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Discussion Starter · #1 ·
Question 1: how did flex fuel work on the early systems, sensor like GM used
Question 2: what's the difference between an NCG4 and NCG4a ECU?

Background.. dodge offered FlexFuel as an option on some on some 2.7l v6 and 4.7l engines starting in 2007/2008 using a ECU NCG4 ...

Extra points: looking for some wiring info on the NCG computer for the FF sensor .. what pins voltages and signal types..

thank you
 

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1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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The PCM determines fuel composition with the O2 sensor feedback. Flex Fuel is a system, there is no actual alcohol content sensor. Ethanol adds oxygen to the fuel and adds water content to the exhaust. The EFI system should be able to adapt from straight gasoline to E85 and anything in between.
The fuel system uses ethanol-safe rubber components like rubber hoses and 'green' neoprene o-rings. Standard rubber parts could deteriorate prematurely, causing pressurized fuel system leaks. Evaporative vapor pressure may be higher with gasohol.

https://www.chryslerminivan.net/threads/understanding-chrysler-flex-fuel-vehicles.8565/
https://www.vehicleservicepros.com/...2044377/modern-fuels-require-modern-fuel-hose

The NGC4 and NGC4a were slightly different in architecture. More memory cells and encryption with the 'a'? I don't know the specifics.
 

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Discussion Starter · #3 ·
Thanks the chyrslerminvan posting says its just based on o2 reading.. my neon has the tables but there zero'd out..

another interesting item is the flex fuel use the same 02 sensor for up stream and down stream where as the neon has a different part number for each
 

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The 1993-95 Acclaim and Spirit FLEX FUEL cars have a "methanol concentration sensor" in the fuel line.

It sent a signal to a revised SMEC and used many stainless components in the fuel system.



Thanks
Randy
 

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1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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I see a Mopar part # 4686069.
Methanol fell out of favor to ethanol as the gasohol blend choice.
 
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