All,

Does anyone know which parts of the NB fuel system are tolerant to E85 and which parts are not? My current fuel system is:
AEM 320 Ethanol spec fuel pump;
Mazda OEM plastic quick connects;
A mixture of OEM Mazda plastic fuel pipe and new ethanol spec rubber fuel hose;
OEM fuel filter;
OEM initial pulsation damper;
E85 spec injectors;
E85 spec aftermarket fuel pressure regulator;
Flex fuel sensor.

I would expect to change out the OEM fuel filter for a metal mesh type filter.

I don't know about the plastic fuel hose and quick connects. My flex sensor came with GM style quick connects which are plastic but I hope are ethanol tolerant and I'm guessing GM cars must use ethanol compliant plastic fuel hose. This doesn't mean the Mazda OEM connects and hose are tolerant so would like to know your experiences?

Many thanks for your help.

 

Even the NA fuel systems are good for e85. If you've been running your fuel filter for extended periods on gasoline, you'll want to replace it to prevent the ethanol from combining with filtered stuff and gumming it up. Plastic is typically resistant to ethanol, its the metal that you need to be careful with due to e85's corrosive nature. Your fuel system seems almost over-prepped for e85 -- just don't let it sit for too long!

 

Thanks for your help.

I'm predominantly using gasoline and E85 will be special use. If I get a stainless filter then I could remove it and clean it periodically to avoid the gumming up you mention.

Does this same gumming up issue happen with the fuel pump filter sock in the fuel tank? Can't think of an easy way to solve that unless I also periodically remove and clean/replace that.

I had read that it was best to flush the system with gasoline if being left stood up for any length of time..

 

I would replace both the in-tank and external filter with new OEM (or OEM replacement) parts.

 

Yup, replace both. As long as you have some sort of fuel running through your system regularly, you won’t have an issue, even if that means starting your car every now and then for a few minutes. If you can’t do that, fill her up with gasoline and flush the system by driving a bit before long term storage!

 

Thanks people - I appreciate your experience. I've had friends have issues with injectors after being stood up with E85 and don't much want any issue with injectors. Their's were different types of cars - hence the Miata specific queries above.