Thread: Do ECUs self learn whilst driving

went for a drive and seems to drive a bit better

Originally Posted by jakeslouw

Then the ECU should compensate if it picks up an incorrect air/fuel ratio (AFR).

Are you sure all manifolds are tight with no leaks? All vacuum pipes sorted? Is there a non-standard cam in the new engine?

Only in closed loop function, which is generally idle and coasting do they utilize oxy sensors

Originally Posted by It'sNotWorthComplaining!

went for a drive and seems to drive a bit better

See how it goes, but comp ratio change should not effect idle much, as it's a closed loop feedback situation, they do self learn a little though

Only in closed loop function, which is generally idle and coasting do they utilize oxy sensors

Rovercare AFAIK Thor runs closed loop Lambda at all times including full throttle.
Regards Philip A

I hooked up the diagnostics today these are the error codes I'm getting.

1."Loop State Open" - I'm not a genius on this but from what has been said it should be a closed loop at idle Correct or No?
What does it actually mean open loop, is this an air/vacuum leak or something?

2.Live data shows " Miss fire Cyl 3 and Cyl 8 " every single sec they miss fire, no other cyls with this fault.
Leads and coil packs in last few weeks were replaced, but plugs approx 8mths old.
I remember having this fault before I replaced the leads and coil packs, 3 & 8 are on the same coil pack.

3. Live data says "Engine rough on cyl 1 ,3 4, ,8"

4. other codes displayed .

P0202 cyl 2 power signal
P0204 cyl 4 power signal
I take it there is an electrical problem on these 2 injectors

P0271 signal missing
P0134 02 probe signal missing
P0154 Bank 2 02 probe
P0135 02 Probe heating
P0155 02 probe heating
P1000
P135 Signal too low
P0304 miss fire detections cyl4
P0302 miss fire detection cyl 2
P1300
P0300
I previously replaced the o2 sensors with new ones, I might put the old ones back in to see if the o2 sensor faults go away. The new ones were aftermarket Land Rover ones.
Idle is rough on petrol and also on sequential injected LPG, so I rule out a fuel issue

Seeing that you are getting O2 signal missing and heater fault, My first thought would be that there is a wiring problem to the sensors ie the plug is undone or not pushed far enough.

All the other errors could stem from this, as the engine cannot be in closed loop without o2 signals.
Check the sensors first, clear the errors then see if it is OK. if not then go further.
Regards Philip A

Originally Posted by PhilipA

Rovercare AFAIK Thor runs closed loop Lambda at all times including full throttle.
Regards Philip A

The ECM runs open loop at WOT and start, more so cold. Otherwise idle, cruise and light throttle is closed loop.

Originally Posted by It'sNotWorthComplaining!

I hooked up the diagnostics today these are the error codes I'm getting.

1."Loop State Open" - I'm not a genius on this but from what has been said it should be a closed loop at idle Correct or No?
What does it actually mean open loop, is this an air/vacuum leak or something?

2.Live data shows " Miss fire Cyl 3 and Cyl 8 " every single sec they miss fire, no other cyls with this fault.
Leads and coil packs in last few weeks were replaced, but plugs approx 8mths old.
I remember having this fault before I replaced the leads and coil packs, 3 & 8 are on the same coil pack.



3. Live data says "Engine rough on cyl 1 ,3 4, ,8"

4. other codes displayed .

P0202 cyl 2 power signal
P0204 cyl 4 power signal
I take it there is an electrical problem on these 2 injectors

P0271 signal missing
P0134 02 probe signal missing
P0154 Bank 2 02 probe
P0135 02 Probe heating
P0155 02 probe heating
P1000
P135 Signal too low
P0304 miss fire detections cyl4
P0302 miss fire detection cyl 2
P1300
P0300
I previously replaced the o2 sensors with new ones, I might put the old ones back in to see if the o2 sensor faults go away. The new ones were aftermarket Land Rover ones.
Idle is rough on petrol and also on sequential injected LPG, so I rule out a fuel issue

What does it actually mean open loop, is this an air/vacuum leak or something?

Basically the ECM ignores the feedback from the Oxygen (nernst cell) sensors. Closed loop the sensor will signal the ECM weather the mixture is rich or lean and the ECM will react accordingly. So
Sensor indicates mixture is rich - ECM leans off fuel injected.
Sensor will now indicate mixture is lean - ECM now adds fuel.
And so it goes on, preferably no less than 10Hz (narrow band sensor).
A wide band works totally different. Basically two narrow band put togeather but one cell used as a pump.

I'm assuming these codes won't clear or just return soon after starting?

Check your power to coil 3/8. And with a LED tester on the switch side at the ECM. Although a flashing LED will not prove the switch is valid. But no switch will prove it won't work.

Same deal with 2 and 4 injectors. (P0204 and P0202)
And injector 4 (poss short) (P0271)

Ignore all Oxygen sensor codes at the moment. The ECM can live without that.

P135??????? Not sure about that.

These are symptoms not faults (P0300 P0302 and P0304).

I haven't looked into P1000 or P1300 yet.

Check out those injector and coil circuits and drivers(best you can) and you're be half way there.
But treat with caution when testing, the ECM may shut the injector driver down if it detects misfires (you may need to clear the codes before testing) on the cylinders to save the cat. But power should still be at the ECM switch side.
For a wild guess I would think the loom has melted/shorted somewhere.

One other thought is the state of the gas electronics system????? Could that be causing problems???????