Lambda sensors dead?
Discussion
mrniceguy351 said:
Thanks for the advice everyone. The car runs and drives pretty well, but I'd really like to solve this.
I'm thinking I will have to make a needle probe attachment for my volt metre and probe the loom where it disappears under the coolant header tank.
If the car is running nicely, you could post a link of some logs? You'd get a lot more accurate feedback from that, than from a screenshot of idle. The logging is pretty simple to start on rs-ajp.I'm thinking I will have to make a needle probe attachment for my volt metre and probe the loom where it disappears under the coolant header tank.
You need to take some steps back
from your screenshot you already have a high TP values so you should already be running in a richer part of the mapping, yet you still have high adaptives and no lambda output. Those things should not exist together. There are several reasons why this might be the case, but you need to go back to basics and start checking some fundamental values.
So ..
Do you have an airflow measuring device? If so what is the airflow through the butterflies?
from your screenshot you already have a high TP values so you should already be running in a richer part of the mapping, yet you still have high adaptives and no lambda output. Those things should not exist together. There are several reasons why this might be the case, but you need to go back to basics and start checking some fundamental values.
So ..
Do you have an airflow measuring device? If so what is the airflow through the butterflies?
DuncanM said:
If the car is running nicely, you could post a link of some logs? You'd get a lot more accurate feedback from that, than from a screenshot of idle. The logging is pretty simple to start on rs-ajp.
I haven't worked out how to do that yet, but the car basically tips in more fuel whenever it spends time in part of the table that it hasn't already maxed out the adaptives for. The lambdas are stuck at 0% at all rpm and throttle ranges with idle TPS set at anywhere from 12% to 20+% mrniceguy351 said:
I haven't worked out how to do that yet, but the car basically tips in more fuel whenever it spends time in part of the table that it hasn't already maxed out the adaptives for. The lambdas are stuck at 0% at all rpm and throttle ranges with idle TPS set at anywhere from 12% to 20+%
+ sign on RS-AJP >Options>Start Logging.It's as simple as that, and will auto save the file as the date. You can then post a link on here (google drive is free) and it will give you a lot better idea as to how your car is behaving under driving conditions.
spitfire4v8 said:
You need to take some steps back
from your screenshot you already have a high TP values so you should already be running in a richer part of the mapping, yet you still have high adaptives and no lambda output. Those things should not exist together. There are several reasons why this might be the case, but you need to go back to basics and start checking some fundamental values.
So ..
Do you have an airflow measuring device? If so what is the airflow through the butterflies?
Idling smoothly at 970 rpm, with the adaptives reset.from your screenshot you already have a high TP values so you should already be running in a richer part of the mapping, yet you still have high adaptives and no lambda output. Those things should not exist together. There are several reasons why this might be the case, but you need to go back to basics and start checking some fundamental values.
So ..
Do you have an airflow measuring device? If so what is the airflow through the butterflies?
Right, so you have lowish airflows and high throttle sensors so it definitely should be running rich not weak, all other things being equal.
So .. when you reset the adaptives does the engine revs fall, and then pick up as the ecu adds fuel ? Or does it barely make any difference ? or does it speed up and then start to lose revs as the adaptives increase?
So .. when you reset the adaptives does the engine revs fall, and then pick up as the ecu adds fuel ? Or does it barely make any difference ? or does it speed up and then start to lose revs as the adaptives increase?
spitfire4v8 said:
Right, so you have lowish airflows and high throttle sensors so it definitely should be running rich not weak, all other things being equal.
So .. when you reset the adaptives does the engine revs fall, and then pick up as the ecu adds fuel ? Or does it barely make any difference ? or does it speed up and then start to lose revs as the adaptives increase?
It sped up when I reset the adaptives, 50-76 rpm.So .. when you reset the adaptives does the engine revs fall, and then pick up as the ecu adds fuel ? Or does it barely make any difference ? or does it speed up and then start to lose revs as the adaptives increase?
Then that suggests your map is already too rich, because as the ecu richens it up further the revs drop, which is the exact opposite of what you would find if it was running weak ..
The proof of that would be with an afr gauge up a tailpipe .. see if it starts rich and goes richer and richer ..
so yes, the ecu appears to be acting correctly based on it's zero volts signal from the lambdas ..
so that means you need to find out why both lambdas are sending no signal to the ecu ... lambda faults / wiring faults / ecu fault?
The proof of that would be with an afr gauge up a tailpipe .. see if it starts rich and goes richer and richer ..
so yes, the ecu appears to be acting correctly based on it's zero volts signal from the lambdas ..
so that means you need to find out why both lambdas are sending no signal to the ecu ... lambda faults / wiring faults / ecu fault?
Remember a lambda sensor doesn't read mixture directly, it reads the oxygen content of the exhaust and the ECU infers the mixture from that. One reason for your symptoms could be a vacuum leak, even on a single cylinder (per bank) would cause too much oxygen in the exhaust regardless of the other cylinders, including if they're running rich.
