Jump to content


Photo

Mpi Not Switch To Closed Loop


Best Answer Ruckus , 07 May 2018 - 02:48 PM

Yes I’ve been testing everything today.
And I have a result, it was the ECU and the old CAM sensor.

I had a tatty ECU from somewhere which I dropped in today and managed to recode the immobiliser and bingo Cam sensor sync and runs smooth.

So it was 3 things. Lambda and Cam sensor and the ECU.

I tested the resistance on the old cam sensor and it was nothing. So maybe this damaged the ECU in some way?
I don’t know but it’s running smoothly now with all sensors reporting as expected. Go to the full post


  • Please log in to reply
39 replies to this topic

#1 Ruckus

Ruckus

    Ice Ice Baby!!!

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,071 posts
  • Location: Top of the hill in Kent
  • Local Club: SMOC

Posted 23 April 2018 - 11:27 AM

Sorry Typo in subject ! should be "Mpi Not Switching To Closed Loop"

 

I wonder if anyone can shed any light on this little doozy.

 

So my Late MPi does not switch to Closed Loop operation when warmed up. Due to this the emissions are not able to pass an MOT, before this started and had very very good emissions and passed with zero problems.
 

I had it looked at last year by a MG/Rover specialist with a Rover T4 Testbook and was told it was most likely a problem in the wiring. After some hunting a NEW complete Engine bay wiring loom was sourced and fitted by myself.

The new loom did not resolved the problem.

 

I have a Pscan.eu unit and the live data at idle shows the below.

 

Now i take it the 'Oxygen sensor voltage bank 1' is the (or should be) reading from the Lambda, but it fixed at 0.48v even if i unplug it! The Cam Postion also does not move from 0.

 

So far I've tried almost everything i can think of.

  • New Loom
  • New MAP sensor
  • A different relay box
  • A different known good Lambda was tried
  • New Cam sensor
  • Ground points all look good

 

 

CDMgbLv.jpg

 

 

The engine is a 1380 so should run a little lean on the stock MEMS but due to not running in Closed Loop and being on a Limp mode its running rich.

The Car does also have a Swiftune SW5-07 MPI Cam, i wonder if somehow its not picking it up correctly (is that even possible?).

 

What could be the problem here? ECU fault..?


Edited by Ruckus, 23 April 2018 - 04:14 PM.


#2 MR J

MR J

    Speeding Along Now

  • Members
  • PipPipPipPipPip
  • 416 posts
  • Location: Doncaster
  • Local Club: Doncaster Mini Owners

Posted 23 April 2018 - 06:45 PM

I have had a similar fault, would run in closed loop for a short while then switch to open loop and stay there until stopped, left for about 10 minutes and started again it would return to closed loop until it switched out again. My lambda was reading a steady 0.45V whilst in open loop.

I tested to see if my O2 sensor relay was working, which it was and I was getting 12v at the O2 sensor heating wires, I also tested the voltage from sensor which was reading 0.45 steady.

I changed the sensor for a Bosch one I had (old one I removed 3 years ago) and it now seems to be running fine in closed loop pretty much all the time.

#3 Ruckus

Ruckus

    Ice Ice Baby!!!

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,071 posts
  • Location: Top of the hill in Kent
  • Local Club: SMOC

Posted 23 April 2018 - 07:21 PM

What would happen if you disconnected the lambda? Or did you not try that?

#4 MR J

MR J

    Speeding Along Now

  • Members
  • PipPipPipPipPip
  • 416 posts
  • Location: Doncaster
  • Local Club: Doncaster Mini Owners

Posted 23 April 2018 - 07:31 PM

Disconnecting the lambda made difference at all when in open loop

#5 MR J

MR J

    Speeding Along Now

  • Members
  • PipPipPipPipPip
  • 416 posts
  • Location: Doncaster
  • Local Club: Doncaster Mini Owners

Posted 23 April 2018 - 07:32 PM

By the way, mines a pretty much standard Spi but I think the Mpi would run the same

#6 Ruckus

Ruckus

    Ice Ice Baby!!!

