Simple tuning for idiots
Discussion
Lets get this right from the start, I'm the idiot.
I've plugged my ECU into the laptop and as if by magic I can see what the engine is actually doing in real time. It's amazing and I feel like I own a real racing car. The problem is the adaptives are saying -20 and -10 all the time. From reading other posts this seems to be wrong.
So what are my variables?
a) Offside idle screw which sets the offside butterfly position. (Controls offside airflow at idle).
b) Link arm between throttle banks. (Controls nearside butterfly position relative to offside butterfly. Used to balance airflow through both banks).
c) Throttle potentiometers. (Tells the ECU the angle of the butterfly. Controls which ECU map is selected for a specific butterfly angle.)
d) ECU maps
1) Get something to measure airflow. Is it called a spirometer? If so what is it and where do I get one?
2) Detatch the link arm and set the correct airflow on the offside bank using the idle screw. (What airflow am I aiming for?)
3) Reconnect the arm and adjust the nearside airflow to match.
4) Adjust the throttle potentiometers until I find a map that sets the adaptive to 0.
5) Keep my fingers crossed that the adaptives remain at 0 through the rev range. (If they are not, and the linkage, pots, lambdas etc are OK, it must be the map.)
6) Take to someone who knows what they are doing.
Please tell me I'm on roughly the right track because my brain is small.
This is what I do next. Detatch
I've plugged my ECU into the laptop and as if by magic I can see what the engine is actually doing in real time. It's amazing and I feel like I own a real racing car. The problem is the adaptives are saying -20 and -10 all the time. From reading other posts this seems to be wrong.
So what are my variables?
a) Offside idle screw which sets the offside butterfly position. (Controls offside airflow at idle).
b) Link arm between throttle banks. (Controls nearside butterfly position relative to offside butterfly. Used to balance airflow through both banks).
c) Throttle potentiometers. (Tells the ECU the angle of the butterfly. Controls which ECU map is selected for a specific butterfly angle.)
d) ECU maps
1) Get something to measure airflow. Is it called a spirometer? If so what is it and where do I get one?
2) Detatch the link arm and set the correct airflow on the offside bank using the idle screw. (What airflow am I aiming for?)
3) Reconnect the arm and adjust the nearside airflow to match.
4) Adjust the throttle potentiometers until I find a map that sets the adaptive to 0.
5) Keep my fingers crossed that the adaptives remain at 0 through the rev range. (If they are not, and the linkage, pots, lambdas etc are OK, it must be the map.)
6) Take to someone who knows what they are doing.
Please tell me I'm on roughly the right track because my brain is small.
This is what I do next. Detatch
Well - section G - Engine, of the workshop manual tells you how to setup the engine
http://homepage.ntlworld.com/dave.hinns/workshop.h...
Or there's the Joospeed useful info doc, which states:
ECU
If the banks are balanced, then the adaptives should be equal. It really is that easy.
The garage should have an airmass meter ... it comes supplied in the cerbera kit that every dealer got along with their computer / software / cam timing gear. I very rarely use the meter and just balance it from the values on the screen which is much quicker, but if you had a SP6 then I'd be worrying...that engine has individually adjustable butterflies for each cylinder and you cannot balance this without the meter.
The basis for setting the V8 is to firstly slacken the linkrod between the banks, then by interpreting the adaptive value relative to the throttle pot value bank to bank you can deduce which bank is sucking more air (assuming equal t-pot values this is the bank with the higher adaptive value) there is no other way of interpreting the values .. it's as simple as that. You just adjust the link / throttle pots and idle screw to get the adaptives equal, but also AS CLOSE TO ZERO AS POSSIBLE! If one bank of your engine has adaptives of around 30 % then this is running about on the rich limit ... it won't enrich any more than that. So this means your engine needs a good tune up.
It's also wrong to say that the ECU throws up spurious fault codes in the garage such as the AFR error ... there's a logged fault because there IS a fault ... it's the difference in airflow that's causing it. The imbalance is more noticeable at small throttles / lightcruise conditions and getting it right can give much better town driving - there's also a Joospeed mod for the 4.2 version to cut out the slop in the cross link that gives a lot of poor running at part throttle.
http://homepage.ntlworld.com/dave.hinns/workshop.h...
Or there's the Joospeed useful info doc, which states:
ECU
If the banks are balanced, then the adaptives should be equal. It really is that easy.
The garage should have an airmass meter ... it comes supplied in the cerbera kit that every dealer got along with their computer / software / cam timing gear. I very rarely use the meter and just balance it from the values on the screen which is much quicker, but if you had a SP6 then I'd be worrying...that engine has individually adjustable butterflies for each cylinder and you cannot balance this without the meter.
