School me on "Flex Fuel"

[sandking]

Got the engine today and according to
1slos10's pic, I have the flex fuel injectors. The engine is clean, but a couple of shady things happened today when I went to pick it up. As I mentioned before, this was from an '08 Suburban that had an interior fire. Well, it ended being an '07, no biggie, but the intake had a melted spot on it along with the harness and a couple of coil packs. They pulled an intake from a different engine and threw it on mine. I got screwed on the harness because it was cut up, I got all accesories (Computer, starter, alt, PS pump, throttle body, AC cond, exhaust mans, air box, throttle pedal, etc) but on a good note, this whole thing only cost me $800 out the door. I was promised a replacement harness as soon as they get one, so thats good if it happens.
Here is a couple of pics. If anybody see's anything out of the ordinary, feel free to let me know. Is the intake correct for an '07 Suburban? I need the cover for the intake, anyone have one?

[RedHeartbeat]

I'll say you got a hell of a deal.

[GasGuzzler]

+1 ^^^

I'd say it's a reeeeaaaallllyyyy good chance that's an E85 (flex fuel) engine.

[sandking]

+1 ^^^

I'd say it's a reeeeaaaallllyyyy good chance that's an E85 (flex fuel) engine.

And your thought on that? Good or bad?

[Frenchy]

nothing wrong with having the flex fuel how it works is (as my understanding, could be wrong) its the exact same motor save for the injectors and ecm programming, the engine is "flex fuel" because it will burn e85 or reg. gasoline. There is a sensor in the tank that tells the ecm what you have in there and the ecm then adjusts as necessary, the reason for the bigger injectors is it takes more ethanol (i've heard twice as much) to get the same air fuel ratio as gasoline. Also these injectors are worth something to guys making there own home made meth injection for there F/I motors as they do not corrode when used with alcohol (obviously). So with a straight gasoline tune in the ecm you will be good to go.

[sandking]

Sounds good, thanks for the explanation.

[GasGuzzler]

I'm not scared of it myself much like everyone else. It needs help like the rest of them. It does have higher flow infectors....or so they say.

[harascho]

you can identify this on the square fuel rails. As far as I know only the flex fuels had them.
There is nothing impossible in swapping a 2007 5.3 into an OBS truck. I just ended my work, put a 2007 5.3 LMG ( flex fuel and AFM) into my 1997 2dr 4wd Tahoe. Here are some pics:

harascho_album - Photobucket - Video and Image Hosting

You will need some sort of programmer (like EFI live or such..) to work around the VATS system and to get some other things to work. Also your instrument cluster will cause some headache. I am using the '07 cluster, 'cause all the information will only be present on the low speed GMLAN bus. If you don't use the '07 cluster you will need some sort of interface to get the info from the low speed bus converted in voltage values for your gauges.

[harascho]

I also saw on the pics that your engine is a AFM (ActiveFuelManagement) which means under light load conditions 4 of the 8 cylinders are cut off. Nice thing but lots of trouble until this works.. mine still doesn't meet all the conditions for the V4 mode. You will find more info on these topics on the EFIlive forum and the GM performance forum..

best regards
Harald

[sandking]

Wow!! Did not know about the AFM. Can I delete that with programming? I dont need another headache only to have little gain. If this was my daily driver, then I might consider. But the Blazer will be a weekend toy on and offroad.

And as far as stock gauges, no problems here, all of my gauges have mechanical senders. I will just us those to make my gauges work like before without going trough the harness.

Thanks for the "Schooling"!!!