S2000 ECU interesting features!!
(standard 2007 s2000 ecu)
I’m getting well on with my s2000 install/build and have removed half the loom, each night disconnecting the battery after testing etc. Anyway it’s
come to my attention that the standard ECU needs to do a re-learn after the battery has been disconnected, which involves letting the car idle for a
few minuets, in this time the idle will vary from 900-1500 rpm and it re sets itself then the idle settles.
Before I realised this sometimes I would connect up the battery start the car and blip the throttle (07 car so by wire) and nothing would happen as it
would almost feel like the throttle was disconnected, this I presume has been confusing the ECU as it would have been in re-learn mode, then I could
re-start the car and throttle would be back.
I also started it up the other night and noticed the exhaust manifold getting hot over quickly as the radiator fan hadn’t even kicked in and the
manifold was hot enough to almost light a bit wood shaving. Fearing it was running lean I turned it off let it cool then without adjusting anything
manually did a restart it all worked as it should, manifold never got that hot again as I tested it with the same bit of wood shaving and no
smouldering. Anyway it all seems fine, but I don’t want to have to do a ECU re-learn every time I disconnect the battery as I intend fitting a battery
master switch so how do you lot that are running standard S2000 ECU get around this. If anyone can elaborate on this or have experience (first hand
please) on these ECU’s I would appreciate any extra info. Thanks.
does it just re learn the idle? or does it stop it running lean right through rev range? your getting on well mate
Quite common for ECUs to go through a learning process when first powered up including starting in with a set of base settings like retarded timing (a bit more stable when things are unknown), which would heat your exhaust manifold more than normal.
Hi Dan,
I'm not sure (when it did this) if its lean or weak, but when I let it do a re-learn it all works well and when the ignition key is turned of
you can here the solenoids or something clicking (as it did in the standard car) in or around the throttle body. When the manifold got hot there
seemed to be no clicks after the key was turned off so I presume something had not connected/opened/closed/worked/ect.
I believe the ecu is quite intelligent even adjusting to driving styles and road condition, but would like to know more if anyone has any experience
with standard ecu. Cheers.
Thanks Coyoteboy, sounds about rite. Cheers
what have you done with the 2 x original lambda sensors in the loom?
The first is in place and the second it in clean air. Both seem to be working as the second one although its not in the exhaust does indeed get warm.
One thing to note is that every time you disconnect the power to the ECU, you also clear any error codes and these will not come back immediately and may take some time to register again. So it may be worth while keeping it connected while you're chopping things out the loom.
quote:
Originally posted by Brett Jones
One thing to note is that every time you disconnect the power to the ECU, you also clear any error codes and these will not come back immediately and may take some time to register again. So it may be worth while keeping it connected while you're chopping things out the loom.
quote:
Originally posted by unijacko67
The first is in place and the second it in clean air. Both seem to be working as the second one although its not in the exhaust does indeed get warm.
There are two options for the air pump, the first is replacing the pump with a resistor, thus tricking the ECU to think it's still there and the second option is fitting a resistor to the temperature sensor making the ECU believe the car is already warm and does not ever need to switch the air pump on.
quote:
Originally posted by coyoteboy
quote:
Originally posted by unijacko67
The first is in place and the second it in clean air. Both seem to be working as the second one although its not in the exhaust does indeed get warm.
This may well confuse it, it's not looking for clean air at the second sensor. I don't have the data on exactly how they interface but there's more than a few instances of people who's secondary sensor has failed/is failing seeing large drops in economy despite not throwing codes.
Post cat lambda is a monitor and doesn't affect fuel trims if the pre cat sensor is working . On a car with the cat removed the ecu will see the output out of range for the second sensor and a code relating to cat effiency . If you send a 0.5 volt signal to the ecu from the post cat output wire it should be within the range for cat efficiency . The ecu ignores post cat output until the engine is warm and steady state running . Some ignore it at idle as the cat may cool down even in closed loop .
quote:
I believe the ecu is quite intelligent even adjusting to driving styles and road condition, but would like to know more if anyone has any experience with standard ecu. Cheers.
