Cerbera Adaptives
Discussion
Hi all, tinkering with the TPots on the Cerbera (V8 4.5) because I was getting AFR faults on 2345 (high adaptives). Found lots of useful information here, but I have a few questions I hope you can answer (also posted on FaceBook).
1. What causes the odd bank's map to be full of zeros while bank 2 has values.
2. If one bank goes massively negative while the other goes positive at a given throttle setting, would that suggest lambdas are swapped ?
3. Why would the engine run rough when either TP is unplugged (won't start and stalls)
4. If you have a custom map, I presume the service manual settings are out of the window, other than trial and error is there a way to find out what the map is expecting ?
5. If head has been gas-flowed, would you expect greater than standard flow at idle (e.g 6/7/8 instead of 4.5/5)
6. How much driving do you have to do to set the maps up ? Getting adaptives right at idle is only one site amongst many. Presume you have to drive through a number of conditions with revs between idle and 3000-ish to hit all the sites.
7. Finally (for now), I presume getting adaptives right at low revs is essential to make sure the car fuels properly at high revs, if TPs are low the map will run the engine lean, if they're high it will run the engine rich under driving conditions (e.g. not trailing throttle).
I am asking these questions because I have the throttle bodies pretty much balanced, but I have a flowed head, custom map and besides the fact that my TPs are a bit erratic (new ones on order + lambdas) I can't get it right with either the service manual or other suggestions here for the TP position, so wondering if my "unique" engine setup means I need to figure out exactly what it wants. But I also want to understand what I am risking if it's not 100% right (e.g. running lean at high revs, etc...)
Many thanks
Greg
1. What causes the odd bank's map to be full of zeros while bank 2 has values.
2. If one bank goes massively negative while the other goes positive at a given throttle setting, would that suggest lambdas are swapped ?
3. Why would the engine run rough when either TP is unplugged (won't start and stalls)
4. If you have a custom map, I presume the service manual settings are out of the window, other than trial and error is there a way to find out what the map is expecting ?
5. If head has been gas-flowed, would you expect greater than standard flow at idle (e.g 6/7/8 instead of 4.5/5)
6. How much driving do you have to do to set the maps up ? Getting adaptives right at idle is only one site amongst many. Presume you have to drive through a number of conditions with revs between idle and 3000-ish to hit all the sites.
7. Finally (for now), I presume getting adaptives right at low revs is essential to make sure the car fuels properly at high revs, if TPs are low the map will run the engine lean, if they're high it will run the engine rich under driving conditions (e.g. not trailing throttle).
I am asking these questions because I have the throttle bodies pretty much balanced, but I have a flowed head, custom map and besides the fact that my TPs are a bit erratic (new ones on order + lambdas) I can't get it right with either the service manual or other suggestions here for the TP position, so wondering if my "unique" engine setup means I need to figure out exactly what it wants. But I also want to understand what I am risking if it's not 100% right (e.g. running lean at high revs, etc...)
Many thanks
Greg
First thing to do is to get the new TP fitted and set as per the book, your map does not make a difference it relays on the throttle pots to tell it where the throttle is.
Gas flowing the heads will not alter the flow you read on a flow meter by any real amount.
Get the TP's set and tracking evenly together then reset adaptive so and see what that does to the symptoms you are currently seeing.
Gas flowing the heads will not alter the flow you read on a flow meter by any real amount.
Get the TP's set and tracking evenly together then reset adaptive so and see what that does to the symptoms you are currently seeing.
1. What causes the odd bank's map to be full of zeros while bank 2 has values.
Assuming that you have reset the adaptives (i.e. to all Zeros); if the Odd Adaptive Map is full of zeros then my guess would be that the corresponding Lambda sensor is not sending any data to the ECU and hence Zeros. The sensor could be dud, the connection could be faulty or the wiring could be failing.
2. If one bank goes massively negative while the other goes positive at a given throttle setting, would that suggest lambdas are swapped ?
I would have thought that if the lambdas were swapped then the massively negative on one bank and massively positive on the other bank would happen at all points in the rev range. So it doesn't suggest so.
3. Why would the engine run rough when either TP is unplugged (won't start and stalls)
If one TP is unplugged then the ECU uses the remaining connected TP for both banks. If it runs rough it suggests that both banks aren't similarly balanced, so the substituted TP value doesn't accurately indicate the throttle position of the bank with the disconnected TP.
