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Old 06-20-2008, 12:39 AM   #1
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Default Will the MS not run without an O2 sensor?

after getting all the issues sorted out with my car and MS except the O2 sensor. right now i have no input going in to the MS so it thinks that the car is always very lean. i managed to get it started. Here is the thing, the only way to get it to idle is to set the req fuel to 15.0 to 20.0!!. i am using RC 550 injectors, so it should be more like 5.7. the cranking and ASEs have to be fat pulses also. i am using the MSPNP 96 map with nothing changed but the cranking numbers and the req fuel. my idle is also hunting constantly between 1100 and 500. this is very tiring and frustrating. is this sort of behavior expected without an O2 sensor? i was under the impression that i could just tune based on the table if i want to just get it running. Sigh...
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Old 06-20-2008, 01:00 AM   #2
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Yes, the MS can run without an O2 sensor. In the "Exhaust Gas Settings" menu, set "Controller Authority" to 0. This will totally disable O2 sensor feedback.

From your description however, it sounds like that's not your only problem. Are your CLT and MAT readings correct? Is MAP stable and believable?

Let's have an MSQ and a log.
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Old 06-20-2008, 03:27 AM   #3
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do you have a mspnp or a megasquirt adapted to your build? if the latter, make sure the firmware was flashed correctly, even try flashing it again because the file could have been corrupted somehow. Make sure AIT mainly, and clt settings are believable, and check your cranking and warmup settings are at least ballpark (i think my warmup is around 120% at 100*F). Finally, i am running 550s on a 1.6 and a 1k idle w/ 5.1 reqfuel has about 30 - 35 ve.

good luck
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Old 06-20-2008, 01:11 PM   #4
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CLT and MAT readings make sense and move in a way i would expect them to

MAP is correct and aligns with my vacuum/boost gauge

I have a MSI V3.0 board that i built and verified on a lab bench to work correctly. I downloaded the MSPNP file and am using that to start. I've already tryied flashing a couple of times with 10G hi res. My crank, ase, and re fuel settings are 3-4X richer than what they should be and thats the only way the car would even fire and hold a 40kpa idle thats lumpy and hunting.

this is a standalone and i have the PWM mod for the IAC. i am using the pnp settings since i believe they should be correct and if not i dont know what to change.

here is my msq. i don't have a log right now. i would appreciate any help, i am lost at this point.
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File Type: zip 96.zip (5.6 KB, 32 views)
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Old 06-24-2008, 09:53 AM   #5
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When you unplug the o2 sensor, I thought MS reports it as super rich?

"tune based on the table "

What does this mean? How do you tune without an o2 sensor? Why don't you plug one in?
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Old 06-24-2008, 11:20 AM   #6
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Back to basics. Confirm your 02 sensor is a name-brand WIDEBAND? Which one? Have you configured your .ini file to "see" that particular wideband? If it's an LC1, have you grounded it "properly"? Have you tried using the software that came with your wideband to see if it's outputting correctly?

Start with ensuring the WB is funtioning correctly. Then progress into why MS isn't seeing it right.
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