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Negative fuel trim? (-20)?

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Old 04-18-2019, 09:53 PM
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Negative fuel trim? (-20)?

Hello,

After getting the gizmo to diagnose a CEL, I have been fascinated by it, and maybe overthinking it? However, I noticed that my Long term Fuel Trim on both banks is around -20. Is it not supposed to be around 0? I have no CEL, but I will list 2 things that may be affecting my fuel trim?:
  1. Exhaust leak at the Flex joints on Y pipe
  2. My car once stalled after flooring it (Once I came to the stop the car stalled) and P0340 showed as pending, but no CEL, hasn't happened again.

So, is the negative fuel trim OK? Or is there something to look for?

2003 Infiniti G35 Coupe
140,000 Miles
Mods:
Stillen Z Tube
Motordyne Plenum Spacer
 
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Old 04-18-2019, 11:23 PM
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Coupe 6MT Premium RAS
ECM subtracting fuel usually means leaking injectors or oversized injectors used with factory ECM fuel maps.
 
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Old 04-18-2019, 11:25 PM
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Technically it could also be a very weak ignition not fully igniting the fuel load, I'd pull the plugs and inspect the gap, replace as needed. I would also change out that cam sensor before it completely fails and leaves you stuck on the side of the road.
 
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Old 04-19-2019, 12:19 AM
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Will replace cam sensor as preventative maintenance as we are going to Texas from Illinois soon.

Any way to identify if my injectors are not OEM? Don't have previous owners contact info anymore.
 
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Old 04-19-2019, 02:42 PM
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You can take the intake manifold off and look :P
 
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Old 04-24-2019, 12:16 AM
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1990 Mustang GT - 351W Lightning bored/stroked 383CI TFS heads 78mm Turbonetics huricane
What is the fuel trim at partial throttle with load (Like 30% throttle going uphill)?
 
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