STR Prep - ECU and Tuning Discusson
Registered User
Joined: Dec 2011
Posts: 56
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From: Seattle, WA
Does anyone know what would cause a un-mapped GEMU to run 10.1 AFR? My tuner did a baseline and I made very little power and the AFR was 10.1. I unplugged the GEMU and plugged in the stock ECU. It then ran mid to low 11's. I have a boomslang harness with Knock and IAT. he's tuning it now but we're both concerned that something might change and all the fuel he's pulling will blow the engine.
Any ideas?
Any ideas?
Registered User
Joined: Sep 2009
Posts: 81
Likes: 0
Does anyone know what would cause a un-mapped GEMU to run 10.1 AFR? My tuner did a baseline and I made very little power and the AFR was 10.1. I unplugged the GEMU and plugged in the stock ECU. It then ran mid to low 11's. I have a boomslang harness with Knock and IAT. he's tuning it now but we're both concerned that something might change and all the fuel he's pulling will blow the engine.
Any ideas?
Any ideas?
Use an OBD scanned to see where your short and long term fuel trims are at the moment. If they are too far off, something is not right. Basically Long Term fuel trims should be as close to 0 as possible with a normal max of -+5%.
Next step would be to see if you have a TPS tap or intercept on your GEMU harness. you might want to either try adjusting the analog output map on the GEMU, or changing the harness to tap, if it is intercepting the tps at the moment and see what happens with your fuel trims.
Hope this is of some help. Good luck.
Registered User
Joined: Dec 2011
Posts: 56
Likes: 0
From: Seattle, WA
Thank you *very much* for the responses so far. Today isn't a very good day for me. I'll go try some of the suggestions in a little bit here. I'm surprised the Emanage was making any differences without any map changes. Here's the data I have thus far:
My Stock ECU vs the Un-tuned Emanage Ultimate
You can see my Stock ECU gets pretty rich, too, but not as rich as the GEMU
And here's a lightly modified S2000 vs mine. I'm not sure why I'm getting that huge power dip
I'm missing the graph of the tuned GEMU, but it wasn't very good. And I don't think he made better than stock ECU power on it. In hind sight, I wish I had hooked up the old Apexi Neo and done a pull on it to see what happened.
For reference, I have a Hytech header, highflow cat, stock resonator, and then 2.5" burns stainless the rest of the way out.
FIPK intake.
Recently replaced NGK plugs and a recent valve adjustment.
My Stock ECU vs the Un-tuned Emanage Ultimate
You can see my Stock ECU gets pretty rich, too, but not as rich as the GEMU
And here's a lightly modified S2000 vs mine. I'm not sure why I'm getting that huge power dip
I'm missing the graph of the tuned GEMU, but it wasn't very good. And I don't think he made better than stock ECU power on it. In hind sight, I wish I had hooked up the old Apexi Neo and done a pull on it to see what happened.
For reference, I have a Hytech header, highflow cat, stock resonator, and then 2.5" burns stainless the rest of the way out.
FIPK intake.
Recently replaced NGK plugs and a recent valve adjustment.
Joined: Dec 2007
Posts: 4,525
Likes: 1
From: Savannah, GA, USA
Originally Posted by dan_uk' timestamp='1361663244' post='22358712
can you tell me how its done realy quick or point me to somewhere I couldn't find anything
Yes,
In this thread we are discussing, about 12 pages back, you will find this post:
https://www.s2ki.com/s2000/topic/904...t__p__21509551
and here is a pic of my current setting for launching on a very slippery road. Note that my vtec is at 3600rpm so I'm probably stronger than a untuned s2000 at the launching revs. If you go that low on gripy tarmac you will probably bog down.
The start revs is your launch control (rev limiter with 0 speed).
the start->normal setting at the bottom is for how long this limiter should be active for. (even 40 is not long enough for me)
the throttle setting says how easy is to activate the launch control. Basically with mine set at 35%, its almost impossible to rev over 5000rpm standing still. You might want to go higher on this, as even if you overshoot the revs and then reach the throttle condition, the limiter will activate and the revs will drop back down to your set point.
The ignition adjustment is quite interesting. It only takes effect if you have the adj. tick box selected. This is ignition retard. On a turbo retard builds boost. On our cars, it just reduces torque, on top of the rev limiter working. Might be beneficial if you are getting too much wheel spin at launch. I believe that the suggestion is not to use it on NA cars, as the exhaust valves get extra hot if you keep on it for more than a few seconds. Also it has the side effect of huge flames coming out of your exhaust if you have no cat and a straight through exhaust and extra loud bangs!!!
