Fatman
Member +
How do you know that out of interest?
jam/blitz/mines ecus..my
- Thread starter turboloon
- Start date
How do you know that out of interest?
dac69er
Super Moderator
surely the only sensor to have any effect on the fuelling in the respect we are talking about would be the lambda? if so its a narrow band and is only used on idle and cruise situations to trim fuelling for economy?
if all that is true there is no way that the ecu can adjust the duty cycle of the injectors on the fly as there is no feedback to use to control this.
or is it looking at the fuelling under idle and cruise situations and then adjusting itself depending on the amount the car is overfuelling under those conditions?
if not i can see no other way this can happen
dac69er
Super Moderator
i would like to know his also/ i can read it on my power fc, but if you can read the pulses from somewhere and then work out your duty that would be cool!
Chris@CCM
Member +
i would like to know this too .
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Chris@CCM
Member +
now ur thinking what ive been for years lol
dac69er
Super Moderator
i agree it can change the fuelling on idle and cruise and will have a different map from standard.
i can see it adjusting the timing side of things itself using the knock sensor.
other than that i cant see it adjusting the fuelling any more than the stock ecu can as there simply isnt enough sensors to make this possible!
i can see it adjusting the timing side of things itself using the knock sensor.
other than that i cant see it adjusting the fuelling any more than the stock ecu can as there simply isnt enough sensors to make this possible!
MARK@CMBAUTOS
Trader
it was cheaked on the dyno
MARK@CMBAUTOS
Trader
cant u do a sensor cheak or look at the values ? it reads it on my dads power fc
dac69er
Super Moderator
yeah, i can read it on my power fc but my other GT is running my old jam ecu so was just interested in reading the duty cycle off it and comparing it to the stock ecu.
MARK@CMBAUTOS
Trader
not sure how do that. u use a multi meter i think. u need it on the dyno
hardcoreep
Member +
The car doesn't simply operate in a vacuum. There are countermeasures to ensure your car doesn't blow itself to bits. In the Toyota ECU there is only one table, a formula is used to calculate the other table based on the single table. The car looks a different variables and matches this back with its pre-programmed settings. I didn't say the ECU adjusted the injectors on the fly.
Let me give you an example. This is on the car we just worked on. It had 460cc injectors. The idle injector duty cycle on start up was 99%. We reset the ECU and left the car to idle for 10mins and came back, duty cycle was 60%. Drove the car for a week idle duty cycle dropped to 40%. You can clearly see that the car after a certain period of time was eventually able to populate the table with enough duty cycle to drive. However, once over 3000rpm at 100% throttle the car would hit 99%. If you rolled on the power you were able to get to 5500rpm before hitting 99%. This was a stock ECU and I know, that nowhere in the factory settings is the car supposed to hit 100% unless in limp mode.
For reference my duty cycle figures were captured using the trace mode on a installed A'pexi AVCR.
hardcoreep
Member +
"However, once over 3000rpm at 100% throttle the car would hit 99%. If you rolled on the power you were able to get to 5500rpm before hitting 99%. This was a stock ECU and I know, that nowhere in the factory settings is the car supposed to hit 100% unless in limp mode."
And again it would not be altered during the run. The car keeps logs of its performance. The cells are populated upon start up but the car has the ability to learn over a period of time altering the cells as its sees fit. The car has a permanent setting, and a temporary. Which is why if you drive for a while your a/f ratio will not be the same as the factory settings.
hardcoreep
Member +
This has been a long standing battle, about self-learning, etc. So let me rehash myself here.
1: All ECUs learn, this is because there is no way to make one program for every conditions.
2: All ECUs have a base map, or multiple base maps from which the car will make long term adjustment to into the volatile memory. Therefore the assumption that the ECU is static is false. This is why when you reset your ECU the behaviour reverts back to stock
3: ECUs fall into two groups, adaptive and reactive. This is the major difference between the Subaru and Evolution ECUs. An adaptive ECU only corrects based on driving habits (Evo). A reactive ECU constantly corrects for optimum performance(Subaru). In a reactive ECU the car will either shift to a preset map based on other external factors, air temp, boost pressure, load, rpm, etc, or try to use one of the short term trim maps.
4: When to start up the short term tables are loaded with the presets from the fixed memory, and as you drive over time the car, via its sensors will repopulate that short term table. Its not instant, but it will do so.