4. If you have a custom map, I presume the service manual settings are out of the window, other than trial and error is there a way to find out what the map is expecting ?
At idle, you're looking for 975 rpm (I actually aim for 1050 so that when I run the AC it idles at 975) and an idle adaptive value of Zero (in an ideal world but +-10% is the norm). A standard or custom map doesn't matter when you're setting up this as the procedure is the same.
5. If head has been gas-flowed, would you expect greater than standard flow at idle (e.g 6/7/8 instead of 4.5/5)
My RR is ported. But I can't remember the flow I measured on my air flow meter. However, with balanced airflow, plus the target idle values mentioned above, coupled with a zero idle adaptive target value, the only other input we need to consider is the TP value. All else being equal you should use whatever is recommended in the user manual. i.e. the goal is to achieve (at idle) a target idle rpm, zero idle adaptive values using a recommended idle %'age TP value - which means the actual flow rate doesn't matter as long at they're the same.
6. How much driving do you have to do to set the maps up ? Getting adaptives right at idle is only one site amongst many. Presume you have to drive through a number of conditions with revs between idle and 3000-ish to hit all the sites.
Once you get the throttle and adaptives correct at idle the rest will fall into line - if there area any issues (elsewhere in the rev rang) due to differences in sensor tolerances, TP resistance tolerances or even Throttle linkage slop; they will be compensated for by the adaptive technology (which I think is a very elegant side effect of something that was added for environmental reasons)
7. Finally (for now), I presume getting adaptives right at low revs is essential to make sure the car fuels properly at high revs, if TPs are low the map will run the engine lean, if they're high it will run the engine rich under driving conditions (e.g. not trailing throttle).
Yes, that's it - just get it correct at the only point in the rev range that you actually have control of (i.e. idle) and the rest will follow suit.
The idle TP value is used as the entry point in the Base Fuel map (i.e. the one that's flashed onto the EEPROM.) There is only one btw, which is shared by both banks.
The individual adaptive maps are bank specific and are just combined with the bass fuel map value to give you the correct injector duration.
So, if you select a low TP idle value, then as you increase the TP value the ECU simply selects a value from the base map and adaptive map corresponding to the TP position. It then uses it to work out how much fuel to inject. Whereby the Adaptive value is changing based on feedback from the lambda sensors.
And reciprocally, if you select a high idle TP value then the ECU will add negative Adaptive map values to the base map to compensate for rich lambda feedback.
One other point worth noting is that the injection system goes open loop over 4000 rpm and no fuel trims are applied to the base map.
I would also add that getting the injectors cleaned is well worth it.
HTH!
Aide
Assuming that you have reset the adaptives (i.e. to all Zeros); if the Odd Adaptive Map is full of zeros then my guess would be that the corresponding Lambda sensor is not sending any data to the ECU and hence Zeros. The sensor could be dud, the connection could be faulty or the wiring could be failing.
2. If one bank goes massively negative while the other goes positive at a given throttle setting, would that suggest lambdas are swapped ?
I would have thought that if the lambdas were swapped then the massively negative on one bank and massively positive on the other bank would happen at all points in the rev range. So it doesn't suggest so.
3. Why would the engine run rough when either TP is unplugged (won't start and stalls)
If one TP is unplugged then the ECU uses the remaining connected TP for both banks. If it runs rough it suggests that both banks aren't similarly balanced, so the substituted TP value doesn't accurately indicate the throttle position of the bank with the disconnected TP.
4. If you have a custom map, I presume the service manual settings are out of the window, other than trial and error is there a way to find out what the map is expecting ?
At idle, you're looking for 975 rpm (I actually aim for 1050 so that when I run the AC it idles at 975) and an idle adaptive value of Zero (in an ideal world but +-10% is the norm). A standard or custom map doesn't matter when you're setting up this as the procedure is the same.
5. If head has been gas-flowed, would you expect greater than standard flow at idle (e.g 6/7/8 instead of 4.5/5)
My RR is ported. But I can't remember the flow I measured on my air flow meter. However, with balanced airflow, plus the target idle values mentioned above, coupled with a zero idle adaptive target value, the only other input we need to consider is the TP value. All else being equal you should use whatever is recommended in the user manual. i.e. the goal is to achieve (at idle) a target idle rpm, zero idle adaptive values using a recommended idle %'age TP value - which means the actual flow rate doesn't matter as long at they're the same.