Although anything is possible (it’s a TVR), I find it hard to believe that both lambda’s have failed together, either due to age/wear or dodgy wiring.
Have you checked for voltage at the plug (with theignition on and immobilized disarmed)? Should get 12V on the heating element wire.
Have you tried swapping the plugs over (odd wire to even lambda)?
Presumably you have attempted a fresh setup?
What happens if you disconnect the drivers side throttle pot? The engine will run from the odd throttle pot alone (the odd TP controls timing for both banks and fuelling for the odd bank or both banks).
Have you disconnected the ECU, waited a while and reconnected?
You can verify the lambda wiring, by disconnecting a lambda, shorting out a pair of terminals and then checking for continuity (with a multimeter) back at the ECU plug (you’ll need the wiring diagram to see which ECU plug pins relate to which pins on the lambda-end) - check the actual resistance in each case (look for the odd one out) and if your multimeter has an audible signal, jiggle the wires around to check for whether there’s a loose connection).
Wish you lots of luck - these issues can be an absolute pig to resolve, but stick with it, you’ll get there!
Have you checked for voltage at the plug (with theignition on and immobilized disarmed)? Should get 12V on the heating element wire.
Have you tried swapping the plugs over (odd wire to even lambda)?
Presumably you have attempted a fresh setup?
What happens if you disconnect the drivers side throttle pot? The engine will run from the odd throttle pot alone (the odd TP controls timing for both banks and fuelling for the odd bank or both banks).
Have you disconnected the ECU, waited a while and reconnected?
You can verify the lambda wiring, by disconnecting a lambda, shorting out a pair of terminals and then checking for continuity (with a multimeter) back at the ECU plug (you’ll need the wiring diagram to see which ECU plug pins relate to which pins on the lambda-end) - check the actual resistance in each case (look for the odd one out) and if your multimeter has an audible signal, jiggle the wires around to check for whether there’s a loose connection).
Wish you lots of luck - these issues can be an absolute pig to resolve, but stick with it, you’ll get there!
mrniceguy351 said:
Does anyone have any suggestions where to buy the male and female plugs for the lambdas?
See here, at least it might give you a start as there are part numbers mentionedhttps://www.pistonheads.com/gassing/topic.asp?t=66...
The thing is, if you can find male and female terminals that will fit, you can make up some break out cables without using plug and socket mouldings. Will need to be careful in getting the connections in the correct order right if using single cables to break out, 3 different coloured cables is the safest way
So I did this...
With the car running if I throw -12v to the earth for the lambda I get a reading. A very low reading (0.1) but still a reading. This is with the exhaust dropped btw, and the lambda sensor is only 50mm from the open exhaust pipe.
Tomorrows mission is to unplug the other sensor,pull that part of the loom into the engine bay, strip the insulation off and look at running a new common earth and maybe power wire to the sensors.
Strangely enough when I probed the red wire that also showed as an earth, I guess because it's earthed via the lambda? It also struck me that the wires to the sensors are tiny!
With the car running if I throw -12v to the earth for the lambda I get a reading. A very low reading (0.1) but still a reading. This is with the exhaust dropped btw, and the lambda sensor is only 50mm from the open exhaust pipe.
Tomorrows mission is to unplug the other sensor,pull that part of the loom into the engine bay, strip the insulation off and look at running a new common earth and maybe power wire to the sensors.
Strangely enough when I probed the red wire that also showed as an earth, I guess because it's earthed via the lambda? It also struck me that the wires to the sensors are tiny!
Who is the man? Me, that's who. The best Cerbera troubleshooter in all of Western Australia!
Fed 12v direct from the battery to the lambdas, and made a new earth to the back of the motor and they both came to life. But they were only reading 0.01v, so I connected the exhaust up and bingo, getting good readings from both. (The screenshot doesn't show it but I did have good readings from the RHS lambda as well.)
Now I just need to decide where to connect the new 12v feed. I have electric power steering so I was thinking of running it from there. A bit of a round about way to do it, but the wiring is all new and oversize. I will need a diode and it's a public holiday today so that will have to wait till tomorrow.
Fed 12v direct from the battery to the lambdas, and made a new earth to the back of the motor and they both came to life. But they were only reading 0.01v, so I connected the exhaust up and bingo, getting good readings from both. (The screenshot doesn't show it but I did have good readings from the RHS lambda as well.)
Now I just need to decide where to connect the new 12v feed. I have electric power steering so I was thinking of running it from there. A bit of a round about way to do it, but the wiring is all new and oversize. I will need a diode and it's a public holiday today so that will have to wait till tomorrow.
glow worm said:
I had lots of trouble last year with "cheap" Lambdas on my Chimaera... caused by poor wiring to the Lambdas not being able to withstand the heat generated are you sure your solution will work in the extreme heat ?
It will work a lot better than the original tiny wires, and will be routed well away from the exhaust.I have a new radiator and fans, I don't really have "extreme" heat under the bonnet.
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