The basis for setting the V8 is to firstly slacken the linkrod between the banks, then by interpreting the adaptive value relative to the throttle pot value bank to bank you can deduce which bank is sucking more air (assuming equal t-pot values this is the bank with the higher adaptive value) there is no other way of interpreting the values .. it's as simple as that. You just adjust the link / throttle pots and idle screw to get the adaptives equal, but also AS CLOSE TO ZERO AS POSSIBLE! If one bank of your engine has adaptives of around 30 % then this is running about on the rich limit ... it won't enrich any more than that. So this means your engine needs a good tune up.
It's also wrong to say that the ECU throws up spurious fault codes in the garage such as the AFR error ... there's a logged fault because there IS a fault ... it's the difference in airflow that's causing it. The imbalance is more noticeable at small throttles / lightcruise conditions and getting it right can give much better town driving - there's also a Joospeed mod for the 4.2 version to cut out the slop in the cross link that gives a lot of poor running at part throttle.
M3cerbera said:
Has there been an updated set up guide added yet in a thread somewhere?
Looking for the same - the only one I found that adds to this is this one that uses vacuum gauges as wellhttps://www.pistonheads.com/gassing/topic.asp?h=0&...
So I measured mine today and my Throttle values are pretty much identical for both banks, which if I am reading Jools and everyone's tuning instructions correctly is good
However at idle (very low in my car at ~850rpm) the Adaptives seem high at 30+%
At revs they drop significantly to ~20% which is good but if I am reading Jools' instructions correctly these should be as close to 0 as possible so that the car isn't running rich / over fuelling
How are these adjusted down - if I am reading it correctly this is done
"Now - look at the adaptives. If they are positive - it means the ECU is trying to add more fuel. So, increase the throttle angles of both banks (small amounts - 0.2 at a time). If they are negative - decrease the angle of both banks."
So does would mean I need to loosen the two white throttle position sensor at the end of each bank and rotate them clockwise to increase the angle to try and get both of them down to 0?
Final question - my battery is reading at 10.51V, even at 1500rpm, so is that a duff battery that can't get a proper charge, or is the alternator not giving out enough power to charge it up - from other cars this is normally ~13.6V when the car is running
Battery = easy to change, Alternator = PIA to change - so thought good to check before embarking on that route!
As ever advice much appreciated and apologies for hogging the forum - I've just got my car back close to me so have lots of time to play with it now
Addition: My car has custom mappings on it (which were done before my ownership) as it has a custom EPROM in the ECU labelled DIM Sport which is a rolling road system / Dyno system dimsport.it/en/dyno
Addition 2: My car was originally de-catted when I got it, which would have probably been with the mapping above. Since then I have put a set of original cats back in which might be changing the numbers
However at idle (very low in my car at ~850rpm) the Adaptives seem high at 30+%
At revs they drop significantly to ~20% which is good but if I am reading Jools' instructions correctly these should be as close to 0 as possible so that the car isn't running rich / over fuelling
How are these adjusted down - if I am reading it correctly this is done
"Now - look at the adaptives. If they are positive - it means the ECU is trying to add more fuel. So, increase the throttle angles of both banks (small amounts - 0.2 at a time). If they are negative - decrease the angle of both banks."
So does would mean I need to loosen the two white throttle position sensor at the end of each bank and rotate them clockwise to increase the angle to try and get both of them down to 0?
Final question - my battery is reading at 10.51V, even at 1500rpm, so is that a duff battery that can't get a proper charge, or is the alternator not giving out enough power to charge it up - from other cars this is normally ~13.6V when the car is running
Battery = easy to change, Alternator = PIA to change - so thought good to check before embarking on that route!
As ever advice much appreciated and apologies for hogging the forum - I've just got my car back close to me so have lots of time to play with it now
Addition: My car has custom mappings on it (which were done before my ownership) as it has a custom EPROM in the ECU labelled DIM Sport which is a rolling road system / Dyno system dimsport.it/en/dyno
Addition 2: My car was originally de-catted when I got it, which would have probably been with the mapping above. Since then I have put a set of original cats back in which might be changing the numbers
Edited by Juddder on Saturday 16th March 17:36
Edited by Juddder on Saturday 16th March 17:49
Addition 2: My car was originally de-catted when I got it, which would have probably been with the mapping above. Since then I have put a set of original cats back in which might be changing the numbers
The map would have been made much richer when the cats were deleted….more airflow needs more fuel. When you put the cats on you will be making it mega rich and I think that can destroy the cats.
Caddyshack said:
The map would have been made much richer when the cats were deleted….more airflow needs more fuel. When you put the cats on you will be making it mega rich and I think that can destroy the cats.
Good point and hadn't thought of that - luckily I have some standard maps as well so will switch those in and see if the adaptives lower off the back of it.The other thing I am thinking of doing is resetting the adaptives (they are dynamic if my understanding is correct) so the ECU should be trying to balance them automatically if the fuel maps are correct.
For the voltage issue thanks Supateg - I will check the back of the alternator and see what is going on...