6. How much driving do you have to do to set the maps up ? Getting adaptives right at idle is only one site amongst many. Presume you have to drive through a number of conditions with revs between idle and 3000-ish to hit all the sites.
Once you get the throttle and adaptives correct at idle the rest will fall into line - if there area any issues (elsewhere in the rev rang) due to differences in sensor tolerances, TP resistance tolerances or even Throttle linkage slop; they will be compensated for by the adaptive technology (which I think is a very elegant side effect of something that was added for environmental reasons)
7. Finally (for now), I presume getting adaptives right at low revs is essential to make sure the car fuels properly at high revs, if TPs are low the map will run the engine lean, if they're high it will run the engine rich under driving conditions (e.g. not trailing throttle).
Yes, that's it - just get it correct at the only point in the rev range that you actually have control of (i.e. idle) and the rest will follow suit.
The idle TP value is used as the entry point in the Base Fuel map (i.e. the one that's flashed onto the EEPROM.) There is only one btw, which is shared by both banks.
The individual adaptive maps are bank specific and are just combined with the bass fuel map value to give you the correct injector duration.
So, if you select a low TP idle value, then as you increase the TP value the ECU simply selects a value from the base map and adaptive map corresponding to the TP position. It then uses it to work out how much fuel to inject. Whereby the Adaptive value is changing based on feedback from the lambda sensors.
And reciprocally, if you select a high idle TP value then the ECU will add negative Adaptive map values to the base map to compensate for rich lambda feedback.
One other point worth noting is that the injection system goes open loop over 4000 rpm and no fuel trims are applied to the base map.
I would also add that getting the injectors cleaned is well worth it.
HTH!
Aide
Re point 6, a garage that rhymes with Pacing Keen returned my car with the cables swapped, I swapped them back and it took a couple of hours driving at different engine speeds for the ECU to learn. At the time I didn't have the where-with-all to reset the adaptives so just drove it and it gradually got better. 
Thanks Gruffalo, Aide and FarmyardPants, this is very useful in filling the blanks, responding to yours answers below.
I've got TPs and Lambdas on order, will swap them all to eliminate any unknowns and start with a clean sheet. Although it's not rocket science, wish me luck, I have a 700mile return trip + runs up and down a runway on 12/13/14 July so not much time to get her sorted.
Aide said:
1. What causes the odd bank's map to be full of zeros while bank 2 has values.
Assuming that you have reset the adaptives (i.e. to all Zeros); if the Odd Adaptive Map is full of zeros then my guess would be that the corresponding Lambda sensor is not sending any data to the ECU and hence Zeros. The sensor could be dud, the connection could be faulty or the wiring could be failing.
That issue seems to have gone since I've tried to swap the Lambdas and back again, maybe there was crud in the connectors that's now gone. But good to know the reasonAssuming that you have reset the adaptives (i.e. to all Zeros); if the Odd Adaptive Map is full of zeros then my guess would be that the corresponding Lambda sensor is not sending any data to the ECU and hence Zeros. The sensor could be dud, the connection could be faulty or the wiring could be failing.
Aide said:
2. If one bank goes massively negative while the other goes positive at a given throttle setting, would that suggest lambdas are swapped ?
I would have thought that if the lambdas were swapped then the massively negative on one bank and massively positive on the other bank would happen at all points in the rev range. So it doesn't suggest so.
By "given throttle setting" I meant stable throttle position, so yes it would happen at all points in the rev range as you said.I would have thought that if the lambdas were swapped then the massively negative on one bank and massively positive on the other bank would happen at all points in the rev range. So it doesn't suggest so.
Aide said:
3. Why would the engine run rough when either TP is unplugged (won't start and stalls)
If one TP is unplugged then the ECU uses the remaining connected TP for both banks. If it runs rough it suggests that both banks aren't similarly balanced, so the substituted TP value doesn't accurately indicate the throttle position of the bank with the disconnected TP.
Ok, makes sense, both banks are balanced according to my flow meter, to within 1kg/hr or so (not sure of the accuracy of the meter itself though). I'll check it again once I have new TPs installed.If one TP is unplugged then the ECU uses the remaining connected TP for both banks. If it runs rough it suggests that both banks aren't similarly balanced, so the substituted TP value doesn't accurately indicate the throttle position of the bank with the disconnected TP.
Aide said:
4. If you have a custom map, I presume the service manual settings are out of the window, other than trial and error is there a way to find out what the map is expecting ?
