Wideband reads lean until ECU restarted

K-Series Programmable ECU installation questions / support issues
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Razathorn
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Wideband reads lean until ECU restarted

Post by Razathorn » Mon Feb 01, 2016 8:24 am

Doug, others... long time no talk/forum.

RSX JRSC K20a2 KPRO w/ 02-04 wideband.

This just started. After a long drive (stop and go traffic) wideband reads lean and voltage shows .005 volts on my OBDII box. Will throw a CEL about it too. Obviously this lean cuts me everywhere with lean cut enabled and is quite annoying. Sensor works fine again immediately after restarting ECU (key off/on, restart). This is a relatively new (last 2-3 years?) sensor that has never seen leaded gasoline. My previous sensor did the classic lean read on throttle and slowly read normal again, hence the reason I replaced it, but this one just appears to go offline until the ECU is reset.

The obvious course of action is to replace the sensor and see if that fixes things, but I don't have another sensor laying around. Before I go and order another sensor, I wanted to ask if this is potentially another issue (based on symptoms) or if it is still most likely just time for another sensor. I think I may have underestimated the effects of having my exhaust rattle a bit on the chassis from time to time if it has killed this sensor.

FWIW, the kmanager that uploaded this config is likely 6+ years old. I don't "real car" much anymore these days.

Wayne
2003 black RSX type-s / jrsc @ 12psi / methanol injection / aftercooled

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Spunkster
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Re: Wideband reads lean until ECU restarted

Post by Spunkster » Mon Feb 01, 2016 10:42 am

It is most likely the sensor that needs to be replaced. I have not heard of this happening before. You should also update the software as quite a bit has changed in 6 years.

Razathorn
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Re: Wideband reads lean until ECU restarted

Post by Razathorn » Wed Feb 10, 2016 1:48 pm

Replaced the sensor. Still have the same issue. I'm starting to think that this might be the combination of two other factors. The first being that I removed my IAC and raised my idle screw, so at times my idle dips pretty low and battery voltage drops down to 12.0 or maybe lower. The second being that my battery voltage seems to dip below 12 volts at all, and goes right back to 11.8 after only a moment or two after the engine stops.

I'm beginning to think that from time to time the ECU is seeing low voltage on the sensor and disabling because my idle dips are exposing my now-obviously-dying battery.

Unless somebody else has a better suggestion, the next item to try is to simply swap out batteries and or artificially raise the idle a bit for a while. This issue started right after I removed my IAC.

Wayne
2003 black RSX type-s / jrsc @ 12psi / methanol injection / aftercooled

Razathorn
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Re: Wideband reads lean until ECU restarted

Post by Razathorn » Thu Feb 11, 2016 9:01 am

Okay, battery tested and was near end of its life (which was obvious without a 'tester'), so that's replaced and the idle has been raised up and it never dips below 900rpm now—voltage was super stable the whole drive. AFR sensor was disabled by ECM again on the drive into work today. About the only thing I can think of now is the heater circuit is failing some how or the wiring is going bad. I highly doubt the wiring has "gone bad" so that leaves me with the o2 heater circuit (relay) and ECM.

Does that sound right? Any suggestions I haven't thought of? Going to probably just replace the heater relay next.

Its worth noting that this last time it failed during a long in-gear deceleration where fuel was obviously cut. My current working theory is that the heater is intermittent and the sensor went cold with no exhaust hitting it and stopped functioning.

Wayne
2003 black RSX type-s / jrsc @ 12psi / methanol injection / aftercooled

Razathorn
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Re: Wideband reads lean until ECU restarted

Post by Razathorn » Fri Feb 12, 2016 8:40 am

Can't be the heater relay. Tried pulling it and it immediately threw the heater code. Simulated the relay being bad by hooking up just the coil side of the relay to the pinout so it would activate the relay without connecting the heater and it immediately threw the heater code, and since i've never seen the heater code, I have to assume I've never lost voltage at the relay.

Only thing left is wiring, ECM, or perhaps alternator. Leaning toward alternator because the lights flicker a lot, even though voltage appears stable (outside the granularity of my readings). Will check wiring for intermittent breaks.

Any suggestions or ideas would be greatly appreciated. I have a sinking feeling that I'm going to have to acquire a new k-pro ECM.
2003 black RSX type-s / jrsc @ 12psi / methanol injection / aftercooled

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Hondata
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Re: Wideband reads lean until ECU restarted

Post by Hondata » Fri Feb 12, 2016 9:23 am

The wideband controller in the ECU seldom goes bad. I would try the ECU in a different vehicle to see if that is the cause. Usually o2 sensors die from vibration or water in the exhaust, and most other problems are corroded ground connections or broken wires.
Hondata

Razathorn
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Re: Wideband reads lean until ECU restarted

Post by Razathorn » Fri Feb 12, 2016 11:48 am

Hondata wrote:The wideband controller in the ECU seldom goes bad.
That's good to hear. I hate intermittent issues that take 30 minutes of driving to reproduce. Ugh.

Wayne
2003 black RSX type-s / jrsc @ 12psi / methanol injection / aftercooled

Corey872
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Re: Wideband reads lean until ECU restarted

Post by Corey872 » Sat Feb 13, 2016 8:43 am

Engine block / chassis grounds? Loose, worn, missing or corroded ground straps will cause a whole list of issues. You might try measuring "voltage" from the negative post on your battery to the engine block, alternator housing, exhaust pipe/sensor, etc. If you see anything other than "0.0V" you likely have a bad ground to that component.
Corey

E85 fueled Acura RSX-S Turbo w/ KPro
∙ 12.5:1 CR ∙ Precision Billet 5857E @ 15psi ∙ OBX Sidewinder ∙ ID 1000's ∙ ACT XTSS ∙ OBX LSD ∙ Custom 3" Magnaflow SS Exhaust

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