c5 flex fuel questions
 

I know there is a bunch of threads about this but im gonna ask some questions to make sure im on the right page. I have a 99 frc with a big cam, 243 heads, fast 102 and I know I dont really need e85 but it is very interesting to me and I just want to try it. There is only one station around me that has e85 and I drive the car so I still need to be able to use pump 93.

I have a lingenfelter walbro pump in my car and I broke the factory fuel line so the lines from the fuel filter to the fuel rail is black braided line. From what I read the factory stuff in the tank will work with e85. So all I really need is the flex fuel sensor, wire it to power/ground and to pin 56 BLUE.

So far am I correct?

Here is some things im not sure about.

What OS do I need to swap to with HP tuners? I am using the stock 12593359 OS but i have read the f-body guys use a 02 suburban OS but will that work with my car with ETC or what would be a better OS to use?

What would be the best sensor to use? Iv read you can use one out of a ford Taurus easier because it is a screw in type instead of a quick disconnect type so you can use an fittings easier.

I am using stock ls2 injectors now that are about 75% duty cycle so the will not be big enough for e85 but i have some SD 60# high impedance injectors i got from a buddy. Will they work for what i want to do?

Is there anything else im missing or i am just completely wrong about?

I'm not a 100% sure but I think you will have to get a p59 PCM (blue & green) to be able to add a flex fuel sensor.

Not true.

eaglegoat can you shed any light on this? I was looking at some different tunes the other day and seen that a 04 zo6 has flex fuel tables in their tune. I wonder if i could do a segment swap with that and it work?

Segment swsps won't work. You've got to find a file that was enabled by the factory.

you can use an express van pcm, considered a p59 pcm. I have 3 bar flex fuel capability in my fbody, and have the option to use either DBC or DBW as the p59 from the express van has a integrated chip that allows the control of DBC idle parameters. All of express van have 4l80 trans segments, so youd have to change that back to 60e if you're auto. As well modify the fuel capacity tables.

You have full control of fuel and timing alcohol tables if you integrate a FF sensor into the pcm.

nice man. ill look into that. how hard was it to swap that pcm in?

its plug and play, your tuner will have to mess with some settings though, if he knows what he is doing, itll be straight forward for him.

i tune it myself for now. so i dont have to change connectors or anything? just take the pcm that is in there out and plug the new one in? then run the wire out to the flex fuel sensor?

and what year express van should i be looking for?

Would this pcm be plug and play in an fbody. I'd love to have 3bar,4l80e and e85 sensor.
I have hp tuners so any tuning won't be an issue.

Yes just take out the pcm out, plugin the express van pcm. Pay the credits/license, if youre standard youre good to go just modify the fuel tables to display the adequate fuel level. You might need to reference your stock file to input the right parameters. Any 03+ express van file should work, i generally use an 06 pcm. The good thing is if you need a 3 bar flex fuel option for DBC then you either have a m6, a th400, or an 80e. The first two don't need a trans segment, and the 80e, well the pcm already comes with an 80e segment. So no need to hunt down compatible OS's. Then just pin the signal wire into the p59, power and ground on the sensor. Tune it, good to go! Make sure the express van pcm OS you buy has a 3 bar upgradable OS first.
Here in houston where im at theres a bunch of e85 stations but sometimes i drive far so having e85 and 3 bar capability is great, and glad to share this info everyone is always VERY secretive on this subject i had to figure it out on my own.

Awesome thanks for the heads up my car is 80e swapped. I did a lot of research on this and everything I found said it wasn't possible for people needing 3bar, 80e, and flex fuel. I will definitely be going this route since I need a new pcm anyways.

you never said you needed 3 bar or 80e capability. There are OS's available to run the 411 with 1 bar and 80e, FYI.

Subone, have you done this in a C5 vette yourself? Car starts, and all factory gauges work? I know it works on the trucks but never tried it on the vette. This is because the people "that have actually tried on a C5" say it will not work. They also stated this route will just result in a no start situation. Vengance claims to have the only c5 with true flex fuel and make it out to be total rocket science.

Also have had good luck with the 411 E85 deals on trucks and F-bodies.

I think you have me confused, I'm not the op

Yes it works in a c5 Vette. In fact, I found this first working on a c5 with an ls3. The owner wanted a DBC throttlebody but keep everything OEM, I stumbled upon the capability of the express van PCM having a "iac chip". More details on that here,
http://www.lt1swap.com/cable_conversion.htm

So I ended up converting the c5 to a DBC and noticed that the express van OS had 3 bar upgrade available AND it had a flex fuel option. After that, I implemented it in my fbody.

It's a shame people make this out to be some black magic deal and don't share the info. Keep in mind i pinned the PCM (added wires) to accompany the IAC motor, and TPS so for a total of 7 wires.

But yes, if you know what youre doing, itll work.

So since I plan on keeping the dbw tb then I shouldn't need to pin anything extra except the flex fuel sensor to pin 56 blue correct? Did you have any problems with the p59 pcm connecting to the bcm or did you just disable vats and it work?

Everything worked and yea just pin the p59 for the ff sensor.

awesome man, thanks. is it still pin 56 blue for the p59 pcm?