It is worth checking the sensor is getting 12v on the heater circuit
Checked and even replaced the relay unit.
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.
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Posted 30 April 2018 - 09:56 PM
It is worth checking the sensor is getting 12v on the heater circuit
Checked and even replaced the relay unit.
Posted 02 May 2018 - 06:12 AM
You will only get a reading from the O2 sensor when disconnected at the plug, if the O2 sensor is hot enough to operate. When connected, the O2 sensor receives 12V to power the heater. When driving, there is sufficient exhaust gas passing the sensor to heat it to an operational temperature. When idling, the sensor may not get hot enough due to only a small amount of exhaust gas acting on it hence the reason for the heater element. The correct way to measure the output directly is actually to tap into the wiring so that you can measure the output with the sensor still connected at the plug and so still getting power to its heater element. I would make sure that you do this before condemning the sensor as otherwise it may just be too cold.
If you disconnect the sensor then this will not stop the car going into closed loop, the ECU will just use an assumed value for the O2 level in the exhaust gas. I was of the understanding that the only reading that is used to determine when to switch to closed loop was the coolant temperature, however that is based on the SPi. I believe that once passed 70 DegC (I may be incorrect on the exact value) the system moves to closed loop. One thing which seems very odd is that the intake air temperature is reading 79DegC! I don't know if the car will use limp mode in the case of a faulty input air temp sensor, I would have thought it would just ignore the value and use an assumed value (and throw a code). You could try to disconnect it.
I do wonder about your cam sensor as it is showing Input was low. The crank sensor should be enough to allow the engine to run but I would think the car may use limp mode in the absence of the cam sensor- again I would expect a code if this is not providing a signal. Have you checked for fault codes? Can you shed any more light on the cam sensor message in the results? Is this saying there is no signal?
At this point my guess is cam sensor. Input from FlyingScot on here would be helpful, he is very knowledgeable about injection minis and will be more familiar with the MPi unit.
Edited by spiguy, 02 May 2018 - 06:14 AM.
Posted 02 May 2018 - 09:01 AM
The output i posted was after a 'fast paced' drive so i don't think that the lambda was too cold or the intake air temp sensor reading was wrong. The engine is a 1380 and has a SC stainless LCB so its hot back there! I have a spare Air temp sensor so i can swap that (In fact I basically have a spare everything now).
The Cam Shaft single reads as OK (the sensor has been changed for new) but the position reading stays at 0 degrees. I would have thought that due to the 0 reading there is no history so it shows as 'too low'.
I was told by my local MG/Rover specialist that until the car goes in to 'Close loop' operation it does not use the Cam sensor and uses a default map (limp mode).
I have a new Lambda sensor in hand now and i can try the original Cam sensor and see if that changes anything.
Posted 02 May 2018 - 12:12 PM
Posted 02 May 2018 - 03:06 PM
Sprocket: I can confirm that the engine keeps running if the Cam sensor is unplugged while running. I did this the other day while troubleshooting. VERY hot back there!
I haven't tried firing it up without the Cam sensor being already unplugged. I never have a problem starting the car, in fact it drives really nice using this default/limp mode.
pete: Interesting that makes me again worry about the Swifttune Cam it has...
So what am I'm looking at now? so much information but I'm none the wiser it seems... LOL
Posted 02 May 2018 - 05:51 PM
Posted 02 May 2018 - 06:26 PM
Posted 02 May 2018 - 06:50 PM
Posted 02 May 2018 - 08:11 PM
Sprocket i cant thank you enough for your insights in to this so far.
So did a bit on the car tonight (only get an hour of day light).
Things have changed for some reason... for the worst!
The car now idles very rough? and the cam shaft signal is now showing as invalid? I couldn't get the car up to full temperature (don't want to upset the neighbors too much) but in the warm up when it normally sounds good it sound lumpy all of a sudden.
I swapped the cam sensor for the original one i took off a few weeks ago and it still shows invalid.
Oh and i swapped the intake air temperature sensor just in case...
What am i looking at here an earthing problems somewhere? its a brand new loom !
I'll try and get under the car on Friday and try what you suggested with the new Lambda sensor.
Edited by Ruckus, 02 May 2018 - 08:16 PM.
Posted 02 May 2018 - 08:47 PM
Under the car? SC manifold? is the lambda sensor in the 'Y' section under the car? How have you lengthened the wires?
It certainly seems the cam sensor is not working for some reason and the cam position angle is more to do with angle since last synchronisation I really don't know.
Posted 03 May 2018 - 06:16 AM
Posted 03 May 2018 - 06:17 AM
Posted 06 May 2018 - 12:28 PM
New Bosch Lambda and another new Cam Sensor and we seem to be working.
O2 is now reading and working. free air on the head as you said Spocket its reads 0.02 down to 0
Installed it reads as you would expect 0.01 up to 0.9xx.
So it looks like when the car went in to the MG/Rover specialist the problem was the link to the Cam sensor AND the Lambda. So when they tried a different Lambda the Cam link was still creating a problem. Therefore they thought the Lambda was not the problem.
Why is the Cam sensor dropping off... looks like i have a little bit of an drive shaft oil leak which is flicking oil up and getting in to the plug connection.
I've covered the connection with a sleeve of heat shrink which i hope should keep it oil free until i can get the oil seal sorted.
I've not had the emission checked yet, but I just listening to the car running it sounds so much smoother now.
Success I think.
Edited by Ruckus, 06 May 2018 - 01:31 PM.
Posted 06 May 2018 - 06:12 PM
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