At idle, you're looking for 975 rpm (I actually aim for 1050 so that when I run the AC it idles at 975) and an idle adaptive value of Zero (in an ideal world but +-10% is the norm). A standard or custom map doesn't matter when you're setting up this as the procedure is the same.
So, getting adaptives to 0 means the throttle opening + TP value are a match with the maps (fuel/ignition) at idle.At idle, you're looking for 975 rpm (I actually aim for 1050 so that when I run the AC it idles at 975) and an idle adaptive value of Zero (in an ideal world but +-10% is the norm). A standard or custom map doesn't matter when you're setting up this as the procedure is the same.
Aide said:
5. If head has been gas-flowed, would you expect greater than standard flow at idle (e.g 6/7/8 instead of 4.5/5)
My RR is ported. But I can't remember the flow I measured on my air flow meter. However, with balanced airflow, plus the target idle values mentioned above, coupled with a zero idle adaptive target value, the only other input we need to consider is the TP value. All else being equal you should use whatever is recommended in the user manual. i.e. the goal is to achieve (at idle) a target idle rpm, zero idle adaptive values using a recommended idle %'age TP value - which means the actual flow rate doesn't matter as long at they're the same.
Ok, makes sense. I was wondering if you'd start with a lower/higher setting for idle if the airflow was that much different to standard. Just to try and remove a few steps in the trial and error.My RR is ported. But I can't remember the flow I measured on my air flow meter. However, with balanced airflow, plus the target idle values mentioned above, coupled with a zero idle adaptive target value, the only other input we need to consider is the TP value. All else being equal you should use whatever is recommended in the user manual. i.e. the goal is to achieve (at idle) a target idle rpm, zero idle adaptive values using a recommended idle %'age TP value - which means the actual flow rate doesn't matter as long at they're the same.
Aide said:
6. How much driving do you have to do to set the maps up ? Getting adaptives right at idle is only one site amongst many. Presume you have to drive through a number of conditions with revs between idle and 3000-ish to hit all the sites.
Once you get the throttle and adaptives correct at idle the rest will fall into line - if there area any issues (elsewhere in the rev rang) due to differences in sensor tolerances, TP resistance tolerances or even Throttle linkage slop; they will be compensated for by the adaptive technology (which I think is a very elegant side effect of something that was added for environmental reasons)
Right so it will take a while to fill the map, 15 miles or so of driving between 1k and 4k rpm (with the occasional clearing of the cobwebs) only seems to fill in a couple/three rows at most, but again if I have slow/duff lambdas and TPs, maybe the ECU isn't registering all rows and I may not be hitting all the sites on my test route. Realistically though as per FarmyardPant's post, it will take a while to fully complete the adaptive maps. Do dealers/indies just set the TP at idle and brief drive ?Once you get the throttle and adaptives correct at idle the rest will fall into line - if there area any issues (elsewhere in the rev rang) due to differences in sensor tolerances, TP resistance tolerances or even Throttle linkage slop; they will be compensated for by the adaptive technology (which I think is a very elegant side effect of something that was added for environmental reasons)
Aide said:
One other point worth noting is that the injection system goes open loop over 4000 rpm and no fuel trims are applied to the base map.
No fuel trims meaning that if the TP isn't right at idle, then the fuelling will be off (rich or lean) once in open loop since the only inputs the ECU has are wrong and not corrected by lambda.Aide said:
HTH!
Very much so yes.I've got TPs and Lambdas on order, will swap them all to eliminate any unknowns and start with a clean sheet. Although it's not rocket science, wish me luck, I have a 700mile return trip + runs up and down a runway on 12/13/14 July so not much time to get her sorted.
New TPs and lambdas fitted, much better. I have a few low spots looking at the adaptive maps, probably need a little tweak to the setup but car feels fine.
Quick question: the adaptive map isn't ever set in stone unlike a fuelling or ignition map is it ? Resetting it merely means knowing where we are starting from, but the map will be constantly updated over time or is it eventually referred to by the ecu with no further updates ?
Also, what is the reason for resetting throttles in the various diagnostic tools ?
Quick question: the adaptive map isn't ever set in stone unlike a fuelling or ignition map is it ? Resetting it merely means knowing where we are starting from, but the map will be constantly updated over time or is it eventually referred to by the ecu with no further updates ?
Also, what is the reason for resetting throttles in the various diagnostic tools ?
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