Adaptives...whats that all about?
Discussion
Hi
Sorry to bring this subject up again but the search function does not work at the moment!
I have had a misfire / uneven running engine problem lately that may be related to over fuelling? When cold the engine starts OK but if stopped when hot then it will not start again and it smells like it is flooding with petrol. When cool it will start again. Its a 4.2 Cerb, ajp engine. Standard ECU, newish leads and plugs, etc.
Connected the laptop and the only obvious discrepancy is with the adaptive %age readings. At tick over, bank 1 runs at about 5% whilst bank 2 is around -2%. I assume these should be balanced. My question is, what causes the imbalance and is it adjustable? Do I have a faulty sensor somewhere? The lambda sensors appear to read correctly and all else is in order. I have reset the adaptives on the PC but they soon revert to the above values.
Any ideas will be greatly appreciated.
Bodger bedge
Sorry to bring this subject up again but the search function does not work at the moment!
I have had a misfire / uneven running engine problem lately that may be related to over fuelling? When cold the engine starts OK but if stopped when hot then it will not start again and it smells like it is flooding with petrol. When cool it will start again. Its a 4.2 Cerb, ajp engine. Standard ECU, newish leads and plugs, etc.
Connected the laptop and the only obvious discrepancy is with the adaptive %age readings. At tick over, bank 1 runs at about 5% whilst bank 2 is around -2%. I assume these should be balanced. My question is, what causes the imbalance and is it adjustable? Do I have a faulty sensor somewhere? The lambda sensors appear to read correctly and all else is in order. I have reset the adaptives on the PC but they soon revert to the above values.
Any ideas will be greatly appreciated.
Bodger bedge
Heres some info on adaptives posted by 'Trackcar Jools', so thank him not me :-)
"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."
"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."
give dave at www.automedon.co.uk a ring and he will give you the info you need,used to set the ajp8,s up from the factory,4.2 and 4.5 also speed sixes hes the man to talk to
Bodger Bedge said:
Hi
Sorry to bring this subject up again but the search function does not work at the moment!
I have had a misfire / uneven running engine problem lately that may be related to over fuelling? When cold the engine starts OK but if stopped when hot then it will not start again and it smells like it is flooding with petrol. When cool it will start again. Its a 4.2 Cerb, ajp engine. Standard ECU, newish leads and plugs, etc.
Connected the laptop and the only obvious discrepancy is with the adaptive %age readings. At tick over, bank 1 runs at about 5% whilst bank 2 is around -2%. I assume these should be balanced. My question is, what causes the imbalance and is it adjustable? Do I have a faulty sensor somewhere? The lambda sensors appear to read correctly and all else is in order. I have reset the adaptives on the PC but they soon revert to the above values.
Any ideas will be greatly appreciated.
Bodger bedge
those adaptive values are nothing to worry about .. if you're in single figures you're ok
those are fine .. what are they like through teh rest of teh rev/throttle permutations thoughGassing Station | Cerbera | Top of Page | What's New | My Stuff