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| Fcon Is Piggyback Mapping Vs Stock Ecu Problems | |
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| Tweet Topic Started: Oct 3 2010, 04:45 AM (1,143 Views) | |
| adian | Oct 3 2010, 04:45 AM Post #1 |
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Soccer Mom
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Hi fellas.. I recently rebuilt my engine and installed an HKS GT-SS turbo kit (2nd hand of course) on 540cc injectors at 0.5bar boost. It's supposedly a bolt-on kit but all in it took me 4 weeks to get done incl the rebuild averaging 20hrs work a week! Couldn't afford the recommended F-CON V Pro so I'm running a 2nd hand HKS F-CON iS piggyback. Chose the iS coz suppsoedly it has a lot of modern features that enables refined fuel and ignition tuning especially as I'm running an autobox. It's a daily driver for wife and 3 kids with the occasional track day and drift session. I've been having heaps of problems with the ECU though, and it's taken me a couple of weeks but finally stumbled across this forum, and there's been a lot said in past threads regarding the stock ECU's fuel-trimming algorithms vs piggy-back mapping, and MAF sensor reading problems with an open pod air-filter. Yup, I've got both of these, plus the autobox. As expected, after the initial running-in and dyno-tune, within 1 week of driving the fuelling went west and the car would sputter and jerk and in some severe cases, become seriously dangerous and undrivable especially in stop-go traffic conditions. Having read all that's available here, I can now confirm that it's the stock ECU's 'long-trim'. I knew the ECUs would sort of 'self learn' but never knew to what extent. Theoretically the F-CON iS can connect to an additional OSC (Oxygen Sensor Computer?) which links to the car's OBD-II and adjusts for O2 sensor adjustments to the fuel-trim but I can't imagine how much adjustment can be made coz fuelling requirements go ballastic when the boost ramps up, and that's usually the point where the stock ECU's fuel-trim goes nuts and everything unwinds! It's quite incredible coz it could be completely undriveable through traffic, and then get onto the freeway and 20mins of 120kmh cruising and it's all hunky-dory again. SO.. I can now assume, what I will be doing next week is: 1. unplug the battery and reset the stock ECU 2. unplug the O2 sensors (I have 2 in my auto-version of the SXE-10) and scr*w the closed-loop program 3. Remap the car 4. When I have more time and money, convert to MAP sensor and remap 5. Forever rest in peace Is there anything I might need to add? This does seem like the most simple and affordable recourse. Any knowledgeable suggestions welcome. Thanks fellas! |
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| Maccabro | Oct 3 2010, 07:54 PM Post #2 |
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beached az!
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i wouldnt un plug your o2 sensors, your ecu will go into limp mode if you do. not cool. |
| altezza 3sge + apexi ax53b60 turbo kit + cwest body kit/ bonnet + modelista angel eye HID head lights +18" enkei NT03 + zeal adjusties + ........................more! | |
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| adian | Oct 4 2010, 03:32 AM Post #3 |
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Soccer Mom
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Will it? Any other suggested methods of getting around this problem? |
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| xnickx | Oct 4 2010, 08:40 AM Post #4 |
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^^ You may thank me ^^
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I'm not running my 02 sensor with my GReddy e-Manage AFAIK it wasn't doing anything anyway. 02 sensors work with the factory ecu to trim fuel around stoichiometric (14.7:1) and anything out of that it doesn't do much anyway. Seen quite a few other cars not have O2 sensors and they seemed fine, just might use a bit more gas as it's not leaning the A:F ratio out. When the oxygen sensor fails, the ECU can no longer sense the A:F ratio, so it ends up guessing and uses more fuel than it needs to, shouldn't go into limp mode though? |
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| Soiled Altezza | Oct 4 2010, 09:01 AM Post #5 |
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I wasn't using my O2 sensor, just threw up an error code everytime you looked at the ecu didn't go into limp mode or stop anything. |
![]() Garage: http://altezza.dualzdesigns.com/viewcar.ph...wner=17&frmpg=0 | |
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| adian | Oct 4 2010, 02:33 PM Post #6 |
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Soccer Mom
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You're right fellas. Researching back on some of the documents posted before on thsi topic, according to http://www.autoshop101.com/forms/h44.pdf and http://www.autoshop101.com/forms/h58.pdf the only thing that'll happen is that the ECU will flag an error code DTC P0125 which refers to the water not getting up to temp. Using the piggybacks, the fuel conpensation by the stock ECU can be tuned out, so the engine should run pretty good. Plus if you gusy are living proof that it works, so it should be all good! Anything else you guys needed to do when you unplugged the O2 sensors? |
