow speed resistor. If the fast speed had cut in at 105 and cut out again below that temperature (as Joe reported) then the result would surely be a cycling fan at high speed, not an overheating indication. The question is far from resolved. Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. Last edited by SD1too; 21st November 2019 at 12:19.. |
|
21st November 2019, 13:08 | #66 |
This is my second home
Rover75 and Mreg Corsa. Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,753
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
|
As I see it, the 2-speed system switches to Speed 1 for the duties provided by 'low' and 'medium' speeds of the earlier system. Speed 1 appears to be faster than the earlier fan's 'low' speed and provides sufficient airflow for 'medium' speed duty. It could be argued that a 2-speed system 'overkills' the 'Low' speed fan duty. I recall that Arctic uploaded a video demonstrating T4 tests of a resistor controlled 2-speed. He trips Speed 1 when the T4 'Low' speed test is applied, then Speed 2 using the 'High' speed test. Unfortunately, he doesn't show T4 and the 'Medium' speed test on this fan. This will answer the question and I guess Arctic will know.
EDIT: I see Arctic's T4 tests were on an isolated fan not installed with an ECU, so perhaps the T4 would be invalid for the medium speed test? TC Last edited by T-Cut; 21st November 2019 at 13:16.. |
21st November 2019, 15:51 | #67 | |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,374
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
Quote:
So your logic, fine as it is, unfortunately doesn't explain what Joe reported. Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
|
21st November 2019, 19:15 | #68 |
This is my second home
Rover75 and Mreg Corsa. Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,753
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
|
Quite so, so it seems current understanding isn't right. However, if the 'low' speed duty is covered by Speed 1 and the old 'medium' and 'high' duties are covered by Speed 2, then I think it all fits. This proposal would also explain why several observers over the years have reported 'no difference' between the medium and high speed T4 tests on a later 2-speed system. Clearly one or the other and simply by replacing the resistor, Joe got things back to normal.
TC |
21st November 2019, 19:24 | #69 | |
Posted a thing or two
Rover 75 2001 Club Sedan V6 2.5 Join Date: Mar 2007
Location: Sydney
Posts: 1,458
Thanks: 18
Thanked 9 Times in 6 Posts
|
Quote:
Did this test and performs exactly as above, thanks again. |
|
21st November 2019, 19:29 | #70 | |
Posted a thing or two
Rover 75 2001 Club Sedan V6 2.5 Join Date: Mar 2007
Location: Sydney
Posts: 1,458
Thanks: 18
Thanked 9 Times in 6 Posts
|
Quote:
My air condenser looks fine, to the best of my knowledge, its not the original one, as i replaced it a few years ago. I'm doing all my maintenance in an underground garage, nice and cool, so not affected by our high heats, just a look a smoke from the bush fires in the air, which are a long way away from where i am, luckily. Last edited by phenonix; 21st November 2019 at 19:37.. |
|
|
|