There are battery cut off switches that have a circuit so Componants that need power all the time can take a feed from the switch whether the main circuit is open or closed
quote:
Originally posted by Bare
quote:
I believe the ecu is quite intelligent even adjusting to driving styles and road condition, but would like to know more if anyone has any experience with standard ecu. Cheers.
Not been around Hondas much huh?.
Honda ECU's are Pre programmed See their PGM label :-)
I've had a few de catted cars that throw up cat efficiency codes and letting the ecu see a voltage within the right range usually .5 volts does the trick . Pretty sure the Honda has a wideband pre cat sensor on it
Because people have been removing cats and foxing the secondary lambda sensors more recent OEM ECU's have more sophisticated methods of
checking the secondary lambda is present and working.
The secondary sensor has no effect on mixture its duty is only to check that the cats are working.
With few exceptions all ECUs including take a while to re-adapt after a reset they re-boot with a very conservative map, a glowing exhaust at
idle is more likely to indicated the ignition timing was retarded than a weak mixture.
If you want to retain settings between periods with the battery disconnected you are going to have to supply enough voltage to the ecu to keep its
volatile memory alive.
Not to change the subject, but can anyone shed light on the SR20DET ECU? It also appears to hunt around at cold startup, prior to settling down. CA18DET did not do this. MAF as standard, which I've kept. I actually have a rather expensive, AEM unit sitting around, I should sell really, and I'm very curious to try, but afraid to screw things that are basically working up.
Thanks for all the replies,
I've had it running tonight and it seems fine without the post cat sensor connected, Quite a few fault codes inc air pump. Will a fault code make
it run incorrectly and need the ecu tricking into thinking its not there via whatever it takes or can I run the car with certain non terminally
destructive fault codes. Thanks for all your help.
Ok, so I'm a couple years slow, but...is the consensus to keep the original S2000 ecu or is it best to start fresh with an aftermarket ecu (in my
case with the unused Omex 710 that I happen to possess)?
Considering buying an F20C motor/box/loom/ecu for my MNR, which was previously intended to use a K20A2 with Omex 710.
This is for a mostly track-oriented racer that will only become road legal if I can figure out some loophole around the horrid Dutch tax laws.
Thanks!
Steve, in the NLs
I think better to go aftermarket ecu. If you keep the standard loom and ecu it's lots of work trimming the loom, but will work. The big down side to this is not being able to do any mapping vtec wise, so it will be a pig to drive unless you have a kpro or flashpro fitted as they allow the standard ecu to be mapped which again add's to the cost of the standard set up. I'm now using dta as things evolve it's good to have some control.
Ah, so YOU were the former U.S. President who got Dan Mason's engine. (I, an American in Holland, have been chatting with Dan and checked out
your website)
Sounds like good advice, but not what I was hoping to hear as I try to reduce costs. Was hoping that you'd say, "No, Honda did all the work
for you and only the most expensive tuners can approach their mapping", so that I could sell off my Omex. The only Omex expert over here that I
can find is a complete...whom I refuse to further bankroll.
Ok, I'll use my Omex and pray for an alternative to appear...or take it over to the U.K. for tuning.
New topic: did you continue to get away with merely a sump baffle or did you eventually add a dry sump? Please tell me a baffle is sufficient for
track days!
Thanks!!!
Steve, in the NLs
Haha, baffled sump worked for me on the standard engine even on slicks. I did create a huge cloud of smoke at Blyton Park upon braking very hard with
red hot slick's, but that was down to forgetting to blank off the rocker box breather that goes into the inlet manifold, as the oil moved forward
it probably got dragged into the rocker cover via the cam chain and allowed the oil to get sucked into the inlet where it then got swiftly burnt
along with the fuel, I got black flagged as it did look like the motor had let go, but all was well and an easy fix.
I have gone dry sump on the new motor so we can run a fair lump of vacuum in the engine, few more bhp and should be safer, lol
If you do decide to use original ecu, which works ace just try to keep the obd port working on the loom as you strip all the redundant circuits off because that's what they use to connect the FlashPro (drive by wire) for a bit of mapping. You might not need to do this as your car might find more grip than mine was at first as it will be a proven set up, mine's getting better, but was lethal when it hit vtec on standard ecu in the beginning. I've altered spring rates and anti roll bar's now and it is a lot more planted, but way off the mark still compared with a westfield.