5: The ECU has two modes, open and closed loop. In open loop it ignores the O2 sensor and uses the data in the short term tables. Should the data in either table not match within a preset level or surpass maximum parameters allowed the car attempts to go into limp mode, or whatever countermeasures were programmed in to handle the situation, if any.
6: Factory ECUs aren't dumb, they're just not programmed to do everything you ask. Their primary job is to maintain the variables as determined by the manufacturer, ie: fuel economy, protect the engine, emissions, etc.
1: All ECUs learn, this is because there is no way to make one program for every conditions.
2: All ECUs have a base map, or multiple base maps from which the car will make long term adjustment to into the volatile memory. Therefore the assumption that the ECU is static is false. This is why when you reset your ECU the behaviour reverts back to stock
3: ECUs fall into two groups, adaptive and reactive. This is the major difference between the Subaru and Evolution ECUs. An adaptive ECU only corrects based on driving habits (Evo). A reactive ECU constantly corrects for optimum performance(Subaru). In a reactive ECU the car will either shift to a preset map based on other external factors, air temp, boost pressure, load, rpm, etc, or try to use one of the short term trim maps.
4: When to start up the short term tables are loaded with the presets from the fixed memory, and as you drive over time the car, via its sensors will repopulate that short term table. Its not instant, but it will do so.
5: The ECU has two modes, open and closed loop. In open loop it ignores the O2 sensor and uses the data in the short term tables. Should the data in either table not match within a preset level or surpass maximum parameters allowed the car attempts to go into limp mode, or whatever countermeasures were programmed in to handle the situation, if any.
6: Factory ECUs aren't dumb, they're just not programmed to do everything you ask. Their primary job is to maintain the variables as determined by the manufacturer, ie: fuel economy, protect the engine, emissions, etc.
Fatman
Member +
All very good info there, however in the case of the 4e-fte ECU (modified or otherwise) they have no provision for 'self tuning' their high load tables, other than basic knock detect/retard functionality. They can certainly correct (to an extent) for larger injectors when in closed loop mode but it's impossible for a stock type ECU to fuel correctly for a turbo/intake/exhaust it was never designed for. If by some chance it does fuel correctly, it has a totally unknown timing curve which may be totally incorrect for the conditions.
There is no doubt they can work well if programmed correctly, when you're buying a secondhand unit without any of its original history you have no guarantees!
Modified stock type ECU's have their place, but that place is certainly not for the kind of money that would buy you a good quality alternative that can be tuned for your particular situation. Using them without knowledge of what's going on is potentially very dangerous for your engine, as demonstrated by the countless stories of failures (often followed by a Jam ecu for sale thread)
There is no doubt they can work well if programmed correctly, when you're buying a secondhand unit without any of its original history you have no guarantees!
Modified stock type ECU's have their place, but that place is certainly not for the kind of money that would buy you a good quality alternative that can be tuned for your particular situation. Using them without knowledge of what's going on is potentially very dangerous for your engine, as demonstrated by the countless stories of failures (often followed by a Jam ecu for sale thread)
hardcoreep
Member +
You miss my point. The ECU can correct for whatever you program to. Its job is to maintain a specific a/f ratio or injector duty cycle to match flow it expects. No factory ECU is programmed to match exactly, all have overhead. At Toyota, they didn't design the ECU to work with your modifications. The aftermarket ECUs do and they have the capacity to work with a wider range of options than a standalone.
I used to think like that. When I got ready to buy my Blitz Access I was able to speak with a Blitz dealer. He advised that I shouldn't purchase the ECU because I didn't have the octane in Jamaica to handle the aggressive timing the JDM fuel allowed. However in 2004 I purchased the Access used for US$714, and I haven't regretted it since. The ECU adjusted fine to the local conditions and has more than been able to cope with everything from a CT9 to a td04-15g, to a FMIC, etc all on our 93RON fuel.
From my own experience people who use standalones seem to have more problems than me and as I've said multiple times I've yet to see a standalone provide significantly more power than a JDM ECU locally. And all the guys I see blowing up here on GTTurbo generally are running a standalone or have pushed the stock ECU past its limits via whatever method.
dac69er
Super Moderator
i cant think of any time anyone has had an engine blown up due to a jam/blitz etc ecu being fitted!?
normally its due to a fcd being fitted with no fuelling mods.
Chris@CCM
Member +
ive seen it a few times