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| xnickx | Oct 4 2010, 02:42 PM Post #7 |
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^^ You may thank me ^^
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Have heard some piggybacks even leaning the A:F and needing a reset as the ECU is fighting against the piggybacks for the A;F ratio. Not sure how mine was tuned as my O2 sensor is still physically there but has been disabled (reading only 0.01V), not sure if it was a E-Manage setting or they added a resistor to the loom or similar. Should be just as easy to unplug and bung up the thread and get it tuned without the sensor |
Contacting me for parts![]()
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| Soiled Altezza | Oct 4 2010, 03:00 PM Post #8 |
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Don't quote me on this as it was over 3 years ago now, but I'm pretty sure mine was just unwired in the drivers side kick panel. It was still physically sitting in the exhaust doing nothing. |
![]() Garage: http://altezza.dualzdesigns.com/viewcar.ph...wner=17&frmpg=0 | |
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| Maccabro | Oct 4 2010, 04:06 PM Post #9 |
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beached az!
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my 20v 4age conversion in a aw11 mr2 didnt like the o2 being removed but i must say it was running a factory ecu so im just going off that and what toyota told me at the time. |
| altezza 3sge + apexi ax53b60 turbo kit + cwest body kit/ bonnet + modelista angel eye HID head lights +18" enkei NT03 + zeal adjusties + ........................more! | |
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| adian | Oct 7 2010, 06:58 AM Post #10 |
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Soccer Mom
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Ok here's an update: Went back to the rolling road on Monday, unplugged both O2 sensors (AT cars have one before and one after the cat). unplugged the battery and reset the ECU, got the tune done. Went on the road and tweaked the maps. Been driving it for 2 days now, and I must say that it's brilliant! No worries with any ECu trouble, and the tune is no longer going outta whack from the fuel-trimming. Cars a bit crappy until it's up to full operating temp, due to the ECU going thru the warm-up cycle but without the O2 sensor it's not getting a proper feedback so is probably running lean for longer than it should (the stock ECU does this to heat up the cat). Peculiar thing we found out about the HKS F-CON iS is that without any fiddling, it's limiting the airflow readings, dont know why it does that. So we've had to adjust that side of things, but it was a bit of a bugger to sort out on the road initially. The iS also has a few other tricks up its sleave such as bypassing the speedcut (dont work in my AT car tho) and being able to fiddle with how the AT transmission decides when to shift-up or shift-down, and adjust for fuel leaning out when it does so: I never knew ATs leaned out just as they shift gear. So we learn something new ![]() I'll post pics/videos of my car soon. |
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| Leiden | Oct 7 2010, 08:15 PM Post #11 |
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NZ, Whangarei
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They shouldn't lean out, unless its a way of making the shift smoother by limiting engine output, in that case you do learn something new every day! |
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| adian | Oct 8 2010, 04:01 AM Post #12 |
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Soccer Mom
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Leiden: My thoughts exactly! Gonna hook up the HKS power writer software again when my tuner has the spare time (that's the prob with HKS stuff: limited only to HKS ProShops. Why oh why can't they just make it freely available like everyone else??) and we'll fiddle with this feature and see what we can do with it. |
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| Leiden | Oct 12 2010, 03:44 PM Post #13 |
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NZ, Whangarei
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Can you tune the warm up side of things using the Water Temp Sensor as an input in the F-CON? |
| Project Thread | |
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| JohnS | Aug 18 2012, 10:31 PM Post #14 |
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Soccer Mom
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Is there anyone who is using the OSC with iS HKS ECU? Looks like Adian is gone because he is not responding to my email to him. BTW I have iS on Stagea fitted and working but recently I acquired the OSC box hover without the harness and have no idea how to connect? Anyone can help with screenshots of the harness, plugs, connectors and maybe connection diagram or instruction manual how to combine all the boxes and make them to work. Could you please email me or PM? |
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