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,071 posts
  • Location: Top of the hill in Kent
  • Local Club: SMOC

Posted 23 April 2018 - 08:57 PM

Whats odd for me that when disconnected I still see 0.48v ?

Edited by Ruckus, 23 April 2018 - 08:59 PM.


#7 tmsmini

tmsmini

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 706 posts
  • Local Club: MOASF

Posted 28 April 2018 - 02:25 PM

Does PSCAN let you see live lambda values?

Did the garage with the T4 say why they thought it was a wiring issue? Was it the lambda value issue?

 

When you say this, "Whats odd for me that when disconnected I still see 0.48v ? 

,"Whats odd for me that when disconnected I still see 0.48v," do you mean you just disconnected it at the plug? 



#8 Homersimpson

Homersimpson

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 797 posts
  • Location: Redditch

Posted 28 April 2018 - 06:46 PM

If you disconnect the lambda sensor and put a multimeter on the output from the sensor you should see the voltage fluctuate between around 0.1 and 0,9 volts.  If it steady and the engine is running and warm it would suggest that the sensor is faulty.

 

You may need to rev the engine to make it change as your car won't necessarily be doing the rich/lean/rich/lean that the control would introduce, it also depends upon how quickly your multimeter responds to voltage change. Make sure you set the meter up for the right voltage type (I think it should be DC) and is on the lowest scale, if you get 1 on most meters it means the scale is wrong.

 

Can you also check that the lambda wires are continuous all the way through to the ECU?

 

One thing to remember is that the lambda sensor might be giving you the wrong output because its faulty but it might also be telling the truth and the fault might be elsewhere.

 

You mentioned that the cam sensor says 0, does the car have a cam sensor, if not then this would explain.



#9 Ruckus

Ruckus

    Ice Ice Baby!!!

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,071 posts
  • Location: Top of the hill in Kent
  • Local Club: SMOC

Posted 29 April 2018 - 12:02 PM

Yes Pscan give live data.

The 0.48v on the lambda reading is at idle, at red line and everything in the middle.
It’s been monitored while drive etc.

And yes the car has a CAM sensor I did say I’ve replaced it in the first post... :)

Please explain how the lambda can give reading if it’s disconnected?

#10 Ruckus

Ruckus

    Ice Ice Baby!!!

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,071 posts
  • Location: Top of the hill in Kent
  • Local Club: SMOC

Posted 29 April 2018 - 12:03 PM

@tmsmini yes I disconnected the plug and the reading stays at 0.48!?

#11 Sprocket

Sprocket

    Great on Injection faults

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 7,266 posts
  • Location: Warrington
  • Local Club: Manchester Minis

Posted 29 April 2018 - 10:12 PM

@tmsmini yes I disconnected the plug and the reading stays at 0.48!?

That is normal.

 

It is not normal if you have the lambda sensor connected, suggesting the sensor, wiring or the connectors are at fault.



#12 Ruckus

Ruckus

    Ice Ice Baby!!!

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,071 posts
  • Location: Top of the hill in Kent
  • Local Club: SMOC

Posted 30 April 2018 - 01:19 PM

Ordered another new sensor! I'll try that.

 

wiring is all new as i replaced the whole front loom...



#13 tmsmini

tmsmini

    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 706 posts
  • Local Club: MOASF

Posted 30 April 2018 - 01:44 PM

Did you find a new loom somewhere or is it re-purposed?



#14 Sprocket

Sprocket

    Great on Injection faults

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 7,266 posts
  • Location: Warrington
  • Local Club: Manchester Minis

Posted 30 April 2018 - 09:34 PM

It is worth checking the sensor is getting 12v on the heater circuit



#15 Ruckus

Ruckus

    Ice Ice Baby!!!

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,071 posts
  • Location: Top of the hill in Kent
  • Local Club: SMOC

Posted 30 April 2018 - 09:44 PM

Did you find a new loom somewhere or is it re-purposed?

 

Brand new, in the rover wrapper and everything.

 

It came from a load of new old stock spares found in a dealer in France.


Edited by Ruckus, 30 April 2018 - 09:56 PM.





0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users