74goldtarga

How do I switch from gas to E85 with my M-tune? Can I run the tank down to basically empty, fill er up with E85, pull the coding plug and go? Or is there more to it? I just haven't used E85 yet.

BTW I have 044 pump, big injectors, new fuel lines etc. so the fuel system should be ready.

Scott H

Yup, unless you enjoy being really **** or have too much time on your hands.

refresh951

I believe E85 is second map, coding plug ON. Also, I try not to get on it much after a switch until new fuel runs through the fuel lines.

74goldtarga

my coding plug is plugged in already - jumper plug connected to a black plastic terminal with a black and brown wire. Am I driving around with the E85 tune on gas? My mechanic set it up with email help from Josh, I just swapped the chip tonight because the car was starting poorly. I will have to bother Josh to make sure I haven't got it wrong.

74goldtarga

"Nathan,
With the plug off, the DME uses the primary mapping - so premium pump gasoline. With the plug on, the secondary mapping is utilized..." This is from an old PM from Josh, looks like my mechanic had it set wrong. We can change the title of the post to really, really dumb E85 question. I think my AFR at WOT was around 10.0, I remember 12.0 with the old chip which was premium and race gas. If I have E85 and am on the wrong map I will be lean right? and conversely, rich if I am running gas on the E85 program.

I think I definitely want to avoid E85 fuel and pump gas map combo - correct?

jlturpin

Yes, lean if dme is on pump gas tune and you have E85 in tank.

If you were running gas on E85 tune it will not run that great and AFR under boost will be 10 or richer and feel very held back until it just saturates and it can't ignite. No harm done. Ger a simple switch installed to make it easier.

Rogue_Ant

Nathan, yes you are thinking correctly... with pump gas and using E85 mapping, you have left power on the table, and definitely makes for a hard hot-starting car!

Mighty Shilling

I had mine wired to a toggle switch on the dash so that way if I needed to switch 'on the fly' like if there wasn't an E85 station near, I could. It's super easy. Cut the code plug loop, solder in a length of wire long enough to run to where you want it, solder in the switch, and go.

74goldtarga

I pulled the plug, the car runs fine (although not that different from with the plug on). Hot start is much improved to the point where it seems to be a non-issue although the car does not start every time. AFR at WOT is minimum 10.7 compared to 10.0 with the plug in. We'll see how E85 goes later.

jlturpin

You might want to check fuel pressure or use FQS settings to take out some fuel.

74goldtarga

Thanks for the input, are you suggesting this because of my minimum AFR? - I'm getting that from the max/min readout on the gauge - I think it dips to 10.X when I mash on the throttle. Steady state AFR is 12.0 so I think fuel is OK.

I also need to thank Refresh for reading between the lines of my post and seeing the error.

jlturpin

12 AFR steady state is rich by 1 to 1.5 afr. You should see 12 at 3-5psi and get to 11.5 by 14 PSI.

Rogue_Ant

Yep, Jonathan (jlturpin) is correct.
Check fuel pressure with the vacuum line off - it should be ~43psi.
Additionally, what FQS position are you in?

74goldtarga

I was being a little imprecise, I don't have datalogging so I was looking down at the AFR gauge during a full throttle run up the on-ramp. I had my son ride with me and watch, it is closer to 11-11.5 at WOT in third at max boost. I assume this is ok.

I can't remember how you check the FQS but I know it is in the DME so I'll figure it out and let you know.

Rogue_Ant

FQS info:

http://www.lindseyracing.com/LR/Parts/DMEFQSSWITCH.html

If you are on position #0, then switch to position #2 - this will pull out a little bit of fuel, and should get your AFRs right in-line.