Lammbda 1.84 - Causes???
Discussion
I have fitted two new lambdas - very fiddly and annoying. However, got the job done and hooked up the laptop. Excellent, very pleased with myself and readings switching all over the place - lovely.
Then 2 minutes later, MIL light keeps coming on and getting a reading of 1.84 popping up regularly on lambda 1.
Any ideas what might be causing this and what's the next best step forward.
Cheers and all info. appreciated...
MB
Then 2 minutes later, MIL light keeps coming on and getting a reading of 1.84 popping up regularly on lambda 1.
Any ideas what might be causing this and what's the next best step forward.
Cheers and all info. appreciated...
MB
Edited by marcus1970 on Saturday 28th April 15:15
GreenV8S said:
Didn't get the wires crossed over did you?
When you say wires, do you mean the whole connector to each lambda sensor?
I have nearside lambda - lambda 1 on laptop - servicing the odd bank 1 3 5 7 according to the little yellow label on the wires, with the offside lambda 2 on the laptop - servicing the even bank 2 4 6 8 according to the little yellow labels on the wires.
Hope this is right?
Why would it make a difference to the lambda readings if the wires were crossed over, surely it would just mean that lambda 2 would be showing the fault with the 1.84 readout instead of lambda 1, wouldn't it?
MB
Edited by marcus1970 on Friday 27th April 21:18
Edited by marcus1970 on Saturday 28th April 15:16
Hi !
If you cross the wires the ECU will adjust the amount of fuel on the wrong bank when it tries to correct the mixture. The lambda reading is depending on the air-fuel mixture. After a while the ECU wouldn´t be able to get the adaptive values within the correct levels and then the ECU switches on the MIL. Do you have a AFRbad fault code ?
// Peppe
If you cross the wires the ECU will adjust the amount of fuel on the wrong bank when it tries to correct the mixture. The lambda reading is depending on the air-fuel mixture. After a while the ECU wouldn´t be able to get the adaptive values within the correct levels and then the ECU switches on the MIL. Do you have a AFRbad fault code ?
// Peppe
Peppe said:
Hi !
If you cross the wires the ECU will adjust the amount of fuel on the wrong bank when it tries to correct the mixture. The lambda reading is depending on the air-fuel mixture. After a while the ECU wouldn´t be able to get the adaptive values within the correct levels and then the ECU switches on the MIL. Do you have a AFRbad fault code ?
// Peppe
If you cross the wires the ECU will adjust the amount of fuel on the wrong bank when it tries to correct the mixture. The lambda reading is depending on the air-fuel mixture. After a while the ECU wouldn´t be able to get the adaptive values within the correct levels and then the ECU switches on the MIL. Do you have a AFRbad fault code ?
// Peppe
I've swapped them over and the MIL light no longer comes on, but now the adaptives are well out. When I reset the adaptive maps the engine runs quite well for a minute or so but then starts to run rough again. Idles around 600 -700 rpm.
The funny/frustrating thing is that the lambda connections have odd and even on the wires in yellow, but someone has written odd and even in marker pen on the actual connectors that contradict the yellow labels???
I need a drink !!!
MB
Hi Marcus !
Hope the drink was good
.
As you have the car apart. Take of the big connector on the ECU and measure how the wires are put together from the engine bay to the ECU.
Signal for odd bank should go in to the ECU on pin 21, and the even bank is on pin 3. (This info is taken from the wiring diagram that comes whith the old version of the diag. software.)
If the Lambdas are connected OK and the throttle pots are adjusted and your car is still running rough, i think you need to balance the throttles, if they are out of balance the adaptive values will be well out.
I know that Joolz do this without a vacuum meter, but i think it is easier for a DIY mecanic to do it with a vacuum meter.
If you have the workshop manual it is easy if you follow the instructions on engine setup that is in the manual, the only thing you don´t do is to measure a certain vacuum reading (4-5) as it say in the manual, with another vacuum meter you measure that the vacuum is the same on both sides of the engine.
Byker28i has the workshop manual on his excellent homepage:
http://homepage.ntlworld.com/dave.hin
Peppe
Hope the drink was good
. As you have the car apart. Take of the big connector on the ECU and measure how the wires are put together from the engine bay to the ECU.
Signal for odd bank should go in to the ECU on pin 21, and the even bank is on pin 3. (This info is taken from the wiring diagram that comes whith the old version of the diag. software.)
If the Lambdas are connected OK and the throttle pots are adjusted and your car is still running rough, i think you need to balance the throttles, if they are out of balance the adaptive values will be well out.
I know that Joolz do this without a vacuum meter, but i think it is easier for a DIY mecanic to do it with a vacuum meter.
If you have the workshop manual it is easy if you follow the instructions on engine setup that is in the manual, the only thing you don´t do is to measure a certain vacuum reading (4-5) as it say in the manual, with another vacuum meter you measure that the vacuum is the same on both sides of the engine.
Byker28i has the workshop manual on his excellent homepage:
http://homepage.ntlworld.com/dave.hin
Peppe
of how you could find out which bank is even and which is odd. Check the wires that go to the throttle pots and the injectors, they should be marked with odd and even. All even wires on the even side of the engine. 
Ok so here goes - according to the diags, ECU info from you guys, the manual etc.
On my car right now I have starting from the front...
Throttle pot odd on near side, bank 1 odds 1357 on n/s, but according to the yellow label I have lambda even connected to the odd bank.
Throttle pot even on off side, bank 2 evens 2 4 6 8 on o/s but according to the yellow label I have lambda odd connected to the even bank.
Now, could it be that some muppet has yellow labelled them incorrectly at the factory, as since this time some mechanic somewhere has labelled the connectors oppositely to the yellow labels ie the wire says even but the connector is labelled odd.
The car seems to be running ok but the lambda and adaptive readings on each bank are well off.
MB
On my car right now I have starting from the front...
Throttle pot odd on near side, bank 1 odds 1357 on n/s, but according to the yellow label I have lambda even connected to the odd bank.
Throttle pot even on off side, bank 2 evens 2 4 6 8 on o/s but according to the yellow label I have lambda odd connected to the even bank.
Now, could it be that some muppet has yellow labelled them incorrectly at the factory, as since this time some mechanic somewhere has labelled the connectors oppositely to the yellow labels ie the wire says even but the connector is labelled odd.
The car seems to be running ok but the lambda and adaptive readings on each bank are well off.
MB
Edited by marcus1970 on Sunday 29th April 14:56
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