Registered User
Joined: Dec 2011
Posts: 56
Likes: 0
From: Seattle, WA
Originally Posted by WebMasterP' timestamp='1362859446' post='22392046
Does anyone know what would cause a un-mapped GEMU to run 10.1 AFR? My tuner did a baseline and I made very little power and the AFR was 10.1. I unplugged the GEMU and plugged in the stock ECU. It then ran mid to low 11's. I have a boomslang harness with Knock and IAT. he's tuning it now but we're both concerned that something might change and all the fuel he's pulling will blow the engine.
Any ideas?
Any ideas?
Use an OBD scanned to see where your short and long term fuel trims are at the moment. If they are too far off, something is not right. Basically Long Term fuel trims should be as close to 0 as possible with a normal max of -+5%.
Next step would be to see if you have a TPS tap or intercept on your GEMU harness. you might want to either try adjusting the analog output map on the GEMU, or changing the harness to tap, if it is intercepting the tps at the moment and see what happens with your fuel trims.
Hope this is of some help. Good luck.
I long term fuel trim was 0 during the whole drive. Short term was 0 on one bank and then -2% at times on the other but mostly hung around 0.
The thing that concerned me was IAT. What's that normally? It's like 54 degrees out right now. Cruising at 35 MPH I was getting IATs from 96-110 F (hanging around 105ish most of the time). Is that normal?
During the run I mostly just cruised to see if I could bring the IAT down. When the car was fully warm, I did a couple of short 3rd gear pulls, one up a hill.
Timing advance and IAT
Short and Long Term Fuel Trim
Joined: Dec 2007
Posts: 1,715
Likes: 1
From: Mill Creek, WA
You will only get STFT and LTFT readings on Bank 1. We don't have a second bank of cylinders.
Either your datalogger is not looking at the correct parameter or your ECU is staying in open loop the whole time, which could be the cause of your AFR problems. Make sure your throttle position is set up properly in Emanage, that you selected the correct throttle setting for your harness, and that you aren't doing anything funny in your analog out map.
Either your datalogger is not looking at the correct parameter or your ECU is staying in open loop the whole time, which could be the cause of your AFR problems. Make sure your throttle position is set up properly in Emanage, that you selected the correct throttle setting for your harness, and that you aren't doing anything funny in your analog out map.
Registered User
Joined: Dec 2011
Posts: 56
Likes: 0
From: Seattle, WA
You will only get STFT and LTFT readings on Bank 1. We don't have a second bank of cylinders.
Either your datalogger is not looking at the correct parameter or your ECU is staying in open loop the whole time, which could be the cause of your AFR problems. Make sure your throttle position is set up properly in Emanage, that you selected the correct throttle setting for your harness, and that you aren't doing anything funny in your analog out map.
Either your datalogger is not looking at the correct parameter or your ECU is staying in open loop the whole time, which could be the cause of your AFR problems. Make sure your throttle position is set up properly in Emanage, that you selected the correct throttle setting for your harness, and that you aren't doing anything funny in your analog out map.
Registered User
Joined: Sep 2009
Posts: 81
Likes: 0
Originally Posted by blade954' timestamp='1361670763' post='22358885
[quote name='dan_uk' timestamp='1361663244' post='22358712']
can you tell me how its done realy quick or point me to somewhere I couldn't find anything
can you tell me how its done realy quick or point me to somewhere I couldn't find anything
Yes,
In this thread we are discussing, about 12 pages back, you will find this post:
https://www.s2ki.com/s2000/topic/904...t__p__21509551
and here is a pic of my current setting for launching on a very slippery road. Note that my vtec is at 3600rpm so I'm probably stronger than a untuned s2000 at the launching revs. If you go that low on gripy tarmac you will probably bog down.
The start revs is your launch control (rev limiter with 0 speed).
the start->normal setting at the bottom is for how long this limiter should be active for. (even 40 is not long enough for me)
the throttle setting says how easy is to activate the launch control. Basically with mine set at 35%, its almost impossible to rev over 5000rpm standing still. You might want to go higher on this, as even if you overshoot the revs and then reach the throttle condition, the limiter will activate and the revs will drop back down to your set point.
The ignition adjustment is quite interesting. It only takes effect if you have the adj. tick box selected. This is ignition retard. On a turbo retard builds boost. On our cars, it just reduces torque, on top of the rev limiter working. Might be beneficial if you are getting too much wheel spin at launch. I believe that the suggestion is not to use it on NA cars, as the exhaust valves get extra hot if you keep on it for more than a few seconds. Also it has the side effect of huge flames coming out of your exhaust if you have no cat and a straight through exhaust and extra loud bangs!!!
[/quote]
Raised limiter is fuel cut off only. This tab for ignition settings is the only ignition cut off you can set on our cars. So basically you set up your fuel cut off(raised rev limiter) a bit higher than required and then use the ignition limiter to set your limiting rpm, as ignition limiter is way smoother than fuel cut off.