FarmyardPants said:
Also check/replace the 100A fuse in the little black box at the back of the engine. This is inline with the charging circuit.
Is the battery dash light on?
Thanks FP - no dashboard light on and I'll check the fuse as I attempt to check the alternator - hoping I can get some clamps on to the back of it somehow to connect up to my multimeter to testIs the battery dash light on?
FarmyardPants said:
Also check/replace the 100A fuse in the little black box at the back of the engine. This is inline with the charging circuit.
Is the battery dash light on?
Thanks @FarmyardPants - spot on with the big fuse being blown, and I did a write up of the removal process while I was doing it just so that everyone else has a better reference than I did Is the battery dash light on?
https://www.pistonheads.com/gassing/topic.asp?h=0&...
https://docs.google.com/document/d/1f77vGGQkTiFgk-...
For 4.2 AJP Engines.
Reset adaptives, and clear faults via software.
With the idle screw, set the idle to ~1200rpm - this is to reduce the chance of stalling, when tuning the 2 banks.
Driver's side: moving only the throttle pot, and not the idle screw, adjust until the adaptive is showing 0, or as close to 0 as you can get it. Note that the throttle pot number does not matter at this point, only that you get the adaptive set to 0, or as close as you can, via the throttle pot (not idle screw).
In theory: now showing
Throttle 21 adaptive 0
Passenger side: moving only the throttle pot, and not the throttle bar, adjust until the adaptive is showing 0, or as close to 0 as you can get it. Note that the throttle pot number does not matter at this point, only that you get the adaptive set to 0, or as close as you can, via the throttle pot (not the throttle bar).
In theory: now showing
Throttle 22 adaptive 0
It would be boring and unrealistic for both to be the same (perfect) straight away.
You now need to balance the 2 banks (throttle numbers) , so that they match. You only use the throttle bar for this leaving the idle screw, and throttle pots alone. You are adjusting the passenger side, to match the driver's. Once both banks are showing the same throttle numbers, you need to test, that when opening the throttle, the adaptives stay relatively low on both sides, and also (arguably more importantly), that they trim in the same direction.
Perfect theoretical world:
Idle 1200
Bank1 21 adaptive 0
Bank2 21 adaptive 0
In reality you will need to make micro adjustments on the pots, and bar, but do not touch the idle screw yet, you are always working towards matching the passenger side to the driver's, not the other way around.
Once micro adjustments are made, and you are happy that the throttles both trim the same way (important!), you can finally reduce the idle, with the screw, I recommend 1000rpm.
By separating the task into two, as advised above, you are making the job much easier, and won't get yourself into a mucking fuddle. I might update this in the future, with pictures etc.
For 4.2 AJP Engines.
Reset adaptives, and clear faults via software.
With the idle screw, set the idle to ~1200rpm - this is to reduce the chance of stalling, when tuning the 2 banks.
Driver's side: moving only the throttle pot, and not the idle screw, adjust until the adaptive is showing 0, or as close to 0 as you can get it. Note that the throttle pot number does not matter at this point, only that you get the adaptive set to 0, or as close as you can, via the throttle pot (not idle screw).
In theory: now showing
Throttle 21 adaptive 0
Passenger side: moving only the throttle pot, and not the throttle bar, adjust until the adaptive is showing 0, or as close to 0 as you can get it. Note that the throttle pot number does not matter at this point, only that you get the adaptive set to 0, or as close as you can, via the throttle pot (not the throttle bar).
In theory: now showing
Throttle 22 adaptive 0
It would be boring and unrealistic for both to be the same (perfect) straight away.
You now need to balance the 2 banks (throttle numbers) , so that they match. You only use the throttle bar for this leaving the idle screw, and throttle pots alone. You are adjusting the passenger side, to match the driver's. Once both banks are showing the same throttle numbers, you need to test, that when opening the throttle, the adaptives stay relatively low on both sides, and also (arguably more importantly), that they trim in the same direction.
Perfect theoretical world:
Idle 1200
Bank1 21 adaptive 0
Bank2 21 adaptive 0
In reality you will need to make micro adjustments on the pots, and bar, but do not touch the idle screw yet, you are always working towards matching the passenger side to the driver's, not the other way around.
Once micro adjustments are made, and you are happy that the throttles both trim the same way (important!), you can finally reduce the idle, with the screw, I recommend 1000rpm.
By separating the task into two, as advised above, you are making the job much easier, and won't get yourself into a mucking fuddle. I might update this in the future, with pictures etc.
Juddder said:
aide said:
Get an air cooled Porsche.
TVR's are for girls.
Be honest, you miss us all really Aide and the world of TVR ownership TVR's are for girls.
Especially the free, open and honest sharing of distilled knowledge
https://photos.app.goo.gl/kTk2NHND16semPDa8
Gassing Station | Cerbera | Top of Page | What's New | My Stuff